Local ecological knowledge of recreational fishers reveals different meridionalization dynamics of two Mediterranean subregions

Abstract

Marine recreational fishers accumulate a vast amount of Local Ecological Knowledge (LEK) during their fishing activity that can be of paramount importance for monitoring how climate change affects the structure of biological communities. Here, we accessed the LEK of recreational anglers and recreational spearfishers to investigate the increase in the abundance of five northward expanding indigenous thermophilic fish species in two subregions of the Mediterranean Sea: the Adriatic/Ionian Seas and the Tyrrhenian/Ligurian Seas. We used an online survey administered through Twitter and Facebook between 2017 and 2018 to both Italian and Croatian recreational fishers. A total of 794 respondents completed the questionnaire (386 from the Adriatic/Ionian subregion and 408 from the Tyrrhenian/Ligurian one). Overall, the species perceived as most increasing in abundance were Pomatomus saltatrix (71% of replies) followed by Sphyraena viridensis (58%). The rest of species (Coryphaena hippurus, Balistes capriscus and Sparisoma cretense) ranged between 17% and 25%.We showed that recreational fishers have a stable system of beliefs about meridionalization, which is perceived homogeneously between recreational anglers and spearfishers. Moreover, our results indicate that latitude is negatively correlated with meridionalization in the Adriatic/Ionian, but not in the Thyrrenian/Ligurian Seas, suggesting that meridionalization of the Adriatic/Ionian Seas could be a process that is temporally lagged with respect to the Tyrrhenian/Ligurian Seas. Our study

The Use of Recreational Fishers’ Ecological Knowledge to Assess the Conservation Status of Marine Ecosystems

“…Key concepts were grouped to identify the main impacts on marine ecosystems and access motivations of the recreational fishers. To ensure groups were consistent and coherent (Saldaña, 2015), they were compared with main topics identified in the texts of the transcriptions by using the LDA tool of the topicmodels library in R, that generated a probabilistic framework for the frequency occurrences of the key concepts of the interviews (Hornik and Grün, 2011). Key concepts were also used to quantify changes in fishing gears and techniques separately for anglers and spear fishers by using the following scale: 0 (no changes); 1 (minor improvements); and 2 (great improvements).…”

“…Given that there are many more recreational than commercial fishers (Hyder et al, 2018;Arlinghaus et al, 2019a), recreational fishers represent a relatively untapped source of long-term information on marine ecosystems (Brewin et al, 2017). Recreational FEK has been used to quantify variations in abundances and distribution of different fish stocks (e.g., Azzurro et al, 2011;Zukowski et al, 2011;Beaudreau and Levin, 2014;Sbragaglia et al, 2020). However, to our knowledge, it has not been used to integrate perceptions of trends of fish stocks with the conservation status of the whole ecosystems.…”

Using online questionnaires to assess marine bio-invasions: A demonstration with recreational fishers and the Atlantic blue crab Callinectes sapidus (Rathbun, 1986) along three Mediterranean countries

“…So far, online questionnaires, have been extensively adopted in freshwater ecosystems, to investigate public perception of IAS (Nanayakkara et al, 2018) biosecurity practices (Sharp et al, 2017), or invasion pathways (Cerri et al, 2018). However, to the best of our knowledge, their application to IAS monitoring has been nearly inexistent, both in freshwater and in marine environments (Sbragaglia et al, 2019).…”

Analyzing publicly available videos about recreational fishing reveals key ecological and social insights: A case study about groupers in the Mediterranean Sea

“…S1), which is an international network and research infrastructure funded by the world's governments and aimed at providing open access biodiversity data. As such, we argue that recreational fishers could represent an important monitoring tool for climate change effects on marine biota as recently demonstrated by using their local ecological knowledge in the context of meridionalization of the Mediterranean Sea (Sbragaglia et al, 2020).…”