Bacillus subtilis, a probiont isolated from the intestine of Cirrhinus mrigala (Hamilton), was incorporated in fish feed at four different concentrations (5 · 10 8 , 5 · 10 7 , 5 · 10 6 and 5 · 10 5 cells g )1 ) and fed to Poecilia reticulata (Peters), Poecilia sphenops (Valenciennes), Xiphophorus helleri (Heckel) and Xiphophorus maculatus (Gunther) for a period of 90 days. The growth parameters, proximate composition of whole body, digestive enzymes and gut microbiology were monitored at regular monthly intervals. The increments in length and weight and the survival were significantly higher (P < 0.05) and the values of food conversions were significantly lower (P < 0.05) in fishes fed the probiotic feeds. The administration of B. subtilis in diet resulted in an increase (P > 0.05) in body ash and protein content and in the specific activity of protease and amylase in the digestive tract of all the fishes. The counts of total heterotrophs, motile aeromonads, presumptive pseudomonads and total coliforms were significantly lower (P < 0.05) in the gut of the probiotic fed fishes. Bacillus subtilis persisted in the fish intestine and in the feed in high numbers during the feeding period. The high survival and low infectivity recorded in the probiotic feed fed fishes when challenged by immersion assay with the pathogenic Aeromonas hydrophila demonstrate that the probiotic strain confers disease resistance in live-bearing ornamental fishes. A probiotic concentration of 10 6 to 10 8 cells g )1 is adequate for improved growth performance and survival and for healthy gut microenvironment and use of higher concentration of the probiont did not always lead to significantly better results. KEY WORDS

A probiotic bacterial strain, Bacillus subtilis, isolated from the intestine of Cirrhinus mrigala (Hamilton), was incorporated in ¢sh feed at four di¡erent concentrations (5 Â 10 8 cells g À 2 , 5 Â 10 7 cells g À 2 , 5 Â 10 6 cells g À1 and 5 Â 10 5 cells g À1 ) and fed to four species of livebearing ornamental ¢sh, Poecilia reticulata (Peters), Poecilia sphenops (Valenciennes), Xiphophorus helleri (Heckel) and Xiphophorus maculatus (Gunther) for one year duration to observe the effect of dietary probiotic supplementation on their reproductive performance. Sixty virgin females of each species were stocked separately in circular FRP tanks (350 L) and fed diets with varying levels of probiotic cells and control feed. Broodstock performance was evaluated based on gonadosomatic index (GSI), fecundity and fry production of female broodstock. The results showed that supplementation of feed with probiotics increased signi¢cantly (Po0.05) the GSI, fecundity and fry production of spawning females and length and weight of fry in all the four species of ¢sh. The number of dead and deformed fry were also signi¢cantly lower (Po0.05) in ¢sh fed with the probiotic feeds. The use of higher concentration of the probiont in diet did not always lead to sig-ni¢cantly improved reproductive performance of the spawners. Collectively, this study showed that female livebearers bene¢t from inclusion of probiotics in diet during their reproductive stages.

A B S T R A C TThe present study describes the first trial on broodstock development, induced breeding and larval rearing of Indian pompano, Trachinotus mookalee. Indian pompano fingerlings were collected from wild and raised to adults having an average size of 2.84 ± 0.10 kg weight and 47.6 ± 1.43 cm length. These adult fishes were stocked in 125 t capacity circular tank having re-circulatory facility for broodstock development. The fishes were fed with squid along with clam meat and matured in four months. Mature females with > 500 μm ova and oozing males were selected in the ratio of 1:2 (female:male) and were induced with single dose of hCG at the rate of 350 IU /kg body weight. Three trials with same sex ratio and hormonal doses were tried. The fish spawned after 36-38 h of induction at a temperature 29 ± 1°C. Eggs were collected and treated with iodophore and stocked in 1 t FRP tank for hatching. The eggs hatched out after 18-20 h of incubation at a temperature of 29 ± 1°C. The overall fertilization and hatching rate was found to be 69 ± 1.55% and 87.67 ± 0.81%, respectively. Larval rearing was carried out in 2 t capacity fibre reinforced plastic (FRP) tanks using green water system. The newly hatched larvae was 2.12 ± 0.02 mm in total length, with an oval shaped yolk sac of 0.55 mm 2 and an oil droplet of 0.06 mm 2 in area. The mouth opening was formed 40-46 h post hatch with mouth gape measuring 228.10 ± 1.31 μm. A systematic and overlapping regime of live feed beginning from copepod nauplii, rotifer, Artemia nauplii and artificial pellet were utilized during larval rearing. Weaning of larvae to inert diet was started from 15 th day post hatching (DPH) onwards. Larvae started metamorphosis by 17 th DPH onwards and was completed by 21 st DPH, when the larvae reached 27.33 ± 0.10 mm. The larval rearing protocol resulted in an average survival rate of 21.53 ± 1.45% till complete metamorphosis. The present study showed T. mookalee to mature in captive conditions. The potential for induced spawning in captivity and larval rearing with a survival rate of 21.53% makes Indian pompano an excellent candidate for mariculture. This forms the first report of broodstock development, induced breeding and larval rearing of this species in captivity. The results of this study would facilitate mass scale seed production of Indian pompano in captivity, which is essential for its aquaculture.

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Pomfrets (genus Pampus), a highly commercial fishery resource distributed in the Indo-Western Pacific that includes Lessepsian migrants, have witnessed a series of systematic reforms. In this study, based on comprehensive sampling spanning type localities and coevals in the Northern Indian Ocean, the cryptic and valid species Stromateus griseus is resurrected from the synonymy and re-described as Pampus griseus (New Combination) based on 35 specimens from the Bay of Bengal, corroborated by a molecular analysis, which indicated a confined distribution of the species. The Bayesian phylogeny of the genus was reconstructed, incorporating redressed barcodes (582 nucleotides) and concatenated mitochondrial gene sequence data (1,822 nucleotides) generated from the recorded species P. candidus, P. chinensis and the neophyte along with sequences from GenBank entrusting the latest literature. The phylograms differed in topology as for seven valid species, and the one predicated on the concatenated data erected a highly supported polytomous clade for the P. cinereus complex (P. griseus, P. cinereus, and P. candidus) which shares synapomorphies. Pampus argenteus and P. minor, together, formed a sister clade to the rest. Climate-driven vicariant events during glacial epochs and the Indo-Pacific Barrier effect can be the drivers behind the Indian and Pacific Ocean sister lineages in P. chinensis. A multivariate analysis isolated the cryptic species from its congeners. This article portrays the systematics revision of genus Pampus with an integrative taxonomic approach compiling distinctive molecular, morphological, and anatomical features, revised key for species identification, taxonomic archives of Indian stromateids, and winds up with specific remarks.

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The hilsa, Tenualosa ilisha fishery in the northern Bay of Bengal (nBoB) is passing through a crisis manifested by the persistent decline of fish catch in spite of increasing efforts. During the period 2002-2015, the number of boats engaged in the fishery increased by 25% while the hilsa catch decreased by 13%. The exponential value (b) and condition factor (K) of hilsa has also decreased by 46% and 28% respectively. The value of fishing mortality (F = 2.34 year -1 ) has considerably exceeded the natural mortality (M = 0.56 year -1 ) during the study period. It is observed that in place of maximum exploitation rate (E max ) of 0.78, the current exploitation rate (E) of hilsa is 0.81 which is above the sustainable limit. It is a matter of serious concern that with 75% probability the first spawners of the population are being targeted by the present fishing practice. The present study observes that the hilsa population of nBoB are being significantly overexploited in the present level of fishing pressure. The maximum sustainable yield (MSY) limit for hilsa is estimated to be around 25,440 tons per year with the corresponding effort (f MSY ) that may be deployed to achieve the above mentioned catch ranged from 3571 to 3987 (number of boats). It can be inferred that the hilsa fishery in the nBoB is being unsustainably exploited.

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