Local Ecological Knowledge Indicates Temporal Trends of Benthic Invertebrates Species of the Adriatic Sea

Abstract

In the Adriatic Sea, shifts in benthic community structure have been attributed to multiple stressors, from the effects of climate change to the impacts of commercial fishing. Some fishing practices, such as bottom trawling, have caused a widespread decline in exploited fish stocks. Bottom trawling is also expected to have negative impacts on benthic habitats, usually structured by and hosting a large array of invertebrate species, which provide important ecological services to fish and commercial invertebrate stocks. However, in contrast to commercial species for which long-term time series of the abundance exist, data on these habitat-forming invertebrates are scarce, as they are usually caught as bycatch and discarded. Therefore, there is great uncertainty about their long-term trends, and if these populations are stable or declining. Here we used interview surveys conducted with bottom-trawling fishers of the central Adriatic Sea to gather local ecological knowledge on megabenthos abundance occurring in their fishing domain, as an alternative source of information to conventional fisheries data. We interviewed 44 fishers, from the most important ports of the Marche region of Italy, to understand how megabenthic species have changed in abundance within the area since the 1980s. Specifically, we asked fishers to provide qualitative abundance scores for 18 invertebrate species in five phyla (Porifera, Cnidaria, Bryozoa, Mollusca, and Echinodermata) based on their recollection of these species' presence in bycatch. We stratified responses in homogeneous temporal periods and geographic sectors of the study area, and analyzed their response with mixed effect ordered logistic regression models in order to evaluate spatiotemporal changes in the perceived abundance of each species. Our analysis suggests that the abundance of the sponge Geodia cydonium, the molluscs Pecten jacobaeus, Atrina fragilis, Neopycnodonte cochlear, and the group of holothurians, have declined. From fishers' perceptions, only the bryozoan Amathia semiconvoluta has increased. Local ecological knowledge can provide important information on environmental change and can highlight species and ecosystems at risk when conventional scientific data are scarce or absent. This approach can be expanded to other regions of the Adriatic and broader Mediterranean Sea to reconstruct change of this heavily exploited marine region.

Climate change, biological invasions, and the shifting distribution of Mediterranean fishes: A large‐scale survey based on local ecological knowledge

“…To achieve this, the use of standardized and cost-effective procedures is needed to underpin a large-scale observation strategy that can accommodate countries across a range of baseline knowledge levels and capabilities (Bélisle, Asselin, LeBlanc, & Gauthier, 2018;Latombe et al, 2017). Yet, accessing this expert knowledge (hereafter referred as local ecological knowledge or LEK) is offering new opportunities to Mediterranean research Azzurro, Moschella, & Maynou, 2011;Bastari, Beccacece, Ferretti, Micheli, & Cerrano, 2017;Coll et al, 2014;Damalas et al, 2015;Mavruk, Saygu, Bengil, Alan, & Azzurro, 2018), providing new opportunities to overcome practical and budgetary constraint, especially in poorly studied areas. In this, fishers are a particularly interesting group of stakeholders, as they spend a considerable proportion of their lives in close contact with the marine environment and they become familiar with local species.…”

The occurrence of two morphologically similar Chaetozone (Annelida: Polychaeta: Cirratulidae) species from the Italian seas: Chaetozone corona Berkeley & Berkeley, 1941 and C. carpenteri McIntosh, 1911

“…These two species showed wide distribution in sandy, muddy or mixed sediments at a wide depth range in sites disturbed and undisturbed (Table I and Figure 3) by fishing activities. From the coast to offshore, benthic assemblages are exposed to a heavy and prolonged history of exploitation, and are subjected to chronic and intensive effects of bottom trawling and fishing, with habitat degradation which in turn homogenised and simplified the benthic assemblages themselves (Bastari et al 2017). In the five sampling periods of this study (from winter 2014 to winter 2016), C. corona was present at low density (5-10 ind.…”

Macrofaunal communities in the Gioia Canyon (Southern Tyrrhenian Sea, Italy)

“…In Pierdomenico et al (2016Pierdomenico et al ( , 2018 documented in the Gioia basin high level of disturbance due to high sedimentation, turbidite flows and intense bottom trawling effort that resulted in scarce environmental status and low abundances of megabenthic communities. It is largely reported that canyons represent very exploited fishing grounds at global level (Ramirez-Llodra et al 2011) and that the bottom trawling is cause of strong alterations of biodiversity and functioning in ecosystems, as in the Blanes and La Fonera canyons (Northwestern Mediterranean Sea), and of negative effects on benthic communities (Pusceddu et al 2014;Bastari et al 2016;Lastras et al 2016;Romano et al 2016). In the northern coast of Sicily, Romano et al (2016) reported significant differences between the macrofaunal assemblages from areas where the fishing activity is forbidden and those where the trawling is permitted.…”