Fisheries in atolls- Tradeoffs between harvest and conservation

Atolls are ring shaped coral reefs including a coral rim that encircles a lagoon partially or completely and with or without a coral island/cays on the rim. Most of the world’s atolls are in the Pacific Ocean and Indian Ocean. Lakshadweep islands, Maldives and the Chagos Archipelago are the atolls in the Indian Ocean. Lakshadweep are the only atoll islands in India. They lie scattered in the Arabian Sea between Latitude 8.26° to 12.4° N and Longitude 71.7°-73.75° E, comprising of 36 islands, 3 reefs and 5 submerged banks. These islands consist of coral formations built upon the Laccadive-Chagos submarine ridge rising steeply from a depth of about 1500 m to 4000 m off the west coast of India. While the total land area is 30 sq.km, the length of the coastline is 132 km and lagoon area of 4200 sq.km. Its territorial water spread is 20000 sq.km and it constitutes 0.4 million sq.km to the EEZ of Indian Union. Out of the 36 islands, 11 are inhabited with a population of 64,473 (2011 census). The atolls have 4 distinct biomes comprising of the islands, lagoons, reefs and the Open Ocean. Few threats to the atoll systems are sea level rise, salt water intrusion, reduced availability of fresh water, coral bleaching, disturbances to reef ecosystem, shrinking of livelihood and excessive dependence on external resources, excessive harvest of reef resources etc

Integration of Spatial Attributes in Fishery Biological Studies: The Paradigm and a Case Study of Large Pelagic Fishery In the NW Coast In: ICAR Sponsored Winter School on Recent Advances in Fishery Biology Techniques for Biodiversity Evaluation and Conservation, 1-21 December 2018, Kochi.

Wide spatial distribution and temporal variations in abundance are unique features of fishery resources (Vivekanandan, 2005). The spatial variability of the stock reflects the pattern in fishing effort, thereby the fishing mortality owing to the target stock being aggregated or due to management restrictions, distance to port, vessel size, and the experience and habits of individual fishers (Yong, 2014). Ignoring this spatial variation can lead to serious biases in estimates of fishing mortality and yield (Hart 2001). Indexes related to catch rates or abundances are used often in the stock assessments or are the indexes for monitoring fish stocks despite the fact that the non-random spatial distribution of fish and fishing effort makes the interpretation of commercial catch rate (CPUE) difficult (NRC 1999). Such targeted deployment of fishing effort results in constant or increasing CPUE even though the stock size is decreasing till a point where the stock is at very low levels. A number of fish stock shave collapsed due to such misinterpretation of CPUE, the prominent being the case of northern cod (Hilborn and Walters 1992)

Stress amelioration during live transport of fish.

Experiments were conducted to evaluate the stress ameliorative effects of temperature reduction, pre-packing anaesthesia and packing with supplementary oxygen on long duration live transport of groupers. Survival, water quality parameters like dissolved oxygen, ammonia and pH as well as serum parameters like glucose, alkaline phosphatase and total protein were studied as indicative response of the transportation stress. Elevated levels of ammonia and all the serum parameters and lower levels of dissolved oxygen and pH leading to mortality observed in the control group indicate that the treatments succeeded in ameliorating the stress caused by the transportation procedures. Packing water temperature of 15°C to 20 ®C, anaesthesia with lOOppm clove oil and oxygen packing are found essential for transporting live grouper of biomass 700g for period extending up to 24h

Stress amelioration during live transport of fish.

Experiments were conducted to evaluate the stress ameliorative effects of temperature reduction, pre-packing anaesthesia and packing with supplementary oxygen on long duration live transport of groupers. Survival, water quality parameters like dissolved oxygen, ammonia and pH as well as serum parameters like glucose, alkaline phosphatase and total protein were studied as indicative response of the transportation stress. Elevated levels of ammonia and all the serum parameters and lower levels of dissolved oxygen and pH leading to mortality observed in the control group indicate that the treatments succeeded in ameliorating the stress caused by the transportation procedures. Packing water temperature of 15°C to 20 ®C, anaesthesia with lOOppm clove oil and oxygen packing are found essential for transporting live grouper of biomass 700g for period extending up to 24h

Plastic debris in the stomach of a Longman’s Beaked Whale, Indopacetus pacificus (Longman, 1926) stranded off Sutrapada, Veraval, Saurashtra coast, India

Longman’s beaked whale or the Indo- Pacific beaked whale (Indopacetus pacificus) is a rarely occurring whale with very poor information on sighting or stranding, though more common in western Indian Ocean region. Threat to marine fauna from the ingestion of plastic carry bags and other non-biodegradable debris scattered on the ocean surface and at the seafloor is increasing at alarming proportions. This communication describes the stranded adult female Longman’s beaked whale near off Sutrapada, Veraval, Gujarat coast that has presumably been choked to death due to the ingestion of four thick plastic bags, which was revealed from the autopsy conducted by the Gujarat Forest Department and the Wildlife Treatment Centre, Sasan Gir, Gujarat

लक्षद्दीप समूह जीववैविधता और व्यवस्था

कृपया पूरा लेख पढे

Seagrass restoration trials in Kavaratti Lagoon, Lakshadweep: Growth patterns of transplants and their impact on overgrazing

It is essential to restore degraded seagrass habitats as they are among the major blue carbon ecosystems undergoing degradation at alarming proportions throughout the globe. As our earlier attempts at seagrass transplanting trials ended up in grazing by herbivores, fresh trials in enclosed rafts were initiated which resulted in an 80% survival rate. The results indicated the magnitude of overgrazing on seagrass shoots and the height of transplants after 37 days in the enclosed rafts was 105 mm registering a net height of 71.05±9.1mm, while in the exposed rafts the leaves of the transplants were found grazed and the final mean height was only 13.3 mm registering a net height of shoots far below its initial height. Any initiative to restore seagrass meadows in the degraded areas must be taken up under protected mode or the existing seagrass meadows should be allowed to recover on their own by preventing overgrazing and checking man-made interferences

CMFRI establishes a Pilot Farm in the outfall channel of the Coastal Gujarat Powers Ltd., Mundra, Kutch District, Gujarat

A customized sea cage for the running waters of the outfall channel was designed and fabricated by the scientists of the Regional Centre, Veraval. Two square cages of 5m size made of Galvanised Iron pipes of 1.5" size, with base collars and hand rails was fabricated at the site and mounted with the square shape culture nets of suitable size procured

Observations on selected biological aspects of the spadenose shark (Scoliodon laticaudus Müller & Henle, 1838), landed along Saurashtra coast

Spadenose shark, Scoliodon laticaudus (Family: Carcharhinide) locally known as “sandhi” is a common species inhabiting near shallow coastal waters along the Saurashtra coast. It is exploited by trawls and gillnets throughout the year in fair abundance. The dietary components of the species were studied and expressed as percentage of numerical composition (CN), percentage of gravimetric composition (CW) and percentage of frequency of occurrence (F). The major food item in the stomachs of the species was determined using an Index of relative importance (IRI). Food and feeding analyses confirmed the carnivorous feeding behavior of this species and the food mostly comprised fishes, shrimps and squids. There was no evidence of cannibalism. Overall sex ratio was 1.18 that showed the predominance of females over males. As there is limited information about the biological aspects of this species from Saurashtra coast, the results of the present investigation may play a vital role in the management of the resource as well as for the efficient exploitation of this species

Rough triggerfish, Canthidermis maculata from Gujarat coast

A specimen of the Rough triggerfish, Canthidermis maculata (Bloch, 1786) was landed by a multiday trawler on 25th November 2015 at Mangrol Fisheries Harbour, Gujarat. The specimen was brownish grey in colour with characteristic white spots all over the body including the head. It measured 309 mm and 256 mm in Total length and Standard length respectively with a weight of 580 g (Fig. 1). The fish is usually found in areas having sandy, muddy or rocky bottoms at a depth range of 50-100 m and is reported from the Western Indian Ocean