Mapping change in bottom trawling activity in the Mediterranean Sea through AIS data

Ferrà, Carmen; Tassetti, Anna Nora; Grati, Fabio; Pellini, Giulio; Polidori, Piero; Scarcella, Giuseppe; Fabi, Gianna

doi:10.1016/j.marpol.2017.12.013

Cited by 62 publications

(40 citation statements)

References 32 publications

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“…An index of the fishing effort in the Mediterranean Sea could then be calculated by evaluating the fishing time by vessel characteristics (Kroodsma et al, 2018). However, as most of the fishing boats in the Mediterranean fleet are less than 10 m and AIS is only compulsory for large European vessels, effort would remain underestimated (Ferrà et al, 2018). Fitting an ecosystem model based on catch data is a difficult task in the Mediterranean due to the poor quality of fishery statistics (Pauly et al, 2014;Piroddi et al, 2017).…”

Section: Species Catchesmentioning

confidence: 99%

Capturing the big picture of Mediterranean marine biodiversity with an end-to-end model of climate and fishing impacts

Moullec

Velez

Verley

et al. 2019

Progress in Oceanography

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The Mediterranean Sea is one of the main hotspots of marine biodiversity in the world. The combined pressures of fishing activity and climate change have also made it a hotspot of global change amidst increasing concern about the worsening status of exploited marine species. To anticipate the impacts of global changes in the Mediterranean Sea, more integrated modelling approaches are needed, which can then help policymakers prioritize management actions and formulate strategies to mitigate impacts and adapt to changes. The aim of this study was to develop a holistic model of marine biodiversity in the Mediterranean Sea with an explicit representation of the spatial, multispecies dynamics of exploited resources subject to the combined influence of climate variability and fishing pressure. To this end, we used the individual-based OSMOSE model (Object-oriented Simulator of Marine ecOSystEms), including 100 marine species (fish, cephalopods and crustaceans) representing about 95% of the total declared catch, at a high spatial resolution (400 km2) and a large spatial scale (the entire Mediterranean basin)the first time such a resolution and scale have been modelled. We then combined OSMOSE with the NEMOMED 12 physical model and the Eco3M-S biogeochemical low trophic level model to build the endto-end model, OSMOSE-MED. We fitted OSMOSE-MED model with observed or estimated biomass and commercial catch data using a likelihood approach and an evolutionary optimization algorithm. The outputs of OSMOSE-MED were then verified against observed biomass and catch data, and compared with independent datasets (MEDITS data, diet composition and trophic levels). The model resultsat different hierarchical levels, from individuals to the scale of the ecosystemwere consistent with current knowledge of the structure, functioning and dynamics of the ecosystems in the Mediterranean Sea. While the model could be further improved in future iterations, all the modelling stepsthe comprehensive representation of key ecological processes and feedback, the selective parameterization of the model, and the comparison with observed data in the validation processstrengthened the predictive performance of OSMOSE-MED and thus its relevance as an impact model to explore the future of marine biodiversity under scenarios of global change. It is a promising tool to support ecosystem-based fishery management in the Mediterranean Sea. Highlights ► An End-to-End model (OSMOSE-MED) was built at the whole Mediterranean scale. ► One hundred marine species, representing 95 % of total declared catches, were embedded. ► OSMOSE-MED was fitted to observed and estimated data of biomass and catch. ► Results were consistent with current knowledge and observations on the system. ► The model can be used in support to fisheries management and biodiversity conservation.

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Section: Species Catchesmentioning

confidence: 99%

Capturing the big picture of Mediterranean marine biodiversity with an end-to-end model of climate and fishing impacts

Moullec

Velez

Verley

et al. 2019

Progress in Oceanography

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“…The system has been providing valuable Monitoring, Control and Surveillance (MCS) data on a large amount of European fishing activities. Moreover, its voluntary adoption by several non-European fishing fleets has been supplying additional information to map the areas exploited by these fleets, such as the Mediterranean Sea (Ferrà et al, 2018). Automatic Identification System is the only existing largescale system supplying actively transmitted data (Ford et al, 2018) and provides valuable information to understand maritime routes and fishing activities.…”

Section: Introductionmentioning

confidence: 99%

Using AIS to Attempt a Quantitative Evaluation of Unobserved Trawling Activity in the Mediterranean Sea

et al. 2020

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In the past decades, the Automatic Identification System (AIS) has been employed in numerous research fields as a valuable tool for, among other things, Maritime Domain Awareness and Maritime Spatial Planning. In contrast, its use in fisheries management is hampered by coverage and transmission gaps. Transmission gaps may be due to technical limitations (e.g., weak signal or interference with other signals) or to deliberate switching off of the system, to conceal fishing activities. In either case such gaps may result in underestimating fishing effort and pressure. This study was undertaken to map and analyze bottom trawler transmission gaps in terms of duration and distance from the harbor with a view to quantifying unobserved fishing and its effects on overall trawling pressure. Here we present the first map of bottom trawler AIS transmission gaps in the Mediterranean Sea and a revised estimate of fishing effort if some gaps are considered as actual fishing.

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“…In terms of overall abundance, the Balearic Islands (GSA 5), Maltese waters (GSA 15), the Gulf of Lions (GSA 7), eastern Corsica (GSA 8) and the eastern Ionian Sea (GSA 20) are the areas with the highest relative biomass of gurnards, while the lowest biomasses are observed in the Alboran and Tyrrhenian seas (GSAs 9 and 10), on the Italian side of the Adriatic (GSA 17a) and in the western Ionian Sea (GSA 19). At first glance this pattern in gurnard abundance could likely be the result of the current distribution of trawl fleets and fishing effort in the Mediterranean (see Colloca et al 2017, Ferrà et al 2018. The areas with the highest gurnard relative biomass are those that have the lowest trawl pressure on the continental shelf, while the opposite is observed in areas that have a high effort.…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal trend in the abundance and distribution of gurnards (Pisces: Triglidae) in the northern Mediterranean Sea

Colloca¹,

Milisenda²,

Capezzuto³

et al. 2020

Sci. Mar.

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In this study we investigated the spatio-temporal distribution of gurnards (8 species of Triglidae and one species of Peristediidae) in the northern Mediterranean Sea using 22 years of MEDITS bottom trawl survey data (1994-2015). Gurnards showed significant differences in terms of abundance, dominance and composition among geographical sub-areas and ecoregions, with the highest relative biomass (BIy) being found in Malta, eastern Corsica, the Balearic Islands and the eastern Ionian Sea. The lowest gurnards BIy were observed in the highly exploited areas of the western Mediterranean and the Adriatic Sea, where the largest number of species with a negative linear trend in BIy was also found. The temporal trends in species abundances highlighted a general decrease for the coastal species (C. lucerna, C. lastoviza, C. obscurus) as compared with the species inhabiting the deep continental shelf and slope (T. lyra, P. cataphractum). The results provide for the first time an overview of the spatiotemporal trend in the abundance of gurnards over the wide spatial scale of the northern Mediterranean Sea, also suggesting the possible use of these species as indicators for monitoring the impact of fishing pressure on demersal fish assemblages.

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Mapping change in bottom trawling activity in the Mediterranean Sea through AIS data

Cited by 62 publications

References 32 publications

Capturing the big picture of Mediterranean marine biodiversity with an end-to-end model of climate and fishing impacts

Capturing the big picture of Mediterranean marine biodiversity with an end-to-end model of climate and fishing impacts

Using AIS to Attempt a Quantitative Evaluation of Unobserved Trawling Activity in the Mediterranean Sea

Spatial and temporal trend in the abundance and distribution of gurnards (Pisces: Triglidae) in the northern Mediterranean Sea

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