Analisis ekobiologi sebagai dasar pengelolaan sumberdaya kerang darah (Anadara granosa) di Teluk Lada Perairan Selat Sunda

Abstract

Blood cockle is one of the potential resources which plays an important role both ecologically and economically. This research was carried out at Lada Bay Sunda Strait for 6 months from July to December 2011. The purposes of this research are to investigate eco-biological status, to scrutinize aspects of utilization and to determine appropriate and best-use strategies of safe and sustainable blood cockle (Anadara granosa) resources at Lada bay Sunda strait. The research method used is ex post facto. Samples were taken by swept area method, employing fishing gear "garok" in 5 zones and each zone consists of 3 observation stations. Results showed that the catch of blood cockle (Anadara granosa) was not evenly distributed in each zone with the highest density found in zone V (Suladengan) while the lowest in zone II (Tegal Papak). Total Suspended Solids (TSS), turbidity, NH3, Hg, Pb and Cd have exceeded the recommended quality standards. Correlational analysis of length-weight on male and female cockle, and combination between male and female cockle has negative allometric growth pattern with each correlational equation W = 0.043H1.578, W = 0.029H1.734 and W=0.003 H1.678, with b rate < 3, indicating that the wide growth of the cockle is faster than its tissue weight growth. Condition factor on male cockle started rising in September while on female, it started rising in August and both reached their peak in October. It seemed to indicate that female cockle spawned faster with longer spawning time than male cockle. Condition index showed rate < 2.5 thus all the cockles caught were categorized to be thin(skinny). Infinity width on both male and female cockle are 34,14 and 43,59 mm, however the size of male cockle, in average, is smaller than female cockle. Growth coefficient (K) of males and females were 0.990 and 0,53 respectively, indicated that the growth rate of male cockle is relatively faster than female cockle. Total mortality rate (Z) of male is bigger than female, while in which caught mortality rate (F) is bigger than natural mortality rate (M). The rapid rate of exploitation is >0.5 which means that the fishing of cockle at the Lada Bay is categorised as overfishing. Sex ratio is balance namely 1:1. The highest Gonad Maturity Stages (GMS) percentage is shown by GMS I (50%), followed consecutively by GMS II (29%), GMS III (24%) and GMS IV (1%). The first stage of gonad maturity on male cockle is on the size 28.30 mm and on female cockle is on 27.31 mm. Strategies in managing blood cockle (A. granosa) resources taking into account the ecological and biological dimensions as a management priority at Lada Bay Sunda Strait can be executed by the basic concept of management cockle, consist of 4 (four) cockle resource management strategies, namely: (a) Regulating the disposal of industrial waste (b) The planting and regeneration of mangroves vegetation, (c) Regulating the activity of sand mining and (d) Regulating of fishing activities , including time, area (fishing ground) and fishing gear.