Mesh size selectivity of surface and mid-water gillnet for catching freshwater sardines “Sardinella tawilis” (Herre, 1927) in Taal Lake, Philippines
Technical information on the mesh size selectivity for tawilis fishery in Taal Lake is presently unknown or undocumented and different mesh sizes of gillnets are employed to exploit the species at various sizes. The study investigated the mesh size selectivity involving gillnet fishery for Sardinella tawilis using four different mesh sizes: 3.39 cm (10k), 3.05 cm (11k), 2.77 cm (12k), and 2.65 cm (12.5k). Fishing trials were conducted in Taal Lake, Philippines from October 2014 to September 2015. A total of 4,456 pieces of S. tawilis were caught with the length ranges from 8.5 cm to 14.5 cm mid-length. The seasonal changes in the gonadosomatic index (GSI) showed that S. tawilis spawns between March-May and August. Length at 50% maturity (L50) was estimated at 11.66 cm and used as the criterion for selecting the appropriate mesh size. The optimal length for each mesh size was estimated employing the Baranov-Holt method. The estimated optimal lengths of S. tawilis were estimated at 10.6 cm, 11.08 cm, 13.07 cm, and 14.53 cm for the mesh sizes of 12.5k, 12k, 11k, and 10k, respectively. Hence, the appropriate gillnet mesh size for S. tawilis corresponding to length at 50% maturity was 3.05 cm (11k).
| Main Authors: | , , |
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| Format: | article biblioteca |
| Language: | English |
| Published: |
2018
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| Subjects: | Conservation, Fisheries, Policies, optimum mesh size, selectivity, sustainable exploitation, gill net, |
| Online Access: | http://hdl.handle.net/1834/40949 |
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