Habitat characteristics and relative abundance of the mud crab Scylla serrata (Forskål, 1775) in Lawele Bay, Southeast Sulawesi, Indonesia

Abstract

Based on similarity of natural features of salinity, turbidity, soil substrate, mangrove vegetations and intertidal flat of the stations studied, there were three habitats (A, B, and C) of Scylla serrata (Forskål, 1775) in Lawele Bay. The characteristics of habitat A were preferred by S. serrata since it had the highest relative abundance of S. serrata. With relative abundance of 11.87%, habitat B as transition habitat between habitats A and C was less preferred by S. serrata. The characteristics of habitat C were in contrary with habitat A and S. serrata caught was only 1.19%. The relative abundance of S. serrata at habitat A differed significantly with habitats B and C (p < 0.05), while at habitat B was not significantly different with habitat C (p > 0.05). It suggests that S. serrata tended to move forward at habitat A and occupying such habitat which was characterized by low salinity, high turbidity, the thickest mangrove vegetation, muddy substrate and the widest intertidal flat. The relative abundance of males was significantly different with females either during flood tide or ebb tide (p < 0.05). Both sexes had two peaks of abundance. A major peak was in July and August and a minor peak in February. The lowest relative abundance was in December. However, seasonal relative abundance was not significantly different (p > 0.05). It suggests that the relative abundance may depend on seasons but they are found all year round.

Kepiting Genera Scylla di Pesisir Kota Langsa: Distribusi, Dimensi Tangkapan Alami dan Analisis Bioekonominya

“…Hal ini karena ekosistem mangrove adalah habitat bagi biota-biota pesisir dan laut (Syahrial et al, 2017;Syahrial dan Karsim, 2018;Lestari et al, 2021;Harahap et al, 2022;Saleky et al, 2023) termasuk kepiting genera Scylla. Murniati et al (2016), Saputri dan Muammar (2018), Oktamalia et al (2018), Saragi dan Desrita (2018), Jacobs et al (2019) serta Kusuma et al (2021) menyatakan bahwa ekosistem mangrove adalah habitat utama bagi kepiting genera Scylla, kemudian kepiting genera Scylla merupakan salah satu biota kunci bagi perubahan ekosistem mangrove, dimana kepiting genera Scylla sangat menyukai perairan ekosistem mangrove yang bersubstrat lumpur (Sara et al, 2014;Suryono et al, 2016) karena kepiting genera Scylla dapat bersembunyi atau membenamkan diri di dalam lumpur tersebut (Wijaya et al, 2018) dan lumpur-lumpur mangrove tersebut juga telah menyediakan berbagai material organik serta jenis-jenis pakan alami yang disukai kepiting genera Scylla baik itu alga, bangkai hewan, akar, jenis siput, kodok, katak, daging kerang, udang, ikan maupun dedaunan yang telah membusuk (Kasry, 1996). Hasil penelitian Chadijah et al (2013) dan Dewi et al (2017) sangat mendukung terhadap survei distribusi kepiting genera Scylla di 12 desa Kota Langsa bersamaan dengan keberadaan ekosistem mangrovenya, dimana antara kepiting genera Scylla dan ekosistem mangrove memiliki hubungan yang sangat erat yaitu semakin tinggi kerapatan mangrove, maka kepadatan dan keanekaragaman kepiting genera Scylla juga akan semakin tinggi.…”

On the abundance and occurrence of the mangrove crabs, Scylla spp. (Crustacea: Portunidae) from Munjang mangrove, Bangka Belitung Island

“…The abundance of S.serrata was also reported being correlated with the mangrove density and the species of mangrove, mostly from Rhizophora spp. (La Sara et al, 2014;Tahmid et al, 2015). The characteristics of the sediment also influence the presence of the mud crab.…”

“…The Scylla spp., mostly has a wide tolerance to the condition of temperature and salinity. Tropical and subtropical condition is very suitable for their lives (Avianto et al, 2013;La sara et al, 2014;Alberts-Hubatsch et al, 2016;Karniati et al, 2021). However, temperatures below 16°C causes them in active (Hill, 1980).…”

“…However, temperatures below 16°C causes them in active (Hill, 1980). They also can tolerate the salinity from low conditions to the higher condition (Davenport & Wong, 1987;Hill, 1979;La Sara et al, 2014;Karniati et al, 2021), however, extreme salinity (more than 64) is lethal for their life (Hill, 1979). Water and mud depth including the dissolved oxygen also cause an impact on the living of the mud crabs (Karniati et al, 2021).…”