The exploitations status of the orange mud crub (Scylla olivacea Herbst, 1796) in Aru Islands and adjacent waters, Maluku, Indonesia

Abstract

The increasing exploitation and fishing of the orange mud crab (Scylla olivacea) are threats against the sustainability of the crab resources. Therefore, it is critical to carry out a scientific study that can serve as the basis of the fisheries management. This study was carried out from March to November 2019 several crab landing sites in Aru Islands (Dobo). It employed survey and monthly data collection methods, assisted by an enumerator. The results revealed that the capace width orange mud crab was of 110–185 mm in size where 135 mm was the dominant size and 137.8 mm was the capace width at first capture (CWc). Its growth rate (K) was 0.59 per year and its asymptotic capace width was 191.5 mm. The recruitment of the species occurred all year long, peaking in February at 18.53%. Its fishing mortality (F) was 0.74 per year, while its natural mortality (M) was 0.77 per year. The exploitation rate (E) of the orange mud crab was 0.49% (moderate state). To ensure the sustainability of the crab resource in Aru Islands, people should be advised to maintain the sustainability of the crab habitats, i.e. the mangrove forests, and not to capture the orange mud crabs below 120 mm in size.

Orange mud crab (Scylla olivacea) exploitation at Sorong waters

“…The size structure of the orange mud crabs (Scylla olivacea) in these waters is 80-190 mm, with modes of 115 mm and 125 mm (Figure 2 [13] ; [21] ; [22] ; [23] ; [24] ; [25] ; [26] ; [27]. The difference in size is due to differences in the means of capture and the location of the arrest.…”

“…However, Sorong's coastal city's mangrove forest area has been degraded due to the increasing expansion of residential areas, so an approach is needed to provide understanding [42]. The preservation of mangrove forests, which serve as mud crab habitats, nurseries, and feeding grounds, should be part of community education programs [21] and [30]. By controlling fishing by figuring out the right size to catch them and maintaining mangrove forests as their habitat, it is possible to keep the preservation of crab resources.…”

Population dynamics of mud crab, Scylla olivacea (Herbst, 1796) from the Sundarbans of Bangladesh

“…Their natural mortality (0.77 year –1 ) was higher than their fishing mortality (0.74 year –1 ). Thus, their exploitation rate ( E ) 0.49 indicates that they were being caught moderately (Pane et al., 2020). Likewise, baby crabs were also recruited year‐round in the Pichavaram mangroves of India (Viswanathan et al., 2018).…”