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The influence of fluctuating water temperature and dietary oxytetracycline (OTC) at 0 (0X), 80 (1X), 240 (3X), 400 (5X) and 800 mg (10X)/kg biomass/day for 30 consecutive days on the safety of monosex (all male) Nile tilapia Oreochromis niloticus fries in terms of feeding, growth, survival and histopathology of vital organs were assessed. A dose-dependent decline in feed intake and biomass was recorded. The OTC-dosed groups recorded higher mortalities than the control. The therapeutic OTC-dosing (1X) in conjunction with low temperature caused 75.56 ± 8.01% mortality and 25.75% reduced feed intake in 30 days. The mortalities increased with increasing OTC-doses from 85.19 ± 3.39% (1X) to 95.56 ± 2.22% (10X) and fluctuating temperature (12.00-21.50°C) even after the withdrawal of OTC. Relatively mild to moderate histopathological lesions were observed in the kidney, liver and intestine of OTC-dosed fries. These results suggested that dietary OTC and low water temperature may cause adverse effects on monosex O. niloticus fries.

The risk factors, management issues and impacts of diseases in carp aquaculture in West Bengal were evaluated. The relative risk was calculated for 35 variables related to pond connection/establishment, pre-stocking, stocking, post-stocking management, hygiene and climate. Practices such as the use of rainwater, draining of pond water, pond bottom drying for > 20 days, liming, treatment of fish seeds before stocking, drying and disinfection of fishing nets and training in aquaculture were identified as sparing factors for infectious diseases. On the other hand, variables such as presence of wild fish in ponds, use of sewage water, intensification of culture, presence of more number of grow-out ponds in farms, presence/poor maintenance of nursery ponds, black pond bottom, sludge disposal on pond dyke, mortality of fish seeds during transportation, inclusion of Cirrhinus mrigala and Labeo bata as culturable species, and low temperature were identified as putative factors. These sparing and putative factors are the areas where the resource-poor farmers can attempt interventions with ease to prevent the diseases and to augment fish production. This calls for effective fish health management strategies and participation of all those involved in the development of carp aquaculture.

In the present study, an attempt was made to document the spatial distribution and diversity inventory of macro-benthic fauna from 21 sampling stations of the Indian Sundarbanfor a period of six months from November 2014 to April 2015. A total of 1,871 individuals belonging to 35 species were recorded which comprised 12 species of molluscs, 20 species of crustaceans, one species each of xiphosurid, sea anemone and fish. The frequency analysis of species revealed that the most dominant species were Telescopium telescopium and Tubuca rosea among molluscs and crustaceans, respectively. The density analysis of the species showed that Pirenella cingulata and T. rosea had maximum values among molluscs and crustaceans, respectively. The average values of Shannon-Wiener diversity index, Simpson diversity index, dominance index and Margalef diversity index were found to be 2.712, 0.888, 0.111 and 4.513, respectively. Keywords:Indian Sundarban, Macro-benthic fauna, Spatial distribution, Species diversity

Pama croaker, Otolithoides pama (Hamilton, 1822) is one of the commercially important demersal fish of Hooghly-Matlah estuarine system, West Bengal, India. Reproductive biology of 618 samples of O. pama (Hamilton, 1822) collected from the Hooghly-Matlah estuarine system of West Bengal, India for a period of 18 months (November 2016 to April 2018) was investigated. The total length (TL), body weight (BW) and ovary weight (OW) of the samples varied from 100-384 mm, 7.29-470.71 g and 1.5-29.49 g, respectively. The sex distribution was 1 male for 1.07 female and the ratio did not differ statistically. The length at first maturity (L m ) was recorded as 183 mm for males and 196 mm for females. The reproductive activity was found throughout the year with three peak spawning season with high gonadosomatic index (GSI) values, i. e ., during February-March, June and September-November. The absolute fecundity ranged from 4652 to 170688 eggs (24950±32441.2) and relative fecundity ranged from 96 to 808 eggs per g body weight (382±176.83). Fecundity exhibited a relatively higher significant correlation with ovary weight (r = 0.973, p

Fish are continuously exposed to multiple environmental stressors that work cumulatively and synergistically. This study assessed the stress responses of Indian major carps (IMCs) cultured in a sewage-fed pond (SP) in the East Kolkata Wetland (EKW), India and compared with the normal carps in situ. The experiment was conducted in two farms that cultured Labeo rohita, Catla catla and Cirrhinus mrigala for seven months, covering the summer and winter periods. Serum biomarkers of primary (cortisol) and secondary (glucose, total protein, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH)) stress responses, and oxidative stress (superoxide dismutase (SOD)) were quantified using standard kits. The health status of carps was evaluated as a tertiary response. The biological oxygen demand, hardness, total dissolved solids, ammonia and phosphate levels of both ponds exhibited marked variations. The SP carps had significantly low haemoglobin and total protein, and high serum glucose, creatinine, ALT, AST and LDH levels. The SOD and cortisol levels were comparatively low in SP carps. The winter temperature had a significant effect on serum glucose, cortisol, SOD, creatinine, ALT and AST. Carps had a high degree of ectoparasitic infestation during the winter. Cirrhinus mrigala of the SP had significantly high serum creatinine levels. The increasing levels of serum glucose, creatinine, ALT and AST suggested that these indices, which were more pronounced in the carps of EKW in conjunction with winter temperature, could be useful biomarkers of stress, kidney and liver functioning in carps, respectively.

The present study analysed the morphometric and meristic characters of Otolithoides pama (Hamilton, 1822) collected from the Hooghly-Matlah estuarine system of West Bengal, India. A total of 618 specimens (298 males and 320 female) were collected during the period of 18 months from November 2016 to April 2018 with length ranging from 100-384 mm and weight 7.29-470.71 g, respectively. The analysis of 14 morphometric characters revealed that standard length has the fastest growth rate when compared to total length, while eye diameter has the lowest growth rate when compared with head length. A high degree of significant positive correlation with the ‘r’ values ranging from 0.978 to 0.997 was observed among different morphometric characters of O. pama. Among nine of the meristic counts, the coefficient of variation was found to be highest in anal fin rays (6.31%) and minimum in dorsal fin rays (1.12%). Based on the meristic counts, the fin formula of O. pama from the present study can be described as B. 7 , D. 9-10/1/44-45, P. i/16-17, V. 1/5 , A. 2/7-8, C. 19-21, L. 48-52. The number of gill rakers on the first left gill arch ranged from 19-21. Keywords: Hooghly-Matlah Estuary, Morphometric characters, Meristic counts, Otolithoides pama, West Bengal

Use of probiotics as the biocontrol agent for disease prevention in aquaculture is gaining importance as an alternative to the indiscriminate use of antibiotics and other chemotherapeutics. In view of this trend, the probiotic properties of a potent antagonistic bacterium, Pseudomonas aeruginosa FARP72, was characterized in terms of safety, antagonistic activities, in vitro immunomodulation, and in vivo disease resistance. Immunomodulatory activity was ascertained by measuring the production of intracellular superoxide anion, nitric oxide, total leukocyte peroxidase content, and the leukocyte proliferation in head kidney leukocytes. The bacterium isolated from the skin mucus of freshwater catfish Clarias batrachus was harmless to Labeo rohita. It showed inhibitory activity against Aeromonas caviae, A. hydrophila, Edwardsiella tarda, Pseudomonas putida, and Streptococcus agalactiae as revealed by cross and parallel streaking methods. Significantly higher superoxide anion and nitric oxide production, peroxidase content, and proliferative responses of leucocytes delineated the strains’ ability to interact with immune cells to activate the immune system in vitro. Significant growth inhibition of A. hydrophila from 1.55 × 105 CFU/mL was observed when co-cultured with P. aeruginosa FARP72 in phosphate-buffered saline (PBS) at levels ranging from 2.61 × 107 to 2.61 × 109 CFU/mL in 10 days. P. aeruginosa FARP72 increased the survival rate of rohu fingerlings against pathogenic A. hydrophila challenge in biocontrol study in vivo as determined by cohabitation challenge. These results suggest that P. aeruginosa FARP72 is a potential probiotic strain and can be used in aquaculture to improve the health status and disease resistance of fish.

Immunomodulation is one of the useful tools to prevent diseases in aquaculture. In this study, the immunomodulatory effects of vitamin-E (100 mg/kg feed) and commercial probiotic consortia, Rhodomax™ (5 g/kg feed) on the innate immunity of Labeo rohita and their protective effect against Aeromonas hydrophila infection were evaluated and compared. Three groups of fish at 30 numbers/tank were fed with vitamin-E, probiotic and control diets at 3% body weight for 30 days, in triplicate. Following this, the fish of all groups were injected intramuscularly with A. hydrophila N10P at 2.40 × 107 cells/fish. The growth indices like specific growth rate (SGR) and feed conversion ratio (FCR) during the feeding and the non-specific immune responses during the feeding and post-challenge regimen were recorded. The dietary supplementation of vitamin-E and/or commercial probiotics caused significant improvements in the innate immunity of L. rohita compared to control. Nevertheless, the vitamin-E diet offered markedly better results in terms of SGR, FCR, ceruloplasmin, antiprotease, myeloperoxidase and phagocytic activities of L. rohita during the feeding and post-challenge regimen. While the respiratory oxidative burst activity was enhanced in probiotic diet-fed L. rohita only during the feeding regimen. All the immune parameters reached normalcy on day 15 post-injection with A. hydrophila. These findings revealed that supplementation vitamin-E at 100 mg/kg feed may improve the growth indices, prime the non-specific immune responses of L. rohita against A. hydrophila infection and enhance the overall health status than the tested commercial probiotics.

The leaves and bark of guava (Psidium guajava) have a long history of medicinal uses. The immunomodulatory effect of Guavarine®, an aqueous guava leaf extract, was investigated on Cyprinus carpio v...

The length-weight relationships (LWRs) of Otolithoides pama (Hamilton, 1822) from the Hooghly-Matlah estuarine system of West Bengal were estimated. The study is based on 618 samples (298 male and 320 female) collected at monthly intervals for a period of 18 months (November 2016 to April 2018) from artisanal catch. No significant difference (p>0.01) was observed in growth rate for both the sexes. The ‘b’ values were estimated at 2.88, 2.84 and 2.86 with ‘r2‘values as 0.96, 0.95 and 0.95 for male, female and pooled samples respectively. The growth pattern was found to be negatively allometric. The month-wise mean ‘K’ value ranged from 0.70±0.07 to 0.78±0.07 for male and 0.71±0.05 to 0.89±0.11 for female. The length-wise estimated mean ‘Kn’ value varied from 0.92 to 1.17 for male and 0.76 to 1.29 for female indicating the moderately good condition of the fish in the study area. The results can be used for sustainable management and conservation of this commercially important species in this estuary

The pathogenicity and pathology of Chryseobacterium sp. PLI2 in experimentally challenged Carassius auratus goldfish were studied. Chryseobacterium sp. PLI2 produced typical chryseobacteriosis symptoms in intraperitoneally challenged and abrasion-bath treated C. auratus. The LD50 was determined to be 3.13×107 cells/fish. It caused 40% mortality within 3 weeks in abraded fish when challenged at a level of ≈2.50×107 cells/mL. The challenged fish were lethargic, anorectic and exhibited erratic movement. With disease progression, they all had white patches on the gills, excessive mucus secretion, caudal peduncle lesions, focal cutaneous haemorrhages, haemorrhagic eye and opercula, scale loss, skin discoloration, skin peeling, emaciation, pale kidneys and black spleen. Histologically, inflammation of the cartilaginous tissue, fusion of the lamellae and extensive necrosis were noticed in the gills. The spleen showed sinusoidal dilation, melanomacrophage aggregate, marginated leucocytes with a hypertrophied nucleus and necrotized areas. Granuloma-like formations, inflamed renal tubules and glomerulus, extensive necrosis, mild melanomacrophage aggregate, acentric nucleus, constricted renal tubules with a vacuolated surrounding, hypoplastic haematopoietic tissue, degeneration of tubular epithelium with proteinaceous casts in the tubular lumen, and fibrosis around the renal tubules were observed in the kidneys. The challenge experiment indicated that Chryseobacterium sp. can cause systemic disease in goldfish., U ovome je radu analizirana patogenost i patološke promjene u zlatnih ribica Carasius auratus pokusno inficiranih bakterijom Chryseobacterium sp. PLI2. Lezije tipične za krizeobakteriozu razvile su se u intraperitonealno inficiranih i abrazijskom kupkom tretiranih riba. Određena je LD50 od 3,13×107 stanica/ribi, koja je uzrokovala 40 % pomora unutar tri tjedna u riba inficiranih dozom od 2,50×107 stanica/mL. Zaražene su ribe bile letargične, anoreksične i ataksične. S razvojem bolesti sve su razvile bijele mrlje po škrgama, intenzivan sluzavi sekret, lezije na stražnjim pedunkulima, žarišna krvarenja po koži, krvarenja u oku i škržnim poklopcima, ljuštenje kože i mršavljenje, a utvrđeni su i blijedi bubrezi i tamno obojena slezena. Histološki je na škrgama utvrđena upala hrskavičnog tkiva, spajanje lamela i proširene nekroze. U slezeni je zamijećeno proširenje sinusoida, nakupljanje melanomakrofaga, marginacija leukocita s hipertofičnom jezgrom i nekrotičnim područjima. U bubrezima je uočeno formiranje granuloma te upalne promjene u tubulima i glomerulima, proširene nekroze, blago nakupljanje melanomakrofaga, acentrične jezgre, suženje tubula s vakuoliranom okolinom, hipoplazija hematopoetskog tkiva, distrofija tubularnog epitela s talozima proteina u lumenu i fibroza okolnog područja. Pokus je dokazao da Chryseobacterium sp. može uzrokovati opću bolest u zlatnih ribica.

Transportation of fish, although stressful, is an inevitable procedure in aquaculture practices. In this study, we investigated the changes in biochemical and haematological indices in advanced fingerlings of rohu, Labeo rohita in order to optimize the packing density as is imperative to avoid transportation stress and associated mortality . The fish (14.00–15.00 cm) were packed in sealed double layer oxygen packed polythene bags of 30 L capacity containing 7.5 L of water and transported for 2 h and 30 min in a motor vehicle at three packing densities, viz., 67 g L −1 , 134 g L −1 , and 201 g L −1 and transported from hatchery to Kolkata, India covering a distance of about 55 km. A cumulative mortality of 30% was recorded during and after transportation in fish transported at 201 g L −1 ; while the other two packing densities recorded no mortalities. Transportation and packing density induced stress affected the functioning of liver and kidney. The activities of transaminases and lactate dehydrogenase, breakdown of protein and creatinine phosphate, cortisol induced glucose production were significantly increased in advanced rohu fingerlings to cope with the energy demand posed by transportation and higher packing density stress. Low levels of dissolved oxygen and high levels of ammonia-nitrogen were noticed in different packing densities after transportation. The results suggested that the optimum packing density for advanced rohu fingerlings for 2–3 h duration of transport would be 134 g L −1 , which kept the stress at low levels. The serum alanine aminotransferase levels can serve as a good marker for fish liver health as the increment was more prominent when subjected to transportation stress.

Topical steroids are one of the most commonly abused drugs. There are few studies available which have highlighted the severity of this problem in India. However, these studies have concentrated mainly on the topical steroid abuse and its side effects over the face.

The insulin-like growth factor-1 (IGF-1) plays an important role in the regulation of development and growth of fish. Aquaculture researchers consider it as a potential growth rate indicator. Reports on the IGF-1 of carps are limited. This study was undertaken to determine the serum IGF-1 levels of Indian major carps (IMCs) cultured in the normal pond, sewage-fed pond and captive conditions. Labeo rohita of the normal pond recorded the highest serum IGF-1 level (2.10±0.14 ng/ml), followed by Catla catla (1.99±0.17 ng/ml) and Cirrhinus mrigala (1.82±0.12 ng/ml). Captive held C. catla recorded the highest serum IGF-1 (2.10±0.19 ng/ml) compared to L. rohita (2.04±0.08 ng/ml) and C. mrigala (1.90±0.09 ng/ml). In the sewage-fed pond, C. catla, L. rohita and C. mrigala recorded the serum IGF-1 levels of 2.38±0.36 ng/ml, 2.06 ±0.03 ng/ml and 1.07±0.06 ng/ml, respectively. Significant differences existed among the serum IGF-1 levels of C. mrigala reared in the normal and sewage-fed pond as well as the captive and sewage-fed pond (P < 0.05). It appears from the results that C. catla and L. rohita are the ideal cultivable species under the sewage-fed aquaculture. The serum IGF-1 level may be an effective indicator of the differences in growth of carps.

The food and feeding habits of Otolithoides pama collected from three different sites of Hooghly-Matlah estuary, West Bengal, India for a period of 18 months (November 2016 to May 2018) were studied. Both fishes and prawns have dominated the food items in the gut. A very high percentage of empty stomach frequently occurred throughout the year. The species is a macrophagous carnivore and feeds mainly small fishes and prawns. The feeding intensity was more in juveniles stages with prawns and fishes dominated the gut contents while teleosts preferred by the adults. Among the teleosts the main food items were Otolithoides pama, Harpadon nehereus, Secutor insidiator, Sardinella spp., Setipinna spp., other sciaenids like Johnius spp., other clupieds like Tenualosa ilisha, Ilisha megaloptera, Polynemus paradesius, Arius spp., mullets like Mugil and Chelon spp., Rastrelliger kanagurta, Coilia dussumieri, Bregmaceros maclellandi, Trichiurus spp., and unidentified teleosts body parts. Among non-penaeid prawns Acetes spp. was the most dominant food items, among penaeids Parapenaeopsis spp., Metapenaeopsis spp., Metapenaeus spp., Parapenaeus spp., Solenocera spp. constitute food items. GaSI was found high during February, June and October and low during July–August for both the sexes. The monthly mean RLG values were highest during October for male and March for female. Both seasonal changes in diet composition and ontogenetic changes were noticed between juveniles and adults.

The present study was carried out for a period of 42 days to find out the effect of different acclimation salinities (0-control, 2, 4, 6 and 8 ppt) on the haematology of Labeo rohita fingerlings. The fish remained active and showed normal feeding and swimming behaviour up to 4 ppt salinity level; however, at 6 and 8 ppt, they get stressed but were able to survive. There was no significant difference in haematological parameters among fishes in the control, 2 and 4 ppt treatments. Haematocrit (Ht%) values were within the optimum range at 0, 2 and 4 ppt salinity. The mean haematocrit values ranged from 22.21 (at 8 ppt) to 27.03 (control). The highest mean haemoglobin content was observed at 0 ppt (7.09 g dl-1) and it was lowest at 8 ppt salinity (5.36 mg dl-1) on the day of termination of the experiment. Mean total erythrocyte count (TEC) was highest (1.83x106 mm-3) at 2 ppt salinity and the lowest was at 8 ppt salinity (1.52 x106 mm-3). The mean total leukocyte count (TLC) was highest at 8 ppt (4.81x103 mm-3) and the lowest value was recorded at 0 ppt (4.35 x103 mm-3). The mean plasma glucose level at 8 ppt (62.43 mg dl-1) was the highest among the different groups and lowest of 44.70 mg dl-1 was seen in control fishes. Results of the study indicated that increasing salinity up to a certain level is tolerated by L. rohita through osmoregulation, however, extreme salinity stress can lead to alterations in the haematology as well as physiology and further the inability to adapt, leads to metabolic downregulation, thereby affecting growth.

The bacteria involved in nitrogen and sulphur cycles and physicochemical characteristics of water and sediment in traditional, modified extensive and semi-intensive shrimp culture systems of West Bengal, India were monitored. The physicochemical parameters, except salinity and sediment pH, were observed to be well within the optimum levels recommended for shrimp culture. The levels of ammonia (NH3; P≤0.05) and nitrite (NO2−; P