Indian Council of Agricultural Research


Extending Geographical Distribution Range of Reef Needlefish Strongylura incisa

Present study deals with new distributional records of Strongylura incisa (Belonidae) based on five specimens collected from the Andaman Islands and Tuticorin Coast (Tamil Nadu), India during 2016–17. Specimens were identified by absence of scales at bases of dorsal and anal fins, 19–20 dorsal fin rays, 21–23 anal fin rays, 102–113 predorsal scales, dorsal fin origin over 4–5 anal fin rays, prominent elongate spot on cheek between opercle and preopercle, and double lobe of gonad. Strongylura incisa can be distinguished from itsmost similar congener S. leiura based on number of predorsal scales (100–125 in S. incisa versus 130–180 in S. leiura), dorsal fin origin over anal fin rays (4–6 in S. incisa versus 7–10 in S. leiura), number of gonad lobes (2 in S. incisa versus 1 in S. leiura) and colour characteristics (prominent elongate spot on cheek between opercle and preopercle in S. incisa versus black bar on cheek between opercle and preopercle and anterior region of the body in S. leiura). Present study provides the first documented record of S. incisa from the Andaman and Nicobar Islands and East Coast of India with an updated key for Strongylura species. Further, it is an addition to the ichthyofaunal biodiversity of the Andaman and Nicobar Islands and East Coast of India.


Consortia of Specific Bacteria in Callyspongia subarmigera and their Exocellular Activity

The antimicrobial potency of cultivable associated bacteria in Callyspongia subarmigera was determined. C. subarmigera, the predominant sponge along the South east coast of India at 10 to 15 m (Lat 8° 4? 41?, Long 77° 32? 28? E) of the Indian Ocean was collected off ‘by catch’. The temperature and pH for maximum retrieval of colonies were standardized at 30 °C and 8.5. The retrievable associates from the sponge were isolated for a period of 1 year and their antibacterial activity studied against 16 test pathogens. Among the 56 isolates, six isolates with broad antibacterial spectrum were optimized at different cultural conditions and biochemically characterized. Two Lactobacillus isolates in MRS agar and an extreme salt tolerant isolates in Halophilic agar were noticed during the isolations. The isolates survived the pH range of 4.0–13, while S. rubidae CSP and B. amyloliquefaciens CSG propagated at temp range of 20°- 45 °C. The cell free filtrates of Serratia rubidaea CSP and Bacillus amyloliquefaciens CSG showed profound antibacterial activity even during prolonged incubation timewhile the antifungal activity noticedwas considerably low. Consortia of specific cultivable bacteria in Callyspongia diffusa were isolated. The two potent strains were characterized to the species level. Further studies are required to sort out the antibacterial principle in the sponge associated bacteria.


Investigations on unexplored brachyurans, Charybdis hoplites and Charybdis smithii from trawl discards

The effectiveness of GIS-based resource mapping to strengthen the database for Ecosystem-Based Fisheries Management (EBFM), was tested in an attempt at resolving the existing gap in the data on non-commercial resources. In this paper we describe the result of that try by giving an example of one of the most important influential species in the benthic ecosystem of the Southeast Arabian Sea (SEAS). An estimated 2803 t of Charybdis hoplites, a relatively little known species from the coast, are yearly caught and discarded by trawlers operating from the Mangalore fisheries harbour. A GIS-aided study on distribution and abundance estimated, that the average biomass of the species is 322.7 t, at any time in the area covered. This study brings out the fact that a number of non-commercial biota are serving as non-detectable factors in sustaining productivity. The identification of their role and the quantification of their biomass thus constitute important data for an effective implementation of EBFM.


Filling missing links in albuneid crab distributions in Bay of Bengal, Eastern Indian Ocean

Albuneid crabs are specialized and active sand-burrowing organisms. Despite their substantial diversity, their ability to avoid fishing gear leads to “under collection” and a discontinuous record of distribution. The present study documents the first distributional record of Albunea occulta Boyko, 2002 from the Bay of Bengal, eastern Indian Ocean. Albunea thurstoni Henderson, 1893 is also recorded for the first time from the area, i.e., from the Gulf of Mannar, southwestern Bay of Bengal. This study further reports variation in morphological characters, especially in the carapace grooves (CG) from previous records and across specimens from different regions. Morphometric characters were found useful in species discrimination, which is explained as well.


Mudbanks and fisheries along the Kerala coast – myth and reality

Mudbanks, a unique coastal oceanographic phenomenon occurring along the southwest (SW) coast of India during the SW monsoon season, are synonymous with the fishery of this region. Here we examine the validity of the popular notion that mudbanks directly support rich fisheries, using a high temporal resolution water column data collected from the Alappuzha mudbank region in Kerala during April to September 2014, in conjunction with fisheries data. Our study reveals that the upwelling which occurs during the SW monsoon season along this coast brings oxygendeficient subsurface water to the upper water column. Escaping the oxygen-depleted waters, the fish aggregate within a thin upper layer allowing easy visual identification and capture of fish shoals. This process occurs throughout the coast and is not confined just to the mudbanks. Mudbank being a calm region, traditional fishermen using non-motorized country craft were able to carry out fishing within this region only during the SW monsoon. With the induction of motorized and mechanized fishing, the link between mudbanks and fisheries is becoming less prominent, although the former still continue to be important fish landing centres.


First report of Philometra sp. infestation in Yellow edged lyretail grouper from Indian waters

Studies were carried out to assess the prevalence of nematode infestation in the gonads of the yellow edged lyretail grouper, Variola louti, over a two year period. The results showed the presence of nematodes during post monsoon months. Incidences of gonad atrophy were also noted leading to isolation and identification of the nematode. The Yellow edged lyretail a species which contributes to the hooks and line fishery, was seen to be infected with nematodes from the Philometra genera. Since the nematode is very specific to each fish further studies are essential for its identification.


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