Indian EEZ Research Articles

<b>A first record of the Bentfin Devil Ray <I>Mobula thurstoni</I> (Lloyd, 1908) (Myliobatiformes: Mobulidae) from the Indian EEZ of the Andaman Sea</b>

This manuscript deals with the Bent-fin Devil Ray Mobula thurstoni for its first time occurrence in the Andaman & Nicobar waters around the Indian EEZ which is a new locality record confirming the range extension of the species to the southeast of Bay of Bengal (the Andaman Sea). A female specimen of 318mm disc length and weighing 2.47Kg was caught by a multiday bottom trawler operated off North Bay and was landed at Junglighat fishing harbour, South Andaman. A detailed diagnostic description and morphometric measurements of M. thurstoni is provided. For the first time this species has been described from Indian waters and compared with the other related species, and so documenting its first occurrence in the Andaman & Nicobar waters.

<b>A first record of the Smallfin Gulper Shark <I>Centrophorus moluccensis</I> Bleeker, 1860 (Chondrichthyes: Squaliformes: Centrophoridae) from the Andaman & Nicobar waters, Indian EEZ</b>

The Smallfin Gulper Shark Centrophorus moluccensis is reported for the first time from the Andaman & Nicobar waters of the Indian EEZ. A male specimen of 785mm total length and weighing 2.34kg was landed by a motorized longliner at Burmanallah, South Andaman District. The specimen was caught off Chidiyatapu, South Andaman at a depth of 250m. A detailed morphological description of the specimen and comparison with previous literature is provided.

First Report of Echthrogaleus denticulatus (Smith 1874) on the Pelagic Thresher Shark (Alopias pelagicus Nakamura 1935) from Indian EEZ of Andaman Sea

The present study reports the occurrence of the pandarid parasite, Echthrogaleus denticulatus as an ectoparasite on the pelagic thresher shark (Alopias pelagicus) from the Indian EEZ of Andaman Sea. A total of 36 parasite specimens were found aggregated near the cloacal aperture of eight pelagic thresher sharks caught as bycatch by multifilament tuna longliner MFV Blue Marlin during July 2015 and February 2016 voyages in Andaman and Nicobar waters. This is the first report of ectoparasite from the Indian EEZ of the Andaman Sea.

Efficacy of spatial study on catch and effort from fishing vessels for strengthening fisheries management

Ever since marine fishery operations were extended beyond territorial waters of respective states, the need was felt for incorporating spatial component of fishing effort and catch for formulating marine fishery policies. The present study is an attempt of spatio-temporal analysis of changing scenario of fishing operations in GIS platform with catch and effort data collected from fishermen, to highlight the need for the change in approach in fisheries management and also for updating the information of fishing along the Indian coast. Marine fishing operations by commercial fishing vessels operated from different states has extended up to 200 m depth since 2000 and duration of fishing, especially trawling extended from single day to 8-13 days per voyage. Present findings were drawn from the analysis of 1,217 days of trawling operations during 2007-2013 by a sampling trawler supplemented by additional fishing operational data support from a group of commercial trawlers. Study reveals that there is an organised and confidential maintenance of log sheets in most of the progressive trawler operators and the information available in spatial platform can be utilized for better fisheries management with fishermen’s participation. Spatial analysis of fish catch from the sampling trawler operated from Mangalore showed that more than 70% of the fish landed in Mangalore was brought from the area beyond the territorial waters of Karnataka signifying that majority of fish catch landing to the state is from waters beyond their jurisdiction. Even though the fishery beyond territorial waters of all maritime states is s governed by Government of India, so far, there is no comprehensive management plans regarding fishing operations beyond territorial waters of the states. The study further reveals that fishing grounds beyond territorial waters of each state are being intensively fished without any fishing regulations and there were many conflicts being reported from these waters concerning the fishing rights of different sectors and different states. In the light of the findings from the study on fishing operations and fishery, an action plan to regulate the fishery off the territorial waters of each state is felt essential. “Regional fisheries committees” with members constituting the officials from neighbouring states sharing same resources with the aegis of Central Government is recommended as a viable option to take care of the management of the fishery within the Indian EEZ.

DNA barcoding reveals species composition of sharks and rays in the Indian commercial fishery

DNA barcoding was successfully used for the accurate identification of chondrichthyans in the Indian commercial marine fishery. About 528 specimens of 111 chondrichthyan species and 34 families, collected from the Indian EEZ, were barcoded for a 655 bp region of the mitochondrial gene cytochrome c oxidase subunit 1 (COI). Generally, five specimens per species were barcoded, but numbers ranged from 2 to 13. The average Kimura 2 parameter (K2P) distance separating individuals within species was 0.32%, and the average distance separating species within genera was 6.73%. Ten species were suggested as putative new species requiring formal descriptions. Based on the morphology and molecular support, 11 elasmobranch species were confirmed first records for Indian waters. The present study confirms the ability of DNA barcoding for the accurate identification of sharks, rays, and their products from Indian waters.

Evaluation of feeding indices of cobia Rachycentron canadum (Linnaeus. 1766) from Northwest coast of India

Cobia Rachycentron canadum (Linnaeus. 1766) is an esteemed table fish occurring along both east and west coast of India. Feeding indices of the species inhabiting waters of the northwest coast of Indian EEZ was studied to understand the variation of its feeding intensity based on season, sex and life history changes. Monthly variation of stomach condition of cobia male, female, pooled and size wise were analyzed. In general, 56% of fishes were found in either actively fed or moderately fed state. Except during April and July they were found in actively fed condition. Analysis of occurrence of empty stomach in different length classes of fishes revealed that the percentage of occurrence of empty stomachs decreased with the fish growth. Month- wise Mean Index of Feeding intensity (MIF) and Index of Fullness (IF) values showed that cobia fed well during post monsoon periods but poor feeding activity was noticed in July. Gastrosomatic index for male, female and pooled samples of matched with the MIF and IF values. The results indicated a seasonal variation in feeding intensity of cobia. On an average, feeding intensity during July was low.

Occurrence and Distribution of a Diatom-Diazotrophic Cyanobacteria Association during a Trichodesmium Bloom in the Southeastern Arabian Sea

Symbiotic diatom-diazotrophic cyanobacteria association (DDA) of Rhizosolenia hebetata and Rhizosolenia formosa with endosymbiotic cyanobacteria Richelia intracellularis was noticed and documented for the first time during a bloom of the cyanobacterium Trichodesmium erythraeum in the oligotrophic shelf waters along Kochi and Mangalore transects, southeastern Arabian Sea (SEAS), during spring intermonsoon (April 2012). Although the host is frequently seen, the symbiont is rarely reported in the Indian EEZ. The presence of nitrogen-fixing symbiotic association of Rhizosolenia-Richelia along with Trichodesmium erythraeum highlights the significance of DDAs on the nutrient and energy budgets of phytoplankton in the oligotrophic environments of the Arabian Sea during spring intermonsoon.

Is Occurrence of Harmful Algal Blooms in the Exclusive Economic Zone of India on the Rise?

Occurrence, increase in frequency, intensity and spatial coverage of harmful algal blooms during the past decade in the EEZ of India are documented here. Eighty algal blooms were recorded during the period 1998–2010. Of the eighty algal blooms, 31 blooms were formed by dinoflagellates, 27 by cyanobacteria, and 18 by diatoms. Three raphidophyte and one haptophyte blooms were also observed. Potentially toxic microalgae recorded from the Indian waters were Alexandrium spp., Gymnodinium spp. Dinophysis spp., Coolia monotis, Prorocentrum lima, and Pseudo-nitzschia spp. Examination of available data from the literature during the last hundred years and in situ observations during 1998–2010 indicates clear-cut increase in the occurrence of HABs in the Indian EEZ.

WITHDRAWN: Transport of nutrients in the upper thermocline layer along the Indian EEZ during winter

This article has been withdrawn consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

Maritime surveillance of the Indian EEZ

(1998). Maritime surveillance of the Indian EEZ. Strategic Analysis: Vol. 22, No. 1, pp. 49-59.

Maersk Navigator oil spill in the great channel (Andaman Sea) in January 1993 and its environmental impact

Observations on oil slicks, tar residues and dissolved petroleum hydrocarbons (DPH) shortly after the oil spill resulting from the tanker accident in January 1993 showed negligible impact on the Indian EEZ of the Great Channel (Andaman Sea). DPH were between 0.31 and 1.85 μg l −1 in the area examined. Tar residues were absent throughout the study area. Prevailing NE wind with resultant SW surface current appears to have pushed the oil patches out towards the open Indian Ocean. A follow-up survey of the same area was carried out in September-October 1993 and observations similar to those made during the earlier survey were recorded. The zooplankton biomass had increased considerably during the interval between the two surveys, but this was probably due to seasonal changes and natural variability. The spill did not cause any perceptible impact on the environment.