Do cage fish farms promote interference in the trophic niche of wild fish in neotropical reservoir?

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).

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

Aquaculture Reports ◽

10.1016/j.aqrep.2020.100478 ◽

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

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Seasonal patterns and diets of wild fish assemblages associated with Mediterranean coastal fish farms

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn091 ◽

2008 ◽

Vol 65 (7) ◽

pp. 1153-1160 ◽

Cited By ~ 65

Author(s):

Damian Fernandez-Jover ◽

Pablo Sanchez-Jerez ◽

Just Tomás Bayle-Sempere ◽

Carlos Valle ◽

Tim Dempster

Keyword(s):

Fish Assemblages ◽

Abundant Species ◽

Stomach Content Analysis ◽

Wild Fish ◽

Seasonal Patterns ◽

Fish Farms ◽

Coastal Fish ◽

Fish Stocks ◽

Floating Structures ◽

Cage Fish

Abstract Fernandez-Jover, D., Sanchez-Jerez, P., Bayle-Sempere, J. T., Valle, C., and Dempster, T. 2008. Seasonal patterns and diets of wild fish assemblages associated with Mediterranean coastal fish farms. – ICES Journal of Marine Science, 65: 1153–1160. Fish are attracted to floating structures, including coastal cage fish farms, sometimes in dense aggregations. To understand better the influence of aquaculture on wild fish stocks, we carried out seasonal visual censuses around three southwestern Mediterranean farms over 2 years to assess the temporal patterns of the aggregated fish assemblage. In addition, we analysed the diet of the five most abundant species. Aggregations around all farms were large throughout the year, although species composition and abundance differed among farms and seasons. Fish farms are attractive habitats for certain species of wild fish in specific seasons. Adult fish of reproductive size dominated the assemblages, and stomach content analysis revealed that 66–89% of fish of the five most abundant taxa had consumed food pellets lost from the cages. We estimated that wild fish consume up to 10% of the pellets used at farms, indicating that food is a key attractant. Regional monitoring of farm-associated wild fish assemblages could aid management of the interaction of aquaculture and wild fish resources, because changes in feeding behaviour may have consequences for fish populations and local fisheries.

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

Hydrobiologia ◽

10.1023/b:hydr.0000038870.13985.0f ◽

2004 ◽

Vol 525 (1-3) ◽

pp. 245-248 ◽

Cited By ~ 72

Author(s):

Tim Dempster ◽

Pablo Sanchez-Jerez ◽

Just Bayle- Sempere ◽

Michael Kingsford

Keyword(s):

Wild Fish ◽

Fish Farms ◽

Coastal Sea ◽

Sea Cage ◽

Cage Fish

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Attraction of wild fish to sea-cage fish farms in the south-western Mediterranean Sea: spatial and short-term temporal variability

Marine Ecology Progress Series ◽

10.3354/meps242237 ◽

2002 ◽

Vol 242 ◽

pp. 237-252 ◽

Cited By ~ 146

Author(s):

T Dempster ◽

P Sanchez-Jerez ◽

JT Bayle-Sempere ◽

F Giménez-Casalduero ◽

C Valle

Keyword(s):

Mediterranean Sea ◽

Temporal Variability ◽

Western Mediterranean ◽

Wild Fish ◽

The South ◽

Fish Farms ◽

Short Term ◽

Western Mediterranean Sea ◽

Sea Cage ◽

Cage Fish

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

Ege Journal of Fisheries and Aquatic Sciences ◽

10.12714/egejfas.2019.36.3.08 ◽

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.

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Vertical variability of wild fish assemblages around sea-cage fish farms: implications for management

Marine Ecology Progress Series ◽

10.3354/meps304015 ◽

2005 ◽

Vol 304 ◽

pp. 15-29 ◽

Cited By ~ 58

Author(s):

T Dempster ◽

D Fernandez-Jover ◽

P Sanchez-Jerez ◽

F Tuya ◽

J Bayle-Sempere ◽

...

Keyword(s):

Fish Assemblages ◽

Wild Fish ◽

Fish Farms ◽

Sea Cage ◽

Cage Fish ◽

Vertical Variability

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Interference of cage fish farm on diet, condition factor and numeric abundance on wild fish in a Neotropical reservoir

Aquaculture ◽

10.1016/j.aquaculture.2013.07.013 ◽

2013 ◽

Vol 414-415 ◽

pp. 56-62 ◽

Cited By ~ 13

Author(s):

Igor P. Ramos ◽

Heleno Brandão ◽

Augusto S. Zanatta ◽

Érica de O.P. Zica ◽

Reinaldo J. da Silva ◽

...

Keyword(s):

Condition Factor ◽

Fish Farm ◽

Wild Fish ◽

Cage Fish

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Diet of otters (Lutra lutra) in various habitat types in the Pannonian biogeographical region compared to other regions of Europe

PeerJ ◽

10.7717/peerj.2266 ◽

2016 ◽

Vol 4 ◽

pp. e2266 ◽

Cited By ~ 12

Author(s):

József Lanszki ◽

István Lehoczky ◽

Antoinette Kotze ◽

Michael J. Somers

Keyword(s):

Habitat Type ◽

Hierarchical Cluster ◽

Trophic Niche ◽

Lutra Lutra ◽

Fish Diet ◽

Fish Farms ◽

Habitat Types ◽

Mediterranean Regions ◽

Biogeographical Region ◽

Study Sites

Knowledge of the effect of habitat type and region on diet and feeding behaviours of a species facilitates a better understanding of factors impacting populations, which contributes to effective conservation management. Using spraint analysis and relative frequency of occurrence data from the literature, we described the dietary patterns of Eurasian otters (Lutra lutra) in 23 study sites within the Pannonian biogeographical region in Hungary. Our results indicated that diet composition varied by habitat type and is therefore context dependant. The differences among habitat types were however lower than expected. We noticed a decline in the fish consumption with a concomitant increase in trophic niche breadth and amphibian consumption in rivers, ponds (fish farms), backwaters, marshes and small watercourses. The main differences in diet were not attributed to the consumption of primary and secondary food types (fish and amphibians), but rather to differences in other, less important food types (mammals, birds). Using hierarchical cluster analysis, rivers and ponds could clearly be separated from other habitat types. We found the main fish diet of otters in most of these areas consisted of small (<100 g), eurytopic, littoral and non-native, mostly invasive species. Dietary studies from 91 sites in six European biogeographical regions showed that fish are consumed most frequently in the Atlantic and Boreal, less in the Continental and Pannonian, and least in the Alpine and Mediterranean regions. Comparative analysis indicated that the Mediterranean region (with frequent crayfish consumption) and Alpine region (frequent amphibian consumption) cluster separate from the other regions.

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