STOCK STATUS OF BLUE SWIMMING CRAB (Portunus pelagicus) IN TANAH LAUT, SOUTH KALIMANTAN, AND ITS ADJACENT WATERS

Abstract

A study on the stock status of blue swimming crab (Portunus pelagicus Linnaeus, 1758) was conducted in Tanah Laut, South Kalimantan waters, based on data collected in March to November 2017. The results showed that the growth pattern of blue swimming crab in Tanah Laut waters was negatively allometric and the sex ratio of males to females was 1.0 : 1.7. The chi-square test indicated that the total males and total females of the blue swimming crab was significantly different. It means that there was an imbalance in numbers between males and females. The estimated length at first capture (Lc) was 127.26 mm (carapace width; CW), smaller than the length at first maturity (Lm) at 133.24 mmCW. The growth parameter of blue swimming crab was 1.1year with a maximum carapace width (L) of 204.3 mmCW. The estimated instantaneous total mortality (Z) and natural mortality (M) were 3.04/year and 1.24/year, respectively. While fishing mortality (F) and exploitation rate (E) were 1.80/year and 0.59/year, respectively, the estimated spawning potential ratio (SPR) was 11.1 %. Therefore, the stock status was categorized as overfishing. In order to ensure the sustainability of the blue swimming crab, a precautionary approach,, such as reducing fishing effort by 18 % of the current situation, is strongly recommended to apply.

Spawning and Reproductive Potential of Blue Swimming Crab (Portunus pelagicus) at Spermonde Archipelago, Indonesia

“…The BSC's SPR in Spermonde Islands is considerably low compared to other fishing grounds in Indonesia. For example, BSC's SPR in Tanah Laut was reported to be (Suman et al, 2020), Kasiputeh 13% (Prince, 2014), and Java Sea 15% (Ernawati et al, 2017). However, it is slightly higher when compared with the SPR in Belitung Island which was only 5% (Ernawati et al, 2015).…”

“…Analysis of carapace width will provide information on Bartalanffy growth parameters (K, L∞, t0) and size at first captured. Gonad Maturity Stage (GMS) analysis will produce information on size at first maturity (Lm 50 ) (Hordyk et al, 2015;Wujdi & Wudianto, 2015;Permatahati et al, 2020;Suman et al, 2020). Previous study has been done by researchers concerning input parameters required for BSC's SPR study in Spermonde Islands using different analysis (Table 1).…”

Management status of blue swimming crab (Portunus pelagicus Linnaeus, 1758) based on EAFM in the coastal of Pangkep Regency, South Sulawesi

“…Blue swimming crab (BSC) (Portunus pelagicus Linnaeus, 1758) is a fisheries resource with crucial economic value [1] and a high export market [2], which is exported mainly to the US [3], Singapore [4], Japan [5], and Netherlands [6]. The BSC export volume in 2017-2019 was 27.792 tonnes with an export value of US$ 472 million [7].…”

“…This species is widely dispersed in Indonesia, spreading from the western coast of Sumatera to the northern coast of Java [4], the southern and eastern coasts of Kalimantan, the southern part of Sulawesi, and the western area of Papua [8]. So far, to meet market demand, fishermen still rely on catches directly from nature [6] using traps and gill nets [9]. There had been no aquaculture activity as it was still in the research process and the best aquaculture technique has not been found [3].…”

“…If BSC continues to be exploited without good planning [2] and sustainable capacity management [14], sooner or later the BSC resources will face the risk of extinction. Although renewable resources can be categorized as BSC resources, fishing activities that are extremely intensive and unmanaged can contribute significantly to resource depletion [6]. So far, fishermen only prioritize economic fulfilment without considering the habitat conditions and tend to ignore applicable regulations.…”