... literature there are several studies investigating codend selectivity for hake (Ferretti and ... more ... literature there are several studies investigating codend selectivity for hake (Ferretti and Froglia, 1975; Petrakis and Stergiou, 1997; Fiorentini and Leonori, 2002; Campos et al., 2003; Campos and Fonseca, 2003; Petrakis and Tosunoğlu et al., 2003; Özbilgin et al., 2005), but no ...
Summary The growth and mortality of Mullus barbatus from Izmir Bay (Aegean Sea) was investigated ... more Summary The growth and mortality of Mullus barbatus from Izmir Bay (Aegean Sea) was investigated based on length frequency data using the fisat software. Total length of the sampled 110 891 fish ranged from 5.0 to 23.0 cm. The seasonalized von Bertalanffy growth resulted in parameter values of L∞= 24.26 cm, k= 0.565, t 0=− 0.305, C= 0.27 and WP= 0.45. Potential lifespan was estimated to be 5.3 years. Total mortality (Z) based on the length converted catch curve was 3.70 (seasonal data) and 3.85 (non-seasonal data). Natural ...
If fish that have passed through the meshes of a fishing net are capable of escaping more easily ... more If fish that have passed through the meshes of a fishing net are capable of escaping more easily on subsequent encounters, there may be important implications for the efficiency and selectivity of fishing gears in heavily fished populations. Here we report on the effect of learning on mesh penetration of haddock (Melanogrammus aeglefinus) under laboratory conditions. Ten haddock were trained using a classical conditioning procedure (with food) to race between two alternately flashing light emitting diodes (LEDs) positioned at the ends of a 6-m-long oval swimming pool. Once the fish were conditioned to race between the LEDs, their penetration ratios in netting barriers of 200-mm and 100-mm bar length, square-mesh curtains in their path on each food presentation were calculated. Fish were reluctant to penetrate mesh barriers of 200 mm at the beginning of the experiment, but all the experimental animals did manage to penetrate. The ratio of these fish in penetrating the smaller mesh si...
We investigate the variation in three separate months of trawl codend size selection for haddock,... more We investigate the variation in three separate months of trawl codend size selection for haddock, paying attention to changes in the length/girth relationship, and size of the total catch in the codend. Three cruises were conducted on the same fishing grounds using the same fishing gear on board the same commercial trawler in April 1995, September 1995, and February 1996. The periods coincided with postspawning in April, post-summer feeding in September, and prespawning in February. The seawater temperature at the seabed on the fishing grounds was near its annual maximum in September (12.2°C) and annual minimum in February (7.2°C) and in April (7°C). There was significant variation in selectivity of haddock with month and total catch in the codend. Fish length and, for two of the three cruises, fish maximum girth were used as variables in selectivity analysis. The probability of being retained was lowest in September, when the fish were in good condition and water temperature was hi...
... Using a reduced number of meshes around the codend has been reported to result in an increase... more ... Using a reduced number of meshes around the codend has been reported to result in an increase in L50 values for several fish species (Lök et al., 1997; Fiorentini & Leonori, 2002; Özbilgin et al., 2005) in the Mediterranean. ...
... Comparison of the selectivities of double and single codends. Fish. Res., 63: 143-147. ÖZBILG... more ... Comparison of the selectivities of double and single codends. Fish. Res., 63: 143-147. ÖZBILGIN, H., Z. TOSUNO ˘GLU, C. AYDIN, H. KAYKAÇ & A. TOKAÇ, 2005. ... Fish. Res., 67: 317-327. TOKAÇ, A., Z. TOSUNO ˘GLU, G. GÖKÇE, H. KAYKAÇ & H. ÖZBILGIN, 2005. ...
... Then, the crabs were released into the stocking tank. Six trials were Page 4. 280GÖKHAN GÖKÇE... more ... Then, the crabs were released into the stocking tank. Six trials were Page 4. 280GÖKHAN GÖKÇE ET AL. conducted in each experimental tank per day. The mean number of crabs used in each trial was 132 (±11.67 se). The ...
Turkish Journal of Veterinary and Animal Sciences, Jun 8, 2006
Abstract: Demersal trawling in Turkish waters yields a considerable amount of by-catch and discar... more Abstract: Demersal trawling in Turkish waters yields a considerable amount of by-catch and discard. Data presented in this study were collected during a demersal trawl codend selectivity trial carried out on board the RV Egesüf (27 m, 500 HP) between August 9 and ...
... literature there are several studies investigating codend selectivity for hake (Ferretti and ... more ... literature there are several studies investigating codend selectivity for hake (Ferretti and Froglia, 1975; Petrakis and Stergiou, 1997; Fiorentini and Leonori, 2002; Campos et al., 2003; Campos and Fonseca, 2003; Petrakis and Tosunoğlu et al., 2003; Özbilgin et al., 2005), but no ...
Summary The growth and mortality of Mullus barbatus from Izmir Bay (Aegean Sea) was investigated ... more Summary The growth and mortality of Mullus barbatus from Izmir Bay (Aegean Sea) was investigated based on length frequency data using the fisat software. Total length of the sampled 110 891 fish ranged from 5.0 to 23.0 cm. The seasonalized von Bertalanffy growth resulted in parameter values of L∞= 24.26 cm, k= 0.565, t 0=− 0.305, C= 0.27 and WP= 0.45. Potential lifespan was estimated to be 5.3 years. Total mortality (Z) based on the length converted catch curve was 3.70 (seasonal data) and 3.85 (non-seasonal data). Natural ...
If fish that have passed through the meshes of a fishing net are capable of escaping more easily ... more If fish that have passed through the meshes of a fishing net are capable of escaping more easily on subsequent encounters, there may be important implications for the efficiency and selectivity of fishing gears in heavily fished populations. Here we report on the effect of learning on mesh penetration of haddock (Melanogrammus aeglefinus) under laboratory conditions. Ten haddock were trained using a classical conditioning procedure (with food) to race between two alternately flashing light emitting diodes (LEDs) positioned at the ends of a 6-m-long oval swimming pool. Once the fish were conditioned to race between the LEDs, their penetration ratios in netting barriers of 200-mm and 100-mm bar length, square-mesh curtains in their path on each food presentation were calculated. Fish were reluctant to penetrate mesh barriers of 200 mm at the beginning of the experiment, but all the experimental animals did manage to penetrate. The ratio of these fish in penetrating the smaller mesh si...
We investigate the variation in three separate months of trawl codend size selection for haddock,... more We investigate the variation in three separate months of trawl codend size selection for haddock, paying attention to changes in the length/girth relationship, and size of the total catch in the codend. Three cruises were conducted on the same fishing grounds using the same fishing gear on board the same commercial trawler in April 1995, September 1995, and February 1996. The periods coincided with postspawning in April, post-summer feeding in September, and prespawning in February. The seawater temperature at the seabed on the fishing grounds was near its annual maximum in September (12.2°C) and annual minimum in February (7.2°C) and in April (7°C). There was significant variation in selectivity of haddock with month and total catch in the codend. Fish length and, for two of the three cruises, fish maximum girth were used as variables in selectivity analysis. The probability of being retained was lowest in September, when the fish were in good condition and water temperature was hi...
... Using a reduced number of meshes around the codend has been reported to result in an increase... more ... Using a reduced number of meshes around the codend has been reported to result in an increase in L50 values for several fish species (Lök et al., 1997; Fiorentini & Leonori, 2002; Özbilgin et al., 2005) in the Mediterranean. ...
... Comparison of the selectivities of double and single codends. Fish. Res., 63: 143-147. ÖZBILG... more ... Comparison of the selectivities of double and single codends. Fish. Res., 63: 143-147. ÖZBILGIN, H., Z. TOSUNO ˘GLU, C. AYDIN, H. KAYKAÇ & A. TOKAÇ, 2005. ... Fish. Res., 67: 317-327. TOKAÇ, A., Z. TOSUNO ˘GLU, G. GÖKÇE, H. KAYKAÇ & H. ÖZBILGIN, 2005. ...
... Then, the crabs were released into the stocking tank. Six trials were Page 4. 280GÖKHAN GÖKÇE... more ... Then, the crabs were released into the stocking tank. Six trials were Page 4. 280GÖKHAN GÖKÇE ET AL. conducted in each experimental tank per day. The mean number of crabs used in each trial was 132 (±11.67 se). The ...
Turkish Journal of Veterinary and Animal Sciences, Jun 8, 2006
Abstract: Demersal trawling in Turkish waters yields a considerable amount of by-catch and discar... more Abstract: Demersal trawling in Turkish waters yields a considerable amount of by-catch and discard. Data presented in this study were collected during a demersal trawl codend selectivity trial carried out on board the RV Egesüf (27 m, 500 HP) between August 9 and ...
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