Recreational angling as a vector of freshwater invasions in Central Italy: perceptions and prevalence of illegal fish restocking

Abstract

Italian freshwater ecosystems were strongly affected by biological invasions during the last few decades. Recreational angling contributed to this, through the widespread use of invasive alien species for fish restocking. To date, no research is available about the psychological and structural determinants of deliberate fish restocking in Italy. This work aims to fill this research gap, through structured questionnaires administered to a sample of recreational anglers (n = 276) in the Arno river basin (Central Italy). A predictive model for fish restocking, based on a quasi-binomial logistic regression, was fit and multi-model inference was drawn, to highlight the most significant predictors. Respondents, who expected that most anglers practiced restocking and who believed restocking could create closer fishing spots, were more prone to illegally restock fish. Our findings indicate that expectations about illegal fish restocking might exist among specialized segments of anglers. Targeted communication campaigns must be enforced as soon as possible to change them. Furthermore, fish restocking is supposed to reduce the travel costs for angling: future research about this is needed to model invasion hotspots.

Historical, human, and environmental drivers of genetic diversity in the red swamp crayfish (Procambarus clarkii) invading the Iberian Peninsula

“…Since most alien species in inland waters are dispersed by human vectors (Cerri, Ciappelli, Lenuzza, Zaccaroni & Nocita, 2018;Strayer, 2010), clear spatial structuring of genetic variability is often lacking among populations of invasive freshwater species (Audzijonyte et al, 2017;Blakeslee et al, 2017). However, we observed a strong genetic structure among red swamp crayfish populations in the Iberian Peninsula, likely generated by the two expansion ways from both introduction foci.…”

Spoiled for Choice during Cold Season? Habitat Use and Potential Impacts of the Invasive Silurus glanis L. in a Deep, Large, and Oligotrophic Lake (Lake Maggiore, North Italy)

“…In the second half of the 1970s, the first established S. glanis population was reported in the Po River, where the species was likely introduced in the 1950s [29]. Its introduction occurred mainly via stocking, often in put and take lakes, to enhance fishery for recreational angling [15,17,30] or, in some cases (e.g., Isonzo River), as a biocontrol agent to control other invasive species [31]. The species has now spread in all the major basins of northern and central Italy and in some large rivers of southern Italy (i.e., Aterno-Pescara and Volturno catchments; Supplementary Figure S1), where it has flourished in many environments, typically represented by the eutrophic, turbid, and still waters of canals, shallow lakes, and large rivers [17,25], also taking advantage of the degraded environment [32] and of climate change [33].…”

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

“…Here we accessed the knowledge of recreational fishers, a particular group of sea users, which is familiar with internet and social media (Giovos et al, 2018) and can be recruited for online surveys with minimum efforts and costs (Banha et al, 2015;Martin et al, 2012;Venturelli et al, 2017). 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).…”