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This report contributes to the understanding of how the the socio-economic contribution of Nordic fisheries/aquaculture are affected by the environment and environmental management, with focus on nitrogen. The report contains two case studies of how the socio-economic contribution of Danish/Swedish cod fishery in the Western Baltic Sea are affected by the nitrogen in the sea, and on how salmon growth rates in aquaculture in the Bokna Fiord are affected by nitrogen concentration. A Nordic workshop was held with the title: Fisheries, aquaculture and the marine environment: Environmental challenges and regulation, with focus on nitrogen. The finding of the case studies was presented at the workshop, together with presentations made by invited speakers on the role of nutrients and their management for Nordic fisheries/aquaculture. The discussion at the workshop is summarized in this report.

Trabajo presentado en la MareFrame Final Meeting (MareFrame Policy & Scientific Days / Conference Co-creation of Ecosystem Based Fisheries Management - MareFrame final meeting), celebrada en Bruselas el 13 y 14 de diciembre de 2017.

The ICES herring assessment working group (HAWG) met for seven days in March 2017 to assess the state of five herring stocks and four sprat stocks. HAWG also provided advice for seven sandeel stocks but reported on those prior to this meeting. The working group conducted update assessments for five of the herring stocks. An analytical assessment was performed for North Sea sprat and data limited assessments were conducted for English Channel sprat, Celtic Sea sprat and 3.a sprat.The North Sea autumn spawning herring SSB in 2016 was estimated at 2.20 m tonnes while F2–6 in 2016 was estimated at 0.26, at the management plan target F2-6 and below Fmsy. Fishing mortality on juveniles, mean F0-1 is 0.05, just below the agreed ceiling. Recruitment in 2017 is estimated to be very low. The estimate of 0-wr fish in 2016 (2015 year class) is estimated to be at approximately 29 billion, being low but in line with recent recruitment. Year classes since 2002 are estimated to be consistently week with year classes 2002 to 2007 to be among the weakest. ICES considers that the stock is still in a low productivity phase. The Western Baltic spring spawning herring assessment was updated. The SSB in 2016 was relatively stable compared to recent years and is estimated to be around 97 000 tonnes. Fishing mortality has been estimated at 0.41 and seems to have increased again after a period of reductions. It is above the estimate of Fmsy (0.32). Recruitment in 2016 is very low and potentially the lowest in the time-series. Under an historical perspective the estimates of SSB are considered still low, and the stock seems not to be able to recover to these higher biomass levels. The Celtic Sea autumn and winter spawning stock is estimated to be at a low level, declining from a recent high biomass that peaked in 2011. SSB is currently estimated at 46 000 tonnes in 2016, coming down from 140 000 tonnes in 2011. Mean F (2–5 rings) was estimated at 0.4 in 2016, having increased from 0.07 in 2009. Recruitment has been good in recent years with several strong cohorts (2003, 2005, 2007, 2011, 2012) entering the fishery but has come down substantially in the most recent years with the poorest year class in 2015. The 2016 SSB estimate of 6.a/7.b, c herring (the combined stock of 6.aN and 6.aS/7.b, c) was 151 000 tonnes, well below Bpa. Low recruitment has caused a decline of the stock while fishing mortality is low at 0.05-0.1 in recent years. Advice has been drafted to setup a monitoring fishery to ensure data relevant for the assessment and genetic studies are secured. Irish Sea autumn spawning herring was benchmarked in 2017 and the assessment shows a stable SSB in 2016 compared to previous years at around 26 000 tonnes, estimated substantially higher than pre-benchmark. The stock increased owing to large incoming year classes in most recent years. Fishing mortality is estimated at the lowest level in the time series at 0.17, below Fmsy. Catches have been relatively stable since the 1980s, and close to TAC levels in recent years. North Sea sprat came down from a time-series high since the early ’80, driven by high recruitment in 2014 and shows another increase owing to the 2016 year class. The stock appears to be well above Bpa (142 000 t) in 2016 at 246 170t. Fishing mortality in the last years has fluctuated between 0.4–1.6. Expected recruitment for 2017 is estimated to be in line with long-term recruitment. Sprat in Division 3.a was benchmarked in 2013 (WKSPRAT) but an analytical assessment is not presented. Short term projections are to be based on a combination of indices providing in year advice for 3.a based on the ICES approach for data limited stocks (Category 3 / 4). (Category 3/4). The surveys show variability over time without a clear trend. The most recent change is negative compared to the 4 years before. Catch advice for sprat in the English Channel (7.d, e) was based on criteria for data limited stocks. Data available are landings and a short time series of acoustic biomass (2013–2016). The acoustic biomass indicates a decline in the stock. Quantitative advice was provided for Sprat in the Celtic Sea (spr-irls) based on criteria for data limited stocks where only data on landings are available. The HAWG reviewed the assessments performed on seven sandeel stocks and the related advice of these stocks. Section 11 of this report contains the assessment of sandeel in Division 3.a and Subarea 4.Standard issues such as the quality and availability of data, estimating the amounts of discarded fish, availability of data through industry surveys and scientific advances relevant for small pelagic fish were discussed.All data and scripts used to perform the assessment and perform the forecast calculations are available on GitHub and accessible to anyone.

Trabajo presentado en la MareFrame Final Meeting (MareFrame Policy & Scientific Days / Conference Co-creation of Ecosystem Based Fisheries Management - MareFrame final meeting), celebrada en Bruselas el 13 y 14 de diciembre de 2017.

Three meetings were held between 2013 and 2015 (Stockholm, London and Woods Hole), with progress being made on all the Terms of Reference. WGSAM has been making significant contributions required to enable ICES to develop its capability to give advice on the ecosystem impacts of fishing and climate change. This is a priority area identified in the ICES strategic plan and is consistent with scientific needs to support implementation of the Common Fisheries Policy and Marine Strategy Framework Directive. This final report summarises the key progress made against each ToR. A particularly important area established during this period has been the discussions that have led to guidelines on quality assurance of ecosystem models in-tended for advice giving. WGSAM prepared a specific briefing on this issue and con-tinues to work on issues related to model review processes, model validation and developing methods for generating advice from multi-model ensembles. These are all important areas of work in the evolution toward giving integrated, ecosystem-based advice to ICES clients. We recommend that ICES supports continuation of WGSAM new ToRs and considers more specifically how to support WGSAM in developing advice relevant products.

Spatio-temporal density-dependent processes are crucial regulatory factors for natural populations. However, there is a lack of studies addressing spatial density-dependence in fish growth. A previous investigation has suggested spatio-temporal density-dependence in body condition of Baltic sprat. Here, we used different techniques, such as centre of gravity, distance, and homogeneity indices, to better characterize the spatial and temporal variations in sprat density and body condition in the Baltic Proper. Our results evidenced a negative spatio-temporal co-variation between the centres of gravity of density and maximum condition. In the 1980s-early 1990s both centres were located in the middle of the Baltic Proper. From the mid 1990s the centres progressively separated in space, as the sprat population moved towards the north-eastern Baltic Proper, and the centre of maximum condition towards the south-western areas. Moreover, at low abundances, sprat density and condition were homogeneously distributed in space, whereas at high abundances both density and condition showed pronounced geographical gradients. The ecological processes potentially explaining the observed patterns were discussed in the light of the Ideal Free Distribution theory. We provide evidence that the shift in the spatial distribution of cod, the main predator of sprat, has been the main factor triggering the overall spatial changes in sprat density, and thus condition, during the past thirty years. The spatial indices shown here, synthesizing the spatio-temporal patterns of fish distribution, can support the implementation of the EU Marine Strategy Framework Directive.

The present doctoral thesis investigated fundamental aspects of temporal and spatial dynamics of hake (Merluccius merluccius) recruitment in the Tyrrhenian and Ligurian Sea (Mediterranean). We identified recruit and post-recruit as two well distinct phases of hake juvenile life stage according to a marked bathymetric segregation. Hake juveniles enter the post-recruit stage at a length range between 13.2 cm and 15.8 cm through a sharp migration from the margin of the shelf-break and upper slope to the shallower continental shelf waters. Spatial models provided accurate identification of the main areas of aggregation of hake recruits before their migration and spreading on the shelf. We found that nurseries in the Tyrrhenian and Ligurian Sea are characterised by some of the highest densities of recruits observed in the Mediterranean, suggesting these areas could play an important role for the dynamics of hake population at a larger scale far beyond the study area. The analysis of time series data for two different periods of the year demonstrated an inter-annual and seasonal stability in the spatial location of the main nursery areas and a strong association for specific habitats of the shelf-break. Together with these main nurseries, a certain number of secondary nurseries were detected only in certain years, but their variability and importance for the population remain to be addressed. Wide fluctuations in the abundance of hake recruits were found to be strongly influenced by both oceanographic and biological processes. Thermal anomalies in summer, characterised by high peaks in water temperature, revealed a negative effect on the abundance of recruits in autumn, possibly due to a reduction in hake egg and larval survival rates. Recruitment was also reduced when elevated sea-surface temperatures in summer were coupled with low levels of water circulation. Enhanced spring primary production related to late winter low temperatures are known to affect water mass productivity in the following months, and according to our results hake spring recruitment. We found a dome-shaped relationship between wind mixing in early spring and recruitment that was interpreted as an “optimal environmental window” in which intermediate water mixing level can play a positive role in phytoplankton displacement, larval feeding rate and appropriate larval drift. The temporal and spatial persistence of hake nurseries represented fundamental features for testing the effects of a spatial management of the population particularly during the highly vulnerable recruit phase. The effect of different levels of protection on recruits were tested through model simulations and compared with a more general reduction of fishing effort, providing unexpected results on the mature portion of the population. Partially funded by BECAUSE project (Critical Interactions BEtween Species and their Implications for a PreCAUtionary FiSheries Management in a variable Environment — a Modelling Approach), EU contract no. 502482.

Maiorano, L., Bartolino, V., Colloca, F., Abella, A., Belluscio, A., Carpentieri, P., Criscoli, A., Jona Lasinio, G., Mannini, A., Pranovi, F., Reale, B., Relini, G., Viva, C., and Ardizzone, G. D. 2009. Systematic conservation planning in the Mediterranean: a flexible tool for the identification of no-take marine protected areas. – ICES Journal of Marine Science, 66: 137–146. We propose the use of systematic conservation planning in the Mediterranean context for the identification of no-take marine protected areas (NTMPAs). We suggest a logical framework that should be used for the identification of areas to be targeted for multispecies, spatially explicit conservation actions. Specifically, we propose seven steps: (i) definition of the study area; (ii) selection of the species or habitats to be considered; (iii) definition of the planning units; (iv) measurement of the fishing effort; (v) definition of the conservation targets; (vi) review of the existing conservation areas; (vii) selection of additional NTMPAs. Moreover, we consider the potential impact of different conservation plans on existing fishing vessels. A working example is presented, focusing on a limited number of species and on a limited study area. This framework can be easily expanded to include datasets of different origin and to accommodate larger spatial scales. Such a process involves major data-collection and capacity-building elements, and conservation of productive commercial fisheries must be a priority.

The vertebral system in Hippocampus hippocampus is highly specialised because of the vertical locomotion and tail prehensility. The vertebral elements represent a special case of morphological changes, being the metameric structures organised along a natural functional series. We investigated the shape changes along the vertebral spine in H. hippocampus through geometric morphometrics, in order to describe functional and structural patterns. Actually, the dorso-ventral tail bending ability in the genus Hippocampus is one of the most impressive morphological modifications in the evolutionary history of fishes. Vertebrae were analysed using a 2D configuration from the left lateral view. The variation along the vertebral series suggests the identification of cervical, abdominal, dorsal, and caudal groups. The first three (cervical) elements and the lOth (supra-dorsal) structure show peculiar morphologies and local adaptations, associated with neck angulation and dorsal fin muscles, respectively. The vertebral size decreases from the anteriormost element backward, with some local variation at the dorsal area. Major changes are related to allometric variation at the neural región. The caudal elements are characterised by a marked size decrease, with consequent allometric shape changes involving the rotation of the posterior vertebral opening. This allometric trajectory leads to a natural ventral bending of the tail, promoting its prehensile function. This morphological survey suggests an interesting structural network between posture, locomotion, and vertebral anatomy, underlying the main functional changes in the Hippocampus biomechanics. Geometric morphometrics is rather suitable to approach metameric studies in terms of serial variation and functional adaptations. El sistema vertebral en Hippocampus hippocampus es altamente especializado, debido a la locomoción vertical y la cola prehensible. Los elementos vertebrales representan un caso especial de cambios morfológicos, siendo estructuras metaméricas organizadas a lo largo de una serie funcional natural. Se investigaron los cambios en la forma, a lo largo de la columna vertebral en H. hippocampus a través de morfometría geométrica, con el fin de describir sus patrones funcionales y estructurales. Actualmente, la capacidad de flexión dorso-ventral de la cola en el género Hippocampus es una de las más impresionantes modificaciones morfológicas en la historia evolutiva de los peces. Las vértebras se analizaron mediante una configuración 2D de la vista lateral izquierda. La variación a lo largo de la serie vertebral sugiere la identificación de grupos cervicales, abdominales, dorsales, caudales. Los tres primeros elementos (cervicales) y la 10ª (supra-dorsal) muestran una estructura morfológica peculiar y adaptaciones locales, asociadas con la angulación del cuello y los músculos de la aleta dorsal, respectivamente. El tamaño vertebral disminuye desde elemento más anterior hacia atrás, con algunas variaciones locales en la zona dorsal. Los principales cambios están relacionados con la variación alométrica en la región neural. Los elementos caudales se caracterizan por una marcada disminución de tamaño, con los consiguientes cambios en la formas aloméricas de rotación de la abertura vertebral posterior. Esta trayectoria alométrica conduce a una flexión ventral natural de la cola, promoviendo su función prensil. Este estudio morfológico sugiere una interesante red estructural entre postura, locomoción y la anatomía vertebral junto a los principales cambios funcionales en la biomecánica de Hippocampus. La morfometría geométrica es bastante adecuada para los estudios con enfoques metaméricos, en términos de variación de serie y adaptaciones funcionales.

Hake recruitment has been examined in relation to environmental variables in two of the main reproductive areas of the central Mediterranean, the northern and central Tyrrhenian Sea. Seventeen years time series data from trawl surveys revealed high fluctuations in recruit abundance that could not be just explained by spawning biomass estimations. Generalized additive models were developed to investigate hake recruitment dynamics in the Tyrrhenian Sea in relation to spawner abundance and selected key oceanographic variables. Environmental data were explored in attempt to explain survival processes that could affect early life history stages of hake and that accounted for high fluctuations in its recruitment. Thermal anomalies in summer, characterised by high peaks in water temperature, revealed a negative effect on the abundance of recruits in autumn, probably due to a reduction in hake egg and larval survival rates. In the northern Tyrrhenian, recruitment was reduced when elevated sea-surface temperatures were coupled with lower levels of water circulation. Enhanced spring primary production, related to late winter low temperatures could affect water mass productivity in the following months, thus influencing spring recruitment. In the central Tyrrhenian a dome-shaped relationship between wind mixing in early spring and recruitment could be interpreted as an “optimal environmental window” in which intermediate water mixing level played a positive role in phytoplankton displacement, larval feeding rate and appropriate larval drift. Results are discussed in relation to the decline in hake stock biomass and within the present climate change and global warming context.

The caudal skeleton is one of the most important tools to evaluate teleostean interrelationships, but just the anatomy of few species have been investigated. Black-striped pipefish (Syngnathus abaster) has never been examined for its caudal morphology. Here, red alizaryn is applied as specific staining for calcified structures, providing a better understanding of caudal skeleton organization. Our results and interpretation just partially fit with previous knowledge on other Syngnathus species. This emphasizes both the importance of facing same problems with new technics and methodologies, and the existence of a heterogeneous situation between close-related taxa El esqueleto caudal es una de las más importantes herramientas para evaluar las interrelaciones de teleósteros, pero la anatomía de pocas especies han sido investigada. Nunca se ha estudiado la morfología de la cauda del pez aguja de río de rayas negras (Syngnathus abaster). Se usó una técnica específica de tinción con alizarina roja, para visualizar estructuras calcificadas, obteniéndose un gran conocimiento de la organización del esqueleto caudal. Los resultados e interpretación de ellos coinciden parcialmente con los hallazgos en otras especies de Syngnathus. En ambos casos se enfatiza la importancia de tratar los problemas con nuevas técnicas y metodologías