ASSESSMENT OF SAND LOBSTER (PANULIRUS HOMARUS) RESOURCES IN PALABUHANRATU WATERS OF SUKABUMI, WEST JAVA, INDONESIA

Lobster fisheries resources are popular food commodities with high economic value. Consequently, lobsters are captured globally and have very high selling prices. Palabuhanratu Bay is one of the lobster fisheries centers in West Java, Indonesia. Sand lobster ( Panulirus homarus ), one of the lobster species in Palabuhanratu Bay, has experienced a decrease in the catch. This research aims to (1) examine the sand lobster population based on biological aspect and population dynamics aspect; (2) identify the utilization status and management of sand lobster resources. Population parameter was analyzed using the FISAT II program and Maximum Sustainable Yield (MSY) potential assessment. The results showed that sand lobster carapace length ranged between 30-101 mm with 97.6% carapace length below 8 cm. The growth pattern of sand lobsters was negative allometric. The Lc <Lr value indicated that female sand lobsters have been caught before reaching the mean size at onset of spawning. Asymptotic length (L∞) of male sand lobsters was smaller than female sand lobsters, while growth coefficient (K) of male sand lobsters was faster than female sand lobsters. The rate of exploitation (E) values for male and female sand lobsters showed above optimum values of 0.59 and 0.61. The sustainable potential and lobster resource utilization level in WPP 573 Waters was 662.93 tons/year and 910 thousand trips with nets as standard fishing gears. Catch fluctuated with a decreasing trend and the rate of exploitation above the optimum value. It indicated that overfishing has occurred.

The high economic value of lobsters is one of the factors causing continuous lobster fishing with no attention to the resource and environmental conditions. Lack of awareness of fishery practitioners (communities, businesspersons, and fishermen) on the importance of environmentally-friendly fishing practices that can guarantee the sustainability of sea lobster stocks will damage lobster ecosystem and habitat, causing a reduction in the commodity stocks (Wardiatno and Mashar, 2013).
Palabuhanratu Waters is a potential waters with abundant fisheries resources and used as fishing areas for fishermen, one of which is lobster fishing. The high economic value of sand lobsters (Panulirus homarus) is one of the factors that encourage Palabuhanratu fishermen to conduct continuous fishing activities without regard to the resources and environmental sustainability. Fishermen are lack of awareness to control fishing as well, for example by regulating the number of catches and lobster fishing effort.

LITERATURE REVIEW
Palabuhanratu community identifies sand lobsters with the name of crayfish. Classification of sand lobsters according to Chan (1998)   In general, the growth rate of lobsters in the family Palinuridae ranges between 0.27-0.54/year. The asymptotic carapace length is quite diverse but generally ranges between 118-164 mm. The values of the growth rate and the asymptotic carapace length are used to determine the maximum lifespan of a lobster population. From some research results, the maximum lifespan of lobsters in the family Palinuridae ranges between 10-14 years (Kadafi et al., 2006). Cobb and Phillips (1980) state that lobsters are found mostly in coastal waters, especially on rocky bottoms or coral reefs, and sometimes on sandy bottoms mixed with aquatic plants. Adult lobsters generally molt and breed during the summer, so that a ban on lobster fishing during this period provides an opportunity for population development (Moosa MK and Aswandy I, 1984).
Population dynamics refers to how populations change in size over time. Population dynamic of lobster resources in waters is characterized by changes in population size both through additions and subtractions (Wijaya, 2007). In the balance of population dynamics, additions to the population can be caused by births, deaths, and migrations of lobster resources. According to Badrudin (2012), the catch per unit effort (CPUE) is a measure of relative abundance as one indicator of lobster resource status, while production levels can act as economic performance indicators. The CPUE trend of fisheries is an important indicator of fishery health.

METHODS OF RESEARCH
The research location was the waters around Palabuhanratu, Sukabumi Regency, West Java Province (WPP 573). Palabuhanratu waters is located in the Indian Ocean region at the geographical position of 06 0 50'-07 0 30' S and 106 0 10'-106 0 30' E. The preparation stage until the field survey was conducted from March to May 2018.

Figure 2 -Research Location in Palabuhanratu Bay Waters
Samples were observed for 3 months with data collection intervals once every two weeks using the census and simple random sampling method. The census method was utilized when the lobster catches were few that enabled thorough observation. Data measured included carapace length (mm), weight (mg), lobster sex, and the number of eggbearing lobsters. Lobster measurements were carried out on the species of P. homarus caught by previously selected fishermen. Carapace length of the lobsters used as the samples was measured using a caliper with a precision of 0.1 mm and weight was determined using a digital balance with a precision of 0.01 g. Functional maturity of the female lobsters was observed by direct observation of the presence/absence of eggs under the abdomen (berried female). Primary data collection for economic aspects in this research was conducted using a structured interview method with a questionnaire list. In-depth interviews covered all aspects of production activities, including lobster selling prices and fishing operational costs, such as ships, machinery, fishing gear, fuel, and ship crew supplies.
Data on sand lobster carapace length were categorized into several length groups, so the i th length group had a frequency. Estimation of the size group was conducted by analyzing the lobster carapace length frequency using the ELEFAN I (Electro Length Frequency Analysis) method with the FISAT II (FAO-ICLARM Stock Assessment Tool) program to determine lobster frequency distribution based on length and weight and lobster identification based on sex and gonad maturity. In addition, the growth and mortality rate of sand lobsters could also be examined through the curves produced by the FISAT II (FAO-ICLARM Stock Assessment Tool) program. Production and fishing armadas data were grouped and tabulated using Microsoft Excel to obtain the productivity value of fishing gear, Catch per Unit Effort (CPUE), fishing season, and Fishing Power Index (FPI). Thus, the utilization of sand lobsters in Palabuhanratu can be analyzed.
The length-weight relationship was calculated based on the following formula proposed by Effendie (1997) The length at first capture value or the length at which 50% of a fish at first capture was calculated by the following formula (Sparre & Venema, 1999 in Nuruludin and Sadhotomo, 2013).
Equation can be rewritten as: The mean size at first gonad maturity (Lm) was calculated using the Spearman-Karber formula developed by Udupa (1986) as follows:

RESULTS AND DISCUSSION
Previous lobster research in Palabuhanratu Bay obtained a range of carapace length (CL) which was not significantly different from Zairion et al.'s (2017) research. Carapace length of lobsters caught using nets ranged between 28-100 mm.  The carapace length-weight relationship of male and female lobsters obtained the coefficient of determination (R2) of 0.73 and 0.76. It means the lobster carapace length influenced 73% of weight for male lobsters and 76% for female lobsters. The analysis results also obtained the growth pattern with the length-weight relationship of W = 0.0353CL 2.0612 for male lobsters and W = 0.0348CL 2.0651 for female lobsters. It means male sand lobsters had a faster growth of carapace length than weight compared to female sand lobsters.
The ELEFAN I method in the FiSAT II program was used for age group analysis. The analysis results of the age groups of male sand lobsters and female sand lobsters indicated growth with an increase in the cohort line.
The mean length at first capture (Lc) is the length at which 50% of the animals sampled are caught on the selectivity of fishing gear. The mean carapace length at first capture for male and female sand lobsters were 43.56 mm and 52.71 mm respectively. These research results were not significantly different from Zairion et al.'s (2017) research in which the mean carapace length at first capture (Lc) of male lobsters was 50.45 mm and female lobsters was 59.87 mm. The size of the lobster catches results indicated high activity intensity condition in fishing activities and the high rate of exploitation.

CONCLUSION
Distribution of carapace length frequency of sand lobster (Panulirus homarus) in Palabuhanratu Waters ranged between 30-101 mm with 97.6% carapace length below 8 cm. The growth pattern of male and female sand lobsters was negative allometric. Many female sand lobsters have been caught before reaching the mean size at onset of spawning.The rate of exploitation of sand lobsters was above the optimum value of lobster fishing. The status of lobster resources utilization in Palabuhanratu waters showed a decreasing utilization trend which indicated overfishing.