Escape vents and trap selectivity in the fishery for the Juan Fernández rock lobster (Jasus frontalis), Chile |
| |
| Authors: | Patricio M Arana Juan Carlos Orellana Álvaro De Caso |
| |
| Institution: | 1. SINTEF Fisheries and Aquaculture, Fishing Gear Technology, Brattørkaia 17C, 7010 Trondheim, Norway;2. Fisheries and Aquaculture Industrial Research Fund (FHF), Universitetsgata 10, 0164 Oslo, Norway;1. Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7, 9220, Aalborg, Denmark;2. Oslo Centre for Biostatistic and Epidemiology, University of Oslo, Norway;3. DTU Aqua, National Institute of Aquatic Resources, North Sea Science Park, P.O. Box 101, DK-9850 Hirtshals, Denmark;4. SINTEF Fisheries and Aquaculture, North Sea Science Park, DK-9850, Hirtshals, Denmark;1. Shoals Rodrigues, Marine Research, Training & Education Centre, Pointe Monier, Rodrigues, Mauritius;2. School of Biology, Ridley Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK;1. Marine Biophysics Unit, Okinawa Institute of Science and Technology, Onna, Okinawa 904-0412, Japan;2. Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom |
| |
| Abstract: | To develop ways to catch fewer undersized specimens of Jasus frontalis in the traps of the rock lobster fishery off the Juan Fernández Archipelago (Chile), we studied the use of lobster traps with different-sized escape vents (circular windows of 80, 85, or 90 mm diameter). The traps used in the present fishery served as controls. Selection curves were fit to each of the vent sizes examined in the study. The method of alternating hauls was used for this purpose in a manner similar to that employed with trawl nets. We compared the size–frequency distributions obtained for each vent size with those determined for the control traps. We monitored 2437 traps and obtained a total catch of 13,444 specimens. Undersized individuals decreased in the catch as the diameter of the openings increased. The selection curves fit a logistic-type model adequately. A direct relationship was established between the vent size and the length corresponding of the first catch (L50). The CPUE for legal-sized rock lobster increased in traps having up to 85-mm vents, but this yield dropped in traps fitted with 90-mm vents. The CPUE for undersized rock lobster, however, was inversely proportional to the size of the vents. Unlike typical selectivity literature that relies on the L50, the objective of this study was to maximize the number of legal (≥98 mm Lc) specimens retained in the traps while simultaneously minimizing the retention of undersized specimens. To achieve this, we used a model relating vent size to L50 and the slope of the selection ogives. The optimal diameter for vents in this fishery was determined to be 83 mm. Furthermore, underwater recordings were used to register the escape behavior of the lobsters. These recordings contributed new data on the way in which the lobsters detect, confront, and escape through the vents. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
