Vulnerability of the Small-Scale Fishery to Climate Changes in the Northern-Central Adriatic Sea (Mediterranean Sea)

Climate change is altering the functioning of ecosystems and species distribution worldwide, with negative impacts on human activities, including fisheries. The Adriatic Sea is an extremely productive area for fisheries, due to the strong outflow of nutrients from rivers and the periodic mixing of nutrients from the Mediterranean. However, the Adriatic Sea is also a semi-closed basin, where species do not have the ability to move to higher latitudes to avoid warming of the waters. Climate change acts on biodiversity in a variety of ways, such as causing changes in the trophic network-favoring the intake of thermophilic alien species, often in competition with local species-and altering the biological cycles of acclimatized marine species to temperate-cold climates. These problems become critical factors for the survival of species and for fisheries relying on these resources. Within this context, to have estimates of possible modifications of the nektonic community in the near future could be quite useful for preparing adaptation plans. In this paper, using Maximum Entropy models under RCP 4.5 and 8.5 scenarios, we estimated the future habitat suitability for a set of marine nektonic species of different thermal affinity (e.g., cold, temperate and warm species) within GSA17 (Northern and Central Adriatic Sea), among the most productive-and most exploited-areas of the Mediterranean Sea. This study shows how, at the current pace, climate change could modify marine ecosystems to the extent that future habitat suitability will decrease for nearly half of the species considered, with a decrease in landings from 13.5 to 86.9%, depending on the scenario. Only for the blue crab Callinectes sapidus has an increase in habitat suitability been observed. For most of the species considered, temperature was the most important variable to explain the probability of relative presence within the GSA17. On the other hand, GSA17 climatic conditions in the near future under the tested scenarios could become a suitable environment for tropical species, which could find here a suitable habitat, at least in terms of thermal features. Results of the present study can help the management of fishery resources and local markets in the near future, providing information to predict changes in the composition of the aquatic community and draw up management plans that take into account the effects of climate change

Some biological parameters of the thin-lipped mullet Liza ramada (Pisces, Mugilidae) in the Neretva River delta (Eastern Adriatic, Croatian coast)

International audienceAspects concerning age, growth, reproduction and recruitment were analysed inthe thin-lipped mullet, Liza ramada, collected in Neretva River delta estuary (East A d r i a t i c ,Croatian coastline). The study was based on the collection of a total of 362 individuals on amonthly basis. The von Bertalanffy growth curve parameters were estimated: T L= 59.96 cm,K = 0.269 year- 1, t0= -0.455. Natural mortality was estimated at 0.32 year- 1. Total mortality (Z)was estimated at 0.70 year- 1(range 0.55-0.85 year- 1). Fishing mortality was estimated at0.38year-1and the exploitation ratio at E = 0.54. The gonado-somatic index profile shows a sin-gle peak during the year in October. The sex ratio profile shows skewed sex ratios throughoutthe year except the period prior to reproduction peak. This L. ramadapopulation is suggested tobe in good status

Is the Small-Scale Fishery more sustainable in terms of GHG emissions? A case study analysis from the Central Mediterranean Sea

Small-Scale Fishery (SSF) is recognized as one of the more sustainable among the activities currently exploiting marine renewable resources. This is mainly due to the use of fishing gears characterised by a low environmental impact and a high selectivity. However, there is still room for improvement when analysing the sustainability of SSF sector. Within this context, Greenhouse Gases (GHG) emissions - CO2 in particular - are one of the most relevant aspect to be considered. In particular, fuel consumption and its reduction represent the main issue when discussing sustainability, especially to cope with climate changes. In this paper, the first inventory of CO2 emissions from the SSF vessels in the Central-Northern Adriatic Sea (GSA17) has been compiled, based on data collected from SSF operators, validated by means of a geospatial-based method. Emission intensity estimates - 7.01 kg of CO2 emitted per kg of landing or 2.08 kg of CO2 emitted per euro of landing - confirmed the lower values by SSF vessels in comparison with other fleet segments. Results are discussed in the light of the mitigation of GHG emissions for the SSF, considering the technological features of Adriatic SSF, fishers' behaviour and an improved management of the fishery

The use of fishers' Local Ecological Knowledge to reconstruct fish behavioral traits and fishers' perception of conservation relevance of elasmobranchs in the Mediterranean Sea

The Mediterranean Sea has a long-lasting history of fishery exploitation that, together with other anthropogenic impacts, has led to declines in several marine organisms. In particular, elasmobranch populations have been severely impacted, with drastic decreases in abundance and species diversity. Based on their experience, fishers can provide information on marine species oc- currence, abundance and behavioural traits on a long-term scale, therefore contributing to research on the poorly studied biolog- ical aspects of elusive or rare elasmobranch species. In this study, for the first time, the Local Ecological Knowledge (LEK) of fishers was applied to study the behavioural traits of sharks, rays and skates in 12 FAO-GFCM geographical sub-areas (GSAs) of the Mediterranean Sea. This study found both new insight and proved the reliability of LEK-based catch seasonality, reflect- ing seasonal movements, by comparing LEK-based findings and available literature on five elasmobranch taxa (Mustelus spp., Squalus acanthias, Raja spp., Myliobatis aquila and Scyliorhinus stellaris) in the Adriatic Sea and 7 taxa (Mustelus spp., Raja spp., Prionace glauca, Scyliorhinus canicula, Torpedo spp., Pteroplatytrygon violacea and Isurus oxyrinchus) in the remaining Mediterranean GSAs. In addition, LEK provided new insights into a novel comprehensive representation of species aggregations (Mustelus spp., S. acanthias, M. aquila and S. canicula) in the sampled GSAs and supplied the first descriptions of the size, num- ber of individuals and sex composition of the aggregations. When the limits and shortcomings of LEK-based research are consid- ered, this methodology can be a complementary and cost-effective tool used to study elasmobranchs in either a data-poor scenario or a scenario in which a baseline is missing. LEK can also be useful for the evaluation and inclusion of fishers’ perceptions of bottom-up management and to provide important evidence for conservation plans