Direct interaction between wild fish aggregations at fish farms and fisheries activity at fishing grounds: a case study with Boops boops

Abstract

Coastal aquaculture installations concentrate large numbers of wild ¢sh species of both ecological and economic importance, including schools of bogue, Boops boops (L.), in high abundance and biomass. The aggregated species consume large quantities of the easily available pellets lost from cages. As a consequence, the physical condition of farm-associated wild ¢sh is increased and their physiology is altered. These changes may in£uence local ¢sheries as many of these aggregating species are targeted by ¢shers. We assess whether local ¢shers catch wild ¢sh that have previously aggregated at ¢sh farms by comparing the body condition, trophic indexes, diet overlap and the fatty acid (FA) composition of B. boops obtained from local ¢sh markets and around ¢sh farms. Bogue captured by trammel-nets and around ¢sh farms facilities presented a similar biological condition, as well as high quantities of pellets in the gut, and their FA pro¢le was a¡ected by vegetalderived FAs. In contrast, bogue captured by trawlers were not in£uenced by ¢sh farms, as they consumed natural trophic resources.We conclude that artisanal ¢shers exploit these aggregated ¢sh populations once they have dispersed away from farms, and bene¢t from a 'biomass export' from ¢sh farms at a local scale.

Assessing the Influence of Salmon Farming through Total Lipids, Fatty Acids, and Trace Elements in the Liver and Muscle of Wild Saithe Pollachius virens

“…In our study, higher fat content in liver tissues was detected in F-Saithe than in U-Saithe, which were captured >25 km away from farms. Previous studies on Saithe, but also on other farm-aggregated species, revealed higher lipid levels and condition indices (i.e., Fulton's condition index, hepatosomatic index) in farm-aggregated fish compared with nonaggregated individuals (Skog et al 2003;Fernandez-Jover et al 2007, 2011bArechavala-Lopez et al 2011;Izquierdo-Gomez et al 2015). The incorporation and storage of FAs in fish tissues strongly depends on the FA profile of the diet (Sargent et al 2002).…”

First occurrence of Caprella scaura Templeton, 1836 (Crustacea: Amphipoda) on off-coast fish farm cages in the Mediterranean Sea

“…This concentration of fish increases the fishing pressure around the farms, with commercial and recreational fishing vessels moving around different fish farms along the same coastal area (Arechavala-Lopez et al 2011). Thus, fishing vessels attracted by fish farms could also spread C. scaura not only from one farm to another but also between coastal and offcoast locations.…”

Spatial and temporal extension of wild fish aggregations at Sparus aurata and Thunnus thynnus farms in the north-western Mediterranean

“…Fishing near fish farms is a common practice that has been reported in Spain (Fernandez-Jover et al 2008, Arechavala-Lopez et al 2011, Croatia (Šegvić Bubić et al 2011), Greece (Machias et al 2006) and Norway (Maurstad et al 2007), and even within farms in Turkey (Akyol & Ertosluk 2010). The farms studied here are located in waters within the jurisdiction of the local government, which has not implemented any fishing restrictions in their vicinity.…”