Diversity Of Genus <i>Octolasmis</i> Infestation On Mud Crabs (<i>Scylla Serrata</i>) From Traditional Brackish Water Ponds Of Semarang Gulf, Indonesia

Abstract Mud crab ( Scylla serrata ) is generally caught and cultured in traditional brackish water ponds in the Semarang Gulf’s surroundings. The problem with this product was the infection of the parasite, namely: Octolasmis sp. It caused a low price in the market, and consumers rejected it. This research aimed to determine the clinical symptoms of mud crabs infested by Octolasmis sp, its diversity, and the parasites’ intensity, prevalence, and dominance. Two hundred wild and cultured mud crabs were observed with an average carapace length of 8.63 ± 0.91 cm and a weighted average of 117.45 ± 5.03 g. The results showed that the clinical symptoms of mud crabs infested by these parasites were melanosis in the gill, and the structure resembles bean sprouts in the gill. The types of parasites Octolasmis sp, which infects mud crabs in Semarang brackish water ponds, were Octolasmis cor and Octolasmis angulata . The total value of Octolasmis sp. parasites intensity was 69.2, and the total prevalence value was 43.5%. It might be the Pirst report on Octolasmis infestation in Semarang Gulf. This Pinding indicated that Octolasmis moderately infested most mud crabs from traditional brackish water ponds from Semarang Gulf. Regular monitoring and proactive management are vital to maintaining healthy crab populations and reducing the risks of ectoparasitic infestations.