The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution

Abstract

Abstract. Nur I, Aris EA, Yusnaini Y, Beavis S. 2021. The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution. Biodiversitas 22: 3764-3772. Artisanal small-scale gold mining and the use of mercury is widespread across Indonesia, often characterized by relatively short-lived gold rushes. In the late and post-mining phases, mercury stored in mine tailings and river beds was transported down catchment, posing risks to ecosystems and human health over much longer time scales. These risks can be under-rated when mercury concentrations in water, sediments, and aquatic species are low enough to meet relevant guideline thresholds. In this study in Southeast Sulawesi, Indonesia, we have investigated the Costraca barnacle, Octolasmis, as a bioindicator of mercury contamination. The presence of Octolasmis parasites in mud crabs, Scylla spp., and the accumulation of mercury (Hg) in the hosts, parasites, and the ambient environment, were analyzed across both dry and wet seasons. Severe infestation of Octolasmis was assessed using prevalence, abundance, and intensity. Hg concentrations were significantly higher in the Octolasmis parasites than in the host tissues, water and sediments. The mean bioconcentration factor (BCF) of Hg equaled 7938.21 from water to parasites, and 28.91 from the host’s gill tissue to the parasites. The results suggest that Octolasmis spp. can be used effectively as a bioindicator in coastal catchments impacted by mercury contamination, even when concentrations of mercury are low in water and river sediments. The study provides the first report of Octolasmis spp. parasitized to mud crabs as a reliable bioindicator of Hg contamination and pollution.

Evaluation of the quality of mangrove ecosystems using macrozoobenthos as bioindicators in the Southern Coast of East Java, Indonesia

“…Gastropods and crabs play a role in food webs in aquatic ecosystems (Batvari et al 2016). Gastropods and crabs are often used as ecosystem bioindicators because they live attached to the substrate and at the bottom of the water (mud and sand), which causes direct contact with pollutants that enter their habitat (Sharma et al 2018;Nur et al 2021;Sueb et al 2021). Gastropods and crabs also have relatively long and sedentary life cycles, so they can be used to detect ecosystem temporal and spatial changes (Shaiek et al 2018;Afwanudin et al 2019).…”

Diversity and distribution of crustaceans in the mangrove forest of Nusa Lembongan, Bali, Indonesia

“…Bojko et al (2022) reported the presence of parasites from a group of viruses in the intestinal epithelium, ciliated protozoa in the gill lamellae, fungi in the gonads, and metazoan ectoparasites in the gills of the Aratus pisonii mangrove crab. Nur et al (2021) reported parasites from the phytoplankton arthropods Octolasmis spp. on mangrove Scylla spp.…”