भारत में समुद्री अक्वापोनिक्स प्रणालियों की जीवन क्षमता

Viability of marine aquaponics systems in Indi

Seagrasses of India- an account on diversity

Seagrasses are marine angiosperms, basically monocotyledons, found submerged fully in coastal and estuarine waters. It is the world's only flowering plant which can sustain in seawater and withstand an incredible ally in the war against climate change

Biofilm developed on plant substrates enhances growth and survival of post larvae of Macrobrachium rosenbergii

A five-week laboratory experiment was conducted to evaluate the efficacy of plant-based substrates for biofilm production and their effect on water quality as well as growth and survival of freshwater prawn Macrobrachium rosenbergii (De Man, 1879) postlarvae. The experiment consisted of three treatments with a control, each with three replicates following a completely randomized design. The substrates evaluated were dried sugarcane bagasse (T1), paddy straw (T2) and Eichhornia (T3). Tanks without substrates acted as control. Seven days after the introduction of substrates at the rate of 300 g /tank, post-larvae were stocked at 40 nos/m2. The mean initial length and weight of the post-larvae was 10.3 mm and 0.008 g, respectively. The post-larvae were fed with commercial pellet feed (30% protein) at 20% of initial biomass. Results revealed significantly higher (p<0.05) levels of total ammonia- nitrogen, nitrite-nitrogen and nitrate-nitrogen in the control tanks (0.07 ±.004 mg L-1; 0.03 ±.01 mg L-1; 1.40 ±.05 mg L-1, respectively) compared to treatment tanks. Addition of natural substrates enhanced survival and growth of post-larvae with highest growth recorded in paddy straw (0.15 ±0.05 g) followed by sugarcane bagasse (0.14±0.04 g) and Eichhornia (0.10±0.01 g) treatment. The enhancement of growth of PL in natural substrate corresponds to the heterotrophic bacteria that are using the substrate, probably as a food resource and as a probiotic. Further, there was no water exchange during the experimental period, which indicated that the presence of a biofilm reduces the necessity of water exchange and saves water during the postlarval rearing of M. rosenbergii at this density

Influence of sediment chemistry on mangrove-phosphobacterial relationship

The study reveals importance of sediment chemistry in mangrove-phosphobacterial relationship. The various physicochemical parameters of sediment, bacterial distribution, and acidic- alkaline phosphatase activity were studied in Avicennia marina mangrove sediments. The sampling sites were four mangrove forests along West India. Rhizospheric, pneumatophoric and bulk/non-rhizospheric sediment were collected. The rhizospheric sediment showed higher bacterial activity. The pH was observed low in the rhizospheric sediment and good abundance of phosphate-solubilizing bacteria (PSB). This was also supported by other physico-chemical parameters. Acid phosphatase activity was found to be higher in rhizospheric sediment indicating acid production at rhizosphere by microbial action and root exudation. It is the first study indicating that alkaline phosphatase activity was observed to be higher in pneumatophoric sediment. This coincides with higher number of phosphatase-producing bacteria (PPB) and high inorganic P in the pneumatophoric sediment, revealing that this region of A. marina harbours favourably more PPB with utilization of organic P by bacterial load and conversion to inorganic forms stressing that strong bonding exists between mangrove-sediment-phosphobacterial relationships

Low saline aquaponics system with Silver Pompano as a candidate species

Aquaponics is a sustainable food production system that integrates hydroponics and aquaculture practices in order to attain optimum utilization of nutrients by re-cycling. Aquaponics facilitates the symbiotic production of vegetables and fishes with minimum inputs, organic farming like management and higher control on production. Aquaponics system is extremely water efficient, does not require soil and does not use fertilizers or chemical pesticides. Silver pompano Trachinotus blochii is a preferred candidate species for mariculture due to the availability of hatchery produced seed, adaptability to commercial pellet feeds, good market demand and excellent meat quality. The species has proven good for farming in both marine as well as low saline water bodies. Adopting the principles of nutrient utilization in aquaponics and the ability of silver pompano to grow in low saline conditions, a prototype of a low saline aquaponics system integrating one month reared fingerlings of silver pompano T. blochii, with a common, leafy vegetable Amaranthus by employing a 0.25 hp submersible pump for recirculation was developed

Orange Chromide (Etroplus maculatus): A promising indigenous fish for marine aquariums

Etroplus maculatus, commonly known as Orange chromide is a euryhaline fish endemic to brackishwater streams, lagoons, estuaries and the lower reaches of rivers in peninsular India and Sri Lanka. In India, it occurs in Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu. The Orange chromide at present is mainly utilized as freshwater and brackishwater ornamental fish as it is reported to survive in water close to 21‰ salinity after gradual acclimatization. The present study was conducted to determine the salinity tolerance of E. maculatus to know the scope of this species to be selected as a marine ornamental fish

Seasonal availability of commercially important fish seeds in estuaries of Kozhikode, Kerala

Availability of fish seed for culture is one of the major constraints in expanding mariculture in India. Capture-based aquaculture (CBA) is the practice of rearing wild collected fish seeds from early life stages to adults in captivity to marketable size, employing different aquaculture techniques. It is estimated that about 20 percent of world aquaculture production comes from CBA. The availability of cultivable fish seeds in estuaries of Kozhikode district in Kerala has been surveyed and the potential wild seed grounds identified were in Kadalundi, Korapuzha and Karuvanthuruthi estuaries. The quantitative availability of fish seeds in these localities during different seasons was evaluated

Acanthopagrus berda - a potential species for mariculture in India

Sea breams belonging to the sparidae familyare excellent food fishes and important candidate species for aquaculture. Globally, the river bream, Acanthopagrus berda is highly valued in commercial fisheries and aquaculture due to their excellent meat quality, market demand, easy adaptability to captivity and ability to tolerate wide variations in both salinity and temperature. A. berda is distributed in the estuarine and shallow coastal waters of Kerala, Tamil Nadu, Andhra Pradesh, Maharashtra and Gujarat coasts (Fig.1). Locally known as “Karuthaeri” along Kerala coast they are fished by artisanal fishers using cast nets and hook & line and fetch ` 400-500 per kg in the domestic markets. At present, India is looking for native food fishes for mariculture development and A. berda is considered as a priority species due to their high market demand

Gonadal Assessment of Picnic Sea Bream Acanthopagrus berda (Forsskål 1775), a Potential Aquaculture Candidate for Indian Waters

Gonadal assessment of Acanthopagrus berda (Forsskål 1775), a commercially and recreationally important fish from Indian waters, was studied by collecting 250 fishes from the Korapuzha estuary, Calicut, Kerala using cast net during December 2015 to January 2016. External morphology of the gonads reveals that A. berda is bisexual (with ovo-testis) in nature with the ovarian lobe in the mid-dorsal region of the abdominal cavity and the testicular lobe as a band along the ventro-lateral wall with a major portion running along the extreme posterior region of the gonad. Males were dominant in lower length classes (17–23 cm) while females dominated in upper length classes (24–43 cm), confirming protandrous hermaphroditism in the species. Gonado-somatic index (GSI) was significantly higher (P<0.05) for the females. Males and transitional groups were showing almost similar GSI. External morphological and histological evaluation of the gonads of A. berda during the 2-month study revealed the presence of different developmental stages such as matured testis with oozing milt, an intermediate gonad structure with an anterior thin ovary-like structure and a posterior thick testis-like morphology indicating a transitional ovo-testis, maturing ovary and matured ovary. The simultaneous availability of milt oozing males and matured females from the wild indicates the opportunity for development of captive breeding, seed production and hatchery technology for this important commercial food fish

Present status of Halophila beccarii seagrass bed in Kadalundi Community Reserve

The occurrence of Halophila beccarii seagrass bed in the Kadalundi community reserve area was estimated to be covering an area of more than 2 hectares with a clayey substratum. The seagrass was growing predominantly with seaweed Enteromorpha linza and found exposed during the low tide period. The density of the seagrass H. beccarii ranged from almost nil during July 2012 to 420 g wet weight/m2 (260 plants/ m2) during December 2012. During April 2013 the distribution of Halophila plants was represented only by sparse occurrence of underground parts comprising rhizomes and roots (80 g/ m2). Shoots could not be seen above the sediment substratum