Grow-out Ponds Research Articles

Deformities in Litopenaeus vannamei caused by infectious hypodermal and hematopoietic necrosis viral (IHHNV) infection in intensive grow-out ponds of South east coast of India

Deformities in <i>Litopenaeus vannamei</i> caused by infectious hypodermal and hematopoietic necrosis viral (IHHNV) infection in intensive grow-out ponds of South east coast of India

Exploring environmental condition of silvofishery pond to support the sustainability of mangrove management in Berau Regency, Indonesia

The integration of mangrove management with aquaculture, termed the silvofishery pond system, has been implemented in Berau Regency, East Kalimantan Province, Indonesia. A detailed survey was conducted to assess the features of mangrove terrain surrounding silvofishery ponds, aiming to enhance the productive and sustainable management of these mangrove areas in Berau Regency. This survey focused on various land characteristics such as topography, tidal patterns, water quality, soil properties, climate, and the state of mangrove vegetation. The health of mangrove vegetation was assessed by calculating the Important Value Index (IVI) across different growth stages: trees, saplings, and seedlings. The findings reveal that the mangrove adjacent to the silvofishery ponds in Berau Regency are home to 14 species from 13 genera and 10 families. Rhizophora mucronata displayed the highest IVI scores across all growth stages: 75.17% for trees, 93.14% for saplings, and 66.98% for seedlings, the latter shared with Rhizophora apiculata. Soil quality emerged as a critical limiting factor for land use in silvofishery ponds, particularly due to high potential acidity (low pH) and low nitrogen (N) content. To enhance soil quality, it is recommended that soil management practices such as remediation (via drying, submerging, flushing, or liming) and N supplementation through fertilization be employed. Furthermore, given the sparse mangrove vegetation density at the tree level (1,012 trees/ha), efforts to promote natural mangrove regeneration and prevent deforestation and degradation are advised. Considering the unique characteristics of the mangroves, the implementation of the komplangan model—a silvofishery approach that segregates mangroves restoration pond from grow-out ponds—is recommended to boost productivity and ensure sustainability in the coastal region of Berau.

Methane and nitrous oxide emissions in the rice-shrimp rotation system of the Vietnamese Mekong Delta

Rice-shrimp rotation systems are one of the widespread farming practices in the Vietnamese Mekong Delta coastal areas. However, greenhouse gas (GHG) emissions in the system have remained unclear. This study aimed to examine methane (CH4) and nitrous oxide (N2O) emissions from the system, including (i) land-based versus high-density polyethylene-lined (HDPE) nursery ponds and (ii) conventional versus improved grow-out ponds inoculated with effective microorganisms (EM) bioproducts. The results showed that CH4 flux in land-based and HDPE-lined nursery ponds were 1.04 and 0.25 mgCH4 m−2 h−1, respectively, while the N2O flux was 8.37 and 6.62 μgN2O m−2 h−1, respectively. Global warming potential (GWP) from land-based nursery ponds (18.3 g CO2eq m−2) was approximately 3 folds higher than that of the HDPE-lined nursery pond (6.1 g CO2eq m−2). Similarly, the mean CH4 and N2O fluxes were 15.84 mg CH4 m−2 h−1 and 7.17 μg N2O m−2 h−1 for the conventional ponds, and 10.51 mg CH4 m−2 h−1 and 7.72 μg N2O m−2 h−1 for the improved grow-out ponds. Conventional practices (2388 g CO2eq m−2) had a higher 1.5-fold GWP compared to the improved grow-out pond (1635 g CO2eq m−2). The continuation of the land-based nursery pond and conventional aquacultural farming practices increase CH4 emission and GWP, while applying HDPE-lined nursery ponds combined with improved grow-out ponds could be a promising approach for reducing GHG emissions in rice-shrimp rotation systems. This study recommends further works in the rice-shrimp rotation systems, including (i) an examination of the effects of remaining rice stubbles in the platform on the availability of TOC levels and GHG emissions and (ii) ameliorating dissolved oxygen (DO) concentration on the effectiveness of GHG emission reduction.

Comparison of Fulton’s Condition Factor of Nile Tilapia (Oreochromis niloticus L.) Reared in Ponds in Lubao, Pampanga, Philippines During the Dry Season

This study has evaluated the condition factor of Nile tilapia (Oreochromis niloticus L.) that were reared in grow-out ponds in Lubao, Pampanga, Philippines during the 2018 dry season by using data of lengths and weights. The Fulton’s condition factor was computed by sex, life stage and physical health condition of the fish. From the 400 tilapia samples in 20 grow-out farms, 244 were males and 156 were females, 156 were juveniles and 244 were adults, and 251 were presumed healthy and 149 were presumed non-healthy. Juvenile tilapia (1.956±0.505) had a significantly lower condition factor compared to adults (2.232±0.498). Additionally, presumed healthy tilapia (2.235±0.536) had a significantly higher condition factor than presumed non-healthy (2.026±0.480). By farm level, the condition factor of male tilapia reared in farm 11 (2.792±0.765) was significantly higher as compared to farms 1 (2.043±0.333), 2 (1.997±0.255), 4 (2.049±0.326), 5 (1.994±0.144), 6 (2.084±0.225), 7 (1.782±0.526), 10 (2.098±0.308), 13 (1.716±0.425), 14 (1.804±0.289), 15 (1.960±0.531), 17 (2.028±0.352) and 20 (1.974±0.351). By female sex, statistical comparison of the condition factor of the 20 farms showed no significant difference. The condition factor values of juvenile tilapia in farms 3 (2.257±0.283), 11 (2.242±0.335) and 18 (2.250±0.914) were significantly higher as compared to farm 7 (1.271±0.703). By adult tilapia, the computed condition factor in farm 11 (2.976±0.791) was significantly higher compared to farms 1 (2.178±0.592), 2 (2.177±0.591), 5 (2.028±0.213), 7 (1.952±0.459), 8 (2.193±0.303), 10 (2.052±0.380), 15 (2.160±0.558) and 18 (2.094±0.189). The presumed healthy tilapia samples in the 20 farms had comparable values of condition factors; meanwhile, in the presumed non-healthy samples, the condition factor of farm 11 (2.455±0.819) was statistically higher compared to farm 13 (1.605±0.266). The probable factor that influenced the condition factors based on sex, life stage and physical health condition was water quality, specially dissolved oxygen, nitrite and phosphorus, since most of the 20 grow-out farms shared comparable cultural and management practices.

Oral administration of recombinant outer membrane protein A-based nanovaccine affords protection against Aeromonas hydrophila in zebrafish.

Aeromonas hydrophila, an opportunistic warm water pathogen, has always been a threat to aquaculture, leading to substantial economic losses. Vaccination of the cultured fish would effectively prevent Aeromoniasis, and recent advancements in nanotechnology show promise for efficacious vaccines. Oral delivery would be the most practical and convenient method of vaccine delivery in a grow-out pond. This study studied the immunogenicity and protective efficacy of a nanoparticle-loaded outer membrane protein A from A. hydrophila in the zebrafish model. The protein was over-expressed, purified, and encapsulated using poly lactic-co-glycolic acid (PLGA)nanoparticles via the double emulsion method. The PLGA nanoparticles loaded with recombinant OmpA (rOmpA) exhibited a size of 295 ± 15.1nm, an encapsulation efficiency of 72.52%, and a polydispersity index of 0.292 ± 0.07. Scanning electron microscopy confirmed the spherical and isolated nature of the PLGA-rOmpA nanoparticles. The protective efficacy in A. hydrophila-infected zebrafish after oral administration of the nanovaccine resulted in relative percentage survival of 77.7. Gene expression studies showed significant upregulation of immune genes in the vaccinated fish. The results demonstrate the usefulness of oral administration of nanovaccine-loaded rOmpA as a potential vaccine since it induced a robust immune response and conferred adequate protection against A. hydrophila in zebrafish, Danio rerio.

Combining nursery closed-system and pond grow-out common carp (Cyprinus carpio) production is a profitable business in Hungary

Extensive, large-scale long-term pond fish production has several challenges and high economic risks, such as continuous bird predation. Moreover, common carp (Cyprinus carpio) production costs are relatively high using this production strategy. To reduce risks and improve production safety and efficiency, European common carp farmers are challenged to shorten the classic 3-year production cycle. This study aimed to comprehensively analyze the main farm parameters, production efficiency, cost and revenue of a production strategy based on combining hatchery/nursery closed-system, a second phase of the nursery in ponds and a final phase of pond grow-out of common carp. A deterministic economic model was used. Combined production has a lower fish loss by bird predation, a shorter production cycle, a better feed conversion ratio than conventional pond fish production, and a similar yield at a cost of approximately 2.02 USD/kg. This value are higher than those assumed in the conventional extensive 3-year common carp, completely pond-based production strategy. However, the current assets turnover ratio is much lower in the latter case. The yearly average net revenue can increase by implementing a more intensive combined production strategy. The combined strategy can improve security and predictability of production while reducing the pond area used for grow-out of extensive common carp farm.

Performance of An Aerated Wastewater Stabilization Pond for the Treatment of Cultivation Wastewater of Pacific White Shrimp (Litopenaeus vannamei) Grow-out Ponds

Pacific white shrimp (Litopenaeus vannamei) is a major cultivated crustacean species whose aquaculture production has doubled in the last decade. The implementation of shrimp pond systems using closed or intensive methods is widely carried out. However, wastewater produced by intensive shrimp farming may cause environmental effects. This study is aimed to evaluate the feasibility of the aerated wastewater stabilization pond to treat the cultivation wastewater. The physicochemical parameters monitored were temperature, pH, salinity, ammonia, nitrite, nitrate and phosphate. In the case of this study, almost all physicochemical parameters of the water coming out of the aerated wastewater stabilization pond are suitable for use as input water for integrated multitrophic aquaculture (IMTA). Temperature, pH, salinity, nitrite, nitrate, and phosphate were 27.1°C to 32.2°C, 7.86 to 8.79, 30 ppt to 34 ppt, 0.003 mg/L to 0.068 mg/L, and 0.19 mg/L to 1.31 mg/L, respectively. Only ammonia concentration significantly fluctuated in the range of 0.44 mg/L to 12 mg/L.

Stock Evaluation of the Euryhaline Cichlid, Etroplus suratensis (Bloch, 1790), from Significant Brackish and Freshwater Regions of India

The present study evaluates stocks of Etroplus suratensis concerning length-weight relationships (LWRs), condition factor (K), and truss analysis from different habitats, viz., West Bengal (freshwater hatchery), Gujarat (brackish water grow-out pond), and Odisha (Chilika lagoon) in India. All the stocks were collected using gill nets with various mesh sizes of 20–50 mm and cast nets with mesh size of 15 mm from February 2021 to September 2021. The total length (L), weight (W), and digital pictures were taken for LWRs and principle component analysis (PCA). The total length (L) and total weight (W) were measured to the nearest 0.1 cm and 0.01 gm, respectively, followed by regression analysis. The values of parameters “b” in the LWRs equation were estimated within the range of 2.50–3.82 and intercept “a” values (0.235–0.779) and “K” (1.07–3.37), respectively, for all different habitats and ecosystems with significant correlation values (R2 ≥ 0.85). In truss morphometric analysis, principal component 1 (PC1) contributed the highest (93.1%) and principal component 2 (PC2) contributed 4.6% to the size and shape variation amongst the stocks from different habitats and ecosystems. The scatter plot analysis and canonical variate analysis (CVA) have shown that the Gujarat and West Bengal stocks are closely placed and separated from the Chilika-Odisha stock. Similar variations were also observed in the ANOSIM boxplot analysis, where Chilika-Odisha stock scored higher than the other two stocks. Since data available regarding LWRs and truss morphometry studies of E. suratensis from different habitats are limited, the present study will provide a clear insight into the differentiation of E. suratensis stocks from different habitats in India. The overall findings of the present study could be utilized for the conservation and sustainable management of E. suratensis.

Study of microsporidians in white faecal syndrome affected farmed shrimp (Penaeus vannamei) Boone, 1931 of West Bengal, India

Enterocytozoon hepatopenaei (EHP), an intracellular microsporidian parasite, has been reported in cultivated Penaeus vannamei infected with white faecal syndrome (WFS) in south-east Asian shrimp producing countries. The appearance of white faecal strings floating on the surface of the ponds indicates a severe microsporidian infection. In the present study suspected shrimps and floating faecal strings were collected from culture ponds of study area located in Purba Medinipur district of West Bengal. This study aims to unveil the presence of microsporidians in hepatopancreas and associated histopathological changes in it using light and scanning electron microscopy, and microsporidian identification by nested PCR. Microscopic study revealed the presence of oval-shaped microsporidian spores in the hepatopancreas and nested PCR study confirmed that these spores belong to E. hepatopenaei. The spores isolated from the floating faecal strings exhibited similar morphology with those found in hepatopancreas. Histopathology of the hepatopancreas of WFS-affected shrimp exhibited alterations in hepatopancreatic tissues along with haemocytic infiltration into the inter-tubular spaces and evidence of necrosis, vacuolation and degeneration. The findings from the nested PCR analysis indicated a total of 18 positive results (69.23%) out of 26 samples studied. WFS infection can be considered a gastrointestinal disorder caused by severe EHP infection, which is significant in the grow-out ponds in the regions under study.

Biofloc Technology for Sustainable Growth of Shrimp Species: Litopenaeus Vannamei

Aquaculture stands as the fastest-growing food-producing sector globally, undergoing continuous development, expansion, and intensification across all regions. Despite the anticipation of higher production levels, the global growth of aquaculture is constrained by the severe scarcity of water and the limited availability of suitable land. Biofloc systems have emerged as a viable solution tailored for water-scarce areas. This innovative system offers a potential food source for shrimp reared in an environmentally friendly, limited or zero water exchange environment, with minimal effluents released into the surrounding ecosystem. The present study was conducted at a corporate aquaculture farm facility located in Cuddalore district, Tamilnadu. The research focused on evaluating the water quality, survival rates, and growth performance of Litopenaeus vannamei, ranging from post-larvae (PL-9) to 26.6 grams, over a 120-day period within a Biofloc system. Three cement tanks, designated as C1 (control) and C2, C3 (test), were utilized, each with a stocking density of 120 PL/sq.m. After reaching a weight of 2 grams, the shrimp were transferred to grow-out ponds. The results indicated that shrimp reared in Biofloc tanks exhibited significantly higher final weights, survival rates, and favorable water quality parameters compared to the control group, which relied solely on commercial feed. Significantly, as the biofloc volume rose, there was a noteworthy decrease in the requirement for feed application, thereby establishing the Biofloc system as a financially efficient option for shrimp cultivation.

Stocking density affects culture performance and economic profit of adult all-female Chinese mitten crabs (Eriocheir sinensis) reared in earthen ponds

As female Chinese mitten crab (Eriocheir sinensis) generally offer the higher edible yield, greater nutritional value, and consequently, higher market price compared to males, therefore all-female monosex culture has been popularized for the farming E. sinensis. However, the optimal stocking density remains unknown for all-female culture of E. sinensis. The present study was conducted to evaluate the effect of different stocking densities (D1.3: 1.3 inds/m2, D1.9: 1.9 inds./m2, D2.5: 2.5 inds./m2 and D3.8: 3.8 inds./m2) on growth performance, gonadal development, and economic profits of all-female E. sinensis during nine months culture period. The results showed that all growth parameters including mean body weight, body weight gain (BWG) and specific growth rate (SGR), exhibited an inverse relationship with stocking density. However, stocking density did not have a significant effect on the percentage of puberty molting, gonadosomatic index (GSI) and hepatosomatic index (HSI). At the end of the experiment, the survival rate significantly decreased with the increasing stocking density, while both final production yield and economic feed conversion ratio (eFCR) significantly increased with stocking density (P < 0.05). Profitability analysis showed that total cost and total return increased significantly with the stocking density, but the highest net profit (129.68 × 103 CNY/ha) and return-on-investment (ROI, 87.65%) were achieved at the D2.5 group. Overall, these results suggested that the optimal stocking density might range from 1.9 to 2.5 individuals/m2 in grow-out ponds for all-female mono-culture of E. sinensis.

Heavy metals in wild and cultured shrimp, supplied feeds, and their habitats: Assessing public health risk

The contamination and risk assessment of heavy metals (HMs) in highly priced tiger shrimp and its associated ecosystems and farming conditions (hatcheries and commercial grow-out ponds) were scarcely investigated in South Asian countries. In this study, we determined the five HMs (Cu, Zn, Pb, Cd, and Cr) concentrations in PL14 (fourteen days of Post-Larva) of Penaeus monodon, commercial diets, surface water, and sediments from hatcheries, farms, rivers using ICP-MS for two years. The results revealed that surface sediments of rivers and hatcheries had the highest amounts of Cr (65.85 ± 0.82 and 72.50 ± 0.42 mg/kg), Cu (18.82 ± 3.96 and 19.26 ± 4.61 mg/kg), and Zn (63.74 ± 11.14 and 87.42 ± 17.96 mg/kg), whereas commercial farms had the greatest levels of Cd (0.09 ± 0.05 mg/kg). Pb was significantly higher in sediment of hatcheries and farms than in other sites. Except for Zn in surface waters, all metals were found above the recommended limit. In case of supplied feed, all values were in the safe limit excepting Cr (3.39 ± 1.45 to 108.92 ± 3.49 mg/kg). On the other hand, among the metals, only Cr (VI) ranging from 1.75 ± 1.39 mg/kg in P. monodon samples exceeded the suggested international guidelines. The Igeo values of all the metals were Igeo <0, indicating that the study areas were practically unpolluted. PLI values in every station were found to be below 1 which indicates the perfection of the sediment. The Potential Risk Index (PERI) values were less than 150 suggesting low risk of metals in sediments. The public health risk assessment estimated through the calculated daily intake (EDI), target hazard quotient (THQ) and hazard index (HI) has shown that the shrimp was safe for consumers except for Cd and Cr. The THQ for Cd and Cr were higher than the threshold (>1) indicating potential health hazards. The low CR values for Cd, Cr Pb were 3.1 × 10−4, 3.7 × 10−4 and 1.6 × 10−4, respectively indicates no cancer risks upon consuming P. monodon.

The structure, composition, and predicted microbiome functional genes in Pacific white shrimp (Litopenaeus vannamei) grow-out ponds with different survival rates through high-throughput sequencing

The structure, composition, and predicted microbiome functional genes in Pacific white shrimp (Litopenaeus vannamei) grow-out ponds with different survival rates through high-throughput sequencing

Immune responses and histopathological analyses of giant river prawn (Macrobrachium rosenbergii, De Man 1879) challenged with a sub-lethal dose of decapod iridescent virus 1 (DIV1) and chemical control investigation.

Decapod iridescent virus 1 (DIV1) is a lethal virus that has a significant influence on the shrimp and prawn culture industries. The mechanism through which infected prawns respond to the DIV1 virus is currently unknown. Here, we examined in detail the clinical signs, histopathology, and humoral, cellular, and immune-related gene responses after a sub-lethal dose of DIV1 during the acute infection period of 0-120h post infection (hpi). Interestingly, at the end of the experiment, DIV1-infected prawns had black lesions on several external regions. The DIV1-infected prawns also exhibited few karyopyknotic nuclei in the gills and intestine tissues and exhibited increasing immunological responses, as revealed by significant increases in all examined parameters, including total hemocytes, phagocytosis, lysozyme, and overall bactericidal activity, from 6 to 48 hpi. In addition, between 72 and 120 hpi, all immune response activities of DIV1-infected prawn were impaired compared with those of normal prawns, indicating negative impacts on immunological parameters. A viral load analysis of various tissues by qPCR indicated that hemocytes were the dominant initial viral target tissues, followed by the gills and hepatopancreas. An expression analysis of crucial immune-related genes by qRT‒PCR revealed various expression patterns in response to DIV1 infection; in particular, fold changes in the relative expression of anti-lipopolysaccharide factors (ALFs), prophenoloxidase (proPO), lipopolysaccharide and β-1,3-glucan binding protein (LGBP) were observed. Additionally, five common chemicals, calcium hypochlorite [Ca(OCl)2] at 16.25-130ppm, hydrogen peroxide (H2O2) at 8.75-70ppm, povidone iodine (PVP-I) at 3-24ppm, benzalkonium chloride (BKC) at 20-160ppm, and formalin at 25-200ppm, had a significant effect on the killing of DIV1 particles in vitro within 24h after exposure. These data will be helpful for determining the health status and immune defense mechanisms of giant river prawns during DIV1 infection periods. The study performed the first application of very common disinfectants, and the obtained information will be useful for implementing effective strategies to prevent and control DIV1 infection in both hatchery and grow-out ponds.

Human activity as a factor causing the biomass, structure and seasonal dynamics of phytoplankton in adjacent fishponds

The role of phytoplankton as one of the main sources of energy entering the water food network is especially evident in fish-rearing ponds. Indeed, in these comparatively small ponds (unlike many lakes), variations in the abundance of phytoplankton can be extremely sensitive to the action of external factors, including human activity. Here, we present results of the analysis of the phytoplankton dynamics in adjacent fishponds and in supplying/recipient river courses upstream and downstream of the ponds during a growing season. In the grow-out ponds, phytoplankton biomass is shown to reach maximums in spring and in early autumn, while in the nursery pond, the phytoplankton dynamics is characterized by one long peak. The specificity of fish-rearing ponds as the human-regulated reservoirs clearly manifests itself under comparison of phytoplankton biomass of ponds with the biomass of phytoplankton inhabiting a nearby river. The averaged phytoplankton biomass in the ponds was 6.2–10.1 times higher than in the river. Besides, we show here that the taxonomic composition of phytoplankton in the river differs significantly from the composition of phytoplankton in the fish-rearing ponds. In particular, Cyanobacteria and Chlorophyta were revealed as the major portion of the phytoplankton in the fish-rearing ponds, while in the river their abundances were low.

Growth potential and immunity of the Indian white shrimp, Penaeus indicus (H. Milne-Edwards, 1837), cultured in grow-out ponds at varying densities and salinities

Growth potential and immunity of the Indian white shrimp, Penaeus indicus (H. Milne-Edwards, 1837), cultured in grow-out ponds at varying densities and salinities

The fate of probiotic species applied in intensive grow-out ponds in rearing water and intestinal tracts of white shrimp, Litopenaeus vannamei

Abstract Introduction Probiotics have been commonly practiced in commercial shrimp farms to increase pond production. However, these possibilities were based on the results of in vitro studies or laboratory in vivo trials. While studies on probiotic applications in commercial-scale farms are still rarely investigated, this study addresses the fate of probiotic species in ponds and the intestinal tract of white shrimps reared in an intensive aquaculture system. Material and methods Four commercial probiotic species (Lactobacillus plantarum, Lactobacillus fermentum, Bacillus subtilis, and Pseudomonas putida) were applied to the commercial shrimp ponds (@800 m2 area of high-density polyethene ponds) in the morning at a dose of 5 ppm once every 2 days in the first month, and once a week from second month onward. Then, the presence of the probiotic species was traced by collecting the rearing water and shrimp’s intestines on day 47 of culture to monitor their composition and abundance using high-throughput sequencing. Results None of the commercial probiotic species could be detected from both rearing water and shrimp intestinal tracts. These results suggest that the probiotic species had low viability and adaptability in the rearing pond as well as the shrimp intestines when applied on commercial-scale farms. These facts may explain the high variation in the yield among shrimp ponds in spite of having similar treatments. Conclusion Probiotic strains had low viability and adaptability in commercial farms. Thus, methods and strategies in probiotic application to commercial-scale shrimp farms should be evaluated and further developed to increase probiotic efficacy.

Whiteleg shrimp Litopenaeus vennamei: Current status, future prospects and opportunities for Bangladesh Aquaculture

Shrimp aquaculture plays the key role in Bangladesh seafood export industry. It includes the species of Tiger prawn Penaeus monodon, and Giant river prawn Macrobrachium rosenbergii, which have been widely farmed after 1980s. The industry is severely damaged due to diseases outbreaks in hatcheries, nurseries and grow-out ponds since 2000, thus this sector shows shrinkage from global export market. However, the last few decades an alternate aquaculture decapod species, Whiteleg shrimp Litopenaeus vannamei has been recognized as the most important in world-seafood export item. Bangladesh aquaculture has very recently been introduced with the Whiteleg shrimp L. vannamei for shrimp production boost up. This review focusses on the current state of arts for L. vannamei aquaculture techniques and their possible implication to farming in Bangladesh. Recently, several Whiteleg shrimp pilot scale farming were initiated which showed promising production ranged from 5.0 to 8.9 MT/ha. Private entrepreneurs now become interested and it is perceived that the Whiteleg shrimp could gear up shrimp production in near future in terms of better production performance, technology development and extension work besides other indigenous culture-shrimp species. By introducing this shrimp, we forecast that, depending upon the technology adoption in present culture areas, the export frozen seafood earnings from shrimp sector will increase up to 5 to 10 folds from the present. Thus, proper understanding and knowledge based innovative approach for its sustainable rapid extension and strategies is in need. This review suggests the regional reproducible pilot culture program for hatchery, nursery and grow-out under controlled environment ensuring better footprint and low residues impact to natural aquatic systems. Adaptive research should be initiated to develop intensive or super-intensive culture techniques besides the traditional practices in the selected confined areas. The pond culture, biofloc farming, aquamimicry farming and green water raceways could be excellent options for L. vannamei culture in Bangladesh. Bangladesh J. Zool. 50 (2): 143-184, 2022

Benefits of stocking fewer but larger individuals with implications for native fish recovery

Artificial propagation is commonly used to reduce extinction risk for native, imperiled fish species. Thus, identifying stocking strategies that most effectively augment adult abundance is a critical aspect of successful adaptive management. The threatened June sucker ( Chasmistes liorus) , endemic to Utah Lake, UT, USA, experienced major declines in abundance following extensive ecosystem degredation. Over 800 000 June sucker were stocked from hatcheries, grow-out ponds, and refuge populations from 1990–2019 across a range of sizes and seasons. Here, we evaluated post-stocking survival of June sucker using a Cormack–Jolly–Seber model with three covariates: size at stocking, origin, and season. Survival was positively correlated with size at stocking, with evidence of a possible size-selective predation threshold between 200 and 300 mm, and spring stocking appeared to produce higher survival rates than summer or fall. We also compared cost and benefit for stocking hatchery-origin June sucker at different sizes, finding that stocking fewer but larger (age-2) individuals was more cost-effective than stocking more but smaller (age-1) individuals. Our results highlight operational changes that can help maximize the efficacy of native fish hatchery programs.

Genetic analysis of digital image derived morphometric traits of black tiger shrimp (Penaeus monodon) by incorporating G × E investigations.

The black tiger shrimp, Penaeus monodon, is the second most economically important aquaculture shrimp species in the world, and in Australia it is one of the most commonly farmed shrimp species. Despite its economic significance, very few studies have reported the genetic evaluation of economically important morphological size and shape traits of shrimp grown in commercial grow-out environments. In this study we obtained genetic parameter estimates and evaluated genotype-by-environment interaction (GxE) for nine body morphological traits of shrimp derived from images. The data set contained image and body weight (BW) records of 5,308 shrimp, from 64 sires and 54dams, reared in eight grow-out ponds for an average of 133days. From the images, landmark based morphological distances were computed from which novel morphological traits associated with size and shape were derived for genetic evaluation. These traits included body weight (BW), body length (BL), body size (BS), head size (HS), Abdominal size (AS), abdominal percentage (AP), tail tip (TT), front by back ratio (FBR), condition factor (CF) and condition factor length (CFL). We also evaluated G×E interaction effects of these traits for shrimp reared in different ponds. The heritability estimates for growth related morphological and body weight traits were moderately high (BW: h 2 = 0.32 ± 0.05; BL: h 2 = 0.36 ± 0.06; BS: h 2 = 0.32 ± 0.05; HS: h 2 = 0.31 ± 0.05; AS: h 2 = 0.32 ± 0.05; and TT: h 2 = 0.28 ± 0.05) and low for abdominal percentage and body shape traits (AP: h 2 = 0.09 ± 0.02; FBR: h 2 = 0.08 ± 0.02; CF: h 2 = 0.06 ± 0.02; and CFL: h 2 = 0.003 ± 0.004). G × E interaction were negligible for all traits for shrimp reared in different ponds, suggesting re-ranking is not prevalent for this population. Genetic correlations among growth related morphological traits were high ranging from 0.36 to 0.99, suggesting these traits can be simultaneously improved through indirect genetic selection. However, negative genetic correlations were observed for FBR & CF shape traits with major growth traits (ranged -0.08 to -0.95), suggesting genetic selection for rapid growth will likely result in thick/fatty shrimp over generations. Our study showed image-based landmark data can be successfully employed for genetic evaluation of complex morphological traits of shrimp and is potentially amenable to machine-learning derived parameters in semi-automated high volume phenotyping systems needed under commercial conditions.