THE CORRELATION OF CARAPACE WIDTH – BODY WEIGHT, CONDITION FACTOR, AND ABUNDANCE OF SCYLLA SERRATA FORSSKÅL, 1775 IN EMBANKMENT LANE SILVOFISHERY DEVELOPMENT AREA OF MAROS DISTRICT

The research aims to find out the correlation of carapace width – weight, condition factor and abundance of mangrove crab based on observation time and sex in the coastal waters of Maros district, South Sulawesi. This research provides information on the pattern of growth and chubbiness of mangrove crabs and its abundance in the coastal area of Maros district, South Sulawesi. The study was conducted from early February until the end of April 2019. Sampling was conducted on the coastal area of Kuri Lompo and estuary of Maros which is an integrated mangrove pond development (silvofishery). 213 mangrove crabs (120 male and 93 female) obtained from fishermen were measured. The coefficient b of male and female mangrove crabs in February and March were 3.3626 and 2.6674, respectively. In April, b value of male and female mangrove crab was 3.5965 and 2.6506, respectively. This relation shows the growth type for males is allometric-positive whereas for females is allometric-negative. In April also saw the same growth coefficient in the previous month allometric positive for males and allometric negative for females. In general, the condition factor of male mangrove crabs in February and March is greater than female mangrove crabs. While, in April the condition factor of female mangrove crab is greater than male mangrove crab. The nature of condition factor of mangrove crab represents the distribution of crab abundance in the embankment lane silvofishery development area of 0.015 ind./m.


Introduction
Mangrove crab (Scylla serrata Forsskål, 1775) is one of the most valuable economical fisheries commodities in Indonesia. It has been known for its delicious and high nutritious meat flavor. Based on the result of proximate analysis, it is known that the meat of mangrove crab contains protein 44.85 -50.58%, fat 10.52 -13.08% and energy 3.579 -3.724 kcal/g. In addition, it contains a variety of important nutrients such as minerals and omega-3 fatty acids. Also, crabs as a source of protein, folate, potassium, vitamin B12, phosphorus, and selenium (Karim, 2013). During this, demand for mangrove crab tends to increase every year, both from domestic and abroad. This causes an increase in the exploitation of mangrove crab in nature. Based on statistical data from the Department of Marine and Fishery of South-Sulawesi Province (2015), the production of mangrove crab catch in Makassar has fluctuated during the last 5 years.
In 2010, the production of mangrove crab catches reached 135.2 tons, in 2011 decreased 104.8 tons, in 2012 increased by 7.3 tons, in 2013 decreased by 8.5 tons, and 2014 decreased by 17.9 tons. The coastal area of Kuri Lompo and Maros estuary which bordered directly with Makassar strait is one of the most important waters because it is directly related to various aspects of community life, including as a fishpond and fishing area that directly adjacent to the mangrove ecosystem development area. Mangrove crab is one of the biota that is utilized by the surrounding community as a source of income and food. By looking at the phenomenon of increasing use of mangrove crab, it is necessary management that pays attention to the sustainable potential of mangrove crab in order to avoid extinction. One factor that supports the management is the availability of information about biological aspects of mangrove crab. Therefore, a research on the correlation of carapace width -weight, condition factor and abundance of mangrove crab especially in around the coastal area of sivofishery development of Kuri Lompo to Maros estuary are needed. This research aims to find out the correlation of carapace width -weight, condition factor and abundance of mangrove crab based on observation time and sex. While, the usefulness of research are to provides information about the pattern of growth and chubbiness of mangrove crabs in coastal waters of Kuri Lompo and Maros estuary.

Time and Location
The research was conducted from early February until the end of April 2019. Sampling was conducted around the waters between Kuri Lompo until Maros estuary, Maros district, South Sulawesi ( Figure 4)

Tools and Materials
The tools used in this research were fishing gear bubu serves to catchs crabs, plastic bags for storing sample, preparatory boards for placing samples, sliding compass for measuring carapace width of crabs, digital scale 0.001 g to measure sample weights, and a camera for documentation. The sample used in this research is mangrove crab (Scylla serrata).

Sampling
Sampling was obtained from the catch of fishermen operating around the waters of Kuri Lompo and Maros estuary. The fishing gear used is bubu. Sampling is done at intervals once a week. After the sample is collected, then put into a plastic bag which is then transferred to the laboratory to measure the carapace width and body weight. According to Rachmawati (2009), carapace width (L) is the distance between the last marginal end on the left with the last right horizontal spine (horizontal), carapace length (P) is the distance between the spine edge of frontal margin and the lower edge of carapace, while carapace height (T) is the length of perpendicular line between the carapace and the abdomen ( Figure 6). For carapace width was measured using a sliding compass 0.1 mm in accurate, while carapace weight using a digital scales 0.001 gram in accurate.  Determination of mangrove crab sexual is done by observing the shape of abdomen. The abdominal segment of male crab is tapered, while the female is wider. Female abdomen like stupa while male like pillar.

Correlation of Carapace Width and Weight
To find the correlation of carapace width and weight of mangrove crab, we To test the regression coefficients, b = 3 or not, then t-test is performed with the following equation: tcount = (3 -b)/sb (Walpole, 1982 in Andy Omar, 2014). If the value of tcount is greater than ttable, then b differs from 3, if otherwise, then b equals 3. Furthermore, statistical tests of regression coefficients on male and female crabs are performed. Then, the data obtained is processed using Microsoft Excel program.

Condition Factor
Calculation of condition factor for crabs whose growth is isometric, using the formula of Fulton (1904) in Sentosa and Sham (2011), i.e: K = (100 W) / L 3 , K = Condition factor, W = Weight (g) and L = (cm). Since the carapace width is measured in millimeters, W x 105 (100000). If the growth pattern is allometric, then the condition factor is calculated by using the relative condition factor which has the following equation:

Correlation of Carapace Width and Body Weight
In this research, total mangrove crabs analyzed were 136 i.e 80 males and 56 females. Statistical analysis of the correlation of carapace width to body weight can be seen in Table 2. As Table 2, it is seen that male crabs in February have an amount equal to that of females, which is 39. b-value for male crabs is 3.3626 while female is 2.6674. T-test analysis showed that male crabs have an isometric growth type; the increase in the carapace width is equal to the body weight, whereas the female crab has a allometric-negative growth type; the increase of the carapace width is faster than the weight gain. The value of correlation coefficient (r) for the male mangrove crab equation is 0.9357 indicates strong correlation and for female is 0.5859 indicates moderate correlation ( Table  2). This is in accordance with Andy Omar (2009)    is faster than the increase of carapace width, whereas female crabs have an isometric growth type, is the increase of carapace width is equal with body weight. The graph of the correlation of carapace width and body weight of male and female crabs is presented in figure 5.  (Table 2). Values indicate there is a moderate correlation between the correlation of carapace width to body weight of male and female mangrove crabs. This is in accordance with the opinion of Andy Omar (2009) which states that if the value of correlation coefficient 0.40 to 0.69 indicates a moderate correlation. Based on the analysis of carapace width and body weight of mangrove crab, it is known that b value in male mangrove crabs during is higher than in females. According to Wijaya et al. (2010), male mangrove crabs tend to be aggressive in finding food so that the energy gained for growth will be higher. Based on the analysis of carapace width to body weight of mangrove crab in the coastal waters of Kuri Lompo to Maros estuary in February showed the isometric growth type for male mangrove crabs and allometric-negative for female mangrove crabs.  (Table 3). Different growth types of male and female mangrove crabs as shown in Table 3 is allegedly due to environmental differences, energy-use and food intake. According to Wijaya et al. (2010) female mangrove crab uses more food intake for molting and gonad maturation process (laying eggs). So the growth of female mangrove crab tends to be more towards the carapace width because the female crab will molting each will perform the process of copulation. While, on male crabs, molting is rare, so food intake tends to be used to lengthen and raise the claw that plays an important role in the marriage process. Rachmawati (2009) also said that factors affecting crustacean growth include 2 (two) factors, namely internal and external factors. Internal factors include size, gender, maturity level, and disability. While the external factors, include the availability of food, temperature, environment and parasites.

Condition Factor
The value of condition factor of crabs caught in the coastal waters of Kuri Lompo up to Maros estuary, based on observation time and sex can be seen in Table 4. crab. In April, the average value of female mangrove crabs was greater than that of males, i.e for females of 14.5626 ± 4.7321 and for males of 1.0681 ± 0.6756. This is due to body weight of female mangrove crab larger than male mangrove crab.
Based on the statistical test, the condition factor of male and female mangrove crabs in February obtained tcount of 34.8515 and ttable of 1.9917. This shows a significant difference between the condition factor of male and female mangrove crabs in February. The statistical test of the condition factor of male and female mangrove crabs in April obtained tcount of 18.0405 and ttable of 2.0032. This shows a significant difference between the condition factor of male and female mangrove crabs in April. For the analysis result of average value of mangrove crab condition factor in several research locations can be seen in Table 5. In Table 5, it is seen that in this research in February and March, the average value of male mangrove crabs is greater than that of female mangrove crabs. Similar results were also found by

Abundance
Abundance of mangrove crabs is more randomly distributed around the integrated mangrove ecosystem area of pond which includes the coastal waters of Kuri Lompo and estuary ecosystem of Maros river, and is evenly distributed at 0.005 ind./m 2 ( Table 6). This clarify the ecological nature of mangroves to environmental factors such as temperature, salinity, pH, abundance of feed and organic material evenly and homogeneous in integrated development areas (silvofishery), and has the protection and buffer powers as ecological factor favored by organisms, crabs and shrimp than in other habitats.  (Richard and Marx, 1981) showed Scylla serrata is randomly distributed with relatively equal composition and amount of abundance at each specimen collection station. This shows the habitat of mangrove crabs in the integrated development areas of ponds and mangroves (silvofishery) is still quite stable to meet the ecological needs of these organisms. Based on the distribution of abundance, the habitat for Scylla serrata in the ecosystem of Kuri Lompo and Maros estuary has a close association with mangrove vegetation of Sonneratia, Rhizophora, Combretaceae, Meliaceae, Bruguiera, and Ceriops. While, ecological supporting factors in the association in the micro-habitat are temperature 24-29 0 C, salinity 17-23 ‰, gravel sandy substrate with composition 3:2:1, pH 6.8-8.7 and brightness 0.90-1.20. Some group of crustaceous such as Panulirus and Penaeid as reference control from Scylla above, show a randomly distribution in sublitoral areas where habitats with ecological and aquatic qualities such as temperature, salinity, pH, turbidity and feed distribution also homogeneously distributed, and this shows a common habitat association in a permanent area (Ludwig, 1988).

Conclusion
Based on result of research about the correlation of carapace width -weight, condition factor, and abundance of mangrove crabs Scylla serrata forsskål, 1775; in embankment lane silvofishery development area, Maros district can be concluded as follows: 1) The growth type in February for male mangrove crabs are isometric and female mangrove crabs are allometric-negative. While, in March for male mangrove crabs are allometricpositive, while the female mangrove crabs are isometric. 2) The average value of the condition factor in February of male mangrove crabs is greater than the female mangrove crab. While in March, the average value of female mangrove crabs is greater than male mangrove crabs.
3) The habitat of mangrove crabs in the integrated development areas of ponds and mangroves (silvofishery) is still quite stable to meet the ecological needs of Scylla serrata. Based on the distribution of abundance, the habitat for Scylla serrata in the coastal waters of Kuri Lompo and estuary of Maros river has a close association with mangrove vegetation of Sonneratia, Rhizophora, Combretaceae, Meliaceae, Bruguiera, and Ceriops. While, the ecological supporting factors in the association in the micro-habitat are temperature 24-29 0 C, salinity 17-23 ‰, and gravel sandy substrate with composition 3:2:1, pH 6.8 -8.7 and brightness 0.90 -1. 20.

Suggestion
Further research is needed with observation time, species and number of sample of mangrove crabs with various sizes, regarding biological aspects, both reproductive and population biology of mangrove crab. Not only on Scylla serrata but in all three types of other mangrove crabs to obtains more complete data and information.