Anodonta cygnea, a freshwater swan mussel, exposed to diazinon: toxicity thresholds in behaviour and physiology.

Swan mussels (Anodonta cygnea) have been suggested as suitable bioindicators for the presence of pollutants in the environment. Application of the physiological and behavioral markers in these sessile species can be beneficial for environmental monitoring. The present study aimed to investigate the relationship between the behavioral disorders of movement and siphoning associated with the inhibition of tissue Acetylcholinesterase (AChE). For experiments, overally 120 bivalves of Anodonta cygnea (mean total length 80.33 ± 6.7 mm) were transported from the agricultural drains and canals in Sari county (Mazandaran Province, Iran) to our laboratory. First, the LC50-96 h of diazinon was estimated according to the Organization for Economic Co-operation and Development (OECD 1992) guideline with static water conditions. The sub-lethal toxicity pesticide experiments were conducted on the basis of the lowest observed effect concentration (LOEC) and the maximum acceptable toxicant concentration (MATC). The LC50-96 h, LOEC, and MATC values of diazinon were 85.2, 42.1, and 8.5 mg L- 1, respectively. Based on the observations of mussels' movement, the burrowing and displacement decreased with the concentration of toxicant in water. Moreover, the presence of diazinon in water and its exposure to experimental animals significantly reduces their siphoning rate. The RDA showed that the AChE activity had a higher correlation with the siphoning behavior than the movement behavior. The comparison of enzyme activity at different exposure and recovery times showed that there was a significant difference among the groups affected by the consumed pesticide (p = 0.001, between contrasts). The most remarkable morphometric characteristic was the siphon opening that was inversely correlated with the enzymatic activity. Studies in bioethics might benefit from paying attention to these traits that are directly related to the level of toxicity and behavioral adaptations required for animal survival.

Nutritional evaluation of elongate mudskipper Pseudapocryptes elongatus (Cuvier, 1816) from Diamond Harbor, West Bengal, India.

The mudskipper Pseudapocryptes elongatus (Cuvier, 1816), (Gobiidae) are caught throughout the year and they are considered as most edible mudskipper species in Sundarbans. They are targeted by special gears and sold live in large quantities in the local markets of Diamond Harbor, Namkhana and Kakdweep. The adult P. elongatus (14-18 cm total length) specimens were purchased from the Diamond Harbor landing center for evaluation of its biochemical components such as Protein, carbohydrate, lipid, amino acid, fatty acid, vitamin, and minerals. The percentage composition of protein was high (27.34%) followed by the carbohydrate (4.57%) and lipid (2.72%). The amino acids both essential (47.72%) and non-essential (42.91%) was found adequate. Among fatty acids, polyunsaturated fatty acid (PUFA) was found the maximum (31.55%) followed by saturated fatty acid (SFA; 27.66%) and monounsaturated fatty acid (MUFA; 19.55%). Vitamin A (112.5 IU/100 g) and Ca2+ (62.2 mg/100 g) were found maximum levels. The present finding supports that P. elongatus is valuable for human consumption due to its high-quality protein with well-balanced amino acids.