Identification guide for cephalopod paralarvae from the Mediterranean Sea

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Effects of fishing restrictions on the abundance, size structure and mortality rate of a western Mediterranean population of Scorpaena scrofa (Linnaeus, 1758)

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Trophic interactions among grouper (Epinephelus marginatus), octopus (Octopus vulgaris) and red lobster (Palinurus elephas) in the Western Mediterranean

In the present paper a first evaluation of the trophic interactions between grouper, octopus and spiny red lobster in the western Mediterranean is presented. The efficiency of octopus preying on lobsters is also estimated from trap catches. Grouper and octopus base their diet on the same major taxonomic groups and this is reflected in the values of diet overlap. Trophic diversity of grouper and octopus is also very similar. The estimation of the octopus efficiency preying on lobsters shows that 23.5% of the attacks are successfulPublicado

The use of Artificial Neural Networks (ANNs) in aquatic ecology

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Life-history, ecology and fishery of Sepia officinalis in the western Mediterranean

Cephalopods constitute important resources for different Mediterranean fisheries such as trawl, artisanal and recreational fleets. Cuttlefish (Sepia officinalis) has been caught there from ancient times on and holds an important seasonal artisanal fishery in the Balearic Islands (western Mediterranean). This fishery takes advantage of the reproductive migration to coastal waters of large, mature individuals, even though the species is also taken by bottom trawlers throughout the year. In this study we used data from the following sources to analyze different aspects of cuttlefish biology, ecology and fishery in the western Mediterranean: 1) monthly biological and size samplings of individuals caught by artisanal boats (2007-08); 2) size samplings on board ofcommercial bottom trawlers (2001-11); 3) biological and size samplings on spring scientific surveys (2001-11); and 4) official fishery statistics from 1965 to the present. The main objectives of this study are twofold. First, use all this information to generate a comprehensive insight on the life cycle of this species linking ecology and life-history traits to seasonal fishery trends. Secondly, analyze interannual variations on landings and the relationship with different environmental parameters (e.g. moon, temperature, climatic indices). Biological (N=950 individuals) and size frequency samplings were used to estimate different species and population parameters such as length-weight relationships, sex- ratio, population structure and dynamics, gonadosomadic index and fecundity. The vast majority of individuals caught by the artisanal fishery between January and July were sexually mature, which confirms the reproductive migration to coastal waters during spring. The clear seasonal trend observed in cuttlefish landings also tallies with this migration, since catches show a marked peak in March-April. Although landings display a sawtooth like pattern from 1965 to 2011 with historical maximums in 1991 and 2005, there is a general increasing trend with time, especially from mid-1990

The importance of cephalopods to trawl fisheries in the western Mediterranean

The aim of the study was to define the commercial importance of cephalopods caught by trawlers from five Italian and Spanish Mediterranean ports. From summer 1995 to spring 1996, samples of the catches of trawlers were taken on board. The type of fishing activity was recorded and data were collected from at least three commercial hauls for each port, season and bathymetric stratum (350 m). The species composition and yield of the retained and discarded portions of the catch were noted for each port. From these data the commercial importance of each species was evaluated. Cephalopods were commercially important particularly in the shallower bathymetric stratum

Libanon : Heiße Spuren im „Mordfall Hariri“?

The teleosts Chelidonichthys cuculus, Trigloporus lastoviza, Serranus cabrilla and Trachinus draco, are important by-catch species, in terms of landed biomass and commercial value, from the continental shelf bottom trawl fishery off the Balearic Islands (western Mediterranean). The main biological parameters of these species were calculated from monthly biological samplings, and were used along with three years pseudo-cohorts (2008-2010) obtained from monitoring on-board of the bottom trawl fleet, to assess their exploitation level through Virtual Population Analysis (VPA) and Yield per Recruit (Y/R) analysis. Time series of fishery independent indicators based on MEDITS surveys data such as the evolution of the abundance and biomass, the distribution range, and the Conservation Status of Fish b (CSFb), were also analyzed. All four species analyzed showed growth overfishing. The reductions of the fishing effort required to reach the Y/RF0,1 reference point were lower, 66-73% depending on the species, to those reported for the target species M. merluccius (87%), but higher than that reported for M. surmuletus (53%), in the study area in the period 2000-2010. The abundance and biomass, and the distribution range did not show any trend for the period 2001-2011, whereas the CSFb showed signs of recovery that may be due to the displacement of the trawl fishing effort from the shelf to the slope during the last decade. Our results underline the necessary incorporation of monitoring and assessment of by-catch species to the management of fisheries as their populations can show a more pronounced overexploitation than target ones

Stock assessment of Mullus surmuletus from GFCM GSA-05 (Balearic Islands)

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Stock boundaries for fisheries assessment and management in the Mediterranean: the Balearic Islands as a case study

The stock concept plays a pivotal role in fisheries assessment and management. Stocks are defined according to biological, geographical, economic or socio-political factors. The General Fisheries Commission for the Mediterranean (GFCM) has established thirty management geographical sub-areas (GSAs) based on political and statistical considerations rather than biological or economic factors. Here, we present our view on the main biological and ecological aspects that should be considered for delineating different management units in the Mediterranean. We focus on the Balearic Islands (GSA05) as a case study highlighting its specificities compared to the adjacent coast of the Iberian Peninsula (GSA06), but the approach could be generalized to the problem of identifying stock boundaries in other areas. The work is based on published information from different marine disciplines such as geomorphology, ecology and fisheries, combined with the analysis of new data coming from official fishery statistics and scientific surveys. This approach avoids the important draw¬backs (inconclusive results, high costs) of other time-consuming techniques used in stock identification, such as genetics. According to the information presented, we conclude that GSA05 should be maintained as an individualized area for assess-ment and management purposes in the western MediterraneanPublicado