Optimal salinity and temperature for early developmental stages of Penaeus merguiensis De Man

The combined effects of temperature and salinity on the hatching success, survival and development of the larval stages of Penaeus merguiensis were investigated in a 4×2 factorial designed experiment employing two temperatures (29±1 and 33±0.5 °C) and four salinities (25, 30, 35 and 40 ppt). Best percentage of hatch was obtained at 33 °C and 35 ppt (87%) followed by 29 °C and 35 ppt (82%). Similarly during naupliar stages, high survival rate was obtained at 33 °C and 35 ppt (89%). Metamorphosis cycle during the protozoeal stages (protozoea 1 to postlarva 1) was extended and survival rate decreased at 25 ppt. Development to PL1 was faster at 33 °C (7–8 days) as compared to 29 °C (8–10 days) regardless of the salinity levels. Maximum survival during the protozoeal stages was at 35 ppt followed by 48% at 33 °C and 45% at 29 °C. Results showed that salinity exerted a greater influence than temperature on the survival and development of larvae. Based on the results, the best temperature–salinity combination for larval survival and metamorphosis of P. merguiensis is 33 °C and 35 ppt. A salinity range of 30–35 ppt is ideal for larval development

Banana shrimp: low cost technology for broodstock development

Global aquaculture production more than doubled in weight and value between 1986 and 1996, and it currently accounts for over one quarter of aquatic production consumed by humans

Studies on ovarian maturation and larval development of Penaeus merguiensis de Man in captivity

The upsurge in recent years in the world food market and uncertainities of capture fisheries has helped in the intensification of global effort on shrimp aquaculture. Penaeus merguiensis de Man, popularly known as Banana shrimp, is an important candidate species with high potential for farming and hence was selected for the present study. The fundamental aspects of its reproductive physiology and larval development were investigated. Eyestalk ablation is the most commonly employed method to induce maturation of shrimps in hatcheries worldwide. Hence in the present study, eyestalk ablations were carried out on adult females of different sizes under varying environmental conditions to induce maturation. Successful results were obtained when ablated females were maintained in marine conditions compared to brackishwater environment, while no effect was visible when females of smaller sizes were subjected to similar treatments. Females ablated during the colder months of the year had a delayed response of ovarian maturation. Administration of exogenous substances like cerebral and thoracic ganglionic extracts and 5-hydroxytryptamine resulted in a significant increase in GSI, while the increase in GSI was not statistically significant when shrimps were administered 17-a hydroxyprogesterone. Larval rearing of P. merguiensis at different salinity and temperature combinations showed that the development during nauplius to postiarval stages was faster at 33°C and 35%oeompared to other tested salinity and temperature combinations. During the postiarval stages maximum survival and growth was observed at 15%0. The ability of P. merguiensis to reach maturation in captive environment, together with the fast growth rate and tolerance of larvae to a wide range of salinity and temperature combinations in captivity, indicates P. merguiensis to be a promising candidate species for aquaculture

Ovarian maturation in the banana shrimp, Fenneropenaeus merguiensis (De Man) by Serotonin (5-hydroxytryptamine) injection

The effect of serotonin (5-hydroxytryptamine, 5-HT) on the histological structure of ovaries of the banana prawn Fenneropenaeus merguiensis (Crustacea: Decapoda) was studied. The Gonadosomatic index (GSI) increased significantly in the treated females, with a majority of oocytes reaching early vitellogenic stage, indicating that ovarian maturation could be induced and accelerated by 5-HT. The changes were also associated with a significant increase (P<0.01) in the female specific protein (FSP) level in the treated females compared to the controls. 5-HT exerts its stimulatory effect on the ovaries of crustaceans indirectly by triggering release of gonad stimulating hormone (GSH) from the brain and thoracic ganglion. Thus, a programme incorporating 5-HT, high salinity and good water quality seems to be a practical alternative to eyestalk ablation to induce maturation in F. merguiensis in captivity

Characterisation of vitellogenin and vitellin of Fenneropenaeus merguiensis (De Man)

Purification and characterisation of vitellogenin and vitellin from haemolymph and mature ovaries respectively of Fenneropenaeus merguiensis were conducted using ammonium sulphate precipitation technique. The vitellogenin level in the haemolymph was low in the early stages of development, but increased significantly in the late maturing stages (Stage III) and fell abruptly in spent females. Purified vitellogenin had an approximate molecular weight of 350kDa as determined by PAGE and was characterised as lipoglycoprotein with calcium affinity on the basis of staining data. Two forms of purified vitellin (Vn1 and Vn2) of molecular weights 550 and 300kDa were also isolated. Vn1 was characterised as a lipo-glyco-calcium complex while Vn2 was glycoprotein in nature based on staining data. SDS PAGE analysis revealed 6 subunits in purified vitellogenin and 5 subunits in vitellin

Induced maturation and spawning of banana prawn, Penaeus merguiensis de Man, under captivity in the inshore waters of Karwar

Investigations were made on the ovarian maturation of banana prawn (Penaeus merguiensis) held in a fixed hapa (2xlxlm) in inshore waters of Karwar bay. The shrimps collected (ablated females and males in the ratio 2:1) were subjected to experimental condition for a period of 10 days. The parameters such as salinity, temperature, pH and primary productivity of the seawater at the site were monitored regularly. Within 3-6 days after eyestalk ablation, 70% of the females matured in the cage and spawned successfully in situ, thereby indicating the possibility of induced ovarian maturation on commercial scale. Brood stock development on commercial scale for other important candidate species of aquaculture has been suggested

Effect of eyestalk ablation on ovarian maturation in the banana prawn, Fenneropenaeus merguiensis de man under different environmental conditions

Investigations were made on the ovarian maturation of eyestalk ablated Fenneropenaeus merguiensis maintained under different environmental conditions. The results obtained indicated no signs of maturation when females of size smaller were ablated. Larger ablated females showed a delay in maturation during the colder months in contrast to those ablated during the warmer months. The study suggests that a system incorporating unilateral eye stalk ablation, high salinity, good water quality and optimum temperature are sufficient to induce maturation in captivity in females above the length of first maturity

Changes in serum proteins and immune response in oreochromis mossambicus induced by aflatoxin B

Studies were conducted to evaluate the molecular changes induced by aflatoxin, the most frequently encountered dietary carcinogen in Oreochromis mossambicus. Three sub-lethal test doses of aflatoxin B1 incorporated in feed (1.5, 5.0 and 15.0mg/kg feed) were given to the fishes for a period of 30 days and the changes in serum protein profile were resolved through SDS PAGE at regular intervals. Similarly, the changes in immune responses were also studied. The study revealed significant changes in both protein profile and immune response in the experimental fishes compared to the control, indicating that the toxin exerts its effect even at sublethal levels

Larval rearing of seahorse Hippocampus kuda under laboratory conditions

Seahorse belongs to a single genus Hippocampus of the family Syngnathidae. This family also includes pipefishes and pipehorses. There are about 30-40 species of seahorses under the genus Hippocampus. They constitute a fascinating group of fishes with their unusual body shape apart from their peculiar mode of reproduction with the males incubating the fertilised eggs in a brood pouch on the abdomen. They are tropical and sub tropical in distribution and are exploited around the world for use in medicines, as ornamental fishes, curios and to a very limited extent as food. Most of them are marine, inhabiting coral reefs and sea grass beds though some occur in coastal mangroves

Growth And Survival Of Penaeus Merguiensis Postlarvae At Different Salinities

The growth and survival of postlarval Penaeus merguiensis were examined to optimize condi- tions and improve farm production. Postlarvae were subjected to one of four salinities (5-35 ppt) for a period of 28 days. Results indicated maximum survival at 25 ppt while the best growth rate was obtained at 15 ppt. The highest performance index was obtained at 15 ppt. Hence, 15 ppt was found to be the optimum salinity for the production of P. merguiensis postlarvae. The fast growth rate and good tolerance of P. merguiensis larvae to a wide range of salinity in captivity indicate that P. merguiensis is a promising candidate for aquaculture