Overview of cage culture – Indian perspective

The decline of fish stocks has been a motivating factor for expanding the role of aquaculture in the fishing industry. Nowadays, the trend demonstrates that while wild harvest volume remains stable (or is in decline in several fisheries), aquaculture production has increased. In this situation, cage farming has an important role in meeting the global demand for fish products. It is one the alternative source to increase the aquaculture production. The development of this type of fish production is a long-term solution to meet the global demand for fisheries products and also provides economic opportunities for displaced and landless fishermen

Physico-chemical parameters for Micro algal culture

Marine microalgae are unicellular in nature, which are the primary producers of the sea. Among microalgae, green algae, flagellate and diatom species, are the primary producers at the base of the marine food chain. It’s an important source of nutrition and is used widely in the aquaculture of other aquatic organisms like finfish and shellfish, etc., either directly or as an added source of basic nutrients. They are cultured in hatcheries for larval rearing of molluscs, crustaceans and fish as a source of nutrition. In hatchery systems, micro algae is also added to the larval rearing tanks to improve ‘quality’ of water. The production of micro algae is very critical in successful hatchery management. Suitably treated seawater enriched with nutrients, like nitrates, phosphates, essential trace elements, vitamins and carbon dioxide is a prerequisite for any successful algal culture. High micro algal biomass with low bacteria content is important to support the growth of finfish or shellfish larvae. In this context Physio-chemical parameters and its management in algal culture systems plays a vital role in enhancing the survival, growth and production of cultivable animals

Exergy analysis of solid oxide fuel cell operating on natural gas

The fuel cell performance can be determined by various methods described in literature like impedence studies, cycle voltametry e�ciency and exergy analysis etc,. In this work exergy analysis is implemented to study the performance of two types of fuel cells namely HT - PEMFC and SOFC. Exergy analysis can be used to determine not only the quantity of energy utilized but also the quality of the energy. Now a days exergy analysis is extensively used to determine the magnitude of energy loss and its location. In this work, exergy analysis is done on HT - PEMFC to identify the locations or equipments where loss of energy could be take place. This can be used to improve the overall performance of the system. In additional to the exergy analysis of HT-PEMFC, the performance of SOFC is also examined by exergy analysis. Assuming that all channels in a stack behave similarly, a single channel is simulated at different temperatures at different cell voltages and variable fuel composition. Also, SOFC is run at constant ow rate condition to validate the exergy analysis

Cage culture requirements - Site selection and water quality needs

Culture of fish in cage is a popular method of rearing the fish along the coastal areas. Site selection and water quality is one of the most important factors that determine the success and failures of cage culture system. It also determines the cost of production and survival of the system in the long run. Controlling water quality parameters in open water cage culture systems is an impractical; therefore, culture of any species must be established in the sites having adequate water quality and frequent exchange. Before establishing a cage culture site, it is foremost important to conduct a field survey for gaining prior knowledge on the environmental/ hydro-biological parameters of the site so as to ascertain that the water body chosen will support the increased biological demand due to cage culture activities in due course of time

First record of Silver moony, Monodactylus argenteus (Linnaeus, 1758) from Visakhapatnam, Andhrapradesh

A specimen of Monodactylus argenteus (Fig. 1) was collected from the commercial trawler at Visakhapatnam fishing harbour on 6th August 2013. After detailed morphological examination, the specimen was fixed with 5% formalin and deposited at the marine fish museum of VRC of CMFRI, Visakhapatnam. The morphometric measurements were taken to the nearest mm and the specimen identified as M. argenteus is the first report on its occurrence along Visakhapatnam, east coast of Indi

Fishery, biology and stock assessment of spotted seer, Scomberomorus guttatus (Bloch & Schneider) off Andhra Pradesh

The fishery, biology and stock of the spotted seerfish, Scomberomorus guttatus (Bloch & Schneider) along Andhra Pradesh was studied during 2012-2014. The annual average landing of spotted seer during the period along Andhra coast was 2,614 t. Major contributors were trawlnets-1,104 t (42.2%) and gillnets-950 t (36.3%). Catches were higher during August-December. Length-weight relationship varied significantly between males, females and indeterminates. Growth was isometric in males and allometric in females and indeterminates. Overall sex ratio was 1:1.87. Length at first maturity was 38.9 cm. Peak spawning was observed during November-April. Higher Gonadosomatic index coincided with periods of peak spawning. Mature ovaries contained both maturing (0.41 mm-0.70 mm) and matured (0.71 mm-0.90 mm) ova. von Bertalanffy growth equation was Lt = 71.98 [1-e -0.23 (t + 0.0722)]. Natural mortality, fishing mortality and total mortality were 0.54, 0.49 and 1.03. Exploitation ratio was 0.48. Annual total stocks, biomass and Maximum Sustainable Yield were 8,546 t, 5,335 t and 2,747 t. A minor increase in yield and yield/recruit is possible by increasing the present level of fishing by 20%

Seasonal occurrence of potential fishing zones along northern Andhra Pradesh coast

228-232Data on potential fishing zones (PFZ), obtained from the Indian National Centre for Ocean Information Services (INCOIS), Hyderabad, and advisories for North Andhra coast were segregated season wise and analyzed to understand the trends and the frequency of occurrences of PFZ in North Andhra coast. Plotting of data revealed location of PFZ near coastal regions during summer months. These zones moved towards deeper waters during pre-monsoon, expanding to a larger area as the monsoon progressed and moved north during post-monsoon season. Plotting also revealed that Kakinada waters have frequent PFZ hits especially nearer to the Kakinada bay. Visakhapatnam waters were observed to get high intensity of PFZ hits during Monsoon followed by those during post-monsoon and summer seasons. However in Kalingapatnam waters, high intensity of PFZ occurred during post-monsoon followed by monsoon and summer seasons

Trophodynamics of Nemipterus japonicus (Bloch, 1791) in the trawl landings along the north-east coast of India

The trophodynamics of Nemipterus japonicus (Bloch, 1791) along the north-east coast of India was studied during 2012-2015 based on specimens collected from trawl landings at Digha, Paradeep (northern region), Visakhapatnam and Kakinada (southern region). Crustaceans were the preferred prey with index of relative importance (IRI) of 50% in the northern region and 42.4% in the southern region. Among crustaceans, Oratosquilla dominated in both the regions followed by crabs and several species of penaeids and nonpenaeids. Finfishes ranked next in importance (IRI% of 32.1 in northern region and 39.9 in southern region) and included Stolephorus spp., silverbellies, Coilia sp., other clupeids, Apogon spp., mackerel, sardines, eels, priacanthids, Bregmaceros sp. and sciaenids. Along northern region, in juveniles and preadults, the diet comprised chiefly of crustaceans (IRI% of 72.27 and 52.76), followed by finfishes (IRI% of 15.37 and 27.65). In the southern region, adult fishes exhibited higher preference for finfishes (IRI% of 47.5 to 62.8). Feeding intensity was low throughout the year with close to half (48.23% in northern region and 43.67% in southern region) of the fishes exhibiting empty or trace stomach conditions which increased with an increase in age and size of fish. High similarity of 75.54% in the northern and 84.19% in the southern region was recorded in the diet contents of smaller and moderate sized adults. Annual and seasonal mean similarity in the diet components between the regions was 69.9 and 53%. Prey contents in juveniles between both the regions exhibited a similarity of 59.5%, while preadults and adults recorded similarities of 62.7 and 68.2% respectively

Reproductive biology of Nemipterus japonicus (Bloch, 1791) in the trawl grounds along the north-east coast of India

The reproductive biology of Nemipterus japonicus (Bloch, 1791) along the north-east coast of India was studied during 2012-2015 based on samples from the trawl landings at Digha, Paradeep, Visakhapatnam and Kakinada. Adults dominated the landings. Significant contribution by females was observed in most months of the year. Size at first maturity for females was 15.1 cm. Peak spawning season was during August to February and September to March in the northern and southern regions. Maturity and gonado-somatic index (GSI) were found to correlate well with sea surface temperature (SST). Fecundity increased with length and weight and varied from 13,176 to 1,30,798. Ova diameter distribution indicated the species to be a multiple/batch spawner

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