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A major constraint to science-based fish stock management in West Africa is the lack of reliable data on target stocks. This especially holds true for inland fisheries, such as those that operate in reservoirs. Due to the low availability of resources and population data, and the limited number of fisheries experts in the region, state institutions and investigators rely heavily on simple catch statistics and empirical models for their estimations of fish production and potential yields. This paper reviews data from the FAO, and published articles and reports on West African reservoirs, with special reference to their morphometric and environmental features in relation to fish catch. In addition, we analyse primary data on three focus reservoirs. First, to improve and update available models of potential harvests from reservoirs, we regress fish catch data against reservoir surface area data for 30 reservoirs in West Africa, yielding the following equation: Catch (tonnes/year) = 17.3 × Area (km2)0.8626. The equation accounts for 95.7% of the variation observed in the fish catches. Analysis of covariance of small ( 2 km2) reservoirs shows no significant difference (F = 0.5895, p = 0.45) in the slopes of the two groups. Second, we apply multiple regressions to a sub dataset of 15 reservoirs with surface area and mean depth as predictors; and we also explore reservoir age as a further variable. We find that fisheries productivity is inversely correlated with both mean depth (r = -0.49) and surface area (r = -0.32), but there is no significant correlation found with reservoir age (r = 0.03).

Performance evaluation of data-limited, length-based methods is instrumental in determining and quantifying their accuracy under various scenarios and in providing guidance about model applicability and limitations. We conducted a simulation–estimation analysis to compare the performance of four length-based stock assessment methods: length-based Thompson and Bell (TB), length-based spawning potential ratio (LBSPR), length-based integrated mixed effects (LIME), and length-based risk analysis (LBRA), under varying life history, exploitation status, and recruitment error scenarios. Across all scenarios, TB and LBSPR were the most consistent and accurate assessment methods. LBRA is highly biased, but precautionary, and LIME is more suitable for assessments with time-series longer than a year. All methods have difficulties when assessing short-lived species. The methods are less accurate in estimating the degree of recruitment overfishing when the stocks are severely overexploited, and inconsistent in determining growth overfishing when the stocks are underexploited. Increased recruitment error reduces precision but can decrease bias in estimations. This study highlights the importance of quantifying the accuracy of stock assessment methods and testing methods under different scenarios to determine their strengths and weaknesses and provides guidance on which methods to employ in various situations.

In February and March 2017, a coastal El Niño caused extraordinary heavy rains and a rise in water temperatures along the coast of northern Peru. In this work, we document the impacts of this phenomenon on the artisanal fisheries and the scallop aquaculture sector, both of which represent important socio-economic activities for the province of Sechura. Despite the perceived absence of effective disaster management and rehabilitation policies, resource users opted for a wide range of different adaptation strategies and are currently striving towards recovery. One year after the event, the artisanal fisheries fleet has returned to operating almost on a normal scale, while the aquaculture sector is still drastically impacted, with many people continuing to work in different economic sectors and even in other regions of the country. Recovery of the social-ecological system of Sechura likely depends on the occurrence of scallop seed and the financial capacity of small-scale producers to reinitiate scallop cultures. Long-term consequences of this coastal El Niño are yet to be studied, though the need to develop trans-local and trans-sectoral management strategies for coping with disturbance events of this scale is emphasized.

Small-scale multi-gear fisheries contribute half of global fisheries landings but are generally data-poor, hindering their assessment and management. Aiming to overcome various existing challenges, we used two complementary length-based approaches to assess the status of three main target species in the small-scale fisheries of Eastern Pacific countries: Spotted rose snapper Lutjanus guttatus, Pacific sierra Scomberomorus sierra, and Pacific bearded Brotula clarkae, using length-frequency catch data (LFCD) from the Colombian Pacific coast. Two data sources – official governmental data and community-based monitoring from a non-government organization – were used to estimate two sets of stock indicators: one based on the derivation of growth and mortality parameters from modal progression, catch curve analysis and a yield-per-recruit model using TropFishR; and the second based on the relative contribution of fish sizes with regard to proposed reference values for healthy stocks. Growth estimates differed between data sources and exhibited large confidence intervals, indicating an overall high uncertainty underlying the LFCD revealed through a novel bootstrapped approach. Estimated values of stock indicators, exploitation rate, fishing mortality and size-proportions converged in suggesting a state of heavy to over-exploitation for the three assessed species, although differences were observed among data sources that we attribute mainly to fisheries selectivity and sampling design. In order to improve future assessments of stocks in multi-gear and data-poor contexts, estimations of fleet-specific selectivity should be used to reconstruct LFCD prior to analyses. Additionally, sampling design should be based on fishing effort distribution among gears and areas and, when feasible, fishery-independent data on stock conditions should be included.

Mangroves are critical nursery habitats for fish and invertebrates, providing livelihoods for many coastal communities. Despite their importance, there is currently no estimate of the number of fishers engaged in mangrove associated fisheries, nor of the fishing intensity associated with mangroves at a global scale. We address these gaps by developing a global model of mangrove associated fisher numbers and mangrove fishing intensity. To develop the model, we undertook a three-round Delphi process with mangrove fisheries experts to identify the key drivers of mangrove fishing intensity. We then developed a conceptual model of intensity of mangrove fishing using those factors identified both as being important and for which appropriate global data could be found or developed. These factors were non-urban population, distance to market, distance to mangroves and other fishing grounds, and storm events. By projecting this conceptual model using geospatial datasets, we were able to estimate the number and distribution of mangrove associated fishers and the intensity of fishing in mangroves. We estimate there are 4.1 million mangrove associated fishers globally, with the highest number of mangrove fishers found in Indonesia, India, Bangladesh, Myanmar, and Brazil. Mangrove fishing intensity was greatest throughout Asia, and to a lesser extent West and Central Africa, and Central and South America., SCOPUS: ar.j, info:eu-repo/semantics/published

Flatfish diversity and depth distribution in the Gulf of Nicoya, Golfo Dulce, and two adjacent areas on the Pacific coast of Costa Rica. Introduction. Information on flatfish diversity and depth distribution is scarce for the Eastern Tropical Pacific. Historical data is important to evaluate changes in ecosystems due to local, regional and global stressors. Objective. To provide information on the presence, depth distribution and lengths of flatfish species collected by trawl nets. Methods. Fish studies were conducted by trawling at four sites along the Pacific coast of Costa Rica by the survey vessels Skimmer (1979-1989), Nishin Maru (1987-1988) and Victor Hensen (1993-1994). The published lists of species were consulted, museum specimens were accessed, and a list of flatfishes assembled. Results. A total of 36 species were found at the four sites over a depth range of 8 to 359 m. The family Paralichthyidae included 13 species followed by the Cynoglossidae with 12 species. Achiridae had six and Bothidae had five. The most speciose genus was Symphurus with 12 species. Thirty-five species were collected at depths from 10 to 235 m in the Gulf of Nicoya and Golfo Dulce. The Gulf of Nicoya estuary yielded 27 species during the Skimmer expedition and over a depth range of 8 to 60 m, while 31 species were found there during the V. Hensen survey at depths from 10 to 228 m. The V. Hensen survey in Golfo Dulce (20 to 235 m) captured 19 species, and 17 in Coronado Bay (21 to 187 m). Off the Nicoya Peninsula (56 to 359 m) 13 species were collected by the Nishin Maru shrimp trawler. A total of 21 species (58 %) were found at depths greater than 100 m and were probably exposed the low oxygen concentrations characteristic of hypoxia. During the V. Hensen survey Symphurus chabanaudi and S. elongatus were captured more frequently in the Gulf of Nicoya, while S. leei was so in Golfo Dulce. Cluster analyses based on presence-absence data for the Gulf of Nicoya and Golfo Dulce revealed low station similarity indicating habitat partitioning among the species. The size (Total length) of 33 species measured from both the Gulf of Nicoya and Golfo Dulce ranged from 8 cm (Syacium cf longidorsale, Trinectes xanthurus) to 50 cm (S. ovale). Only 12 species were found with lenghts over 20 cm. Of the species collected, A. mazatlanus (30 cm) and S. ovale (50) appear to be length records for the region. Data on flatfish landings by the semi-industrial fishing fleet for the period 2000-2016 indicates that this group represents less than 1% of the total landings (shrimp and bycatch), with a minimum of 365 kg in 2001 and a maximum of 13.414 kg in 2013. Conclusions. The diversity of the flatfish fauna of the Pacific coast of Costa Rica appears relatively high but comparable to that found in other tropical regions. The number of trawling ships has declined significantly on the Pacific coast of Costa Rica after 2014. This reduced fishing impact on the populations provides a good opportunity for updating the trophic models available for both the Gulf of Nicoya and Golfo and their use as tools for better management of the ecosystems. Introducción. Es escasa la información sobre la diversidad y distribución batimétrica de los lenguados del Pacífico Este Tropical. Esos datos son importantes para evaluar cambios en los ecosistemas debidos a tensores locales, regionales y globales. Objetivo. Proveer información de la la presencia, distribución batimétrica y longitudes de especies de lenguados colectados por red de arrastre. Métodos. Evaluaciones de los peces mediante redes de arrastre fueron conducidas en cuatro sitios a lo largo de la costa del Pacífico de Costa Rica por los buques de investigación Skimmer (1979-1980), Nishin Maru (1987-1988) y Victor Hensen (1993-1994). Se consultó las listas publicadas de especies. se accesó ejemplares de museo y se integró una lista de lenguados. Resultados. Un total de 36 especies de lenguados fueron encontrados en los cuatro sitios en un ámbito de profundidad de 8 a 359 m. La familia Paralichthyidae incluyó 13 especies seguida por los Cynoglossidae con 12 especies. Achiridae tuvo seis y Bothidae tuvo cinco especies. El género más especioso fue Symphurus con 12 especies.Treinta y cinco especies fueron colectadas entre 10 y 235 m en el Golfo de Nicoya y Golfo Dulce. El Golfo de Nicoya produjo 27 especies durante la expedición del Skimmer y en un ámbito de profundidad de 8 a 60 m, mientras que 31 especies fueron encontradas durante el muestreo del V. Hensen en profundidades entre los 10 y 228 m. El muestreo del V, Hensen en Golfo Dulce (20 a 235 m) produjo 19 especies y 17 en Bahía de Coronado (21 a 187 m). Afuera de la península de Nicoya (56 a 359 m) 13 especies fueron colectadas por el camaronero Nishin Maru. Un total de 21 especies (58 %) fueron encontradas a profundidades mayores de 100 m y probablemente expuestas a las bajas concentraciones de oxígeno características de hipoxia. Durante el muestreo del V. Hensen, Symphurus chabanaudi y S. elongatus fueron capturados más frecuentemente en el Golfo de Nicoya, mientras S. leei lo fue en Golfo Dulce. El tamaño (Longitud Total) de 33 especies medidas en ambos Golfo de Nicoya y Golfo Dulce oscilaron entre 8 cm (Syacium cf longidorsale, Trinectes xanthurus) y 50 cm (S. ovale). Solo 12 especies fueron encontradas con longitudes mayores de 20 cm. De las especies colectadas, A. mazatlanus (30 cm) y S. ovale (50) parecen ser records de longitud. Datos de desembarcos de lenguados por la flota semi-industrial para el periodo 2000-2016 indican que este grupo representa menos del 1% de los desembarcos totales (camarones y fauna acompañante), con un mínimo de 365 kg en 2001 y un máximo de 13.414 kg en 2013.Conclusiones. Los análisis de conglomerados basados en datos de presencia-ausencia para el Golfo de Nicoya y Golfo Dulce revelaron baja similitud de estaciones indicando partición del hábitat entre las especies. La diversidad de la fauna de lenguados de la costa del Pacífico de Costa Rica aparece relativamente alta pero comparable con la encontrada en otras regiones tropicales. El número de buques arrastreros ha disminuido significativamente en el Pacífico de Costa Rica después del 2014. Esta reducción del impacto en las poblaciones provee una buena oportunidad para actualizar los modelos tróficos disponibles para el Golfo de Nicoya y Golfo Dulce y su utilidad como herramientas para un mejor manejo de los ecosistemas.

The further development of the fisheries in Colombia should consider the identification of potential new resources based on knowledge of characteristics of the deep-sea habitats and the organisms which highlight the need for broad exploratory surveys and an ecosystem approach to fisheries management (EAF). The objective of this work was thus to advice management and conservation strategies for the possible new deep-sea crustacean fisheries in the Colombian Caribbean based on an ecosystem approach to fisheries. The management of both the shallow water shrimp fishery and the potential new deep-sea crustacean fishery should be based on baseline information of the population dynamics and size structure of target species and the optimum level of fishing effort and catch volumes and should also consider the development of strategies for constant resource and ecosystem monitoring. Open ocean marine protected areas for the protection of nursery and spawning areas should also be considered.

The South Pacific bay scallop Argopecten purpuratus represents a high-value species harvested along the Peruvian and Chilean coastline for more than 60 years. Following the strong El Nino event of 1983/84, both countries experienced a boom in scallop fisheries, but catches dropped as soon as environmental conditions normalized. Aquaculture production began in Chile, which dominated the Latin American scallop market in the 1990s. Peruvian production remained small until the early 2000s, but has increased dramatically ever since, with a single location in northern Peru, Sechura Bay, contributing most (50%) to the Latin American scallop production. We review the historical trends of this species’ production and analyse the ecological and socio-economic factors that have favoured Sechura Bay's progress, and largely displaced Chilean production through dominance of the market. Advantageous environmental conditions in Sechura Bay (e.g. low water depths, higher temperatures, high natural seed supply) result in improved scallop growth and production, and the socio-economic factors, causing lower operational costs than those of the Chilean production favoured this development. The bottom-up initiation of aquaculture operations by small-scale producers likely created a personal incentive for the long-term sustainable use, which differs from the more industrialized aquaculture activities in Chile.

The structurally most developed Neotropical mangrove forests are found along the southern and central macrotidal Colombian Pacific coast. This extremely rainy area (>7,000 mm year−1) is sparsely populated and sustains a relatively small artisanal fishery. In this article, we present an ecosystem (trophic) model, built using Ecopath with Ecosim, containing 18 functional groups of a representative mangrove area of this coast. Similar to other mangrove ecosystem models, mangroves contribute most (96%) to total system biomass, providing the primary food source for other important compartments (e.g., crabs). However, most of the mangrove litterfall is constantly washed away by tidal currents, a possible reason for the very low mean transfer efficiencies to higher trophic levels and low biomass of epifauna and nekton found, compared with other Neotropical mangroves. Fish biomass is dominated by zoobenthivores (snappers, catfishes) and detritivores (mullets) which represent, together with mangrove cockles, the target resources of a low trophic level-based fishery. Very low salinities throughout the year may contribute to an impoverished community of primary and secondary consumers that is able to withstand but not flourish under these conditions. This mangrove ecosystem may be highly vulnerable to overexploitation according to the low energy reserve (overhead) of the system.

Changes in mangrove vegetation have been identified as important indicators of environmental deterioration. The mangroves of the Tanbi Wetland National Park (TWNP) connect the Atlantic coast with the estuary of the River Gambia and as such, play an invaluable role in the agriculture, tourism and fisheries sectors of The Gambia. Our research seeks to understand the long-term changes in the mangrove vegetation in order to strengthen the formulation of sustainable alternative livelihoods and adaptation strategies to climate change. Mangrove vegetation dynamics was assessed by remote sensing, using decadal Landsat images covering 1973 - 2012. Physicochemical parameters were analyzed during the rainy and dry seasons for correlation with climate data. Our findings indicate that the long-term changes in salinity (24.5 and 35.8ppt) and water temperature (27.6℃ and 30.2℃) during the rainy and dry seasons respectively are retarding mangrove growth. Mangrove vegetation cover declined by 6%, while grassland increased by 56.4%. This research concludes that long-term hyper-salinity is the cause for the stunted vegetation and lack of mangrove rejuvenation in TWNP. We propose that specialized replanting systems such as the use of saplings be adopted instead of the conventional use of propagules. Alternative livelihoods also need to be diversified to support coastal communities.

Tropical coastal ecosystems of the southern Gulf of Mexico including marshes, mangroves and seagrasses of Centla Wetlands and Terminos Lagoon (Grijalva-Usumacinta delta) are known to host a high diversity of aquatic consumers. Nevertheless, the limited research focusing on the energy fluxes that sustain consumers has as yet neither considered the strong seasonality of these systems, nor the linkage of the trophic flow patterns with ecosystem functioning. The present work analyses and compares stable isotope ratios (δ13C and δ15N) of consumers during the dry and rainy season at different wetland sites to determine their resource utilization. The sites compared comprise three fluvio-lagoons and a coastal mangrove creek that differ in vegetational characteristics, distance to the sea, and freshwater input. The results support the hypothesis that a larger isotopic niche breadth of consumers prevails during the rainy season, when resource availability is supposedly higher. This translates into an increase in resource use diversification by consumers and corroborates the flood pulse concept (FPC), which can be particularly applied to those habitats with high riverine influence in the study area (e.g., fluvio-lagoons). However, the FPC alone cannot be applied to understand the main factors influencing the fate and utilization of basal resources in areas interacting more actively with the sea, and therefore further extensions and/or complementary conceptual approaches considering marine systems highly interconnected with coastal floodplains should be considered.

This research was aimed at studying seasonal changes in water quality of Tanbi Wetland National Park (TWNP) and how these interact with the different land use types to influence fish assemblage. Physicochemical properties were measured in situ with a portable YSI multiprobe watermeter and fish sampling was done using a seine net of 100×4 m. To assess nutrient (nitrogen and phosphorus) input and chlorophyll a concentration (chl-a) in TWNP, spectrophotometry (fluorescence method) was applied. Subjecting the main water variables to a Principal Components Analysis (PCA) indicated a strong correlation between water temperature and pH, phosphate and pH, as well as water temperature and phosphate. A further Multidimensional Scaling (MDS) of the environmental variables indicated salinity as the main water variable influencing fish species richness in TWNP. Except at the settlement and agricultural zones, changes in fish assemblage appear not to be influenced by the specific land use types. As judged from a three-decade time series of rainfall and atmospheric temperatures, seasonal variations in environmental conditions have intensified and are negatively influencing fish assemblage in TWNP.

Small-scale fisheries (SSF) remain a largely under-assessed and overlooked sector by governments and researchers, despite contributing approximately 50% to global fish landings and providing food and income for millions of people. The multi-species, multi-gear and data-poor nature of SSF makes implementation of traditional single-species management approaches - like catch-quotas or size limits - particularly challenging and insufficient. A more holistic approach is thus required, which demands assessment of ecological impacts. Here we carried out an estimation of selected ecological indicators of the impact of fisheries (mean length, maximum body size, mean trophic level, trophic and spatial guilds, threatened species and landed by-catch) based on the nominal catch of different gears in three representative SSF along the Colombian Pacific using landings data collected in multiple years (2011 – 2017). Results showed that taxonomic, size-based, functional and conservation features of the nominal catch vary greatly with geographical location and gear type used. Overall, handlines and longlines tend to select larger sizes and higher trophic levels than nets, but they also catch a higher proportion of intrinsically vulnerable species and species of conservation concern. This challenges the idea that more selective gears have overall lower ecological impacts. In contrast, nets target a wider size range – although focusing on small or medium sized fish - and include a higher diversity of trophic and spatial guilds, which could arguably be considered a more “balanced harvest” type of fishing that retains ecosystem structure and functionality. Bottom-trawls, though, exhibited a relatively high percentage of landed by-catch, an undesirable feature for any fisheries in terms of sustainability. We propose that the assessment of a suite of ecological indicators, like those implemented here, should be included as part of periodic evaluations of multi-gear and multi-species SSF in tropical coastal areas, as a practical step towards ecosystem-based fisheries management.

Squat lobsters are distributed worldwide and are ecologically important in deep-sea bottoms. Agononida longipes is reported as the most abundant squat lobster in the southern Gulf of Mexico, and also occurs along the coast of Brazil and in the Colombian Caribbean. This study aimed to describe the spatial and bathymetric distribution of biomass and size structure of the squat lobster A. longipes in the Colombian Caribbean. Specimens were collected in the Colombian Caribbean between 100 and 550 m of depth. A total of 826 deep-sea squat lobsters was caught and analyzed. The size of A. longipes females and males ranged from 21.17 to 57.43 mm TL (mean 45.07 ± 5.51 mm) and from 23.59 to 54.85 mm TL (mean 42.96 ± 5.60 mm), respectively, revealing smaller mean sizes for males than for females. The length-weight relationship showed negative allometric growth for both sexes. Agononida longipes presented the highest abundance in the depth strata 300-400 m with the highest biomass in front of Riohacha in the northern zone and front of Cartagena in the southern zone. The highest abundance of this species in the northern zone of the Colombian Caribbean coincided with a high diversity of other potential deep-sea fishing resources. The knowledge about the distribution, abundance and life cycle of A. longipes is imperative for proper management under an ecosystem approach.

Isla del Coco (Costa Rica) forms part of the five oceanic islands of the Eastern Tropical Pacific and is well known for its high biodiversity and great endemism. While several marine biological and oceanographical surveys have been conducted around the island over the past 35 years, an integrated, systematic view of the shallow water system is lacking as is an assessment of the impact of illegal fisheries. The aim of the study was thus to identify the main biological compartments of the Isla del Coco system and to quantify its energy flow structure through the development of a trophic model for the shallow water environments (≤30 m). With the software Ecopath with Ecosim, and based on the model structure previously used for Darwin and Wolf islets in the Galápagos Archipelago, a trophic model was developed using information from several field surveys and additional data from similar systems. The total biomass of the Isla del Coco system (1,972.25 t km−2) was mainly comprised of high trophic level species such as hammerhead shark, pelagic predatory fish and other sharks. The reef ecosystem is in a healthy (relatively undisturbed) state and dominated by large apex predators and mesopredators. Of the keystone groups identified (toothed cetaceans, tiger sharks, other sharks, benthic omnivorous fish and pelagic predatory fish), toothed cetaceans and tiger sharks were identified as having the strongest influence on the structure and diversity of the community through direct and indirect interactions. The Isla del Coco ecosystem presents a higher biomass than a similar system in the Galápagos archipelago, likely due to lower fishing pressure and higher system maturity. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biología

Mangroves are prevalent coastal ecosystems along the Pacific and Caribbean coasts of Colombia, with several structural features and service provisions that make them important regionally and globally. Despite this importance and the existence of national laws to protect them, research on these ecosystems has been historically scarce if compared to the terrestrial ecosystems of the country. Here, we analyse historical trends of mangrove research in Colombia for the time period 1900 until 2018. To do so, a systematic literature search was carried out based on the Web of Science (WoS), Scopus and Google Scholar scientific citation databases. A noticeable increase in the number of mangrove studies in Colombia was found in the 2001–2010 decade. Although the Colombian Pacific contains ca. 80% of the country's mangroves, a greater number of mangrove studies has been conducted on the Caribbean coast. Cienaga Grande de Santa Marta, a degraded but productive coastal lagoon, is by far the most studied mangrove site in Colombia. Google Scholar was able to capture ~10 times more studies (mostly grey literature and peer reviewed articles in Spanish) than the Web of Science and Scopus databases, indicating the need to include this type of information in systematic reviews. We propose that future mangrove research in Colombia should prioritize: (1) historically understudied areas where degradation threats are strongest (e.g. near planned infrastructure projects), (2) areas poorly examined but likely to contain healthy, carbon-rich and tall mangroves (e.g. most of the Pacific coast) and (3) interdisciplinary studies that provide for a more holistic social-ecological understanding of Colombian mangrove systems. Our broad synthesis approach is applicable to other countries or regions with extensive mangrove areas and it is likely to help scoping future research and conservation efforts in these ecosystems.

Fifty years of artisanal fishing history in Galapagos characterized by boom and bust of resources has changed the natural marine community structure close to fishing ports in the Galapagos Marine Reserve. Nonetheless, the remote Darwin and Wolf Islands are still in a “ near natural state ” harboring high species richness unique for the archipelago and high biomass. Marine life that aggregates to the pinnacles linked to the wider oceanic seascape makes them interesting and unique systems in terms of community structure and study of on-shore/offshore trophic interactions. Although > 200 km from local fishing ports the two islands also support an artisanal fishery targeting large demersal predators of high trophic levels. They are areas prioritized for conservation actions by Galapagos National Park, and local non-governmental organizations given their natural heritage importance, value to local fishers and revenue from dive tourism attracted by the promise of large marine predator aggregations such as sharks. Given that catch data upon which to base conservation recommendations is sparse it is difficult to accurately estimate present day fishing trends in Darwin and Wolf. We used a trophic steady-state model that connects benthic and pelagic communities to assess the potential effects of a change in fishing intensity in the two islands system. A predator–prey matrix was built using the Ecopath with Ecosim (EwE) software with total biomass estimated at 937 t km − 2 . Large fish aggregations accounted for 19%, primary producers for 9.0% and non-fish (seabirds, marine mammals and sea turtles) for less than 0.1% of the total living biomass. The total system size in terms of overall flows was 16,652 t km − 2 year − 1 , four times larger than a generic seamount model but smaller than that modeled for a Galapagos upwelling system based upon the western Bolivar Channel region. Consumption and respiration dominated the flows in the system (53.4 and 31.8% respectively). The Darwin and Wolf system shows a mature state, dominated by respiration, and top–down control via sharks and benthic predatory fish as the most important system compartments in terms of biomass. Model simulations suggest that heavy fishing pressure on top predators would greatly change the system's trophic structure. The nature of impacts depended on the types of gears simulated. Reduced natural predator densities through fishing exert strong direct and indirect influences on the system towards sea urchin-dominated benthos.

During the past decade, the apocalyptic rhetoric of dwindling ocean resources and the destruction of aquatic habitats in the ocean and along our coasts has motivated conservationist, scientists, international Non Governmental Organisations (NGOs) and several coastal states to advocate the separation of ever increasing ocean and coastal areas as Marine Protected Areas (MPAs) to allow for the restoration of the ocean and its resources. At the same time, and analogue to what is happening with industrial agriculture, large industrial fishing fleets are operating in the Economic Exclusive Zones (EEZ's) of foreign countries, extracting a substantial part of their valuable ocean resources for the world market. The sparing of ocean and shelf areas for both, MPA implementation and Distant Water fishing (DWF) has impacted (positively and negatively) the concerned ecosystems and has often caused use conflicts with local stakeholders. I argue that current ocean use and conservation strategies are favouring these ocean-sparing (“blue grabbing”) measures as necessary means for ocean protection and sea food production over the science-based sustainable fisheries management approach, which is based on participatory fisheries assessment and the inclusion of local stakeholders in the management process. I perceive this change from sea sharing to sea sparing approaches as a paradigm shift in ocean management.

The success of the lionfish invasion in the western Atlantic can be explained by its rapid dispersion rate, as well as a rapid population growth due to its high fecundity. The adequate invasion control measures may vary between (sub) populations of the wider Caribbean region with differences in ecological and environmental conditions. Lionfish growth studies have been conducted in several places in the invaded region, but are missing from the southern Caribbean. We estimated the growth parameters and empirical natural mortality rates of P. volitans in the Colombian Caribbean and compare them with other native mesopredatory fish. To do so, we used Tropfish R and fishboot, a recently developed statistical stock assessment package that incorporates resampling techniques and allows for estimating the confidence interval around the estimates. Size records of 1184 speared fish caught between 2014 and 2017 in continental and insular reef areas were analyzed. Our results confirm the rapid growth of lionfish (K=0.44; C=0.62) and reveal high similarities in growth rate among Colombian Caribbean areas but differences among the invaded area regions, primarily explained by water temperature, habitat heterogeneity and structural complexity, food availability, potential bathymetric ontogenetic movement, and the time elapsed since colonization. The invader’s efficiency over its competitors is best explained by the lionfish’s fast growth and early age at maturity.

There are no commercial fishing activities in the deep water of the Colombian Caribbean, but initial surveys have spotted species of great abundance that may have harvest potential. In this study, we report the findings of a systematic trawling of soft seafloor mega-invertebrate assemblages along the Colombian Caribbean coast (from the Gulf of Uraba to Punta Gallinas in La Guajira) in a depth range between 150 and 535 m (three strata: 150–300 m; 300–400 m; 400–535m). We analysed the spatial distribution, species composition, and size structure, as well as the relationship between species abundance and biomass (ABC curves) as an indicator of the state of the system. In the medium depth stratum of the northern zone, general species richness and abundance were highest, and the ABC curves suggest a pristine system state with no signs of community disturbance. The species Pleoticus robustus, Penaeopsis serrata, Aristaeomorpha foliacea, Metanephrops binghami and Plesionika longipes showed the highest abundance (> 60%), biomass (> 72%) and widest range of geographical and bathymetric distribution and may be candidates for a future fishery. However, prior to opening any fishery for these species, studies should be conducted on their life history parameters to estimate the catch fraction of the annual production that may be sustainably be harvested.

Marine capture fishery in Kenya is small contributing only 4% to the overall fish production in the Country. This is because the fishery is artisanal characterized by relatively simple gears and vessels and has as yet received little attention due to the limited understanding of its contribution to coastal livelihoods. Nevertheless the Kenyan reefs are considered to be among the most heavily exploited reefs in East Africa. A review of the coastal artisanal fisheries landings for the past sixty years indicates that significant changes have occurred in the fisheries. There has been an increase in effort evidenced by the increased number of fishers, fishing vessels and change in fishing gears. Overall the landings have remained relatively stable over the past decade fluctuating between 5000 tonnes and slightly more than 8000 tonnes annually which are within the range of the predicted sustainable limit of the fishery based on both the Schaefer and fox model prediction of the maximum sustainable yield (MSY). Our estimate of MSY (8264–8543) and the corresponding effort of 11,171–15,467 fishers, derived from the Schaefer and Fox models, would suggest that yields higher than the presently obtained levels cannot be expected in future and that the inter annual variation in total landings may have to do with environmentally triggered changes in resource productivity. The model results also suggest that the overall effort of the present fishery already exceeds sustainable effort levels by at least 20%, suggesting a general state of overfishing. Therefore, there is an urgent need to not only apply stricter gear restrictions but also regulate new entrants in to the fishery while improving on the collection and monitoring of catch and effort data.

A trophic model of the shallow Danajon Bank, in the Central Visayas, Philippines was developed using a mass-balance approach (Ecopath) to describe the system characteristics and fisheries interactions. The Ecopath model is composed of 37 functional groups and 17 fishing fleet types reflecting the high diversity of catches and fishing operations in the Danajon Bank. Collectively, the catch is dominated by lower trophic level fish and invertebrates as reflected in the mean trophic level of the fishery (2.95). The low biomass and high exploitation levels for many upper trophic level groups and the little evidence for strong natural physical disturbances suggest that top-down fishery is the main driver of system dynamics. The mixed trophic impacts (MTI) analysis reveals the role of the illegal and destructive fishing operations in influencing the ecosystem structure and dynamics. Furthermore, the illegal fisheries' estimated collective annual harvest is equivalent to nearly a quarter of the entire municipal fisheries catch in the area. Improved fisheries law enforcement by the local government units to curb these illegal and destructive fishing operations could substantially increase the potential gains of the legal fisheries.

Previous work has highlighted the critical role of macroalgal productivity and dynamics in supporting and structuring marine food webs. Spatio-temporal variability in macroalgae can alter coastal ecosystems, a relationship particularly visible along upwelling-influenced coastlines. As a result of its equatorial location and nutrient rich, upwelling-influenced waters, the Galápagos Archipelago in the East Pacific, hosts a productive and biodiverse marine ecosystem. Reports and collections of macroalgae date back to the Beagle voyage, and since then, more than three hundred species have been reported. However, their ecology and functional role in the ecosystem is not well understood. According to various disparate and in part anecdotal sources of information, abundant and diverse communities exist in the Western regions of the archipelago, the North is essentially barren, and in the central/South abundance and distribution is variable and less well defined. Both oceanographic conditions and herbivore influence have been theorized to cause this pattern. Extensive changes in macroalgal productivity and community composition have occurred during strong ENSO events, and subsequent declines in marine iguana (an endemic and iconic grazer) populations have been linked to these changes. Iguanas are only one species of a diverse and abundant group of marine grazers in the system, highlighting the potentially important role of macroalgal productivity in the marine food web. This review represents a first compilation and discussion of the available literature and presents topics for future research. Rev. Biol. Trop. 65 (1): 375-392. Epub 2017 March 01. ResumenTrabajos previos han destacado el papel fundamental de la productividad y dinámica de las macroalgas en el mantenimiento y estructuración de las cadenas alimentarias marinas. La variabilidad espacio temporal de las macroalgas puede alterar ecosistemas costeros, particularmente visibles a lo largo del perfil costero en zonas de proliferación. Como resultado de su ubicación ecuatorial y riqueza en nutrientes, además de eventos de proliferación, el Archipiélago de Galápagos en el Pacífico Oriental acoge un productivo y biodiverso ecosistema marino. Informes y recolección de macroalgas se remontan desde el viaje del Beagle, y desde entonces se han informado más de trescientas especies. No obstante, su función ecológica en el ecosistema no ha sido bien comprendida. Según diversas fuentes de información y en parte anecdóticas, existen abundantes y diversas comunidades de macroalgas en las regiones occidentales del archipiélago, el norte es sustancialmente estéril, y en el centro/sur la abundancia y distribución es variable y menos definida. Tanto las condiciones oceanográficas y la influencia de herbívoros han sido teorizadas para causar este patrón. Grandes cambios en la composición de la productividad y comunidad de macroalgas se han producido durante eventos ENOS fuertes y subsecuentemente han provocado la disminución de poblaciones de iguana marina (herbívoro endémico e icónico) y han sido vinculados a estos cambios. Las iguanas marinas son sólo una de las especies de un grupo diverso y abundante de herbívoros marinos en el sistema, destacando potencialmente el importante rol de la productividad de macroalgas en la cadena alimentaria marina. Esta revisión representa una primera recopilación y análisis de la literatura disponible y presenta temas para futuras investigaciones.

Tropical coastal habitats like marshes, mangroves, and submerged grasses comprise diverse plant and animal communities and a certain degree of connectivity with other ecosystems. We compared the food web structure of a fringing mangrove-seagrass habitat and three fluvio-lagoons with marsh-eelgrass and mangrove-bare sediments during a dry season in Terminos Lagoon and Centla Wetlands, Southern Gulf of Mexico. Analysis of δ13C and δ15N stable isotopes in tissues of aquatic consumers, primary producers, and other carbon sources, in combination with isotope-based Bayesian methods, were performed to determine the main food sources and the isotopic niche of the consumers’ communities. Consumers in the mangrove-seagrass site showed high dependence on phytoplankton (average contribution 31 %), macroalgae (20 %) and organic matter derived from seagrasses (17 %). In the fluvio-lagoons, consumers showed high dependence on marginal vegetation (16–46 %). Phytoplankton and mangrove epiphytes comprised other important resources at these sites (with contributions of 24–44 %). The isotopic niche of consumers from the fringing mangrove-seagrass site did not overlap with those from the fluvio-lagoons. Moreover, despite the predominance of generalist consumers in all sites, differences in their isotopic niche area were observed, with consumers from the marsh-eelgrass site showing the narrowest. This suggests that consumer resource availability greatly differs in these habitats. Our results provide valuable information that help increase our understanding about the trophic structure in these important estuarine systems.

This study reviews fisheries and management practices and provides estimates of the present and potential fish yield of Ethiopian inland fisheries. Published and unpublished sources were used, 28 years of fisheries data were analyzed and empirical models were applied to estimate potential yield. Ethiopian waters hold about 180 fish species, some freshwater shrimps and crabs, commercially important microalgae and a diverse vegetation, all together of great economic and socio-cultural values. Fisheries provide economic support directly and indirectly to about half a million people and serve as source of affordable protein for many households. Our estimate of potential yield (94,500 t yr−1 + 5.2% distributed as 73,100 t yr−1 + 3.3% for lentic and about 21,400 t yr−1 + 11.9% for lotic ecosystems) is far above the current yield levels, suggesting substantial scope for fisheries expansion. Nevertheless, some lakes already show signs of overfishing of target species, while others appear to have growing or stable fisheries. As yet, no ornamental fishery occurs in the country and the potential of indigenous fish species for ornamental fish trade needs to be evaluated. Management follows the traditional command and control approach and it seems that there is a general lack of awareness and scientific information on the fisheries. Major challenges of the fisheries are high post-harvest loss, lack of stringent sanitary and phytosanitary standards for assuring good quality products, and overfishing of valuable fish species in some lakes. Thus, continuous fisheries monitoring and yield assessment are urgently needed as is research directed toward unexploited water bodies and species.

Highlights: • A social-ecological system (SES) is analyzed through a multilayer network approach. • The social-ecological network represents the value chain of different fisheries. • The multi-layer network considers the transfers of biomass and money as link types. • Network position reflects individual vulnerability towards external disturbance. • Understanding SES linkages is crucial for designing meaningful management measures. Coastal marine resources provide livelihoods to human communities around the world. The interactions in respective social-ecological systems are usually of complex nature, due to a wide range of different fisheries interacting with the ecosystem. Understanding connectivity within these systems (i.e. among social and ecological actors) helps in establishing meaningful management strategies for sustainable use of marine resources. This work uses the value chain analysis of different fisheries sectors to construct a qualitative social-ecological network (SEN) model of the Sechura Bay in North Peru. Here, a diverse ensemble of small-scale fisheries co-exists with a flourishing mariculture sector, though the respective production chains partially overlap. Directed and unweighted links between actors were defined based on the transfer of biomass (trophic interactions) and money (economic interactions). Several analytical network tools were applied (e.g. degree centrality, dominator tree) to identify the most important nodes of the social-ecological network and to understand interdependencies. Results of the network analysis suggest position of system's components being related to their vulnerability in the face of external disturbances. Fisher groups with a high specialization with respect to fisheries target species were stronger impacted by the last strong El Niño event (the Coastal El Niño 2017), with drastic consequences for actors of the respective production chains. The present approach is envisioned to be applicable beyond this particular case study and to nourish on-going scientific discussions on the use of social-ecological network analysis to describe human-nature interactions. This study allows (i) estimating node (actor) susceptibilities to natural and anthropogenic disturbances, and (ii) reconciling sustainable resource use and nature conservation by enhancing the understanding of the functionality of the respective social-ecological system.

Small-scale fisheries (SSF) contribute to approximately half of the total landings of tuna and tuna-like species in the Indian Ocean and are an important form of employment and source of protein. Research into the properties and dynamics of SSF in East Africa are important for the assessment and sustainable management of fish stocks, however, detailed fisheries data are often inadequate or absent. Fisheries-dependent data on driftnet fisheries in Zanzibar, Tanzania, was collected during the northeast monsoon seasons in 2014 and 2015. The data describes the properties of the driftnet fisheries and allows for comparisons of the length composition of the landings of the SSF with large-scale industrial fisheries (IF) fishing in Tanzania’s Exclusive Economic Zone (EEZ). This data also facil - itates the calculation of stock indicators for the five most abundant tuna and tuna-like species landed in Zanzibar. Results show that the two fisheries (SSF and IF) exploit the same stocks, and landings are representative of a similar length composition, while operating in different parts of Tanzania’s EEZ. High exploitation rates, above reference levels for all species were calculated, in agreement with official assessments by the IOTC, and suggest that calls for the expansion of the SSF should be reconsidered. The assessment and management of straddling stocks are dis - cussed, as well as solutions to challenges faced by local observer programmes.

This chapter discusses the biology, ecology and aquaculture of the scallop, Argopecten purpuratus, in Peru. Of several scallop species, this is the only one exploited and cultured in Peru. During the last three decades, this resource has become one of the most important molluscs in Peru in terms of export value with volume greatly fluctuating since the onset of the export business in the early 1980s. The impact of El Nino on the population of A. purpuratus is discussed by regions in Peru, being favourable in central and southern Peru and detrimental in northern Peru. Conversely, the scallop production in northern Peru is augmented during cold years. Since most of the scallop production is dependent on seed extraction from natural banks, the use of artificial collectors and the production of larvae in hatcheries is proposed and discussed.

Climate change is a global problem and has become an important agenda in both public and private discourse in recent times. Adaptation is more relevant for poorer nations because of their relative vulnerability to the impacts of climate change, [IPCC (Contribution of working group II to the 4th Assessment Report of the IPCC. University Press Cambridge, 2007a); Climate change: impacts, adaptation and vulnerability. Working group II contribution to the Intergovernmental Panel on Climate Change. Summary for policy makers. IPCC Secretariat, Geneva, Switzerland, 2007b]. However, this paper examined adaptation of the artisanal fisher folks to climate change in the coastal region of Ondo state, Nigeria. Data for climate variables (sea surface temperature and rainfall) were obtained from reanalyzed Satellite data and were further analyzed using sophisticated ecological models for further inferences. 5-Scale Likert scale was used to assess the current adaptation strategies adopted by artisanal fisher folks. The result revealed that rainfall pattern showed great variation over time in terms of volume and intensity; this observation is in line with the observation of FAO, 2008, that, climate change is modifying the distribution of marine and freshwater species. The trend of temperature pattern for about 30 years clearly showed high fluctuation overtime. It was observed that the fisher folks in the study area had various adaptation strategies adopted for maximum fish production/catch for livelihood and improve standard of living.

During a strong El Nino event, nutrient and phytoplankton concentrations around the Galapagos archipelago greatly decrease, while sea surface temperature increases (>7°C). Several species suffer under these conditions, while some benefit and new species appear. To understand the mechanisms behind observed changes, a trophic reference model of the Bolivar Channel ecosystem was forced by a 16 yr (1994 to 2009) satellite-derived time series of phyto- plankton biomass including the El Nino period 1997/98. Emergent changes in model compartment biomasses, as derived from dynamic simulations, were compared to in situ observations of the subtidal communities and marine vertebrates over the study period. Observed population reduc- tions of seabirds (penguins and flightless cormorants) and of several fish groups were well pre- dicted by the simulations, suggesting that bottom-up effects largely control the system during an El Nino event. Observational data also enabled modifying the reference model to an El Nino state model. In this El Nino model, ecosystem size (total energy throughput) was reduced by 70.1%. Overall system characteristics show great similarities with other coastal upwelling systems of the Peruvian coast in that strong El Nino events cause disruptions to trophic flows and keep them at a low (but highly productive) development state.

The poorly regulated aquarium trade in live corals poses yet another threat to fragile coral reef ecosystems. The Indonesian authorities routinely allocate some of the highest trade quotas in South Sulawesi to Heliofungia actiniformis despite a lack of data on the impacts of current collection practices on this species. Semi-structured interviews with fishermen and in situ surveys revealed a size-selective fishery towards small polyps. This resulted in a shift of size-frequency distributions, and reduced overall abundances at harvested sites. Total mortality rates calculated using a catch curve approach at harvested sites were significantly higher compared to those known from unharvested sites for polyps sized 0–11 cm. Recorded exploitation rates were 0.1 and 0.7 for polyps sized 0–4 cm and 4–11 cm respectively. The application of a utility per recruit approach, calculated with a Thompson and Bell model, revealed maximum potential economic yield to occur at a size of 5 cm, corresponding to an age of 5 years. This is 5 years before the attainment of reproductive maturity, and 15 years before the attainment of maximum biomass yield per recruit. A predictive model indicated the need for a 5 cm size limit to curb economic overfishing, and protect attached anthocauli stalks capable of maintaining the trade through continued asexual reproduction. In addition, a reduction of exploitation rates for polyps in the 4–11 cm size bracket to 0.5 is urgently needed. Calculations reveal that this would in fact be possible without lowering current profits. Achieving long term sustainability will in addition to a reduction of harvest quotas necessitate an effective protection of spawning stocks through stricter enforcement of existing marine protected areas.

The fungiid Heliofungia actiniformis is one of the most popular coral species in the Indonesian aquarium trade, yet information on the biology of this species is limited. H. actiniformis growth rates, population size–frequency distributions and the seasonality of recruitment rates were measured at three replicate sites in the Spermonde Archipelago, South Sulawesi. Growth and population models were applied to estimate coral ages, mortality rates and the size of maximum yield. Growth decreased linearly with polyp size. High numbers of attached polyps budded from clusters of stalks attached to the reef, with each cluster originating from the settlement of a sexually produced larva. Neither the settlement of sexual recruits, nor their asexual budding, showed seasonality. The overall population structure reflected the high mortality rates of young, attached polyps (Z = 0.5–0.6 yr−1), and the much lower mortalities of free-living individuals (Z = 0.05–0.08 yr−1). There were no statistically significant differences in overall mortality rates and the age–frequency distributions of polyps aged 0–15 years between the sites. Differences in the abundance of large H. actiniformis polyps at the three replicate sites were correlated with percent cover of coral rubble. The application of the Beverton and Holt model revealed the highest biomass per H. actiniformis recruit was 12 cm, corresponding to a polyp age of 20 years.

Peru experiences recurrent ENSO (El Nino Southern Oscillation) events during which the Peruvian bay scallop (Argopecten purpuratus) undergoes substantial changes in its stock size. In the North of the country strong warm ENSO events are synonymous with floods and river discharges that negatively affect scallop biomass, while in the South increased sea surface temperatures lead to an increase in stock size. This paper explores how formal institutions respond to climate variability and resource fluctuations in the scallop fishery, and what role they play in the maintenance or erosion of resilience. The research shows that formal institutions are slow to learn, self-reorganize and respond to climate variability while fishermen’s responses are spontaneous, ensuring a rapid process of individual adaptation. Institutional responses are mostly ex-post, and are not strongly shaped by past experience, thus eroding the resilience of the system. However, fishermen’s responses sometimes lead to negative outcomes such as local stock overexploitation or ‘invasion’ of natural scallop habitats for scallop grow-out, and formal institutions play an important role in resilience building through the control of effort and entry in the fishery. In this paper causal loop diagrams are used to conceptualize the fishery system to highlight key variables and processes. The study thus provides the opportunity to explore the usefulness of causal loop diagrams and conceptual models combined with participatory approaches in the exploration of the resilience of a system. The case study also illustrates that individual adaptation, a feature of resilience, is occurring and will occur spontaneously, changing property right regimes and responding not only to climate variability but also market forces. In order to maintain and build resilience and engender positive management outcomes, formal institutions not only need to shape fishermen decision-making, they must also contribute to knowledge building as well as the adoption of innovative approaches.

This study quantifies and spatially characterizes land use and land cover changes in the Segara Anakan lagoon (SAL), Java, Indonesia, from 1987–2006. Classification of four satellite (SPOT) images from the years 1987, 1995, 2004 and 2006 and field ground truth data from 2004 and 2005 were used for map generation. The results show major changes in the western area of the SAL, with large area increases of rice fields, dry land agriculture, aquaculture and rural areas, and decreases in mangrove cover, mud flat and lagoon area. In the eastern area, minor decreases in mangrove area and increase in aquaculture, rural and industrial areas were also observed. Changes are due to the filling of the lagoon with riverine sediments derived from the hinterland and to mangrove conversion and resources exploitation. The results of this study provide basic information which is required for developing measures towards a sustainable management and conservation of the SAL.

Goetz, S., Wolff, M., Stotz, W., and Villegas, M. J. 2008. Interactions between the South American sea lion (Otaria flavescens) and the artisanal fishery off Coquimbo, northern Chile. – ICES Journal of Marine Science, 65: 1739–1746. The South American sea lion (Otaria flavescens) forages in coastal waters, where it interacts with fisheries and causes considerable economic loss by removing some catch and damaging gear. This study describes for the fishery region of Coquimbo (Chile) where, when, and with what type of gear interactions occur, characterizes the animals involved (group size, sex, and age), and derives some management recommendations. The study was based on 55 interviews with fishers and observations aboard fishing vessels in the main fishing sectors between October 2003 and March 2004. Interactions were primarily at night (88% of interviewees fished at night), in the bay (“Bahía”) of Coquimbo (81% of interviewees fished in this sector), where shoaling fish were abundant, and with purse-seines (100% of interviewees used this gear). Although some large groups of sea lions were seen, most comprised 1–10 animals. Most animals that interacted with the fishing gear were males (67%), probably because of the different feeding strategies of the two sexes. Management options discussed include the adjustment of fisheries to foraging behaviour of sea lions, and the controlled elimination of conflicting animals.

We compared the community structure of reef fish over different physical complexities in 12 study zones of Bahia Honda, Gulf of Chiriqui (BH-GCH), Tropical Eastern Pacific (TEP), Panama, aiming at an analysis of the importance of the physical structure provided by corals, rocks and benthic sessile organisms. This was the first region that emerged in the Isthmus of Panama; it exhibits the oldest benthic fauna and has constant conditions in terms of temperature and salinity. Two hundred and eighty-eight visual fish censuses were conducted on 48 benthic transects from February to July 2003. One hundred and twenty-six fish species of 44 families were found. Plankton feeding pomacentrids and labrids along with haemulids that feed on mobile invertebrates were the most abundant, particularly in shallow areas. Fourteen species showed size-segregations between zones, suggesting ontogenetic migrations (smaller fishes in shallow high-complexity zones, larger-sized fishes in deeper habitats). Highly mobile and site-attached genera were abundant in most shallow, wave-exposed zones particularly on exposed rocky substrates. Planktivores were the most abundant, followed by carnivores, feeders on mobile invertebrate and piscivores. Herbivores and feeders on sessile invertebrate were lower in abundance. Species richness exceeds that of any other studied region close to the mainland in the TEP and correlates with substrate diversity, increasing size-heterogeneity of holes and structural complexity. Species diversity increases with habitat complexity and benthic diversity. It seems that water current strength, tides and waves which select for swimming, play an important role in the community organization. The study region has been proposed as a refuge-centre in the TEP, where reef fishes that evolved on coral reefs have shifted their distribution onto rocky reef habitats.

The sustainability of different integrated management regimes for the mangrove ecosystem of the Caete Estuary (North Brazil) were assessed using a holistic theoretical framework. As a way to demonstrate that the behaviour and trajectory of complex whole systems are not epiphenomenal to the properties of the small parts, a set of conceptual models from more reductionistic to more holistic were enunciated. These models integrate the scientific information published until present for this mangrove ecosystem. The sustainability of different management scenarios (forestry and fishery) was assessed. Since the exploitation of mangrove trees is not allowed according Brazilian laws, the forestry was only included for simulation purposes. The model simulations revealed that sustainability predictions of reductionistic models should not be extrapolated into holistic approaches. Forestry and fishery activities seem to be sustainable only if they are self-damped. The exploitation of the two mangrove species Rhizophora mangle and Avicenia germinans does not appear to be sustainable, thus a rotation harvest is recommended. A similar conclusion holds for the exploitation of invertebrate species. Our results suggest that more studies should be focused on the estimation of maximum sustainable yield based on a multispecies approach. Any reference to holistic sustainability based on reductionistic approaches may distort our understanding of the natural complex ecosystems.

The present contribution is an extension of the trophic models that we have previously designed for benthic communities in Tongoy Bay (north-central Chile). It represents the first attempt to use Levins' loop analysis in a complex harvested system along the Chilean coast. Ecological and extended eco-social models were developed for seagrass, sand-gravel and sand habitats in order to propose sustainable management strategies for the harvest of the red algae Chondrocanthus chamis- soi, the scallop Argopecten purpuratus, the snail Xanthochorus cassidiformis and the crab Cancer polyodon. Based on Levins' loop analysis it was possible to estimate both the local stability (sustain- ability) for each of these model systems and to simulate the changes in the standing stocks of the main groups as response to external factors. Our results suggest that to increase the standing stocks of adult scallops the following man-made interventions should be implemented: (1) seagrass habitat: partial removal of the 3 sea star species Luidia magallanica, Heliaster helianthus and Meyenaster gelatinosus; and (2) sand-gravel habitat: seeding of scallop recruits and juvenile scallops, and removal of the sea star H. helianthus only. According to our results, the sand habitat would not sup- port any harvest. The extended model for the seagrass and sand-gravel habitats were found sustain- able only if the fishermen were 'self-damped', that is, when the fishing effort and fish quota were restricted. Even though loop analysis did not allow for explicit quantitative reasoning, 'what if' questions can be answered with sufficient understanding and realism. Therefore, this qualitative modelling appears as a valuable complementary mathematical tool defining and assessing the sustainability of management options within a holistic scope. We also recommend the application of this framework in other benthic management areas along the Chilean coast.

1.This study is the first attempt using Levins's Theory (loop analysis) in order to develop a sustainable management for the scallop, Argopecten purpuratus, fishery in Peru during El Nino-Southern Oscillation events (ENSO) and upwelling conditions. Based on this theoretical framework, it was possible to estimate the local stability for each of these model systems and to follow the qualitative changes of the variables in response to external factors. 2.Based on our results, we suggest the following management policies to be implemented: (1) during ENSO events the size at the first capture of the scallops should be >70 mm and (2) the increase in the number of fishermen during ENSO events must be prevented. Both measures increase the sustainability of fishery under ENSO and upwelling conditions. The ecological models predict that during ENSO and upwelling events, any management strategy to increase the recruitment of the scallop would not have a positive impact on the adult stock. 3.Finally, we suggest that more efforts must be focused on the development of extended eco-social models, which incorporate further social and economic variables, increasing realism of the abstractions for this fishery activity. Copyright © 2002 John Wiley & Sons, Ltd.

1. A dynamical and spatial simulation model of a harvested benthic ecosystem of central northern Chile (Tongoy Bay) was constructed using the ECOSPACE software package. 2. In this system the red alga (Chondrocanthus chamissoi), the scallop (Argopecten pupuratus), the gastropod (Xanthochorus cassidiformis) and the crab (Cancer polyodon) are harvested intensively. The impacts of harvesting these resources exclusively in the seagrass, sand-gravel, and in the sand habitats, as well as, in the seagrass and sand-gravel and in all habitats were assessed. The goal was to explore policies of sustainable exploitation of the benthic systems. 3. The most important findings were: (a) Fishing exclusively in either the seagrass or sand habitats produces a population increase in the sea star Luidia magallanica, in the seagrass Heterozostera tasmanica, and in the crab Paraxanthus barbiger. (b) Exclusive fishing in the sand-gravel habitat causes only small effects on the species and groups, which suggests that this habitat is the most resistant to harvest. (c) The simultaneous fishing on two or three habitats would produce the largest negative effect on the entire system. Therefore, a habitat rotation fishery is recommended. 4. Our study suggests that trophic-spatially explicit models offer great possibilities for the screening and planning of effective interventions or manipulations of natural systems. Copyright © 2002 John Wiley & Sons, Ltd.

1. This paper sets out to: (1) review previous ecological studies and analyse recent trends of the Peruvian bay scallop fishery in order to better understand and to model the species’ temporal and spatial (meta) population dynamics along the South Pacific coast; (2) develop a fisheries model to protect the stock from overexploitation and optimize the annual yield of the pulse fishery in Independence Bay, the centre of the scallop diving fishery in Peru. 2. Natural stock fluctuations are very pronounced in this species and are positively correlated with the El Nino–Southern Oscillation (ENSO). During such an event, habitat conditions for the Peruvian bay scallop are improved either regionally or locally, such that populations proliferate and larval production and dispersal are greatly increased. Extinct beds and new habitats are recolonized during these periods (producing a strong pulse of metapopulation biomass), although most become extinct very shortly thereafter. 3. For management purposes, two considerations are fundamental: (1) heavy overfishing or extinction of the main scallop source populations would endanger the metapopulation as a whole; (2) rates of growth and survival greatly increase (and with them the potential yield of the scallop stock) locally over an El Nino cycle in a way that can be roughly estimated from past experience, including the most recent El Nino event (1997–1998). 4. We suggest a fisheries management regime capable of adapting to natural changes and propose a procedure for calculating both the optimal yield and the respective fishing effort under normal upwelling and El Nino scenarios, considering changes in the size at first capture (Lc) and fishery mortality (F). Copyright © 2000 John Wiley & Sons, Ltd.

"We developed a transdisciplinary modeling approach for the Huave Lagoon System (HLS), Mexico. This lagoon was selected because it has been used sustainably in various complimentary ways by different ethnic groups since pre-Hispanic times. Over the last few years, however, the ecological impact of artisanal fisheries in the region has grown significantly, thus endangering the balance between society and nature. Because the Huaves and the Zapotecs are ancestral fishing cultures with a profound knowledge of ecosystem resources and local property rights, the aim of this study was to identify ecosystem-level management alternatives capable of diminishing fishing impacts to the HLS. We used a consensus-building process and applied the user???s traditional ecological knowledge (TEK). Our counterintuitive results show that specific management strategies should be considered for each particular fishing seascape within the HLS while taking into account the differences among ecological structures and fishery dynamics. The insights from this research aid in defining holistic management policies and support spatial allocations of use rights in local fisheries."

The brown sea cucumber fishery is active in the Galapagos Islands since the year 1991 after its col- lapse in mainland Ecuador. This paper analyzes the Galapagos Sea cucumber fishery over the past decade and the reasons for its management pitfalls and chronic over fishing, and proposes an improved strategy for estimating stock size and harvest potential. Based on the historical distribution of the fishing fleet and past fishery surveys, 15 macrozones were defined; their areas were estimated from the coastline to the 30m isobaths and the numbers of sample replicates per macrozone were calculated for a density estimate precision of ±25%. Overall stock size was calculated by summing over all macrozones and was multiplied by 0.122 to obtain the annual quota. This multiplier was derived by inserting an exploitation rate of E=0.3 and a published natural mortality value of M=0.17 into Cadimas formula, thereby obtaining a more conservative precautionary quota estimate. Pre-fishery stock densities in 2009 were below the legal threshold value and the fishery remained closed. Mean densities were significantly lower in the deeper (>15m) than in the shallower (

The El Nino of 1997–98 was one of the strongest warming events of the past century; among many other effects, it impacted phytoplankton along the Peruvian coast by changing species composition and reducing biomass. While responses of the main fish resources to this natural perturbation are relatively well known, understanding the ecosystem response as a whole requires an ecotrophic multispecies approach. In this work, we construct trophic models of the Northern Humboldt Current Ecosystem (NHCE) and compare the La Nina (LN) years in 1995–96 with the El Nino (EN) years in 1997–98. The model area extends from 4S–16S and to 60 nm from the coast. The model consists of 32 functional groups of organ

The population dynamics of an intertidal population of Megapitaria squalida was studied from September 2002 to February 2003 in Bahía Magdalena, Mexico. To obtain information about the artisanal and recreational fishery of M. squalida, local fishermen at different parts of the bay were interviewed. Clam densities were determined at one unexploited and two exploited sites along perpendicular transects from the shore line. Average clam density was 2.01±1.41 ind/m², densities did not differ significantly between the three sampling sites. The length-total mass relation was Mtot = 0.0001*SL3.1644 (r2 = 0.9804, n = 92) and the length-tissue mass relation was Mtis = 0.0002*SL2.7144 (r² = 0.945, n = 92). Von Bertalanffy-growth parameters were determined using marked individuals. Strong interindividual and also seasonal differences in growth were observed. Average annual values were: K = 0.655, L∞ = 83 mm. Since M. squalida can reach a shell length of more than 135 mm in deeper waters, it is necessary to consider intertidal and subtidal populations separately. Average total mortality (Z) was 1.61 y-1. No fishing mortality was calculated because total mortality Z at the unexploited control site was higher than Z at the exploited sites. It appears that M. squalida migrates into deeper water with increasing shell length, as average shell length increased at lower tidal levels and marked specimens showed a clear migration towards deeper waters. As yet no overexploitation could be found in the study area. Rev. Biol. Trop. 54 (3): 1003-1017. Epub 2006 Sept. 29.Se estudió la dinámica poblacional de la almeja Megapitaria squalida de setiembre 2002 a febrero 2003 en Bahía Magdalena, México. La densidad se determinó en un sitio no explotado y dos sitios explotados utilizando transectos perpendiculares desde la línea costera. También se entrevistó a pescadores locales de diferentes partes de la bahía para obtener información acerca de la pesquería artesanal y recreacional de M. Squalida. La densidad promedio estimada fue de 2.01±1.41 ind/m², sin diferencias significativas entre sitios. La relación de masa y longitud total fue de Mtot = 0.0001*SL3.1644 (r² = 0.9804, n = 92) y la relación de masa y longitud de tejido fue de Mtis = 0.0002*SL2.7144 (r² = 0.945, n = 92). Los parámetros de crecimiento Von Bertalanffy se determinaron utilizando marcadores individuales. Hay grandes diferencias en crecimiento tanto interindividuales como estacionales. Los valores anuales promedio fueron: K = 0.655, L∞ = 83 mm. Debido a que la longitud de la concha puede superar los 135 mm en aguas profundas, es necesario considerar las poblaciones intermareal e inframareal de manera separada. La mortalidad promedio total (Z) fue de 1.61 y-1. No se calculó la mortalidad de pesca porque la mortalidad total (Z) del sitio no explotado fue mayor que la de sitios explotados. Aparentemente M. squalida migra hacia aguas más profundas al crecer. No se encontró evidencia de que estas poblaciones estén sobreexplotadas.

La Guajira es un ecosistema de surgencia explotado en la costa del Caribe colombiano. Con el propósito de integrar la información disponible sobre el sistema se construyó un modelo trófico de 27 grupos funcionales usando el programa Ecopath 5.0 Beta. Se obtuvo una base cuantitativa para compararlo con otros sistemas de surgencia. La Guajira presenta una biomasa total de 68 t/km²/año, la producción primaria neta del sistema es de 1 248.51 t/km²/año y las transferencias totales del sistema son de 3 275 t/km²/año, lo que indica un ecosistema con una surgencia moderada comparada con otros sitios. Las mayores transferencias de energía se dan del nivel trófico I-II (68.93 %), aunque existe una importante proporción de flujos al detritus (32 %). Los resultados en los atributos de madurez del sistema sugieren que La Guajira es un ecosistema inmaduro debido a que la relación P/R excede a 1 y está en desarrollo debido a la baja ascendencia (33.7 %) y alta capacidad de desarrollo (66.3 %) como ocurre con otras surgencias donde se presentan valores de ascendencia entre 20 % y 35 %. Aunque los datos básicos de entrada en el modelo fueron buenos, gracias a las investigaciones que se han elaborado entre 1995 y 2000, existen algunos grupos donde no se encuentra aún información adecuada; especialmente en los valores de biomasa del fitoplancton, invertebrados, bagres, peces depredadores pelágicos, así como estimaciones de producción en invertebrados, peces depredadores pelágicos y peces pequeños pelágicos. No existe una cuantificación de las poblaciones de mamíferos y aves en el área de estudio, los cuales constituyen depredadores superiores y hacen parte esencial en sistemas de surgenciaBiomass flow and structure of a tropical upwelling ecosystem in La Guajira, Colombian Caribbean. La Guajira is an exploited tropical upwelling ecosystem in the Colombian Caribbean coast. A trophic model of 27 functional groups was constructed using the ECOPATH 5.0 Beta software to integrate the available information on the ecosystem. The model allowed a comparison with other trophic flow models of upwelling ecosystems. Total system biomass (68 t/km²/year), net system production (1248.5 t/km²/year), and total system throughput (3 275 t/km²/year) make La Guajira moderate when compared with other systems. The largest amount of energy throughput is achieved from trophic level I to II (68.93 %), although an important proportion of the total flow originates from detritus (32 %). The production/respiration ratio exceeds 1, suggesting that La Guajira is an immature ecosystem and is in development, as determined by its low ascendency (33.7 %) and high development capacity (66.3 %), similar to other upwellings that have values of ascendency between 20 % and 35 %. Although the basic input data were good and covered 1995 to 2000, appropriate information is still not available on some trophic groups such as biomass (for phytoplankton, invertebrates, catfishes and pelagic predator fishes), secondary production data (invertebrates, pelagic predator fishes, and small pelagic fishes), and seabird and mammal populations, which are top trophic levels and an essential part of upwelling ecosystems. Rev. Biol. Trop. 54 (4): 1257-1282. Epub 2006 Dec. 15

Part 1: The Evolutionary Context 1.1. What Darwin Found Convincing in Galapagos William Durham 1.2. Research on Evolutionary Principles in Galapagos: Research on Evolutionary Principles in Galapagos: An Overview of the Past 50 Years Carloss Valle and Patricia G. Parker 1.3. Evolution of Pathogens and Parasites on the Galapagos Islands Patricia G. Parker and Noah K. Whiteman 1.4. Turning Points in the Evolution of Vertebrates Eibl-Eibesfeld 1.5. The Boat, the Bay, and the Museum: Significance of the 1905-1906: Galapogos Expedition of the California Academy of Sciences Matthew James 1.6. Chapter Summary Part 2: Biodiversity Assessment and Monitoring of Change 2.1. Monitoring the Galapagos Ecosystem: Challenges, Pitfalls and a Vision for the Future James P. Gibbs and Bryan Milstead 2.2. The Neglected Majority - Biodiversity Inventories as an Integral Part of Conservation Biology Frank Bungartz 2.3. The Power of Long-Term Monitoring to Understand Mechanisms of Ecosystem Change: the Case of the Galapagos Marine Reserve Stuart Banks, Rodrigo Bustamante, Diego Ruiz, Natalia Tirado, Mariana Vera and Franz Smith 2.4. Wildlife Health Monitoringand Disease Management Protecting the Biodiversity of Galapagos Patricia G. Parker and Sharon L. Deem 2.5. Chapter Summary Part 3: A Systemic Approach: Modeling and Restoration 3.1. A Review of 40 Years of Eradication Programs in Galapagos: Impacts on the Whole Ecosystem Rachel Atkinson, Mark Gardener, Grant Harper and Victor Carrion 3.2. Food Web Structure of the Galapogas Pelagic Econosystem after a Decade of Protective Insights from Trophic Modelling Matthias Wolff and Cesar Penaherrera 3.3. Mediated Modelling: A System Dynamics Approach To Environmental Consensus Building for the Galapagos Marjan van den Belt 3.4. Chapter Summary Part 4: Reconciliation of the Conservation with Socio-Economic Development 4.1. The Value of Ecosystem Services and Biodiversity Conservation: A Challenge for the Galapagos Robert Costanza