Joe K Kizhakudan

Status of the major lobster fisheries in India

Abstract Commercial exploitation of lobsters from the Indian seas began in the 1950s. Annual landings have been declining from a peak of 4075 t in 1985 to 1364 t in 2002. Major fisheries were located on the north‐west, south‐west, and south‐east coasts. Among the 12 species recorded, only four species of spiny lobsters (three littoral and one deep sea) and one species of slipper lobster are commercially important. At Kayalpattinam and Tharuvaikulam, on the south‐east coast, lobster landings sharply declined for the gill‐net fishery. Of the two species that contributed to the fishery, Panulirus ornatus and Panulirus homarus, the latter has been more affected owing to high vulnerability to fishing activities. Catch composition analysis of the trammel‐net fishery showed that 35% of the landings consisted of P. homarus in the size range of 23–50 mm carapace length. On the north‐west coast, the spiny lobster Panulirus polyphagus and the slipper lobster Thenus orientalis are incidentally caught in trawl nets. However, the fishery for T. orientalis in the waters off Mumbai lasted only up to 1994. Large‐scale exploitation of spawning females, which formed 60% of the total catch, might have been detrimental to the recruitment process resulting in rapid decline and total collapse of the fishery. Abundance of P. polyphagus reached its maximum during September, constituting 23% of the average annual landing during 1988–2002. A high exploitation ratio (>0.7) indicated over‐fishing of the stock. Repeated spawning and high annual egg production are probably responsible for sustaining the stock, despite over‐exploitation. Major problems confronting the resource management of the multi‐gear and multi‐species lobster fisheries in India are discussed. An operational project, involving fisher community, has been taken up for creating awareness of the need for sustainable exploitation of the resource. Regulatory measures, such as closure of the fishery during the peak of the breeding season, ban on trammel‐net, mandatory release of egg‐bearing lobsters, and establishment of lobster sanctuaries are suggested to the State Governments for implementation.

Production of Bio-Diesel from marine macro algae

The world is entering a period of declining non-renewable energy resources popularly known as “Peak Oil”. Climate change is therefore more than a problem with a feasible solution based either in science or markets on which we are likely to reach rapid consensus. Since the mid-20th century it has projected continuation. Earth is already showing many signs of worldwide climate change. One of the greatest challenges facing energy crisis is to replace the petroleum based diesel obtained from crude oil with more environmental friendly Bio-Diesel. Bio-Diesel is made from renewable resources, is bio-degradable and non-toxic and has a higher flash point than normal Diesel. Another significant advantage of Bio-Diesel is its low emission profile and also provides a means to recycle carbon-dioxide, thereby not contributing to global warming and climatic changes. Algal oil is an interesting sustainable feedstock for Bio-Diesel manufacturing. It is an alternative to popular feed stocks like soybean, canola and palm. Algae are the highest yielding feed stock for Bio-Diesel because of its high lipid content. Macro algae are multi cellular organisms which, like plants, use photosynthesis to convert the suns energy into chemical energy. The viscosity of the raw oil has to be brought down by a suitable chemical process called transesterification, so that it can be used as an automobile fuel. It would be concluded that usage of Bio-diesel from algae would be a sustainable way to control of emission of green house gases in the atmosphere and there by controlling the drastic climatic changes. In this research, two macro algal species Gracilaria coticata and Chaetomorpha Antennina were studied for bio-diesel production and their results indicate that bio-diesel can be produced from both the species.

Complete larval development of Thenus unimaculatus Burton & Davie, 2007 (Decapoda, Scyllaridae)

Larval development of the shovel-nosed lobster Thenus unimaculatus Burton & Davie, 2007 is described based on laboratory studies. The larval stages included four stages of phyllosoma (I-IV), followed by a post larval, non-feeding nisto stage which metamorphosed to the juvenile stage, also known as first seed. The nisto stage is reached in 26-30 days, the average duration of each phyllosoma (I-IV) and nisto was 7, 5, 7, 7 and 4 days, respectively. The phyllosomas are characteristically flattened, leaf-like, transparent planktonic larvae, while the nisto, translucent in appearance, remains sedentary at the bottom. The first juvenile stage has a hard exoskeleton and feeds on fresh clam meat. The survival rate from phyllosoma I to nisto was 22%.

Molecular phylogeny of commercially important lobster species from Indian coast inferred from mitochondrial and nuclear DNA sequences

Abstract Lobsters constitute low-volume high-value crustacean fishery resource along Indian coast. For the conservation and management of this declining resource, accurate identification of species and larvae is essential. The objectives of this work were to generate species-specific molecular signatures of 11 commercially important species of lobsters of families Palinuridae and Scyllaridae and to reconstruct a phylogeny to clarify the evolutionary relationships among genera and species included in this study. Partial sequences were generated for all the candidate species from sampling sites along the Indian coast using markers like Cytochrome oxidase I (COI), 16SrRNA, 12SrRNA, and 18SrRNA genes, and analyzed. The genetic identities of widely distributed Thenus species along the Indian coast to be Thenus unimaculatus and the sub-species of Panulirus homarus to be P. homarus homarus were confirmed. Phylogeny reconstruction using the individual gene and concatenated mtDNA data set were carried out. The overall results suggested independent monophyly of Scyllaridae and Stridentes of Palinuridae. The interspecific divergence was found to be highest for the 12SrRNA compared with other genes. Significant incongruence between mtDNA and nuclear 18SrRNA gene tree topologies was observed. The results hinted an earlier origin for Palinuridae compared with Scyllaridae. The DNA sequence data generated from this study will aid in the correct identification of lobster larvae and will find application in research related to larval transport and distribution.