Mesh Size in the Fishery of Greenland Halibut in the NAFO Regulatory Area by

• Main Authors: S. Lisovsky, A. Pavlenko, Yu. Kondratyuk
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Greenland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.488.7360; http://archive.nafo.int/open/sc/2002/scr02-029.pdf

The paper describes the results of selectivity tests for codends with 130.8, 145.2 and 150.2 mm mesh size in Greenland halibut fishery in the NAFO Regulatory Area. Selectivity parameters for males and females were not found to differ significantly; therefore, the results were analyzed regardless of sex. The calculations were made by the generalized logistic (Richard’s) and logistic functions of dependence of fish retention on length. Estimating the likelihood by both models through minimizing Akaike’s Information Criterion (AIC) showed that Richard’s function more precisely described fish retention. In a series of experiments the length of fish corresponding to 50 % retention ranged from 41.7 cm for 130.8 mm mesh to 45.2 and 46.7 cm for, respectively, 145.2 and 150.2 mm meshes. Selectivity range was 6.1- 8.4 cm and selectivity coefficient varied from 3.1 to 3.2. Calculated fish length corresponding to 25 % retention ranged from 38.2 for 130.2 mm mesh to 41.8 cm for that one with 150.2 mm size. Processing the data obtained indicated that an increase of trawl mesh size from 130 mm and over would not be profitable in the long term. Trawl fishery for Greenland halibut would be economically inexpedient owing to a significant reduction in the efficiency of trawls with larger mesh. The commercial size of Greenland halibut for trawls with 130 mm mesh can be increased to 34 cm. In this case, the by-catch of undersized fish will not exceed 10 % in numbers, as adopted by the NAFO Fisheries Commission.