Indian EEZ Research Articles

Insights into reproductive dynamics and feeding biology of Sphyraena putnamae Jordan and Seale, 1905 exploited in the Indian EEZ

The sawtooth barracuda Sphyraena putnamae, widely distributed in the Indo-Pacific region, isone of the commercially important barracuda species exploited by trawls in the Indian EEZ.The present study examined 2,135 S. putnamae collected during 2014-2020 from differentfish landing centres along the Indian coast, to elucidate their reproductive and feedingbehaviour. The fork length of sampled females and males varied from 12.5 to 130.9 cm and16.5 to 90.0 cm respectively. Negative allometric growth was observed with a significantdifference (p<0.05) between the sexes. The observed sex ratio (Female:Male) was 1.23:1,indicating the dominance of females. Size at sexual maturity for females and males wereestimated at 55.3 and 45.4 cm fork length respectively. The higher proportion of spawningcapable individuals and higher gonadosomatic index (GSI) values in females observedduring March to May and November-December revealed the bimodal and protractedspawning nature of this species. Absolute fecundity increased with fork length and weightand varied from 70,080 to 10,18,068 oocytes with an average of 3,16,568 oocytes. Thestomach vacuity index of females and males was 49.09 and 47.92% respectively. Fifty-nineprey items were identified in the diet, with a predominance of fishes confirming S. putnamaehas a piscivorous feeding behaviour. Keywords:Management, Protracted spawners, Piscivore,Sawtooth barracuda, Sex ratio

Assessment of marine fish stocks within India’s ExclusiveEconomic Zone: Status report 2022

India is one of the major fishing nations in the Indian Ocean, with commercial marine fishlandings in the country comprising of nearly 1000 species. A comprehensive and periodicassessment of the stocks is crucial for achieving the goals of sustainable fisheries harvestand management. The ICAR-Central Marine Fisheries Research Institute, Ministry ofAgriculture and Farmers’ Welfare, Govt. of India, is mandated to monitor and assess themarine fisheries resources in the Indian EEZ. In the present study, 135 stocks across 70species were assessed using monthly length-frequency data. The health status of the stockis projected based on a combination of indicators such as relative biomass or spawningstock biomass (B/Bmsy or SSB/SSB0) and relative fishing pressure (F/Fmsy) estimated usinga standard length-based dynamic pool model (i.e., Thompson and Bell Model). Based onthe comparison of estimated values of indicators against the thresholds, the stocks wereclassified as sustainable, overfishing, overfished and rebuilding. The study revealed that91.1% of the assessed fish stocks have a healthy biomass level (sustainable stocks andthose subjected to overfishing), 8.2% of stocks are overfished, whereas 0.7% are in theprocess of rebuilding. Biology-based, Healthy stocks, Length-frequency,Stock assessment, Sustainable, Tropical

Stock status indicators for Cobia Rachycentron canadum in the Indian EEZ

Regional fisheries for cobia (Rachycentron canadum) along the Indian coast was assessedusing length-based stock status indicators. Drift gill nets-cum-hook and line fisheries landedbigger sized cobia as bycatch while multi-day mid-water trawls landed juveniles. Dominantsize groups in the landings along the west coast were 40–160 cm and 60-120 cm on theeast coast. Gear selectivity operating at regional levels because of the multi-gear fisheriesand fishing grounds of the Indian EEZ affects the size distribution of fish caught. Comparedto drift gill net-cum-hooks and line units targeting large pelagics in deeper waters, smallersize groups of cobia dominated as bycatch in trawls. The length at first capture (Lc50) beingsmaller than the estimated length at first maturity of about 60 cm, implementing size-basedoutput controls such as Minimum Legal Size (MLS) is suggested. The indicators for fishingmortality rates (Fmax) on the cobia stocks were on the higher side in certain locations only,but being part of the multi-species bycatch mix, there is little scope to introduce fishinggear regulations solely for cobia. However, the option of short-term, targeted spatiotemporaleffort regulations with fishers’ participation can be explored, based on the stockassessments made at local or regional levels. Keywords:Cobia, Fishery indicators, Length-based indicators,Minimum Legal Size, Rachycentron canadum, Stockstatus

Diet composition and feeding habits of yellowfin tuna Thunnus albacares (Bonnaterre, 1788) from the Bay of Bengal

Though yellowfin tuna (Thunnus albacares) is one of the important fishery resources in the Bay of Bengal, knowledge on its ecology, diet composition and feeding habits are limited from this area. In view of that, present study focuses on the diet composition and feeding habits of yellowfin tuna (YFT) hooked during exploratory longline survey conducted in the Indian EEZ of the Bay of Bengal during 2019–2021. A total of 213 specimens in the length range of 42.0 to 171.0 cm fork length (FL) were examined, of which 28.2% were empty while the remaining 71.8% contained at least one prey item. The modified Costello graphical method shows a wide range of prey items, with a few prey species that are dominant and can be found in high densities in the Bay of Bengal. Due to the fact that this apex predator is a generalist feeder, this might be the case. Cluster analysis based on the %IRI (Index of relative importance) identified two size groups. YFT with smaller (<80 cm FL) is one group. Crustaceans was the most frequently eaten prey in that group followed by cephalopods and teleostea. The second group consists of two length groups medium (81–120 FL), and larger (>120 FL), Cephalopods were the dominant prey items of this group and accounts for 62.0% in %IRI followed by teleostea 31.3% of the diet. Cephalopods (Sthenoteuthis oualaniensis) were the primary food consumed in all the size groups, followed by crustaceans (Charybdis smithii) and Teleost fishes (Cubiceps pauciradiatus). The dietary breadth and the occurrence of empty stomachs were significantly related to size of the yellowfin tuna. With increasing body size, diet breadth gradually increased while the percentage of empty stomachs declined. The yellowfin tuna diet does not vary significantly during the seasons. However, cephalopods were found in 53.5% of the IRI in their diet. Furthermore, there were notable seasonal changes in the percentage of empty stomachs, with the highest percentage observed during the monsoon season (38.3%).

A note on cetacean distribution in the Indian EEZ and contiguous seas during 2003-07

Relatively little is known about the distribution of cetaceans in Indian seas due to lack of systematic surveys. For collecting data on species distribution, 35 opportunistic surveys were conducted onboard FORV Sagar Sampada between October 2003 and February 2007 in the Indian EEZ and contiguous seas. In 5,254 hours of sighting effort, a total of 473 cetacean records were made with 5,865 individuals. The occurrence of 10 species from three cetacean families was confirmed. The Indo-Pacific bottlenose dolphin was the most frequently sighted species, whereas the spinner dolphin was dominant in terms of abundance. Long-beaked common dolphins, Indo-Pacific hump-backed dolphin and sperm whales were also recorded at frequent intervals. Cetaceans were found to have a wide geographical distribution in the Indian EEZ and contiguous seas. High abundance and species richness were recorded in the Southeastern Arabian Sea and southern Sri Lankan waters. From the information collected during the present study, the platform of opportunity has proved to be a useful means for cetacean survey.

An updated checklist of Stomiiformes from Indian waters with nine new records

Abstract Over the years as a part of many fishery surveys, considerable number of stomiiform fishes were collected by the Centre for Marine Living Resources and Ecology (CMLRE) Research Vessel ‘Sagar Sampada’. The collection came from throughout the Indian EEZ and some from the western Indian Ocean. However, a systematic identification of these fishes had never been carried out prior to this paper. Thirty-four species were identified and it was found that eight species were new records to India and one to peninsular India. Among the records, two species, Photonectes paxtoni Flynn and Klepadlo, 2012 and Photonectes barnetti Klepadlo, 2011, are collected from the Indian Ocean for the first time. The paper provides a detailed report on all the new records and a list of stomiiform species collected during these surveys. Differences in barbel morphology observed for many of the stomiids are discussed.

Length-weight relationship and condition factor of four poorly known deep-sea demersal finfishes from Indian EEZ

Length-weight relationship and condition factor of four poorly known deep-sea demersal finfishes from Indian EEZ

Review of the global distribution and hosts of the fish parasitic isopod genus Renocila Miers, 1880 (Crustacea: Cymothoidae) with the description of a new species from Andaman Islands, India

ABSTRACT The global distribution and host records of the external fish parasitic isopod genus Renocila Miers, 1880, are reviewed. A revised generic diagnosis is provided and 11 species of Renocila are regarded as Renocila incertae sedis. Renocila trillesi Aneesh and Kumar sp. nov., parasitizing the coral grouper, Cephalopholis miniata (Forsskål, 1775) collected off Junglighat, South Andaman, India, is described and illustrated, the second species of Renocila from the Indian EEZ. Renocila currently includes 20 valid species including Renocila trillesi Aneesh and Kumar sp. nov. Renocila trillesi Aneesh and Kumar sp. nov., is characterized by: anteriorly truncate rostrum with a ventral posteriorly directed anterior margin; antenna subequal to antennula; pereonite 7 posterolateral angle acute, pleon is 0.85 width of pereon; pleotelson broadly truncate, with weak median longitudinal carina; pereopods 1–3 each with a produced process on the posterodistal angle of basis, gradually increasing the length from 1–3; and pereopods 1–3 inferior margins of articles all without a process or lobe, though ischium of pereopods 1–7 carinate. The present paper also records Acanthurus mata (Cuvier, 1829) as a new host fish for recently described Renocila bijui Aneesh and Bruce 2020. A revised key to the global species is provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:A93A1180-8F8E-4023-BD9B-B64C102AC6B7

Length–weight Relationship (LWR) and Condition Factor (K) of a Deepsea Shrimp Heterocarpus chani Li, 2006 (Decapoda: Caridea: Pandalidae) from Southern Coast of Indian EEZ

Length–weight Relationship (LWR) and Condition Factor (K) of a Deepsea Shrimp Heterocarpus chani Li, 2006 (Decapoda: Caridea: Pandalidae) from Southern Coast of Indian EEZ

Prevalence of epibiosis in plankton community of the Indian EEZ: a review

Prevalence of epibiosis in plankton community of the Indian EEZ: a review

Report of Antennarius hispidus (Bloch & Schneider, 1801) (Lophiiformes: Antennariidae) from the northern Arabian Sea

The present study reports Antennarius hispidus (Bloch & Schneider, 1801) from the northern Arabian Sea. Earlier reports mainly came from the east coast of India, however, the present specimens report the occurrence from northernmost part of the Arabian Sea, in the Indian EEZ (off Okha, Gujarat). The description and the previous distributional records of Antennarius hispidus from India are provided herewith.

First report on an unusual bloom of the potentially toxic epibenthic dinoflagellate Prorocentrum rhathymum from Bangaram Lagoon of the Lakshadweep archipelago: Arabian Sea

Benthic dinoflagellates contribute significantly to the primary production and thereby the sustenance of shallow marine environments. However, some of them are considered potentially toxic or harmful species posing a serious threat to this marine ecosystem. The paper describes an extensive bloom of the dinoflagellate Prorocentrum rhathymum for the first time from the Lakshadweep waters in the eastern Arabian Sea. The dinoflagellates were observed as an intense bloom in the Bangaram Lagoon of Lakshadweep archipelago. The cells of P. rhathymum (7.6 x105 cells L−1) were observed in mucilaginous aggregations with macroalgal debris and filaments of the cyanobacterium, Trichodesmium erythraeum. The bloom area was devoid of other microalgal species, and P. rhathymum was also observed to be attached to fresh macroalgal thalli in the nearshore areas (4.67 x104cells g−1 wet weight of macroalgae). These observations suggest that the debris of macroalgae washed into the water column act as a substrate for the transport of P. rhathymum towards the water column. Warm sea surface temperature (SST, 29.7 °C) and stable conditions of the water column favoured the bloom of P. rhathymum in the Bangaram Lagoon during the spring inter-monsoon season. Coral reef ecosystems along the Indian EEZ are the least surveyed regarding the prevalence of harmful or toxic species, and most of the harmful algal bloom (HAB) events in these systems remain overlooked. Routine monitoring and meticulous bloom physiology studies can provide insights into the prevalence of HAB and prediction of such events in these diverse ecosystems.

Report on Sicklefin Weasel Shark <I>Hemigaleus microstoma</I> (Bleeker, 1852) (Carcharhiniformes: Hemigaleidae) from the Andaman Islands, Indian EEZ with DNA Barcodes

The occurrence of sickle fin weasel shark Hemigaleus microstoma Bleeker, 1852 is reported here from Indian EEZ, off the Andaman Islands in the Bay of Bengal. Two specimens of total length (TL) 610 mm and 628 mm were caught by longline at depths 40-100 m. A detailed diagnostic description and morphometrics of H. microstoma and its comparison with previous literature is provided. COI DNA barcodes were generated for the collected specimens.

Deep-water brachyura from the surveys of the FORV Sagar Sampada off the Andaman and Nicobar archipelagos, India

The deep-water decapod crustacean fauna of the Andaman Sea is interesting in that it has zoogeographical affinities with those of the Indian and western Pacific fauna. The present study reports 17 brachyuran species from 11 families and 17 genera collected by the Indian Fishery Oceanography Research Vessel Sagar Sampada during five separate cruises from 2010–2017. Of these, Homolochunia valdiviae Doflein, 1904 (previously known from East Africa, Madagascar, Seychelles, Comoros and Moluccas) and Dairoides seafdeci Takeda & Ananpongsuk, 1991 (previously only known from Thailand) are new records for the Indian EEZ. In addition, Parilia pattersoni Ng, Devi & Kumar, 2018, described from the western part of the Bay of Bengal, is recorded for the first time from the Andaman Sea as well as Arabian Sea. The taxonomy of Dicranodromia baffini (Alcock and Anderson, 1899), Paromolopsis boasi Wood-Mason in Wood-Mason and Alcock, 1891, Arcania undecimspinosa De Haan, 1841, Platymaia alcocki Rathbun, 1918 and Carcinoplax indica Doflein, 1904 is discussed in detail.

The First Record of the Rearfin Flying Fish, Cypselurus opisthopus (Exocoetidae), from the Waters of South India, with the Assessment of Flying Fish Species Occurring in the Indian Exclusive Economic Zone

The present study reports the first record of the rearfin flying fish, Cypselurus opisthopus (Bleeker, 1865), in the south-eastern Arabian Sea based on a single specimen caught by a commercial trawler off the Kerala coast. Hitherto unknown in the waters off Indian coast, this is the first occurrence of this species in the Indian EEZ, suggesting the extension of distributional range of the species in the Indian Ocean. Detailed information on the morphometric and meristic characters are given and discussed. Molecular confirmation of the species identification was carried out using partial mitochondrial cytochrome oxidase sub-unit I gene. A map of the geographical distribution of C. opisthopus in the Indian Ocean based on published data and a list of flying fishes occurring in the Indian waters (within EEZ) is provided. Up to now, 24 species from 6 genera of flying fishes are recorded from the Indian waters.

New host and geographical record of Eudactylina pusilla Cressey, 1967 from Indian waters with DNA barcodes

The present paper reports the first record of the parasite Eudactylina pusilla Cressey, 1967 from the gills of the pelagic thresher shark, Alopias pelagicus Nakamura, 1935 collected during a multifilament longline operation at a depth of 762 m from Indian EEZ around Andaman Islands. The occurrence of this copepod gill parasite on A. pelagicus in the Indian waters constitutes new host record and extends the parasite’s known geographical distribution, thus contributing to the knowledge of biodiversity of the parasitic copepods in Indian waters. Molecular marker based taxonomical annotation using Mitochondrial 18S r DNA sequencing also confirmed the identity of the E. pusilla specimen.

The first record of active methane (cold) seep ecosystem associated with shallow methane hydrate from the Indian EEZ

Here we report the discovery of cold-seep ecosystem and shallow methane hydrates (2–3 mbsf) associated with methane gas flares in the water column from the Indian EEZ for the first time. The seep-sites are located in the Krishna–Godavari (K–G) basin at water depths of 900–1800 m and are characterized by gas flares in the water-column images. The occurrence of methane gas hydrates at very shallow depths (2–3 mbsf) at some of the seep-sites is attributed to high methane flux and conducive P–T conditions, necessary for the stability of methane hydrate. Chemosymbiont bearing Bivalves (Vesicomidae, Mytilidae, Thyasiridae and Solemyidae families); Polychaetes (Siboglinidae family) and Gastropods (Provannidae family) are also identified from seep-sites.

A Stranding Record of Dwarf Sperm Whale Kogia sima in Lakshadweep Archipelago, India and its Genetic Analogy by Molecular Phylogeny

The distribution of Kogiid whales from the Indian Ocean waters, especially Indian waters are poorly known. It is extremely difficult to differentiate the two species (Kogia sima and K. breviceps) based on their morphological characteristics alone. Our study presents the first confirmed record of dwarf sperm whale Kogia sima from the Indian waters using morphological examinations, skull morphology and molecular identification. The study is based on the stranded animal found in the west coast of Agatti Island in Lakshadweep Archipelago belongs to the Indian EEZ. K. sima showed intra-species genetic variability which confirms the isolation of the species in oceans as the tropical nature of the species restricts its movement.

First report of four deep-sea chondrichthyans (Elasmobranchii and Holocephali) from Andaman waters, India with an updated checklist from the region

This paper confirms the new distributional records of four rare deep-water chondrichthyans viz. sharpnose sevengill shark, Heptranchias perlo (Bonnaterre, 1788); bluntnose sixgill shark, Hexanchus griseus (Bonnaterre, 1788); bramble shark, Echinorhinus brucus (Bonnaterre, 1788); and sicklefin chimaera, Neoharriotta pinnata (Schnakenbeck, 1931) from the Andaman waters in the Indian EEZ. The above-mentioned four fish species have not been reported earlier from this region. More exploratory surveys in the region are essential to understand the diversity and distribution pattern which is essential for critical management actions. An updated checklist of chondrichthyans known from Andaman and Nicobar waters of India is also presented.

First Findings of Rare Fish Heminodus philippinus (Teleostei: Peristediidae) from Indian Waters

A rare peristediid fish Heminodus philippinus Smith, 1917 presented here as first findings from the Andaman waters, based on a single specimen collected from off the Andaman coast of India at a depth ranging from 300 to 325 m. Previous record of H. philippinus only came from south Japan, Indonesia and the Philippines. The present specimen is the first representative from Indian EEZ, comprising Arabian Sea, Bay of Bengal and Andaman waters having a total area of 2.02 million sq. km. Along with the morphometric and meristic values, a short description of the species is also provided.