Department of Marine Science, Mindanao State University-Iligan Institute of Technology, Bonifacio Ave., Tibanga, Iligan City
Corresponding author
ephrime.metillo@g.msuiit.edu.ph
The last assessment of three commercially important mud crab species (Scylla tranquebarica, S. olivacea and S. serrata) in the mangrove dominated Panguil Bay was in 2005; there was already an indication of the stock decline. This study aimed to continue the assessment but focused on production, growth parameters, total mortality, and exploitation rate of the three mud crab species at seven mud crab landing sites from March 2017 to March 2019 following standard fisheries enumeration protocols. Results showed that the total resource production in Panguil Bay decreased from 201.1 MT in 2005 to 103.0 MT in 2017-2019. Growth parameters of the three species for male and female, respectively are as follows: S. tranquebarica (L∞ = 11.5 cm and 11.7 cm, annual growth coefficient K = 0.6 and 0.6, exploitation rate E of 0.5 and 0.5); S. olivacea (L∞ =10.9 cm and 11.4 cm, K = 0.5 and 0.6, E = 0.6 and 0.5); and S. serrata (L∞ = 12.3 cm and 12.9 cm, K = 0.7 and 0.6, E = 0.6 and 0.6). Total production of mud crabs increased, and the three species are highly exploited, but exploitation rates are already slightly below or above maximum sustainable yield (Emax). A total of 1,848 fishers were recorded owning 2,015 boats composed of 1,419 motorized and 596 non-motorized. An inventory showed an increase of 5.36% in the number of motorized boats from the last assessment in 2005. A total of 15 types of gear were recorded, in which the top three include fish corral, crab pot, and gill net. Consequently, this study recommends reducing the present fishing pressure or effort of the three mud crab species, particularly during the spawning season occurring on wet months (July to October), for sustained mud crab fisheries in Panguil Bay.