scholarly journals Exportation of excess feed from Mediterranean fish farms to local fisheries through different targeted fish species

2014 ◽  
Vol 72 (3) ◽  
pp. 930-938 ◽  
Author(s):  
David Izquierdo-Gómez ◽  
Daniel González-Silvera ◽  
Pablo Arechavala-López ◽  
José Ángel López-Jiménez ◽  
Just Tomás Bayle-Sempere ◽  
...  
Keyword(s):  
Wild Fish ◽  
Small Scale ◽  
Fish Feed ◽  
Total Lipids ◽  
Fish Farms ◽  
Pomatomus Saltatrix ◽  
Coastal Fisheries ◽  
Cage Aquaculture ◽  
Sea Cage ◽  
Mediterranean Fish

Abstract Coastal fisheries and sea cage aquaculture coexist along the coastal zone, and it has been suggested that wild fish feed on excess feed around farms. If this occurs, the condition of wild fish can increase and their lipid profile can become modified. However, the influence of fishfarming on coastal fisheries has not been described in detail. Four targeted species of different trophic gilds, Sardinella aurita, Caranx rhonchus, Mullus barbatus, and Pomatomus saltatrix were studied and the lipid profiles of individuals captured by coastal fisheries and around fish farms were compared. Results show that fish captured at farms showed increased levels of total lipids and/or the terrestrial fatty acids contained in feed pellets. Individuals with increased terrestrial fatty acid proportions were detected in the catch of small-scale artisanal fisheries but not among trawled fish. Consequently, this study demonstrates the influence of fishfarming on coastal fisheries through the exportation of excess feed in the shape of wild fish biomass.

Influence of some physico-chemical variables on wild fish richness beneath sea-cage fish farms in the Aegean Sea, Turkey

2020 ◽  
Vol 100 (7) ◽  
pp. 1171-1179
Author(s):  
Okan Akyol ◽  
Aytaç Özgül ◽  
F. Ozan Düzbastılar ◽  
Halil Şen ◽  
José M. Ortiz de Urbina ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Fish Assemblages ◽  
Wild Fish ◽  
Light Transmittance ◽  
Fish Farms ◽  
Physico Chemical ◽  
Sea Cage ◽  
The Relationship ◽  
Cage Fish

AbstractThis study aims to determine the relationship between physico-chemical variables on a seasonal basis and wild fish assemblages beneath sea-cage fish farms. Assemblages of wild fish were counted monthly on two separate days at each of six fish farms between August 2015 and July 2017, by six rapid visual counts (RVC) in 5 minutes with scuba by two divers. Seawater samples were simultaneously taken by a Nansen bottle during the RVC from the fish farm barge. SST (°C), salinity (ppm), dissolved oxygen (mg l−1) and pH were measured by YSI multiparameter, while Secchi disk was also used for light transmittance. Wild fish species richness went up with increasing temperature and salinity in the Izmir region, however, this stopped at about 26°C and about 39 ppm. Wild fish richness increased when the DO was at a level of 7 mg l−1 and the pH at about 7.9 in Izmir. Between 10 and 20 m, light transmittance showed greater wild fish species richness in Izmir region. In contrast, the wild fish species richness of the Muğla region fluctuated more. In terms of wild fish species richness, these fluctuations increased with salinity and DO, while they decreased with SST, pH and light transmittance. However, the range of variation of the recorded physico-chemical variables is rather narrow. The results of the correlation matrix indicate that the relationship between wild fish species richness and pH and SST was statistically significant in Izmir region (P < 0.05).

scholarly journals Seasonal variations in wild fish aggregation near sea-cage fish farms in the Turkish Aegean Sea

2020 ◽  
Vol 18 ◽  
pp. 100478
Author(s):  
Okan Akyol ◽  
Aytaç Özgül ◽  
F. Ozan Düzbastılar ◽  
Halil Şen ◽  
José M. Ortiz de Urbina ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Aegean Sea ◽  
Wild Fish ◽  
Fish Farms ◽  
Fish Aggregation ◽  
Sea Cage ◽  
Cage Fish

Extensive Aggregations of Wild Fish at Coastal Sea-Cage Fish Farms

Hydrobiologia ◽  
2004 ◽  
Vol 525 (1-3) ◽  
pp. 245-248 ◽  
Author(s):  
Tim Dempster ◽  
Pablo Sanchez-Jerez ◽  
Just Bayle- Sempere ◽  
Michael Kingsford
Keyword(s):  
Wild Fish ◽  
Fish Farms ◽  
Coastal Sea ◽  
Sea Cage ◽  
Cage Fish

scholarly journals Wild fish diversity around the sea-cage fish farms in the Aegean Sea

2019 ◽  
Vol 36 (3) ◽  
pp. 271-283
Author(s):  
Okan Akyol ◽  
Tevfik Ceyhan ◽  
F. Ozan Düzbastılar ◽  
Aytaç Özgül ◽  
Halil Şen
Keyword(s):  
Sparus Aurata ◽  
Dicentrarchus Labrax ◽  
Aegean Sea ◽  
Wild Fish ◽  
Fish Diversity ◽  
Fish Farms ◽  
The Mediterranean ◽  
Fish Aggregation ◽  
Sea Cage ◽  
Cage Fish

Structures, floating on the surface of the ocean attract both juvenile and adult fishes in great numbers and diversity. Natural and artificial Fish Aggregation Devices (FADs) in open seas are widely recognised for their capacity to attract pelagic fishes. It can be assumed that floating sea-cages act as a kind of FAD. Even, fish aggregations beneath the sea-cages increase much more by the influence of feeding. In this study, aggregations of wild fish were counted around six sea-cage fish farms in both northern and southern Aegean Sea. Each fish farm cultivated Sparus aurata and Dicentrarchus labrax and the farms deployed between 720 m and 3 km far from the coast. Between July 2015 and July 2017, assemblages of wild fish were counted bimonthly on two separate days at each of these farms. The Rapid Visual Counts (RVC) in five minutes with SCUBA and covering 11250 m3 were performed for six times within each farm. A total of 40 species, belonging to 22 families were recorded at fish farms, with 3 families, Sparidae (7 species), Carangidae (6 species) and Mugilidae (4 species) being particularly abundant. The results of the study and other studies conducted in other parts of the Mediterranean were merged; it was found that a total of 99 fish species were listed around sea-cage fish farms in the Mediterranean Sea.

scholarly journals Some interactions between coastal fisheries and sea birds in the Aegean Sea

2020 ◽  
Vol 37 (2) ◽  
pp. 139-147
Author(s):  
Tevfik CEYHAN ◽  
Okan AKYOL
Keyword(s):  
Bird Species ◽  
Aegean Sea ◽  
Small Scale ◽  
Great Cormorant ◽  
Fish Farms ◽  
Phalacrocorax Carbo ◽  
Sea Birds ◽  
The Difference ◽  
Sea Cage ◽  
Cage Fish

In this study, it is aimed to determine the some interactions between various fishery types and seabirds, results of this interaction and sea bird species that have been interacting due to secondary attraction factors. A total of 80 fishermen, working in fish farms, small scale fishery (SSF) and lagoons located in Izmir, Aydın and Muğla were face-to-face interviewed between September 2016 and December 2018. The great cormorant (Phalacrocorax carbo), yellow-legged gull (Larus michahellis), great white egret (Ardea alba), some yelkouan shearwater (Puffinus yelkouan) and great white pelican (Pelecanus onocrotalus) are the bird species that have an interaction with coastal fishermen and sea-cage fish farms. 82% of employees in sea-cage fish farms mentioned that they have an interaction with sea birds in winter, besides %50 of SSF have an interaction with sea birds in summer. The difference between interaction rate according to seasons has been found as statistically significant (p<0.05). 33% of employees in fish farms expressed that they see sea birds during the day. This ratio is 21.7% and 15% for SSF and fishermen in lagoon, respectively. Furthermore, 8.3% of fishermen in lagoon, 11% of employees in fish farms and SSF mentioned that they have an interaction with seabirds especially in the morning time.

scholarly journals Determining potential conflicts between small-scale fisheries and sea-cage fish farms in the Aegean Sea

2019 ◽  
Vol 49 (4) ◽  
pp. 365-373 ◽  
Author(s):  
Okan Akyol ◽  
Aytaç Özgül ◽  
Halil Şen ◽  
Faik Ozan Düzbastılar ◽  
Tevfik Ceyhan
Keyword(s):  
Aegean Sea ◽  
Small Scale ◽  
Fish Farms ◽  
Small Scale Fisheries ◽  
Sea Cage ◽  
Cage Fish

Sea cage aquaculture affects distribution of wild fish at large spatial scales

2013 ◽  
Vol 70 (9) ◽  
pp. 1289-1295 ◽  
Author(s):  
L. Goodbrand ◽  
M.V. Abrahams ◽  
G.A. Rose
Keyword(s):  
Spatial Scales ◽  
Wild Fish ◽  
Consumer Responses ◽  
Salmon Farming ◽  
Individual Level ◽  
History Of ◽  
Cage Aquaculture ◽  
The Mean ◽  
Resource Patches ◽  
Sea Cage

Aquaculture sea cages are fixed in space and inadvertently provide food to wild animals that is stable through time. We measured the effect of these novel and highly predictable resource patches on the distribution of wild fish across large spatial scales along the south coast of Newfoundland, Canada. Randomized stratified hydroacoustic surveys were used to compare the distribution and abundance of wild fish in bays that contained Atlantic salmon (Salmo salar) farms with control bays. Control bays were areas with no history of salmon farming but have been selected for future use by the industry. We found that measures of total area backscatter (nautical area scattering coefficient, NASC) were significantly greater in bays that contain salmon farming compared with control locations. The mean NASC in farmed bays was not significantly different from mean NASC measurements taken directly adjacent to sea cages. Variability around mean NASC estimates could not be explained by the quantity of feed available to consumers, when the number of sea cages in a farm site was used as a proxy for feed availability. Our results suggest that individual-level consumer responses at sea cages can be transmitted across larger spatial scales.

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