POPULATION DYNAMICS AND AQUACULTURE POTENTIAL OF THE MUD CLAM, Geloina expansa (MOUSSON, 1849) (BIVALVIA: CYRENIDAE) IN LOAY-LOBOC RIVER, BOHOL, CENTRAL PHILIPPINES

Abstract

The status of the mud clam, Geloina expansa, an important bivalve in the artisanal fisheries of the Loay-Loboc River, was assessed using monthly shell length frequency data (October, 2012 to January, 2015 to estimate population parameters. Growth parameters derived were L ∞ = 91.35 mm, K = 0.75 yr -1 and t 0 = -0.16. Predicted L max was 90.39 mm. Estimated growth rates showed fast growth for the first two years. Longevity is approximately 6.1 years. Length-weight relationship showed a positive allometric growth (r 2 = 0.94). The estimated total mortality (Z) was 2.89 yr -1 . Natural (M) and fishing (F) mortalities estimates were 0.90 yr -1 and 1.99 yr -1 , respectively. Estimated exploitation rate (E = 0.69) was higher than the maximum sustainable exploitation (E max = 0.41). Two annual recruitment peaks occurred during the months of December to February and July to August. Monthly condition index (CI) suggested that spawning is year-round. It appeared that the variations in CI of G. expansa in the river was influenced by the water temperature and salinity (r² = 0.54; P < 0.0001). These biological information may be used for aquaculture technique development for G. expansa in central Philippines which will aid in the conservation and management of natural stocks.

Population dynamics of blood clams Tegillarca granosa in Kendari Bay, Southeast Sulawesi, Indonesia

“…celebensis (Bahtiar 2012;Bahtiar et al 2016) and Polymesoda erosa (Dolorosa and Dangan-Galon 2014) (Table 2). The natural mortality of the blood clams was 2.18 yr -1 , and it was similar to that of others in the same genus, including A. granosa (Mirzaei et al 2014) and A. gubernaculum (Fauzan et al 2018), but higher than Polymesoda expansa (Argente and Ilano 2013), Potamocorbula faba (Hariyadi et al 2017), Donax trunculus (Çolakoğlu 2014), Geloina expansa (Yahya 2017), P. erosa (Dolorosa and Dangan-Galon 2014), P. acutidens (Efriyeldi et al 2012), andB. violacea var.…”

“…celebensis along 2 km, especially in smaller species (Bahtiar 2012;Bahtiar et al 2016). 2016) Descriptions: Z: mortality coeffiecient (yr -1 ); M: natural mortality coefficient (yr -1 ); F: fishing mortality coefficient (yr -1 ); E: exploitation rate The fishing mortality of the blood clams in Kendari Bay was 0.29yr -1 , and this was higher than that of other species, namely P. expansa (Argente and Ilano 2013), and Potamocorbula faba (Hariyadi et al 2017). Meanwhile, the value obtained was similar to that of some clams, as shown in Table 3.…”