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This study reports the reproductive cycle, condition index, size at first maturity, growth and the morphometric relationships of the common cockle Cerastoderma edule in Ria de Aveiro (NW Portugal), fundamental knowledge in fisheries management planning and ecosystem conservation. The reproductive cycle was monitored for a period of two years, from January 2013 to December 2014. Spawning extended from June to October, with a peak in the summer months (July to September). The condition index showed a seasonal pattern which appear related to food availability and gametogenic cycle. Sexual maturity was attained at a shell length of 18.6 mm during the first year of life, which stands below the minimum landing size currently in force (25 mm). The von Bertalanffy growth equation was based on size-at-age data obtained from the microscopic analysis of growth rings in sectioned shells: Lt = 40.7[1-e −0.74(t-0.30)]. The morphometric relationships between shell dimensions (length, height and width) were studied in order to understand the effects of ontogenetic changes in cockles` shell morphology, an information that is useful to improve the selectivity of the fishing gears and the size-sorting devices. Some management strategies for the Ria de Aveiro cockle fishery were proposed.

Understanding the diversity and community composition of marine communities in coastal areas is of utmost importance to understand how overlapping anthropogenic pressures impact the marine environment. The demersal and epibenthic communities of the Portuguese northern continental shelf were surveyed using a bottom trawl to understand their taxonomic composition, abundance, spatial distribution, and their relationship with environmental variables such as sediment, organic matter, depth and latitude. Bottom sediments were homogenous, being mainly composed by sand particles. The diversity of the study area was low, but high abundance of important commercial species, as Trisopterus luscus, Trachurus trachurus, Palaemon serratus and Merluccius merluccius, in the juvenile stage of life, points out the importance of the area as nursery grounds. Four assemblages were identified, with a visible geographical pattern. Results obtained supply background information that may contribute to the development of future management and monitoring plans for this important and sensible coastal area. Project PRESPO 2008-1/038; PD/BD/135065/2017 info:eu-repo/semantics/publishedVersion

Coastal bivalve populations are characterized by large temporal fluctuations, driven by recruitment success dependent on environmental conditions. The present study evaluated the relationship of rainfall, chlorophyll-α, sea surface temperature (SST) and wind, with the biomass of four commercial bivalve species (Spisula solida, Donax trunculus, Chamelea gallina and Ensis siliqua) that occur both along the Barlavento (western region), and the Sotavento (eastern region), along the South coast of Portugal, between 1999 and 2011. Multiple regression models were used to test two hypotheses: a) the association between environmental conditions three months prior to the spawning period and the biomass in the following year (response variable) and b) the association between environmental conditions during the spawning season plus one month and the biomass in the following year. Wind was not included in the model to test a). The environmental variables considered were not important for E. siliqua. In the period prior to spawning, temperature was significant for S. solida (both study areas), rain for D. trunculus and C. gallina (western area) and chlorophyll-α for C. gallina (western area). All the correlations were positive. During the spawning period, rain was significant for all three species but with different trends. The correlation with rain in months early in the spawning season was positive for S. solida (both areas) and D. trunculus (western area). The correlation with the rain in months towards the end of the spawning period was negative for D. trunculus, and C. gallina (western area). Chlorophyll-α in months at later stages of spawning was significant and positive for D. trunculus (both areas) and C. gallina (western area). The wind, expressed as an index developed to indicate the overall occurrence of winds blowing parallel to the coast (assumes to favour the retention of larvae in appropriate environments), was negatively correlated with biomass for mid to late spawning season for S. solida (eastern area) and D. trunculus (western area). For C. gallina there was a positive correlation with wind early in the spawning season. The SST was not an important variable during the spawning period with the exception of D. trunculus where the temperature at mid spawning season was significant with a negative correlation in the western coast and positive in the eastern coast. This study highlighted the annual spatial distribution of four commercially important bivalves and how environmental factors are likely to play an important role on both biomass and location of the fishing beds. Monitoring of the environmental variables could provide information to predict biomasses of bivalve species, an important tool for its management, as well as predict trends and plan strategies in response to global environmental changes. info:eu-repo/semantics/publishedVersion

The epifauna associated to farmed mussels in southern Portugal coast was analysed, aiming at identifying the species with spreading potential through commercial transport. The presence of a relevant number of the species here found is not reported to at least one of the common mussel export/transposition countries. Indeed, important species biogeographic dissimilarities between the mussel farm area and the Greater North Sea and Western Mediterranean Sea sub-regions were detected, suggesting the potential transport of non-indigenous species (NIS) into other countries. Among them, fouling species such as the anemones Paractinia striata and Urticina felina, the acorn barnacles Balanus glandula and Balanus trigonus or the bryozoans Bugulina stolonifera and Schizoporella errata exhibit functional attributes that allow them to colonise and spread in new areas. This combined biogeographic and functional approach may contribute to clarify the role of aquaculture on the transport of NIS and to predict and prevent their spreading worldwide. info:eu-repo/semantics/publishedVersion

A multimetric approach was used to detect structural, compositional, and functional shifts in the underlying macrobenthic communities of an offshore mussel (Mytilus galloprovincialis) farm in a Portuguese Aquaculture Production Area. Sampling stations distributed inside and outside this area were used to evaluate sediment descriptors and macrobenthic samples collected before (April and September 2010) and after (June and September 2014) the initiation of mussel farming. Sediment fine fraction, organic matter content, and trace element concentrations were found to increase with depth, independently from the mussel farm. Moreover, the structure and composition of the macrobenthic communities were likewise structured by depth. Turnover was the dominant temporal and spatial pattern of beta diversity for all communities. Furthermore, the functional diversity of these communities was unaffected by the mussel farm. These results suggested that an offshore profile allowed hydrodynamic conditions to weaken the impact of mussel farming and highlighted the importance of conducting an integrative multimetric analysis when studying aquaculture impacts on benthic communities. FEDER Program through the project IAPAA "Avaliacao do impacto da area de producao aquicola da Armona no ecossistema costeiro e comunidades locais" (PROMAR project) [31-03-01-FEP-0014]

Macrobenthic responses to dredging activities were evaluated in a mesotidal coastal lagoon (Ria Formosa South Portugal). Four areas (2 dredged and 2 non-dredged) were analysed along different dredging situations (pre-dredging, during dredge 1, during dredge 2 and post-dredging). Beyond the evaluation of sediment descriptors and classical ecological indicators (number of species and abundance), the beta diversity component (partitioned into turnover and nestedness) was used to detect dredging effects on macrobenthic communities, together with a multivariate analysis (both quantitative and qualitative) including the ecological status assessment. Results confirmed the limitations of alpha diversity indicators in detecting dredging effects in naturally stressed systems, given the absence of clear patterns regarding number of species, abundance and equitability among areas and dredging situations. Moreover, post-dredging presented a higher number of species compared to pre-dredging, suggesting a positive disequilibrium induced by these activities. In contrast, partitioned beta diversity analysis revealed higher nestedness values at dredged areas, while turnover clearly prevailed at non-dredged ones. Such results suggest an effective impact of dredging on these communities, namely through the decrease of rarer species after sediment removal. This qualitative analysis, based on presence absence data (Sorensen dissimilarity), was complemented by multivariate analysis (SIMPER and PERMANOVA) based on quantitative data (Bray-Curtis dissimilarity), highlighting the importance of adopting both approaches to detect dredging impacts on benthic communities. Lower effectiveness was found for M-AMBI index when evaluating benthic Ecological Status, since the apparent absence of organic matter and sediment composition shifts induced by dredging, together with the noticeable high diversity even during dredging situations, strongly limited the analysis. The multimetric approach here proposed can contribute to detect dredging effects on lagoonal benthic communities by disentangling the responses caused by dredging from those resulting from the system natural dynamics. society "Polls Litoral Ria Formosa"

Guyader, O. ... et. al.-- 13 pages, 6 figures, 3 tables, Small-scale fisheries have traditionally received less research effort than large-scale fisheries and are generally under-studied in Europe. In spite of their comparatively low volume of catches and economic importance, small-scale fisheries are socially important and an integral part of the European coastal zone. Considering the high heterogeneity of situations and the paucity of quantitative data, we used an analytical methodology based on the comparative method. We carried out an analysis of small-scale fisheries (SSFs) in Europe based on a selection of nine case studies. Our objective was to obtain a comprehensive description of small-scale fleets covering different areas/fisheries/species, encompassing the diversity and specific conditions under which SSFs operate, in order to demonstrate the ecological and social sustainability of this often overlooked fisheries segment. A common approach formulated so that the case studies could be compared with the case histories of other competing users, required that for each set of criteria - technical, biological, socio-economic, and institutional - a set of relevant items and indicators was established. An analysis of characteristics common to the selected case studies is conducted and an attempt made to extend our comparisons to the whole of the European Union. Our results show that (as compared with large-scale fleets, their main competitor) small-scale fleets: (i) are composed of smaller vessels and, consequently, travel lower distances to fishing grounds, and are more reliant on coastal areas; (ii) have smaller crews (although the global employment figure is similar to that of large-scale fleets in Europe); (iii) use mostly, but not exclusively, passive gears; (iv) use multi-purpose fishing approaches, and can change the fish species they target during the year; (v) have lower extraction rates; (vi) have lower total capital investments (including fishing rights), turnover and costs; and (vii) have lower fuel consumption, making them less sensitive to changing oil prices. Dependence on subsidies is lower (viii). Involvement in fisheries management is variable, conservation and access regulation measures are largely local in origin. For the selected case studies, the most significant competitors are large-scale fleets, and recreational fisheries, but other sources of interaction (water quality, invasive species, etc.) cannot be ignored. © 2012 Elsevier B.V., The study was prepared with the financial support of the European Commission (contract FISH/2005/10)

The present study aimed to assess short-term effects of intertidal bait digging on macrobenthic assemblages of two south Iberian Atlantic coastal systems: the Ria Formosa (RF) lagoon and the Bay of Cádiz (BC). Within each system, two different areas were selected. In each area, six plots were randomly located at least 1m apart from each other. Half of the plots were left undisturbed (control) and the other three were dug (disturbed). Three macrobenthic core samples were taken from each plot, immediately before, one, four and seven days after digging. Samples for analyses of grain-size and organic matter content (OM) were also collected from the top 2cm sediment layers in each sampling period. The effects of bait digging were site specific and were related to sediment and biological composition of the areas before disturbance. Macrobenthic assemblages from the area with proportionally less mud content (RF1), which presented the greatest infaunal diversity and evenness values before disturbance, showed minor effects of digging and assemblages generally recovered within 7 days. On the other hand, the areas located in the Bay of Cádiz, which before disturbance presented the greatest mud content and macrobenthic assemblages dominated by only a few species, were the most affected and did not show signs of total recovery within 7 days after digging. The abundance of sedentary polychaetes from families Spionidae, Capitellidae and Cirratulidae decreased after digging. In contrast, in some areas the abundance of the gastropods Bittium spp., Haminoea hydatis and Retusa truncatula increased after bait digging indicating that they are less affected by this activity. Differences were detected in the response of benthic assemblages to the same intensity, frequency and nature of disturbance between and within coastal systems. Therefore, generalizations of the effects of bait digging and in the recovery of macrobenthic assemblages in the south of Iberian Peninsula are not possible. © 2011 ., S. Carvalho benefited from a post-doctoral grant awarded by Fundação para a Ciência e a Tecnologia (SFRH/BPD/26986/2006).

The present chapter provides a brief review of the main impacts on coastal marine ecosystems resulting from fisheries and aquaculture activities. It covers a wide range of topics, including habitat degradation, fragmentation, and loss; changes in biodiversity, food webs, and trophic interactions; loss of genetic diversity; and spread of parasites and diseases. A number of worldwide case studies on mitigation measures are presented, providing examples of best practices aiming to reduce impacts on coastal marine environments. Several restoration initiatives are also described based on selected case studies. Finally, the importance of restoration methods, as ecohydrology, based on a holistic approach to manage ecosystems and revert degradation, is highlighted.

[Abstract] This study presents an analysis of the genetic diversity in Hexaplex trunculus from three localities of the southern Iberian Peninsula (Ria Formosa and Ria de Alvor in Portugal, and Río Piedras in Spain) using three mitochondrial (12S rRNA, 16S rRNA and cytochrome c oxidase subunit I, COI) and one nuclear (5S rRNA and its non-transcribed spacer, NTS) genes. Restriction digestions of 12S and 16S rRNA genes using four endonucleases were also performed. Low genetic diversity was observed for the four genes studied. Genetic distances ranged from 0 to 0.004 for the mitochondrial genes and these values were slightly higher for the 5S and the NTS. The level of polymorphism within populations, π, was from 0 to 0.0039 (for mitochondrial genes), 0.0111–0.0333 (for 5S rRNA), and from 0.2220 to 0.5079 (for NTS). Furthermore, RFLPs analyses from 12S and 16S rRNA genes showed these localities to be monomorphic. The low genetic variability within populations suggests small population size, and a possible bottleneck due to multiple causes, such as overexploitation, the type of larval development (intracapsular embryos) and/or the peripheral location of the sampled localities considering the geographical distribution of the species. Because these populations show such high genetic similarity, Ria de Alvor and Río Piedras could be potentially used for stock enhancement of the Ria Formosa. Portugal. Fundação para a Ciência e a Tecnologia; FCT: SFRH/BD/5139/2001

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In situ observations of clam dredging showed that the effects of the dredge on the benthic macrofauna may not be constant during a tow. A sand buffer forms in front of the gear approximately 10 m after the beginning of a tow, and this pushes the sediment partially aside. In this study, we analyse differences in abundance, the number of taxa present, diversity, and evenness within sections of dredge-tracks in a disturbed, fished area and a non-fished area along the southern coast of Portugal. These areas were sampled by divers before and after dredge-fishing activity. At each site, three dredge-tracks were produced. These tracks were divided in three longitudinal sections (start, middle and end) and two transverse sections (track and edge). Six quadrats were used to sample macrofauna in each section of every track and edge. Our results show differences exist in macrofaunal distribution and abundance across sections of a dredge-track. These differences should be considered in any assessment of the short-term ecological impact of dredges on benthic macrofauna.