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

Abstract

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.

Opposing genetic patterns of range shifting temperate and tropical gastropods in an area undergoing tropicalisation

“…Under projected carbon emission scenarios, taxa globally are expected to undergo range shifts or contractions (Alsos et al., 2012; Cavraro et al., 2023; Sopniewski et al., 2022). Landscape genetic analyses of temperate plants show that species exhibiting genetic differentiation among populations are more vulnerable to the loss of genetic diversity resulting from range contraction (Alsos et al., 2012).…”

Spatio-temporal connectivity and dispersal seasonal patterns in the Adriatic Sea using a retention clock approach

“…The AS is a recognized biodiversity hotspot in the Mediterranean, driven by the nutrient transport and runoff by rivers and the consequent phytoplankton primary production, and marked by the strong seasonality of the Po River discharges (Cozzi and Giani, 2011). It is a highly productive fishing ground (Cavraro et al, 2022), grouped into two Geographical Subareas (GSA17 in the north, and GSA18 in the south, as shown in Figure 1) according to the General Fisheries Commission for the Mediterranean (GFCM, 2009). GSA17 has a wide variety of seabed habitats, from shallow and muddy bottoms in the east to steep and rocky bottoms in the west, whereas GSA18 is predominantly deep, steep, and rocky, supporting sensitive marine habitats that are under high fishing pressure (Grati et al, 2018).…”

Adriatic Sea Fishery Product Safety, Prospective and Climate Change

“…In addition, weakening of thermohaline circulation in the Adriatic Sea due to climate change can potentially affect deep pelagic and benthic organisms especially biodiversity in niches, such as those found in the nearby Jabuka Pit [82]. In recent decades, many publications have also acknowledged the impact of climate change on hydrological and biological processes in the Adriatic Sea [83][84][85].…”

“…In the last 25 years numerous thermophilous fish species have been recorded for the first time in the Adriatic Sea and their presence might be related to climate change [89,90], while climate change effects are responsible for facilitating the migration of lessepsian fish species. Heavy fishing increases the success of non-commercial species by reducing competition from commercial species for the same resources, thereby allowing previously rare species to form larger and more resilient populations [85]. Secondly, since Adriatic Sea is not isolated from the rest of the Mediterranean, changes occurring in other areas have consequences for the Adriatic ecosystem [84]; [85].…”

“…Heavy fishing increases the success of non-commercial species by reducing competition from commercial species for the same resources, thereby allowing previously rare species to form larger and more resilient populations [85]. Secondly, since Adriatic Sea is not isolated from the rest of the Mediterranean, changes occurring in other areas have consequences for the Adriatic ecosystem [84]; [85]. This is especially important for the presence of lessepsian fish species whose arrival in the Adriatic is not only facilitated by climate change but also by the presence of already established populations in the southern regions which probably act as recruitment areas for subsequent northward spreading [91], while the presence of lessepsian species in the Adriatic Sea is probably facilitated if not a consequence of periodic influx of water originating from the eastern Mediterranean Sea (BiOS) [1].…”