Evaluation of acute toxicity of copper cyanide to freshwater fish, Catla catla (Hamilton)

The acute toxicity of copper cyanide to the juveniles of Indian major carp Catla catla (2±0.5 cm) was evaluated under static renewal conditions. The concentrations of copper cyanide that killed 50% of the carp fingerlings within 96-h (96-h LC50) was found to be 0.76 ± 0.04 mg/L. Fishes exhibited abnormal swimming activity, followed by frequent gill flapping, loss of equilibrium, gulping of air, hyperactivity, convolutions. The respiratory rate of the fish got severely affected (-63.41%± 0.002) when exposed to copper cyanide.

Vibrio ponticus, a new pathogen of cultured cobia

Most of the members of the family Vibrionaceae are natural inhabitants of marine and estuarine ecosystem and several of them are pathogens in cultured aquatic organisms. Vibriosis caused by some pathogenic Vibrio spp., can cause huge mortality in marine fish culture systems. Intermittent mortality with haemorrhagic lesions on the fin, body surface, and head, exophthalmia (Fig.1) and stopping of feeding activity were noticed in cobia (25±5 cm length; 17±4 g weight) reared in sea cages off Polem, Goa during June 2015. The clinical signs lasted for a week with a total mortality of 12%. Isolation of bacteria aseptically from liver and kidney was done

Respiratory distress and Behavioural Anomalies of Indian major carp, Labeo rohita (Hamilton) Exposed to Sodium Cyanide

Sodium cyanide, is highly contaminating aquatic ecosystems as a toxic pollutant, was investigated in the present study for acute toxicity on freshwater fish Labeo rohita. The toxicity tests were conducted by static renewal bioassay method on the juveniles of fish was evaluated. The LC50 value of sodium cyanide to Labeo rohita was found out to be 320 µg/L. One third (106 µg/L) and one fifth (64 µg/L) of the LC50 value was selected for sublethal studies. Behavioural patterns and oxygen consumption were observed in both (1/3rd and 1/5th) sublethal concentrations (1, 5, 10 and 15 days). Sodium cyanide is highly toxic to the animal tested. Fish behaved irregular, erratic, and dartic movements, by followed hyperexcitability, loss of balance, finally settled to the bottom of the test chamber. A decrease in oxygen consumption was observed in 1/3rd (11.62% and -4.52%) and 1/5th (9.11% and -2.82%) sublethal concentrations. Fish under sublethal concentration were found to be under stress but not fatal

Nursery rearing of Asian Seabass

Lates calcarifer species is widely distributed in the tropical and subtropical areas of the western Pacific and Indian ocean including Australia, Southeast Asia, the Philippines and countries bordering the Arabian sea. Seabass spend most of their life in a lagoon which connects to the sea. They spend two to three more years in estuarine areas until they mature, then migrate to the sea water around the mouth of a river or lagoon for spawning. Larvae and juveniles live in the sea grass bed in coastal areas for about six months, attaining a size of about 2 to 5 inches. The fish migrate to freshwater when they grow bigger

Impact of copper cyanide on the key metabolic enzymes of freshwater fish Catla catla (Hamilton)

Short term toxicity experiments were conducted to study the effect of metal cyanide complex (copper cyanide) on the key metabolic enzymes viz., lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), glucose-6 phosphate dehydrogenase (G6PDH), aspartate amino transferase (AST) alanine amino transferase (ALT), acid phosphatase (AcP) and alkaline phosphatase (ALP) activity in Catla catla juveniles. A total of 60 fingerlings were (2±0.5 cm; 1.5±0.2 g) exposed to two sublethal concentrations (0.253 and 0.152 mg/L) for a period of 15 days. Copper cyanide had significant (P> 0.05) effect on the key metabolic enzymes, the highest activities were observed in the group exposed to 0.253 mg/L. Results suggest that metal cyanide complex significantly altered enzyme activities of fish in both the sublethal concentrations

Stranding of spinner dolphin, Stenella longirostris (Gray, 1828) at Karwar, Karnataka

A spinner dolphin, Stenella longirostris , locally called ‘handi meenu’ was noticed in dead condition floating near the marine cage farm of CMFRI, Karwar, approximately 600 m away, from sea shore of Aligadda village in the evening hours on 31st August 2012. The specimen was an adult female of 175 cm total length and 55 kg weight. The animal had a small injury near its left eye probably as a result of getting entangled in fishing nets or got injured in purse-seine operation which resulted in its death

Cobia culture in low volume cages in coastal waters of Uttara Kannada, Karnataka

Cobia, Rachycentron canadum is a marine finfish globally favoured for aquaculture. In India, cage culture of cobia was first reported by ICAR-CMFRI in 2013 with better growth rate recorded under conditions of higher salinities (Philipose et al.2013). The present report is on the growth and production of cobia, Rachycentron canadum in Gangavali estuary (14o 61’ 225’’ N and 74 o35’726’’E) of coastal Karnataka during the period 2018-19

Note on the ocean sunfish, Mola mola (Linnaeus, 1758) landed at Karwar, west coast of India

The spine tail devil ray Mobula japanica (Muller & Henle, 1841) is a large zooplanktivorous ray circumglobally distributed within tropical to warm temperate waters. This species belong to the family Mobulidae. In the genus Mobula, the mouth is located ventrally and is currently represented by nine recognised species

Incidence of whale strandings in Uttara Kannada, Karnataka

Two instances of the whale strandings were observed in the Uttar Kannada district of Karnataka recently. The first one occurred on 06.05.2017 at Mungodlu, Kumta and the second at Karwar on 18.02.2018. The whale stranded at Mungodlu, near Vannalli village of Kumta Taluk, Uttara Kannada district, Karnataka (14° 26' 034" N and 74° 23' 005" E) was washed ashore in highly decayed condition with its dorsal portion upside down and species could not be identified. The total length of the whale was approximately 9 metres. The vertebrae were found exposed in the beach and a few numbers were collected and preserved in the museum of Karwar Research Centre of ICAR- CMFR

Foreign objects observed in the stomach of a cobia (Rachycentron canadum) reared in sea cage at Karwar

Revival of short neck clam Paphia malabarica Chemnitz, 1782 In Kali estuary, Karwar, Karnatak