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

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

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315420001034 ◽

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).

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Ege Denizi’nde Balık Çiftliklerinden Balık Kaçışlarının Nedenleri Üzerine

Turkish Journal of Agriculture - Food Science and Technology ◽

10.24925/turjaf.v7i12.2217-2222.2981 ◽

2019 ◽

Vol 7 (12) ◽

pp. 2217

Author(s):

Okan Akyol ◽

Tevfik Ceyhan ◽

Aytaç Özgül ◽

Faik Ozan Düzbastılar ◽

Halil Şen

Keyword(s):

Aegean Sea ◽

Fish Farms ◽

Face To Face ◽

Sea Cage ◽

Cage Fish

A total of 48 randomly selected fish farms from the coasts of Izmir and Muğla, Aegean Sea were visited face-to-face interviewing with fish farmers and a total of 329 coastal fishermen, catches around the sea-cage fish farms between July 2015 and July 2017. We asked them the reasons for fish escapes from sea-cage fish farms. Answers were concerning with the predator attacks, storms, biting of cage-nets by reared fish and seabirds, slits of the nets, drop during transfer, etc.

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

Ege Journal of Fisheries and Aquatic Sciences ◽

10.12714/egejfas.37.2.04 ◽

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.

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

Acta Ichthyologica Et Piscatoria ◽

10.3750/aiep/02681 ◽

2019 ◽

Vol 49 (4) ◽

pp. 365-373 ◽

Cited By ~ 1

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

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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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Genetic structuring in farmed and wild Gilthead seabream and European seabass in the Mediterranean Sea: implementations for detection of escapees

Aquatic Living Resources ◽

10.1051/alr/2020007 ◽

2020 ◽

Vol 33 ◽

pp. 7

Author(s):

Eirini-Slavka Polovina ◽

Evelina Kourkouni ◽

Costas S. Tsigenopoulos ◽

Pablo Sanchez-Jerez ◽

Emmanuel D. Ladoukakis

Keyword(s):

Mediterranean Sea ◽

Sparus Aurata ◽

Eastern Mediterranean ◽

Dicentrarchus Labrax ◽

Western Mediterranean ◽

Gilthead Seabream ◽

Fish Farms ◽

Genetic Structuring ◽

European Seabass ◽

The Mediterranean

Microsatellite markers were used to investigate the genetic structure of the two most important cultured fish in the Mediterranean Sea, the gilthead seabream (Sparus aurata) and the European seabass (Dicentrarchus labrax), from two (one wild and one farmed) populations in Western Mediterranean (Spain) and from two (one wild and one farmed) populations Eastern Mediterranean (Greece). All populations were in Hardy-Weinberg disequilibrium. Interestingly, wild and farmed populations for both species from Greece were genetically differentiated and could be distinguished from each other. We used Bayesian methods for cluster analysis of farmed and wild populations. Our analysis has implications for the identification of escapees from fish farms to the wild.

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Mycobacterium pseudoshottsii in Mediterranean Fish Farms: New Trouble for European Aquaculture?

Pathogens ◽

10.3390/pathogens9080610 ◽

2020 ◽

Vol 9 (8) ◽

pp. 610

Author(s):

Davide Mugetti ◽

Katia Varello ◽

Andrea Gustinelli ◽

Paolo Pastorino ◽

Vasco Menconi ◽

...

Keyword(s):

Fish Species ◽

Sparus Aurata ◽

Dicentrarchus Labrax ◽

Housekeeping Genes ◽

The United States ◽

Sciaenops Ocellatus ◽

Fish Farms ◽

Farmed Fish ◽

Potential Threat ◽

European Aquaculture

Mycobacterium pseudoshottsii, a slow-growing mycobacterium closely related to M. marinum, has been isolated only in wild fish in the United States and in Japanese fish farms to date. Here, we report cases of mortality in three farmed fish species (Dicentrarchus labrax, Sparus aurata, and Sciaenops ocellatus) caused by M. pseudoshottsii in Italy. Samples underwent necropsy, histology, and culture with pathogen identification based on PCR and sequencing of housekeeping genes (16S rRNA, hsp65, rpoB). Multifocal to coalescing granulomatous and necrotizing inflammation with acid-fast bacilli were observed in the parenchymatous organs, from which M. pseudoshottsii was isolated and identified. Phylogenetic analysis confirmed the results of gene sequencing and allowed subdivision of the isolates into three distinct groups. M. pseudoshottsii poses a potential threat for Mediterranean aquaculture. Its origin in the area under study needs to be clarified, as well as the threat to the farmed fish species.

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