Seaweed farming for income generation and empowerment of coastal rural community

Seaweeds are macroalgae which are found attached to substratum in benthic habitats. They are multicellular autotrophic photosynthetic plants contributing significantly to the primary production of the marine ecosystem. They are non-flowering plants without true roots, stems, leaves and attached to substratum by means of holdfast. They are a significant feature of most shorelines and shallow water environments throughout the world (Robin South, 1993). They can be found mainly in intertidal and in the sub-tidal region up to a depth, where 0.01 % photosynthetic light is available (Domettila et al., 2013). They have an ecological role of providing habitat and substrata for invertebrates, fish, mammals, and birds (Vásquez 1992; Graham et al., 2007) and a source of food for many grazing vertebrates and invertebrates

Case study on the crop rotation in a disease hit coastal tide-fed shrimp pond with silver pompano, trachinotus blochii (lacepede, 1801)

Hatchery produced silver pompano, Trachinotus blochii were cultured in a typical tide fed coastal pond of 1 ha area, semi-intensive culture of tiger shrimp Penaeus monodonwas practiced for many years. Owing to two consecutive collapse of shrimp culture due to white spot disease, a crop rotation in the same pond with culture of hatchery produced T. blochii was performed sequentially after harvest of diseased hit P. monodon stock. Nursery rearing of hatchery produced T. blochii carried out in hapa in same pond resulted in a survival of 99.91 %. Growth performance of T. blochii and the water quality parameters were monitored monthly over a period of 5 months. Feeding was done with artificial floating pellet feeds with a protein of 45% @ 5-7 % of the body weight twice a day. The fishes reached an average weight of 248.30 ± 0.28 g and average length of 22.82 ± 0.90 cm from 9.65 ± 0.59 g and 5.20 ± 0.24 cm respectively upon harvest after 150 days with a survival of 90%.The absolute growth rate and specific growth rate obtained in the present study was 1.6 g day-1 and 2.2 % day-1 respectively. The results of the study revealed that T.blochii is an ideal species for culture in the low salinity traditional coastal tide fed ponds of Kerala. The study also demonstrates the advantage of crop rotation with fish than continuous culture of shrimp in the shrimp culture ponds and the suitability of culturing. T.blochii in polyculture with fish and shrimps

Training Manual on Hatchery production and farming of marine finfishes

Training Manual on Hatchery production and farming of marine finishe

Stunted fingerling production ensures continuous supply of good quality seed for marine finfish farming

Application of compensatory growth pattern in finfishes for enhancing aquaculture production is an innovative method adopted by several farmers in freshwater farming systems. Stocking of stunted fishes have the primary advantages such as growth compensation, suitability for short duration farming, economic usage of feed, extended period of good quality seed availability and enhanced survival rate with better yield. An attempt has been initiated to adopt the principles of compensatory growth pattern in marine aquaculture systems and the possible interventions in these aspects is discussed. Preliminary results reveal that marine finfishes such as Snubnose pompano and Mangrove red snapper exhibits compensatory growth pattern during post- stunting rearing period in both marine and low saline condition

Brief note on infestation of Diplectanum sp. in Asian seabass

Recently open sea cage farming has emerged as an alternative and additional income source for fishermen and fish farmers in India. Asian seabass, Lates calcarifer is widely used in open sea cage culture due to its high market demand. In cage farming, high stocking densities and poor water quality enhance the parasite loads of the cultured fishes. In this study, 47 specimens of Asian seabass collected from cages located in Naganathwada, Sunkeri, Ankola were analysed with the aim of identifying the parasites prevalent among this species. All external and internal organs of each fish were examined separately under microscope for parasites. The collected monogenean parasites were washed in a 0.85% saline solution and fixed in 70% ethanol and identified. Most of the infected fishes had dark coloration of the body and postmortem findings revealed gills with excessive mucus secretion and sticking of the gill tips with greyish coloration

Argulus quadristriatus infestation in cage cultured Asian seabass

In Indian waters, genus Netuma is represented by two species namely N. bilineata and N. thalassina (Order: Siluriformes, Family: Ariidae). Rounded shout, thin lips, inconspicuous median longitudinal groove, and higher anal fin ray count (16-19) are characters of N. bilineata while N. thalassina has conical snout, clearly visible median longitudinal groove and lower anal fin ray count (13-15). Prior to the erection of N. bilineata (earlier considered as synonym of N. thalassina) as valid species, Indian workers had difference of opinion regarding the representation of species under this genus from Indian waters

First report on induced spawning of Siganus vermiculatus in India

Siganids are widely distributed to Indo-West Pacific region and the Siganus vermiculatus (Maze rabbit fish/Vermiculated spinefoot) can reach sizes that weigh up 2.3 kg each. It is a species of great aquaculture importance and hence breeding and seed production protocols are necessary. A major breakthrough in the seed production of Siganus vermiculatus by inducing the fishes to spawn under controlled conditions with Human Chorionic Gonadotropin (hCG) during the first quarter of the lunar cycle is reported. The hatchery processes and early larval stages are described

Report on crested hair tail Tentoriceps cristatus (Trichiuridae) from Goa

A single specimen of ribbon fish Tentoriceps cristatus (Klunzinger, 1884), commonly called the crested hair tail, was landed in Cotbona jetty, South Goa on 26th November 2021. The specimen was collected from a mechanized purse seiner which operated at a depth of 60-80 meters off west of Cotbona

Live feeds in aquaculture

Live feeds are the natural food items of fishes and invertebrates. The culture of live-fed organisms for larval nutrition is an important part of the hatchery operation. Successful larval rearing primarily depends on the supply of the right kind of live food organisms in adequate quantity. In general, microalgae and zooplankton form the most important components in the live feed culture. There is a separate chapter for microalgal culture, so we are mainly concentrating culture of zooplankton as live feed in this chapter. The size of feed is an important concern when compared to the mouth size of larvae. Poor vision, improper digestive system and weaker movements of the larvae make it difficult for the larvae to get proper nourishment. Some fish larvae (precautionary type) have good yolk reserve and start feeding at comparatively developed stages while some others (atresial type) start feeding at smaller and lesser developed stages. Many of the freshwater fish larvae, and marine fish larvae like salmon, cobia and clown fish larvae are comparatively larger than grouper and damsel larvae. Larval feed should be smaller, easily digestible, rich in nutrients and allow autolysis. Formulated feeds are generally not suitable for most of the fish larvae may not meet all these requirements and in most cases, this will reduce the larval survival rate than live food. Moreover, the fish larvae have poor vision and less developed olfactory and digestive organs. Live feed in continuous movement in the water will help the weaker larvae to prey upon these tiny organisms. Copepods, cladocerans, decapod and bivalve larvae, rotifers and ciliates are the important zooplankton organisms which form the food of fish larvae in the wild. The most popular zooplankters used as feed for fish larvae in the fish hatchery are rotifers, cladocerans, artemia and copepods (Lavens and Sorgeloos, 1996)