Report on a sperm whale Physeter macrocephalus (Linnaeus) caught at Chennai coast

In Indian Ocean, sperm whales are distributed in substantial numbers near Madagascar, Mahe banks. East and West coast of India and off Sri Lanka. Instances of sperm whales caught / stranded / sighted are reported from Mahabalipuram, Madras, Tranquebar, Nagapattinam, Pondicherry, Pamban, Manauli Island, Krusadai Island, Quilon, Karwar, Mangalore and Kalpen

Artificial reef and its impact on artisanal fisheries

Artificial Fish Habitat (AFH) is helpful in increasing fish production.Deployment of artifical reefsAn AFH is an object or a construction, which promotes an ecosystem, provides habitat for fishes by attracting and aggregating them and improve the fisherman welfare

Service provided by artificial reef off Chennai: a case study

The fisheries service provided by an artificial reef (AR) with a pile size of 450 m3 deployed at 20 m depth off Chinnandikuppam, 20 km south of Chennai was assessed. In 16 months, the fishermen expended 3843.7 hours of hooks & line fishing in the AR ground and landed 6404 kg. The catch index was 14.2 kg/m3 and the total income was Rs. 2,74,000. Compared with the income per hour of operation of gillnet fishing in the non-AR grounds (Rs. 52.5 kg/h), the income was 36% higher from hooks & line fishing in the AR ground (Rs. 71.3 kg/h). This was possible due to aggregation of high quality fish such as the snappers, emperor and carangids in the AR. Biological investigations on three resident species in the AR show that juvenile fish colonise in the initial months after deployment, grow to a larger size and spawn in the AR, indicating the service provided by the AR for enhancement of resident fish stocks

Ray fishery by trawlers off Chennai and some aspects of biology of the scaly whipray Himantura imbricata (Bloch & Schneider, 1801)

Rays are important components in the elasmobranch landings by different gears at Chennai fisheries harbour, contributing about 75.4% to the annual average elasmobranch landings. The annual average catch of rays during 2002-‘07 was 588.3 t and the maximum catch of 1297.4 t was recorded in the year 2002. Eleven species contributed a major portion to the landings of rays by trawlers at Chennai, among which Himantura jenkinsii dominated the catch, forming 38.6% and H. imbricata, 8.0%. The disc width (DW) range of H. imbricata in the landings was 110-229 mm and 130-289 mm for males and females, respectively. The annual average mean size was greater in females. The annual average sex ratio (M:F) was 1:1.11. The disc width-weight relationships were W = 0.00022DW2.676 and W = 0.00005DW2.965 for male and female, respectively. Analysis of covariance showed that the slopes differed significantly, at 5% level, between the sexes. More than 95% of fishes sampled were in wellfed condition. Analysis of gut contents revealed H. imbricata to be a benthic carnivore feeding mostly on small crustaceans, cephalochordates, molluscs, polychaetes and small fishes

Status of Elasmobranchs Fishery in Chennai, India

Catches of elasmobranchs in India showed an increasing trend from 27.4 thousand t in 1961 to 49 thousand t in 2006. During 2006, among the total elasmobranch catches throughout India, Tamil Nadu contributed substantially with 10.8 thousand tonnes. Observations on elasmobranchs fishery in Chennai for a period of 5 years from 2002–2006 was carried out. In Chennai fisheries harbor, annual elasmobranch catches varied from 489 t to 1735 t for the trawlnets and 194 t to 519 t for mechanized gillnets. In the same harbor, maximum catch of 2074 t of elasmobranchs was recorded in 2002. The contribution of elasmobranch i.e. 4.0 %, 16.0 % & 2.0 % to the trawl, gillnet, and hooks and line (H&L), respectively, with the CPUE of 24.4, 136.7, and 1.3 kg in the respective gears were observed. Trawlers landed heavy catch of more than 100 t of elasmobranchs during June and July with the catch per hour (cph) of 1.4–1.6 kg. Gillnet catches were better during June-September, where monthly catch was above 35 t with CPUE of 203-287 kg. H&L landed good catch during February and March, where the catch was above 1 t with the CPUE of 3.3-4.0 kg

Fish culture in marine farm at Mandapam

The large-scale monoculture and polyculture of the milkfish, Chanos chanos were reported earlier form Southeast Asian countries.This article highlights some interesting and encouraging results obtained during the experiments of milkfish monoculture and polyculture of milkfish with mullet in Mandapam ponds. In the monoculture of milkfish the average size of the fish as well as the production rate could be substantially stepped up by resorting to supplementary feeding. In the polyculture of milkfish, the average growth rate was found to be more or less similar in both the fertilized and unfertilized ponds but the survival and production rates were higher in unfertilized pond. The yield of milkfish under monoculture in the present study is comparable to that of Ceylon, where selective harvesting followed by replenishment gave a production of 799 to 1159 kg/ha/annum. A production rate of 1405 kg/ha/10 months obtained in the present experimental polyculture of milkfish

Spawning, intracapsular development and production potential of viable juveniles of a murex Chicoreus virgineus var. ponderosa Sowerby under laboratory conditions

Muricids are commercially important gastropods and are exploited primarily for shell craft industries. They also occupy a niche in ornamental keeping. Studies on the larval development of muricids in Indian waters are few. Hence, an attempt was made to study with a focus on the optimum requirements for captive brood maintenance; regional variation in egg laying, intracapsular development and to estimate production potential of individual brooder (the length/ weight ranged from 80 - 110 mm/49 - 169 g (average 94.875 ± 3.980 mm/111.625 ± 14.870 g) of Chicoreus virgineus var. ponderosa collected off Tuticorin coast, Gulf of Mannar. Experimental airlift water circulation system fitted in 1 t FRP tanks having an overturn of 300% water is found suitable for long term maintenance and maturation of brooders with near cent percent survival over a year. Spontaneous breeding commenced from June ’09. Eggs cases were ‘vase’ shaped and measured 1.2 - 1.5 cm in height. Egg case numbers varied between 110 and 140 and got reduced to 10 - 40 during October and increased in Nov & December. Number of eggs within the egg case was highly variable ranging from 100 - 380. Eggs were spherical, embedded in jelly mass within the egg case and measured 510 - 608 μ (578 μ). Intra capsular development is detailed and compared with the earlier report on this species from other areas of Indian coast. Development took nearly 20 days and only few free living juveniles measuring between 1.7 - 1.9 mm emerged and the rest of the eggs have functioned as “Nurse eggs”. Average net production potential of a single viable egg case was estimated to be 6.7 nos for Chicoreus virgineus var. ponderosa of Tuticorin coast of Gulf of Mannar

Unusual bumper catch of shrimps at Nochikuppam, near Chennai, east coast of India

Sporadic occurrence of penaeid shrimps consisting exclusively of Fenneropenaeus indicus (Indian white shrimp–Vella eral/Por eral), F. merguiensis (banana shrimp – Vella eral/ Sunnambu eral), Penaeus semisulcatus (green tiger shrimp – Valayampoota era/motta eral/vari eral/ flower), Penacus monodon (giant tiger shrimp – Kotteral/Kathamba eral/kara) are usually recorded by indigenous gears like single-layer gillnet (Pannu valai) and three-layer trammel net (Disco valai/Mani valai). In these nets the shrimp catch rate vary from 2 to 5 kg/unit, while in the trawl net, shrimps form 10 to 15 % of the annual total fish along the Chennai coast. However, an unusual bumper catch of shrimps to a tune of 22.8 t was landed by trammel net at Nochikuppam Landing Centre near Chennai during 10th - 14th December

Atlas on the Elasmobranch fishery resources of India

The elasmobranchs represented by sharks, skates (sawfishes,guitar fishes) and rays are an important group of demersal fishes which are exploited for multifarious uses of their various body parts such as the meat, fins, liver, teeth and the hide. While shark fins are considered as a delicacy fetching increased export market, their liver oil is utilized in pharmaceutical industry. Shark teeth is used for ornamental purposes and their hide for a variety of leather products. This increased commercial demand coupled with their characteristic life history pattern including slow growth rate, delayed maturation, long reproductive cycle, low fecundity and long life span and their trans-boundary migration pattern make them susceptible to over fishing. Because of this background, of late there had been a growing international awareness over the conservation and management of the elasmobranch stocks. This in turn necessitates an understanding of resource characteristics and eco-biological features of different species of sharks, skates and ray