Farm Hatcheries Research Articles

Acute mortality of Penaeus vannamei larvae in farm hatcheries associated with the presence of Vibrio sp. carrying the VpPirAB toxin genes

Acute mortality of Penaeus vannamei larvae in farm hatcheries associated with the presence of Vibrio sp. carrying the VpPirAB toxin genes

Environmental impact assessment of fish farm hatcheries management in lower Niger Basin Area of Nigeria

The environmental impact assessment was carried out in different five geographical zones of Kwara Central, Kwara North, Kwara South, Kogi Central and Kogi West in two phases. Phase 1 was investigation by observation through questionnaire administration and phase 2 was observation by experiment (sampling and analysis) of 5 farms in each zone making a total of 25 farms. Water quality parameters were measured from site to site where alkalinity and hardness differed significantly (p 0.05), while water pollution, insecurity as a result of land exposure and wild life displacement were impacted significantly (p < 0.05). Fish bred and raised were monoculture of family Clariidae of which species of Clarias gariepinus and Heterobranchus longifilis, Heterobranchus bidorsalis and their hybrids were prominent. Poor quality constructions of brood stock ponds, spawning, nursery tanks and fish hatcheries drainage compartments, their effects coupled with uncontrolled discharge of waste water in the hatcheries caused negative residual impacts of pollution, erosion and degradation of farm lands and environment. To prevent the occurrence of these hazards, fish farmers must obtain permits from relevant authorities and contact experts before embarking on pond constructions and fish hatcheries.Keywords: Fish farm hatcheries, impacts, assessments, Kwara state, Kogi state

Impacts and vulnerability of inland fisheries to climate change in the Ganga River system in India

Climate change is evident in India as manifested by increased air temperatures, regional variation in the monsoon, frequent occurrence of droughts, and a regional increase in severe storm incidence in coastal states of India. The impacts are evident for freshwater fisheries and fishers of the River Ganga and the water bodies in its plains and deltaic areas. Analysis of time series data for 32 years from published literature and from current investigations showed a 0.99°C increase in the minimum water temperature recorded in the upper stretch of River Ganga and 0.5 to 1.4°C increases in aquaculture water on the Gangetic Plains of West Bengal. The minimum air temperature showed a 15% shift upwards during the colder months of January–February. Rainfall showed a 1% increase in the post monsoon months of September–December. The impacts were manifest in a geographic shift of warm water fish species such as Glossogobius giuris, Xenentodon cancila into the colder stretch of the River Ganga. The breeding of the Indian Major Carps (IMC) has been affected and a consequent decline in fish spawn availability in River Ganga recorded. However a positive impact on breeding in fish farm hatcheries in the Gangetic Plains was evident in the advancement and extension of the breeding period for IMC by 45–60 days. Drought in West Bengal during 2009 was evident in rainfall deficits of 29% and 27% in the districts of North 24 Parganas and Bankura, respectively, in the fish breeding months of March–September and 92% of fish spawn hatcheries were affected. These districts recorded losses on average 61% to 73% of fish spawn during 2009 compared to the previous four years. A study of the potential impact of cyclones and storms on saline water inundation using a digital elevation model generated for coastal district of South 24 Parganas indicated the potential for 3% to 11% submergence of aquaculture areas in response to 1 to 2 meter rises due to sea water incursions. The inland fisheries sector in coming years will face stiff competition for water from the industrial, municipal and agricultural sectors and climate change will compound these problems. Under such a scenario implementation of integrated water resource management involving different stake holders of fresh water would be the most effective management approach.

The existence of Flavobacterium spp. at rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) hatcheries in Caglarca village, Mersin-Turkey

The aim of this study was to examine the existence of the Flavobacterium spp. at two different rainbow trout farm hatcheries in Caglarca village, Mersin, between December 2006 and April 2007. For this goal samples were collected from milt, ovarian fluid, and all phases from egg till 3 months old fries and from the water used in both farms. In consequence of disease outbreak at the II. farm, 30–40 days after fry started feeding, mortality occured as high as 50 %. Clinical signs at fries were observed as dark coloration of the skin, exophthalmia, erosions on dorsal and caudal fins, lethargy, swimming close to the water surface, weakness and loss of appetite. As autopsy signs anaemia and haemorrhage on gills and liver, and splenomegali were observed. Totally 347 samples, including 77 water and 270 fish samples taken from the hatcheries, were examined. Flavobacterium spp. were isolated and identified using conventional culture methods. 141 (33.71%) Flavobacterium spp. have been isolated from 117 samples. 46 Flavobacterium spp. were isolated from 39 (50.64%) water samples and 95 from 78 (28.88%) fish samples. Off the total isolates 76 (42.93%) were identified as F. aquatile, 30 (16.94%) as F. columnare, 20 (11.29%) as F. branchiophilum, 12 (6.77%) as F. johnsoniae and 3 (1.69%) as F. saccarophilum. Antimicrobial susceptibility test was carried out by agar disc diffusion method. In according to antimicrobial susceptibility test, Flavobacterium spp. strains were sensitive to gentamicin, streptomycin, neomycin, sulphamethoxazoletrimethoprim, oxytetracycline, ofloxacin, clindamycin, amoxycilin/clavulinic acid, and resistant to erythromycine, penicillin and vancomycin, respectively.

Assessing the impact of climate change on inland fisheries in River Ganga and its plains in India

Perceptible changes on a global and regional scale are evident in earth's climate. In India, observed changes include an increase of air temperature, regional monsoon variation, frequent droughts and a regional increase in severe storm incidence in coastal states of India, along with indication of Himalayan glacier recession. The impact is being felt in the inland aquatic resources and their fisheries. Analysis of time series data of 30 years from published literature and from current investigations on the River Ganga and water bodies in its plains, indicate increased minimum water temperatures; 1.5°C in colder stretches of the Ganga and 0.2 to 1.6°C in the aquaculture farms of the State of West Bengal in the Gangetic plains. Rainfall has also increased in the post monsoon months of September–December. The impact is manifested in the breeding failure of the Indian Major Carps (IMC) and a consequent decline in fish spawn availability in river Ganga. Whereas, in fish farm hatcheries on the plains, a positive impact on breeding was observed in the advancement and extension of the breeding period of IMC by 45–60 days. A geographic shift of warm water fish species Glossogobius gurius and Xenentodon cancila to the colder stretch of the river Ganga was recorded. The predator prey ratio in the middle stretch in the river Ganga has also declined from 1:4.2 to 1:1.4 in the last three decades. Fish production has shown a distinct change in the last two decades in the middle stretch of river Ganga where the contribution of IMC has decreased from 41.4% to 8.3% and that of miscellaneous and catfish species increased. Climate change in India will put an additional stress on ecological and socio-economic systems that are already facing pressure. Thus the specific climate variables of importance to inland fisheries viz. enhanced water temperature, extreme events like flood and drought, storms and water stress require specific adaptation actions. An integrated water shed management strategy is essential going from the village level to the river basin level in a unified manner. Finally, it is suggested that assessments of inland fisheries vulnerability to climate change should also assess economic scenarios since adaptive capacity is closely linked to the financial capabilities.

Pathological and immunological study of an in ovo complex vaccine against infectious bursal disease.

The appearance of very virulent strains of infectious bursal disease (IBD) virus at the end of the 1980s made it necessary to develop more effective immunization procedures. To facilitate this, the immunogenicity and the immunosuppressive effect of a mild (G-87), an intermediate (LIBD) and an intermediate-plus (IBDV 2512) IBDV strain were tested after the in ovo inoculation of 18-day-old SPF and broiler chicken embryos. It was established that no noteworthy difference existed between the immunized and the control embryos in hatching rate and hatching weight. The higher the virulence of the vaccine virus strain, the more severe damage it caused to the lymphocytes of the bursa of Fabricius. In SPF chickens, the haemagglutination inhibition (HI) titres induced by a Newcastle disease (ND) vaccine administered at day old decreased in inverse ratio to the virulence of the IBD vaccine strain, while in broiler chickens this was not observed. Despite the decrease of the HI titre, the level of protection did not decline, or did so only after the use of the 'hot' strain. SPF chickens immunized in ovo with a complex vaccine prepared from strain IBDV 2512 and IBD antibody showed the same protection against Newcastle disease as the broilers. In broiler chicken embryos immunized in ovo, only strain IBDV 2512 induced antibody production, and such chickens were protected against IBD at 3 weeks of age. The complex vaccine administered in ovo has been used successfully at farm hatcheries as well.

Distribution of oxytetracycline resistance plasmids between aeromonads in hospital and aquaculture environments: implication of Tn1721 in dissemination of the tetracycline resistance determinant tet A.

Oxytetracycline-resistant (OT(r)) mesophilic aeromonads were recovered from untreated hospital effluent (72 isolates) and from fish farm hatchery tanks (91 isolates) at sites within the English Lake District, Cumbria, England. The transfer of OT(r) plasmids from these isolates was investigated. Using Escherichia coli J53-1 as a recipient, 11 isolates from the hospital site and 6 isolates from the fish farm site transferred OT(r) plasmids (designated pFBAOT1 to 17). Original isolates were identified using fatty acid methyl ester and fluorescent amplified fragment length polymorphism comparisons as either Aeromonas hydrophila HG3 (eight isolates), A. veronii b.v. sobria HG8 (six isolates), and A. caviae HGB5 (one isolate). One isolate remained unidentified, and one could not be assigned a taxonomic designation beyond the genus level. Plasmids pFBAOT1 to -17 were screened for the presence of the tetracycline resistance determinants Tet A to E and Tet G. Only determinant Tet A (10 plasmids) was detected in these plasmids, with 7 tet gene determinants remaining unclassified. In all cases, Tet A was located on a 5.5-kb EcoRI restriction fragment. Hybridization with inc-rep probes N, P, Q, W, and U showed pFBAOT3, -4, -5, -6, -7, -9, and -11, from the hospital environment, to be IncU plasmids. Further, restriction fragment length polymorphism (RFLP) analyses and DNA probing demonstrated that pFBAOT plasmids were closely related to IncU OT(r) plasmids pASOT, pASOT2, pASOT3, pRAS1 (originally isolated from A. salmonicida strains from fish farms in Scotland and Norway, respectively), and pIE420 (isolated from a German hospital E. coli strain). In addition, DNA analyses demonstrated that plasmids pRAS1 and pIE420 had identical RFLP profiles and that all fragments hybridized to each other. The presence of tetracycline resistance transposon Tn1721 in its entirety or in a truncated form in these plasmids was demonstrated. These results provided direct evidence that related tetracycline resistance-encoding plasmids have disseminated between different Aeromonas species and E. coli and between the human and aquaculture environments in distinct geographical locations. Collectively, these findings provide evidence to support the hypothesis that the aquaculture and human compartments of the environment behave as a single interactive compartment.

A systemic fungal disease in Atlantic salmon parr, Salmo salar L., caused by a species of Phialophora

Abstract. A fungal infection of Atlantic salmon parr (0 +) occurring at low water temperatures, principally in January, is reported from fish farm hatcheries in western Scotland. Clinical signs and histopathology of the disease are described, illustrated, discussed and compared with those of certain other fungal diseases of salmonids. The fungus, provisionally placed in the hyphomycete genus Phialophora is described and illustrated from pure culture, with a discussion of its taxonomic position.

An Investigation of the Resistance of White Leghorn Chicks to Salmonella Gallinarum

BREED differences in response to experimental challenge with Salmonella gallinarum (fowl typhoid) were reported by Lambert and Knox (1928) and differences in physiological responses for the resistant White Leghorn (W.L.) and the susceptible Rhode Island Red (R.I.R.) have been described by Garren and Barber (1955) and Garren and Hill (1959). The importance of genetic control of resistance to infection is well recognized (Hutt, 1964; and Fredeen, 1963). However, the bases for such physiological phenomena have not, in many instances, been elucidated.The investigations reported herein were designed (a) to determine what effects the age of the chicken had upon resistance to S. gallinarum, and (b) to explore some factors which might account for the differences in the resistance of the White Leghorn and Rhode Island Red to fowl typhoid.MATERIALS AND METHODSThe W.L. and R.I.R. chicks used in these studies were obtained from the University Poultry Farm hatchery. They …