This study investigated the behaviour and commercial catchability of snow crab(Chionoecetes opilio)in response to different low-powered LED lights under laboratory and field conditions.We created a novel choice-experi...This study investigated the behaviour and commercial catchability of snow crab(Chionoecetes opilio)in response to different low-powered LED lights under laboratory and field conditions.We created a novel choice-experiment in a laboratory setting in which we investigated the behaviour of snow crab in response to coloured LED lights.The results showed that snow crab movement was dependent on light colour,with animals choosing to move toward blue and white lights,away from purple lights,and no detectable effect for green and red lights.We then conducted two field experiments to investigate the effect of the same LED lights on the catch rates of commercial traps during the 2016 snow crab fishery on the east coast of Newfoundland and Labrador.Results from the first field experiment showed that adding white and purple LED lights into baited traps significantly improved Catch Per Unit Effort(CPUE)by 77% and 47% respectively.Results from the second field experiment showed that unbaited traps equipped with only LED lights(no bait),could also catch snow crab in comparable amounts to traditional baited traps,with soak time and depth explaining some of the variation in CPUE.Taken together,these experiments suggest that fishing enterprises can improve their catching performance and profitability by adding LED lights to their traps,or by using LED lights as a bait replacement.展开更多
In frame of fisheries management, a stock assessment using surplus production models incorporating environmental parameters was dealt with one of the most important commercially crustacean fisheries resources along th...In frame of fisheries management, a stock assessment using surplus production models incorporating environmental parameters was dealt with one of the most important commercially crustacean fisheries resources along the Tunisian coast, the Melicertus kerathurus stock. The analysis was carried out for a period of 17 years with a database including fishing efforts, catches, catch per unit effort (CPUE) and sea surface temperature (SST). CLIMPROD is the software used to select the appropriate model and fit to the fishery and environmental data. Overall, SST was positively correlated to the yield and abundance index (CPUE) explaining 47% and 57% of their variability respectively, nevertheless. The incorporation of the SST in global model demonstrated that the SST influenced both the catchability and the abundance of this species separately. In fact the impact of SST leads to consider a production model impacted on the one hand by a linear relationship between the CPUE and the fishing effort, and on the other hand by also a linear relationship between the CPUE and the SST for both catchability or abundance of the species. The interpretation of global model with environmental parameters is changed with the incorporation of climate parameter.展开更多
This study investigated the effect of installing underwater light-emitting diode(LED)lights in different locations(close and distant to the trap entrance)and orientations(normal and upside down direction)inside baited...This study investigated the effect of installing underwater light-emitting diode(LED)lights in different locations(close and distant to the trap entrance)and orientations(normal and upside down direction)inside baited traps targeting snow crab(Chionoecetes opilio)off the coast of Newfoundland and Labrador,Canada.Four experimental treatments were evaluated in comparison with traditional baited traps(control).Our results showed each of the experimental treatments produced significantly higher(39%–57%;48%on average)catch per unit effort(CPUE)compared to the control traps,with no significant differences for both legal and sublegal-sized crab among the different experimental treatments.Longer soak times significantly increased the CPUE of the illuminated traps,but did not affect the catch rate of the control traps.Our results also indicated crab size frequency distributions were independent of experiment treatments.Our results suggest that fishing enterprises could improve their catching performance by adding LED lights to their traps,but the location and orientation of the lights appears unimportant.展开更多
文摘This study investigated the behaviour and commercial catchability of snow crab(Chionoecetes opilio)in response to different low-powered LED lights under laboratory and field conditions.We created a novel choice-experiment in a laboratory setting in which we investigated the behaviour of snow crab in response to coloured LED lights.The results showed that snow crab movement was dependent on light colour,with animals choosing to move toward blue and white lights,away from purple lights,and no detectable effect for green and red lights.We then conducted two field experiments to investigate the effect of the same LED lights on the catch rates of commercial traps during the 2016 snow crab fishery on the east coast of Newfoundland and Labrador.Results from the first field experiment showed that adding white and purple LED lights into baited traps significantly improved Catch Per Unit Effort(CPUE)by 77% and 47% respectively.Results from the second field experiment showed that unbaited traps equipped with only LED lights(no bait),could also catch snow crab in comparable amounts to traditional baited traps,with soak time and depth explaining some of the variation in CPUE.Taken together,these experiments suggest that fishing enterprises can improve their catching performance and profitability by adding LED lights to their traps,or by using LED lights as a bait replacement.
文摘In frame of fisheries management, a stock assessment using surplus production models incorporating environmental parameters was dealt with one of the most important commercially crustacean fisheries resources along the Tunisian coast, the Melicertus kerathurus stock. The analysis was carried out for a period of 17 years with a database including fishing efforts, catches, catch per unit effort (CPUE) and sea surface temperature (SST). CLIMPROD is the software used to select the appropriate model and fit to the fishery and environmental data. Overall, SST was positively correlated to the yield and abundance index (CPUE) explaining 47% and 57% of their variability respectively, nevertheless. The incorporation of the SST in global model demonstrated that the SST influenced both the catchability and the abundance of this species separately. In fact the impact of SST leads to consider a production model impacted on the one hand by a linear relationship between the CPUE and the fishing effort, and on the other hand by also a linear relationship between the CPUE and the SST for both catchability or abundance of the species. The interpretation of global model with environmental parameters is changed with the incorporation of climate parameter.
文摘This study investigated the effect of installing underwater light-emitting diode(LED)lights in different locations(close and distant to the trap entrance)and orientations(normal and upside down direction)inside baited traps targeting snow crab(Chionoecetes opilio)off the coast of Newfoundland and Labrador,Canada.Four experimental treatments were evaluated in comparison with traditional baited traps(control).Our results showed each of the experimental treatments produced significantly higher(39%–57%;48%on average)catch per unit effort(CPUE)compared to the control traps,with no significant differences for both legal and sublegal-sized crab among the different experimental treatments.Longer soak times significantly increased the CPUE of the illuminated traps,but did not affect the catch rate of the control traps.Our results also indicated crab size frequency distributions were independent of experiment treatments.Our results suggest that fishing enterprises could improve their catching performance by adding LED lights to their traps,but the location and orientation of the lights appears unimportant.
