New record of the swimming crab Charybdis (Archias) hongkongensis Shen, 1934 (Brachyura, Portunidae) from India

Charybdis (Archias) hongkongensis Shen, 1934 was collected from the Indian coast of the Bay of Bengal and this is the first record from Indian waters. The distinct key characters of this species are: a relatively more produced last antero-lateral tooth, strongly convergent postero-lateral margins, and a smooth, rounded, reduced apex of the male first gonopod. This is the ninth member of Charybdis (Archias) Alcock, 1899 from Indian waters. The species is diagnosed and figured herein.

Physiological and Molecular Responses in the Gill of the Swimming Crab Portunus trituberculatus During Long-Term Ammonia Stress

Ammonia is a common environmental stressor encountered during aquaculture, and is a significant concern due to its adverse biological effects on vertebrate and invertebrate including crustaceans. However, little information is available on physiological and molecular responses in crustaceans under long-term ammonia exposure, which often occurs in aquaculture practices. Here, we investigated temporal physiological and molecular responses in the gills, the main ammonia excretion organ, of the swimming crab Portunus trituberculatus following long-term (4 weeks) exposure to three different ammonia nitrogen concentrations (2, 4, and 8 mg l–1), in comparison to seawater (ammonia nitrogen below 0.03 mg l–1). The results revealed that after ammonia stress, the ammonia excretion and detoxification pathways were initially up-regulated. These processes appear compromised as the exposure duration extended, leading to accumulation of hemolymph ammonia, which coincided with the reduction of adenosine 5′-triphosphate (ATP) and adenylate energy charge (AEC). Considering that ammonia excretion and detoxification are highly energy-consuming, the depression of these pathways are, at least partly, associated with disruption of energy homeostasis in gills after prolonged ammonia exposure. Furthermore, our results indicated that long-term ammonia exposure can impair the antioxidant defense and result in increased lipid peroxidation, as well as induce endoplasmic reticulum stress, which in turn lead to apoptosis through p53-bax pathway in gills of the swimming crab. The findings of the present study further our understanding of adverse effects and underlying mechanisms of long-term ammonia in decapods, and provide valuable information for aquaculture management of P. trituberculatus.

The coral reef health at surrounding blue swimming crab fishery sites in Mandangin Island, East Java, Indonesia

Blue swimming crab fishery activities very often do not put into account the environmental condition. Coral reef, as one of the blue swimming crab habitats, can be affected by these activities. This study aims to determine the effect of blue swimming crab fisheries on coral health in Mandangin Island, East Java, Indonesia. Data collection points are determined based on the results of interviews by participatory mapping. Water quality data includes visibility, temperature, salinity, pH, DO, current velocity. Collecting coral reef data were using Line Intercept Transect (LIT), while for reef fish Underwater Visual Census (UVC) were used. The coral health index was determined based on the relevance between benthic components and fish components. The average of Mandangin Island’s water quality is in accordance with the quality standards of the Indonesian Minister of Environment Decree No.51 of 2004. Hard coral cover and fish biomass are classified as low, but the value of resilience is high. The coral reef health index value on Mandangin Island is 3.