Wild fish aggregations around fish farms in the Gulf of Aqaba, Red Sea: implications for fisheries management and conservation

Abstract

Fish farm structures attract a variety of fish species by providing solid structure, and 'free meals' in the form of uneaten feed and feces that fall from the cages. In this study, we compared the composition and abundances of wild fish populations around 2 fish farms in the Red Sea and at nearby reference locations. Fish assemblages were evaluated by SCUBA divers carrying out rapid visual censuses in August, September and October 2007. A total of 87 238 fishes, representing 39 species and 25 families and a number of trophic levels, were observed. Overall, the abundance, biomass, and diversity of wild fish were much greater at the sea cages than at the open-water reference sites, at both fish farms. It is noteworthy that 35 out of the 39 species observed at the farms were juveniles and adults of coral-reef fish species. This finding is especially interesting, considering that the nearest coral reefs were > 4 km away and reef fishes generally have small home ranges, typically <1 km. Among these, the Carangidae (5 species), Sparidae (3 species), and Pomacentridae (3 species) contributed the most to species richness. In light of strong fishing pressures in many areas, the large populations of wild fishes at the fish farms, the high availability of nourishment from artificial food pellets, and restrictions on fishing within farm lease areas, we suggest that coastal net-cage fish farms may serve as small marine protected areas.

Attraction and repulsion of mobile wild organisms to finfish and shellfish aquaculture: a review

“…; Bacher et al . ; Özgül & Angel ). Using traditional tagging methods, Bjordal and Skar () found increased numbers of saithe over extended periods (months) around a fish farm in Norway.…”

“…() suggest that Atlantic bluefin tuna ( T. thynnus thynnus ) modify their migration patterns due to the attractiveness of a Mediterranean fish farm. Özgül and Angel () showed that the suite of species associated with Red Sea fish farms were usually associated with coral reefs, including those >4 km distant from cage sites, suggesting that the farms modified the distribution of these species. Anecdotal evidence from fishers in Norway suggests that migrating cod have changed their spawning migratory behaviour since the establishment of salmon farms in some areas.…”

State of the Art and Challenges for Offshore Integrated Multi-Trophic Aquaculture (IMTA)

“…In Galicia (Spain), Peteiro and Freire (2012) observed a number of different Sparidae fish species feeding on the macroalgae S. latissima and Undaria pinnatifida. This grazing problem is caused by the cages functioning as attractors for wild fish species (e.g., Dempster et al, 2002;Ozgul and Angel, 2013).…”

Nutritional quality of amino acid in farmed, farm‐aggregated and wild Axillary seabream ( Pagellus acarne ) with implications to Human Health

“…However, the remarkable growth and extension of cage aquaculture facilities arise concerns in terms of environmental interactions, because marine cage farms attract wild fish populations due to eased foraging on the abundantly available pellets lost from net pens, and provide sheltering to hide from predator attacks in exposed marine conditions (Boyra, Sanchez‐Jerez, Tuya, Espino, & Haroun, ; Dempster, Sanchez‐Jerez, Bayle‐Sempere, GiménezCasalduero, & Valle, ; Dempster, Sanchez‐Jerez, Bayle‐Sempere, & Kingsford, ; Fernandez‐Jover, Sanchez‐Jerez, Bayle‐Sempere, Valle, & Dempster, ; Tuya, Boyra, Sanchez‐Jerez, & Haroun, ). Earlier studies reported aggregation of various wild fish stocks around fish pens in Spain (Dempster et al, ), in Australia (Dempster et al, ), the Canary Islands (Boyra et al, ; Tuya et al, ), in Turkey (Akyol & Ertosluk, ), in the Adriatic Sea (Bubic, Grubisic, Ticina, & Katavic, ), in the Red Sea (Golani, ; Özgül & Angel, ) and in Greece (Neofitou, ). However, to our knowledge so far, there is only one report regarding the aggregation of axillary seabream around cage farms in the Northern Aegean Sea which has been published by our team (Oztekin et al, ).…”

“…. Earlier studies reported aggregation of various wild fish stocks around fish pens in Spain (Dempster et al, 2002), in Australia (Dempster et al, 2004), the Canary Islands (Boyra et al, 2004;Tuya et al, 2005), in Turkey (Akyol & Ertosluk, 2010), in the Adriatic Sea (Bubic, Grubisic, Ticina, & Katavic, 2011), in the Red Sea (Golani, 2003;Özgül & Angel, 2013) and in Greece (Neofitou, 2016). However, to our knowledge so far, there is only one report regarding the aggregation of axillary seabream around cage farms in the Northern Aegean Sea which has been published by our team (Oztekin et al, 2018).…”