Observaciones sobre las madrigueras y comportamiento enterrador de Brachynotus gemmellari y otras especies de los fondos de Squilla en Ancona, Adriático Central

The paper presents information on the burrows of a number of species that occur on Squilla grounds in the coastal Adriatic off Ancona, Italy. The burrows and burrowing behaviour of Brachynotus gemmellari are described for the first time. For Upogebia tipica, Solecurtus strigilatus and Gobius niger, the observations add to sparse burrow information in the literature. Little is known of the burrows of Echiura in the Mediterranean: those of two species are briefly described from surface features.Este trabajo presenta información sobre las madrigueras de diversas especies presentes en los fondos de Squilla en las costas de Ancona, Italia, en el Adriático central. Se describen por vez primera las madrigueras y el comportamiento excavador de Brachynotus gemmellari. En el caso de Upogebia tipica, Solecurtus strigilatus y Gobius niger, las presentes observaciones se añaden a información dispersa sobre las madrigueras de Echiura en el Mediterráneo: se describen brevemente las de dos especies a partir de características de la superfície

An observing system for the collection of fishery and oceanographic data

Fishery Observing System (FOS) was developed as a first and basic step towards fish stock abundance nowcasting/forecasting within the framework of the EU research program Mediterranean Forecasting System: Toward an Environmental Prediction (MFSTEP). The study of the relationship between abundance and environmental parameters also represents a crucial point towards forecasting. Eight fishing vessels were progressively equipped with FOS instrumentation to collect fishery and oceanographic data. The vessels belonged to different harbours of the Central and Northern Adriatic Sea. For this pilot application, anchovy (<I>Engraulis encrasicolus</I>, L.) was chosen as the target species. Geo-referenced catch data, associated with in-situ temperature and depth, were the FOS products but other parameters were associated with catch data as well. MFSTEP numerical circulation models provide many of these data. In particular, salinity was extracted from re-analysis data of numerical circulation models. Satellite-derived sea surface temperature (SST) and chlorophyll were also used as independent variables. Catch and effort data were used to estimate an abundance index (CPUE – Catch per Unit of Effort). Considering that catch records were gathered by different fishing vessels with different technical characteristics and operating on different fish densities, a standardized value of CPUE was calculated. A spatial and temporal average CPUE map was obtained together with a monthly mean time series in order to characterise the variability of anchovy abundance during the period of observation (October 2003–August 2005). In order to study the relationship between abundance and oceanographic parameters, Generalized Additive Models (GAM) were used. Preliminary results revealed a complex scenario: the southern sector of the domain is characterised by a stronger relationship than the central and northern sector where the interactions between the environment and the anchovy distribution are hidden by a higher percentage of variability within the system which is still unexplained. <br><br> GAM analysis showed that increasing the number of explanatory variables also increased the portion of variance explained by the model. Data exchange and interdisciplinary efforts will therefore be crucial for the success of this research activity

Whiting (Merlangius merlangus) Grows Slower and Smaller in the Adriatic Sea: New Insights from a Comparison of Two Populations with a Time Interval of 30 Years

Nowadays, overexploitation and climate change are among the major threats to fish production all over the world. In this study, we focused our attention on the Adriatic Sea (AS), a shallow semi-enclosed sub-basin showing the highest exploitation level and warming trend over the last decades within the Mediterranean Sea. We investigated the life history traits and population dynamics of the cold-water species whiting (Merlangius merlangus, Gadidae) 30 years apart, which is one of the main commercial species in the Northern AS. The AS represents its southern limit of distribution, in accordance with the thermal preference of this cold-water species. Fish samples were collected monthly using a commercial bottom trawl within the periods 1990–1991 and 2020–2021. The historical comparison highlighted a recent reduction in large specimens (>25 cm total length, TL), which was not associated with trunked age structures, therefore indicating a decrease in growth performance over a period of 30 years (L∞90–91 = 29.5 cm TL; L∞20–21 = 22.8 cm TL). The current size at first sexual maturity was achieved within the first year of life, at around 16 cm TL for males and 17 cm TL for females. In the AS, whiting spawns in batches from December to March, showing a reproductive investment (gonadosomatic index) one order of magnitude higher in females than in males. Potential fecundity (F) ranged from 46,144 to 424,298, with it being heavily dependent on fish size. We hypothesize that the decreased growth performance might be related to a metabolic constraint, possibly related to the increased temperature and its consequences. Moreover, considering the detrimental effects of size reduction on reproductive potential, these findings suggest a potential endangerment situation for the long-term maintenance of whiting and cold-related species in the AS, which should be accounted for in setting management strategies

Stock status and potential yield of deep water rose shrimp (Parapenaeus longirostris, Lucas 1846) in the south-central Mediterranean Sea

This document summarises the data used, methods adopted and the results of the joint stock assessment carried out during the MedSudMed and CopeMed II Working Groups on Parapenaeus longirostris and related fisheries held in 2009 and 2010 in Malta and Italy respectively. The aim of this document is to describe the state of the stock of P. longirostris in the south-central Mediterranean Sea using data from Italy, Tunisia and Malta. The long term objective of this study is to provide the baseline for the establishment of a harmonised management regime for the deep water rose shrimp fishery in the south-central Mediterranean Sea. Overall, fishery dependent data from Italy, Malta and Tunisia for the first time were pooled together and jointly processed. The assessment was performed using length cohort analysis (LCA) and biomass and yield per recruits analyses as implemented in VIT4Win. Current mean fishing mortality and exploitation pattern were assessed using the steady state LCA on length frequency distributions (LFD) of 2007, 2008 and 2009 as well as the average 2007-2009 catches, raised to the total landings. Analyses were performed separately by keeping sex and fleet segments separate (i.e. Italy 12-24; Italy > 24; Tunisia; Malta) as first step. A sensitivity analysis was also carried out as implemented in VIT. The results are discussed in the view of providing robust technical advice for the management of national fisheries exploiting P. longirostris in the MedSudMed area taking into account the possible evolution of national fisheries. Some perspective for future joint activities to be carried out within the cooperative framework established by the FAO Projects are also presented.peer-reviewe

The Mediterranean fishery management: A call for shifting the current paradigm from duplication to synergy

Independence of science and best available science are fundamental pillars of the UN-FAO code of conduct for responsible fisheries and are also applied to the European Union (EU) Common Fishery Policy (CFP), with the overarching objective being the sustainable exploitation of the fisheries resources. CFP is developed by DG MARE, the department of the European Commission responsible for EU policy on maritime affairs and fisheries, which has the Scientific, Technical and Economic Committee for Fisheries (STECF) as consultant body. In the Mediterranean and Black Sea, the General Fisheries Commission for the Mediterranean (FAO-GFCM), with its own Scientific Advisory Committee on Fisheries (GFCM-SAC), plays a critical role in fisheries governance, having the authority to adopt binding recommendations for fisheries conservation and management. During the last years, advice on the status of the main stocks in the Mediterranean and Black Sea has been provided both by GFCM-SAC and EU-STECF, often without a clear coordination and a lack of shared rules and practices. This has led in the past to: i) duplications of the advice on the status of the stocks thus adding confusion in the management process and, ii) a continuous managers’ interference in the scientific process by DG MARE officials hindering its transparency and independence. Thus, it is imperative that this stalemate is rapidly resolved and that the free role of science in Mediterranean fisheries assessment and management is urgently restored to assure the sustainable exploitation of Mediterranean marine resources in the future.En prens

Aspects of the early life history of European hake from the central Adriatic

During early development, the left and right sagittae of European hake Merluccius merluccius showed dimorphism in both size and shape due to the different number and size of accessory primordia. Juvenile hake reached the total length (L(T)) of 15 cm in c. 1 year, with monthly growth rates ranging from 1·6 cm month-1 in the third month of life to 1·1 cm month-1 towards the end of the first year. Back-calculated hatch-date distribution indicated continuous spawning with a peak in summer and a second, less evident, peak in February-March. The presence of early demersal juveniles (16-30 mm L(T), c. 40 days old) very close to the Pomo pit area (Central Adriatic Sea) at c. 140 m depths indicates that the change from the pelagic to the demersal phase takes place at c. 40 days close to the area of concentration of juveniles. The daily-increment hypothesis was validated indirectly. (C) 2000 The Fisheries Society of the British Isles.This study was partially supported by the European Union (contract XIV/C/1 MED 1991/003) and by a bilateral agreement between Consiglio Nazionale delle Ricerche (Italy) and Consejo Superior de Investigationes Cientificas (Spain).Peer Reviewe

Ecosystem assessment of the North-Central Adriatic Sea: towards a multivariate reference framework

We analyzed data from catch statistics, scientific surveys and results from ecosystem models to assess main changes in marine resources of the North-Central Adriatic Sea (Central Mediterranean) from the mid 1970s to the early 2000s. We then quantified food-web changes using these datasets and trophodynamic indicators. We applied time series trends and a Principal Component Analysis (PCA) to reduce the number of multivariate dimensions and to define ecosystem reference directions. To assess the correlation between ecological indicators and abiotic (human or environmental)factors, we used the non-parametric BIO-ENV procedure. Results illustrated a general decrease in the biomass and catch of target species with time, with a first phase of increasing catch and biomass of some organisms from the 1970s to the 1980s, a \u27fishing down the food web\u27 process during the 1980s, and a clear trend towards biomass and catch reductions during the late 1990s and early 2000s. These changes occurred in parallel with an increase in fishing effort and human development in the basin and changes in environmental factors such as an increase in the average annual sea water temperature, a decrease in the inflow of highly saline Mediterranean water into the Adriatic Sea, and changes in the atmospheric pressure at sea level. We found a high and significant correlation between ecological indicators and abiotic factors (in particular with human factors: fishing effort and the human development index). Results from the PCA summarized main ecosystem trends and could be used as a reference framework. These results complement traditional single-species fisheries assessments and inform on past trajectories and present ecological status of the North-Central Adriatic Sea