Comparison of a rigid grid to a square-mesh panel in size selection for commercial fishing in the Persian Gulf shrimp trawl fishery

2016 ◽  
Vol 32 (6) ◽  
pp. 1026-1031 ◽  
Author(s):  
M. Eighani ◽  
S. Y. Paighambari ◽  
S. Eayrs
Keyword(s):  
Persian Gulf ◽  
Commercial Fishing ◽  
Size Selection ◽  
Trawl Fishery ◽  
Shrimp Trawl ◽  
Selection For ◽  
The Persian Gulf

scholarly journals Escape rate for cod (Gadus morhua) from the codend during buffer towing

2017 ◽  
Vol 75 (2) ◽  
pp. 805-813 ◽  
Author(s):  
Jesse Brinkhof ◽  
Bent Herrmann ◽  
Roger B Larsen ◽  
Manu Sistiaga
Keyword(s):  
Gadus Morhua ◽  
Disease Susceptibility ◽  
Barents Sea ◽  
Escape Rate ◽  
Commercial Fishing ◽  
Size Selectivity ◽  
Size Selection ◽  
Selection For ◽  
Significant Size ◽  
Growth And Reproduction

Abstract The high abundances of Northeast Arctic cod (Gadus morhua) in the Barents Sea have led to the development of a new fishing tactic called buffer towing. On factory trawlers, the trawl is deployed immediately after taking the catch onboard, a tactic used to ensure a continuous supply of fish is being processed. If the desired amount of fish is caught before the catch from the previous haul has been fully processed, the trawl is lifted off the seabed and towed at a given depth at low speed. This is called buffer towing. Cod that escape from the codend when the trawl is shallower than the initial fishing depth are exposed to an increased likelihood of barotrauma-related injuries, increased disease susceptibility, and predation, which could be lethal, or affect growth and reproduction capability. Therefore, this study quantified the escape rate and size selectivity during buffer towing of cod. A new analytical method was applied that allows using the same trawl configuration as applied during commercial fishing and avoids potential bias in the assessment of buffer towing size selection. Our results demonstrated a significant size selection for cod during buffer towing where cod measuring up to at least 42 cm in length were proven to escape. In particular, at least 60% of cod measuring 20 cm were estimated to escape during buffer towing. For cod measuring 30 and 40 cm, at least 53 and 45% were estimated to escape during buffer towing, respectively.

scholarly journals New approach for modelling size selectivity in shrimp trawl fisheries

2017 ◽  
Vol 75 (1) ◽  
pp. 351-360 ◽  
Author(s):  
Roger B Larsen ◽  
Bent Herrmann ◽  
Manu Sistiaga ◽  
Jesse Brinkhof ◽  
Ivan Tatone ◽  
...  
Keyword(s):  
Barents Sea ◽  
Cold Water ◽  
Small Fish ◽  
Size Selectivity ◽  
Size Selection ◽  
Trawl Fishery ◽  
Size Dependent ◽  
Shrimp Trawl ◽  
Pass Through ◽  
The Individual

Abstract In the deep sea trawl fishery targeting shrimp (Pandalus borealis) and other cold-water shrimp species, fishers often use a Nordmöre sorting grid ahead of a small mesh codend to avoid bycatch. However, small fish can pass through the grid and are subsequently retained in the codend. This makes shrimp size selection complex and the size-dependent curve for both the shrimp and the bycatch species often exhibits a bell-shaped signature. In this study we developed a new model and method to estimate size selection in this fishery, conducted fishing trials in the Northeast Barents Sea, and applied the new method to quantify the individual and combined size selection of the Nordmöre grid and codend for deep water shrimp and two bycatch species. The size selectivity for both bycatch species showed the expected bell-shaped signature with low retention probability of very small and larger fish. The Nordmöre grid had high passage probability for all sizes, although it decreased slightly for the largest shrimps. The smallest shrimps were released by the codend.

scholarly journals Assessment of a juvenile and trash excluder device in a Vietnamese shrimp trawl fishery

2007 ◽  
Vol 64 (8) ◽  
pp. 1598-1602 ◽  
Author(s):  
Steve Eayrs ◽  
Nguyen Phong Hai ◽  
Janet Ley
Keyword(s):  
Juvenile Fish ◽  
Hydrodynamic Performance ◽  
Commercial Fishing ◽  
Total Catch ◽  
Low Velocity ◽  
Trawl Fishery ◽  
Bycatch Reduction ◽  
Shrimp Trawl ◽  
Hydrodynamic Study ◽  
Yield Per Recruit

Abstract Eayrs, S., Hai, N. P., and Ley, J. 2007. Assessment of a juvenile and trash excluder device in a Vietnamese shrimp trawl fishery. – ICES Journal of Marine Science, 64: 1598–1602. In this study, we (i) identified why Vietnamese shrimp fishers land juvenile fish illegally; (ii) identified groups of fishers that would use a bycatch reduction device (BRD) to exclude these fish; (iii) studied the hydrodynamic performance of a juvenile and trash excluder device (JTED) in a flume tank; and (iv) assessed the performance of this device under commercial fishing conditions. Based on the responses of 65 fishers to a questionnaire, we found that juvenile fish are now an important economic component of the total catch, and that fishers operating larger boats were more willing to use a JTED to exclude these fish than fishers operating smaller boats. The hydrodynamic study of a JTED identified the location of low-velocity regions around the device and codend, and this information can be used to identify the location of a secondary BRD to allow more fish to escape. The at-sea assessment of this device found that 73% of juvenile fish, 16% of valuable fish, and 8% of shrimp were excluded by the JTED, although most valuable fish and shrimp were smaller than the minimum legal landing size. Overall, this loss represents a 9% reduction in revenue. Yield-per-recruit analysis indicated that this could be offset by not catching fish less than the minimum legal landing size.

The Pearl Fishing in the Persian Gulf

1917 ◽  
Vol 83 (2146supp) ◽  
pp. 100-101
Author(s):  
Edwin E. Calverley
Keyword(s):  
Persian Gulf ◽  
Pearl Fishing ◽  
The Persian Gulf
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