Wild Stocks Research Articles

Outbreak of Parasitic Dinoflagellate Piscinoodinium sp. Infection in an Endangered Fish from India: Arulius Barb (Dawkinsia arulius).

Freshwater velvet disease is caused by the dinoflagellate parasite, Piscinoodinium sp. This parasite has been reported in tropical and subtropical fishes, and it can cause devastating losses. Moreover, Piscinoodinium sp. is identified as one of the least studied finfish parasites, and the available molecular information about this parasite is meager. Recently, Piscinoodinium sp. was responsible for the 100% cumulative mortality of the captive-bred F1 generation of Arulius barb (Dawkinsia arulius), an endangered freshwater fish native to India. The trophont stages of the parasite were observed in the skin and gills of the affected fish. The total DNA was extracted from the trophonts collected from the affected Arulius barb and the partial nucleotide sequence of the rDNA complex region (2334 bp) was amplified using PCR. The amplified PCR product exhibited a high sequence identity (97.61%) with Piscinoodinium sp. In the phylogenetic analysis of the SSU rDNA, Piscinoodinium sp. emerged as a separate clade from other dinoflagellate species. This is the first report of the infection of Piscinoodinium sp. in Arulius barb and the molecular information generated from this study can serve as a baseline to study the diversity of the parasite in India. Furthermore, the impact of this parasite among wild fish stock is not known, and this parasite needs further research focus to generate more molecular information and to understand the host-pathogen interaction.

Aquaculture over-optimism?

The recent rapid growth in aquaculture production reported by the United Nations Food and Agriculture Organization may have inadvertently generated what we denote here as aquaculture over-optimism. An extreme form of this is the notion that we need not worry about sustaining wild fish stocks because we can meet the global need through farming. Here we investigate whether the recent growth in aquaculture production can be maintained, and we compare aquaculture production projections with the future need for fish to find out whether aquaculture over-optimism can be justified. We show relevant evidence suggesting that aquaculture growth rates in all the cases studied have already reached their peak and have begun declining. Also, our results indicate that without wild fish, the world will face a fish food shortage of about 71 million tonnes annually by 2030, and the aquaculture production growth rate would have to be 3 times current average projected production by the FAO, the World Bank and the OECD in 2030. Finally, the current geographical distribution of farmed fish production suggests that even if aquaculture over-optimism is physically, economically, technically and ecologically feasible, its socio-economic cost to low-income coastal countries could be devastating.

Biotechnological Intervention and Secondary Metabolite Production in Centella asiatica L.

Centella asiatica L., commonly known as Gotu kola, Indian pennywort, and Asiatic pennyworts, is an herbaceous perennial plant that belongs to the family Apiaceae and has long been used in the traditional medicine system. The plant is known to produce a wide range of active metabolites such as triterpenoids including asiatic acid, asiaticoside, brahmoside, and madecassic acid along with other constituents including centellose, centelloside, and madecassoside, etc., which show immense pharmacological activity. Due to its beneficial role in neuroprotection activity, the plant has been considered as a brain tonic. However, limited cultivation, poor seed viability with low germination rate, and overexploitation for decades have led to severe depletion and threatened its wild stocks. The present review aimed to provide up-to-date information on biotechnological tools applied to this endangered medicinal plant for its in vitro propagation, direct or indirect regeneration, synthetic seed production, strategies for secondary metabolite productions including different elicitors. In addition, a proposed mechanism for the biosynthesis of triterpenoids is also discussed.

First releases of hatchery-produced Senegal sole (Solea senegalensis), brill (Scophthalmus rhombus), and wedge sole (Dicologoglossa cuneata) juveniles in the South-western Spanish coast

The regression of fisheries in the Gulf of Cadiz is evident since current fish catches are 33% of that 30 years before. Consequently, some initiatives for the replenishment of exhausted wild stocks are welcome. The objective of the present work is to describe and analyse the results coming from the first flatfish stock enhancements in Andalusia. A total of 3189 fish from three flatfish species: Senegal sole (Solea senegalensis Kaup), wedge sole (Dicologlossa cuneata Moreau), and brill (Scophthalmus rhombus Linnaeus) were tagged and released. Several variables were calculated through the data analysis of recovered fish. Some variables were calculated only for Senegal soles since wedge sole and brill recaptures were not significant. The Senegal sole recapture rate was 2.71 ± 0.72, similar to other published data, the recapture rates for bigger fish being higher though not significant. No significant differences were detected for distance, time, growth, or recapture rate amongst initial Senegal sole sizes. Around 80% of recaptures were registered within 15 weeks after release. The results show that it is possible for the release and recovery of tagged Senegal soles in the Gulf of Cadiz. Future long-term programmes on stock enhancement could help to determine the effects on fisheries and recover stocks.

Comparative study of blood physiological, antioxidant capacity, nutrition and organoleptic quality between wild, factory and cage‐cultured Hexagrammos otakii

Nutrient richness and fast-growing rate have rapidly advanced the aquaculture of Hexagrammos otakii. The current farming methods of H. otakii include wild stocking, cage culture and factory culture; however, the influence of each style on this species is unclear. This study aimed to establish and compare the nutritional profiles, muscle quality and physiological status of wild (WF), factory-cultured (FC) and cage-cultured (CC) H. otakii. Haematological parameters revealed remarkable differences in haemoglobin, haematocrit, mean corpuscular volume and platelet levels between the wild and cultured H. otakii. The proximal composition showed significantly higher and lower levels of crude lipids and proteins, respectively, in the CC group than that in the WF group. Likewise, the WF group exhibited significantly higher scores for texture attributes, such as hardness and springiness in addition to the significantly higher calcium and selenium contents than that in the cultured groups. Moreover, significant variations were determined in liver antioxidant capacity with a higher malondialdehyde content and glutathione peroxidase activity in the CC group than that in the other groups. Furthermore, the levels of all amino acids as well as polyunsaturated fatty acids and docosahexaenoic acid were significantly higher in the cultured groups than those in the WF group. In summary, regular consumption of cultured H. otakii may provide superior health benefits than that of wild H. otakii on the basis of the nutritional structure of muscle; however, wild H. otakii has a better taste and richer mineral composition.

Gene Expression Detects the Factors Influencing the Reproductive Success and the Survival Rates of Paracentrotus lividus Offspring.

The increase in the demand for Paracentrotus lividus roe, a food delicacy, causes increased pressure on its wild stocks. In this scenario, aquaculture facilities will mitigate the effects of anthropogenic pressures on the wild stocks of P. lividus. Consequently, experimental studies should be conducted to enhance techniques to improve efficient aquaculture practices for these animals. Here, we for the first time performed molecular investigations on cultured sea urchins. We aimed at understanding if maternal influences may significantly impact the life of future offspring, and how the culture conditions may impact the development and growth of cultured specimens. Our findings demonstrate that the outcomes of in vitro fertilization of P. lividus are influenced by maternal influences, but these effects are largely determined by culture conditions. In fact, twenty-three genes involved in the response to stress and skeletogenesis, whose expressions were measured by Real Time qPCR, were differently expressed in sea urchins cultured in two experimental conditions, and the results were largely modified in offspring deriving from two groups of females. The findings herein reported will be critical to develop protocols for the larval culture of the most common sea urchin, both for research and industrial production purposes for mass production.

Some biological aspects and fisheries assessment of Diplodus vulgaris (Geoffrey Saint-Hilaire, 1817) (Teleostei: Sparidae) caught by gillnets (Egyptian Mediterranean waters, Alexandria)

This study was conducted to estimate some biological aspects and fisheries assessment of Diplodus vulgaris caught by gillnets during the period 2018–2020 from the Egyptian Mediterranean waters of Alexandria. From an overall of 1004 individuals of D. vulgaris (10.0 – 24.0 cm TL) examined, lengths from 13.0 to 17.0 cm were representing 82.67% of the total fish number. The length-weight relationships for total and gutted weights of the D. vulgaris were: Log W = −1.7144 + 2.9063 Log L (R2 = 0.9982) and Log W = −1.8508 + 2.9903 Log L (R2 = 0.9967), respectively. The condition factor (k) was found to be fluctuating between 1.268 and 1.534 with an average value of 1.395 ± 0.0597. The overall sex ratio (M: F) was 1.00: 0.63 and the chi-square test revealed highly significant difference (χ2 = 24.80; df = 1; P < 0.01). The spawning season of D. vulgaris was observed from December to February for both sexes. The gonadosomatic index (GSI) reached its highest value in December for both sexes. The age composition of the D. vulgaris catch was estimated to be four years and the first age dominated the population. The present von Bertalanffy growth parameters were calculated as follows: the coefficient of growth (K) = 0.128 yr.-1, the asymptotic length (L∞) = 37.06 cm, and the hypothetical age at zero size (to) = −2.773 yr.-1. The growth performance index (Ф') was: Ф'L = 2.24, and Ф'W = 1.00. The reproductive load (Lm/L∞) was low for males (0.39) and females (0.37). The ratio LmaxD/ LmD was 1.36 and 1.39 for males and females, respectively and it was found to be compatible with the Pauly's Gill-Oxygen Limitation Theory (GOLT). The total mortality coefficient (Z) was 1.79, the natural mortality (M) was 0.39 and fishing mortality (F) was 1.40. The M/K was 3.0615 and Lc/L∞ was 0.371. At the level of the current exploitation rate (Ecur = 0.78), the stock is considered highly exploited by gillnets fishery and only 9.34% of the stock biomass is protected. Fishery management for this wild stock is highly required.

Fish oil substitution with vegetable oils in diets for greater amberjack (Seriola dumerili): A consequential life cycle assessment approach

This study assessed the environmental impacts of substituting fish oil with vegetable oils in the diets of greater amberjack (Seriola dumerili), based on both attributional and consequential life cycle assessments. The dietary lipid source was either fish oil (FO diet) or a blend of vegetable oils (linseed oil, sunflower oil, and palm oil, 4:3:3; VO diet). From an attributional perspective, the production of 1 kg of the FO diet released 1.10 kg CO2-eq and 1.60 kg CO2-eq as for global warming potential with and without land-use change, and 8.6 g PO4-eq as for the eutrophication potential; the depleted stock fraction index was equivalent to 2.8E−07. Compared with the FO diet, the production of 1 kg of the VO diet increased global warming potential with and without land-use change (by 5% and 4%, respectively) and PO4-eq by 58%, and reduced depleted stock fraction index by 24%. Consequential modelling revealed that in a scenario using fish oil and fishmeal derived from fish by-products, the marginal production of 1 kg of the VO diet compared with that of the FO diet produced a lower global warming potential with (−19%) and without land-use change (−12%), a greater eutrophication potential (+33%), and reduced depleted stock fraction index (−23%). In a scenario using fish oil and fishmeal diverted from a pre-existing fish production system, compared with that of the FO diet, the marginal production of 1 kg of the VO diet yielded similar values of global warming potentials and depleted stock fraction index, and a considerably higher eutrophication potential (+44%) value. For both FO and VO diets, fish-derived products (oil and meal) notably contributed to global warming potentials, as determined using both the attributional and consequential approaches. In contrast, the two diets differed with respect to the major contribution to eutrophication potential, which originated from non-fish-derived constituents for the FO diet and from vegetable oils (particularly sunflower oil) for the VO diet. Sensitivity analysis indicated that the replacement of sunflower oil with an equal quantity of another oil, e.g. palm oil, could reduce the eutrophication potential of the VO diet. In conclusion, the substitution of fish oil in aquafeeds with a mixture of vegetable oils could contribute to reductions in the exploitation of wild fish stocks and greenhouse gas emissions, although potential trade-offs, such as increased eutrophication, should be taken into consideration to enhance the environmental sustainability of aquafeed production based on an integrated approach.

Feasibility for cage farming in Africa: The case of the Kenyan part of Lake Victoria

AbstractFish catches in Lake Victoria have been on the decline, while demand for fish has been increasing because of rapid human population growth and awareness of the health benefits of fish. This decline is attributed to socioeconomic activities around the lake and climate change effects. To bridge the gap, cage culture has presented itself as a new socioeconomic frontier with good prospects for income in Lake Victoria, besides conserving declining wild fish stocks. However, these cages are greatly influencing the biodiversity of the lake both negative and positive. The study adopted a descriptive survey research where a total of 200 cage fish farmers were targeted. A sample of 60 fish farmers was selected using purposive and simple random sampling methods. Interview schedules and self-administered questionnaires were the main tools for data collection. Both primary and secondary data were collected and analyzed using Statistical Package for Social Sciences. The results were: the majority of cage fish farmers were male (87%) while the female was 13%, with a majority (75%) of the secondary and tertiary level of education. The beach management units and fish farmers were responsible for siting of cages. The fish farmers experienced several challenges including high cost of feeds leading to the use of poor quality feeds that sink and increase eutrophication, which enhances the growth of algae and water hyacinth in the lake. Overstocking leads to the emergence of diseases and fish kills, and fish theft resulting in economic loss. Most (80%) of respondents were not aware of policy guidelines on cage culture in Lake Victoria, while (75%) were not aware if cage culture was promoting climate change effects in Lake Victoria. This paper recommends the government to create awareness of policy guidelines on cage fish farming.

Variability of White Spot Syndrome Virus (WSSV) Envelope Protein VP28 from Diseased Shrimp (Litopenaeus vannamei) in Indonesia

White Spot Disease (WSD) is a viral disease affecting crustaceans. Caused by the White Spot Syndrome Virus (WSSV), this disease has caused significant mortality in commercially cultivated marine shrimp species with severe impacts on the shrimp farming industry and may be a threat to wild shrimp stocks. Thorough studies on the molecular biology of this pathogen are urgently needed to improve understanding of the virus at a molecular level, including variation in key viral protein (VP) components of the WSSV virion. This study aimed to isolate and characterize WSSV VP28 gene encoding envelope proteins from Indonesian Pacific white shrimp (Litopenaeus vannamei) isolates. Infected juvenile shrimp were collected from Pangkep, Barru, and Pinrang Districts in South Sulawesi, Indonesia. Genomic DNA was isolated from infected shrimp muscle tissue using a DTAB-CTAB (dodecyle trimethyl ammonium bromide-hexadecyl trimethyl ammonium bromide) DNA extraction procedure. The WSSV VP28 DNA sequences from Pangkep, Barru, and Pinrang isolates were 640-680 bp in length. Homology of Pangkep isolates with isolates from Barru and Pinrang was 97-99%. BLAST-N (Basic Local Alignment Search Tool-Nucleotide) analysis showed isolates from all three sites clustered with WSSV VP28 accessions from China, Indonesia, Japan, South Carolina and Vietnam. These results increase the geographic spread and host taxon coverage of WSSV VP28 sequence data for Indonesia.

The Piwil1 N domain is required for germ cell survival in Atlantic salmon.

Genetic introgression of farmed salmon into wild populations can damage the genetic integrity of wild stocks and is therefore considered as an environmental threat. One possible solution is to induce sterility in farmed salmon. We have searched for proteins potentially essential for germline survival in Atlantic salmon. One of these is the argonaute protein Piwil1, known to be required for germ cell survival. To examine Piwil1 function in salmon, we induced indels in the N domain by CRISPR-Cas9. The encoded domain is present in all vertebrate Piwi proteins and has been linked to Tdrd1 protein interaction and PAZ lobe structure. The F0 founder generation of piwil1 crispant males and females displayed a mosaic pattern of piwil1 mutations, exhibiting highly mutated alleles (53%–97%) in their fin gDNA samples. In general, piwil1 crispants carried germ cells, went through puberty and became fertile, although a transient and partial germ cell loss and delays during the spermatogenic process were observed in many male crispants, suggesting that Piwil1 functions during salmon spermatogenesis. By crossing highly mutated F0 founders, we produced F1 fish with a mixture of: loss-of-function alleles (−); functional in frame mutated alleles ( + ) and wt alleles (+). In F1, all piwil1 −/− fish lacked germ cells, while piwil1 +/+ siblings showed normal ovaries and testes. Yet, most juvenile F1 piwil1 +/−males and females displayed an intermediate phenotype with a higher somatic/germ cell ratio without an increase in germ cell apoptosis, suggestive of a gene dose effect on the number of germ cells and/or insufficient replacement of lost germ cells in heterozygous fish. Interestingly, the two longest in-frame indels in the N domain also ensured germ cell loss. Hence, the loss of 4–6 aa in this region Phe130-Ser136 may result in crucial changes of the protein structure, potentially affecting piRNA binding of the PAZ lobe, and/or affecting the binding of Piwil1 interacting proteins such as Tdrd protein, with critical consequences for the survival of primordial germ cells. In conclusion, we show that loss of piwil1 leads to loss of germ cells in salmon and that part of the N domain of Piwil1 is crucial for its function.

Effect of rearing temperature in the growth of hatchery reared juveniles of the sea cucumber Holothuria arguinensis (Koehler & Vaney, 1906)

Since the early 1980's there has been an increase in sea cucumber harvest and trade, mainly due to Asiatic market pressure. In the Indo-Pacific regions, the collapse of various stocks of these echinoderms has already occurred due to overfishing. In Europe, sea cucumber exportation depends exclusively on wild stock harvesting, which has demonstrated to be an unsustainable method to supply the markets, as these species are highly susceptible to overfishing. To enable a sustainable development of this emerging market in Europe the need to develop aquaculture techniques for these animals becomes of the utmost importance. At the current early stages of development, the viability of sea cucumber aquaculture for temperate species depends on the optimization of the rearing conditions. As ectotherms, temperature proves to be one of the most relevant parameters that affects the growth of sea cucumbers, as it influences metabolism and energy management and, in turn, future rearing methods and aquaculture sites. Therefore, this study aimed to determine the influence of temperature on the growth of H. arguinensis juveniles. A group of 168 juveniles (3.25 g ± 0.21; 3.81 cm ± 0.31) were placed under four different temperature treatments 18, 20, 22 and 24 °C for 4 months. The highest length (1.45 cm ± 0.16) and weight (2.79 g ± 0.14) gain were recorded at 20 °C. Similarly, the 20 °C treatment also produced the highest values for specific growth rate (0.50%/day) and the daily body length rate (0.30%cm/day). All allometric coefficients showed negative allometry (b < 3), a growth strategy that accentuates with increasing size. This life-history trait shows a higher distance from isometry the more distance the animals are from their optimum stocking temperature. Hence, metrics like the Fulton condition factor (K) show an inadequacy for the assessment of sea cucumber's condition, because a higher relative length decreases the value of K. A rearing temperature of 20 °C resulted in the best growth overall considering all increments in length and weight, pointing towards this as the best rearing temperature for the temperate species, H. arguinensis.

Saving the sea cucumbers: Using population genomic tools to inform fishery and conservation management of the Fijian sandfish Holothuria (Metriatyla) scabra.

The sea cucumber Holothuria (Metriatyla) scabra, known as sandfish, is a high-value tropical echinoderm central to the global bêche-de-mer (BDM) trade. This species has been heavily exploited across its natural range, with overharvesting and ineffective fishery management leaving stocks in the Pacific region heavily depleted. In Fiji, sandfish stocks have not recovered since a 1988 harvest ban, with surveys reporting declining populations and recruitment failure. Therefore, to inform fishery management policy for the wild sandfish resource and to guide hatchery-based restocking efforts, a high-resolution genomic audit of Fijian populations was carried out. A total of 6,896 selectively-neutral and 186 putatively-adaptive genome-wide SNPs (DArTseq) together with an independent oceanographic particle dispersal model were used to investigate genetic structure, diversity, signatures of selection, relatedness and connectivity in six wild populations. Three genetically distinct populations were identified with shallow but significant differentiation (average Fst = 0.034, p≤0.05), comprising (1) Lakeba island (Lau archipelago), (2) Macuata (Vanua Levu), and (3) individuals from Yasawa, Ra, Serua island and Kadavu comprising the final unit. Small reductions in allelic diversity were observed in marginal populations in eastern Fiji (overall mean A = 1.956 vs. Lau, A = 1.912 and Macuata, A = 1.939). Signatures of putative local adaptation were also discovered in individuals from Lakeba island, suggesting that they be managed as a discrete unit. An isolation-by-distance model of genetic structure for Fijian sandfish is apparent, with population fragmentation occurring towards the east. Hatchery-based production of juveniles is promising for stock replenishment, however great care is required during broodstock source population selection and juvenile releases into source areas only. The successful use of genomic data here has the potential to be applied to other sea cucumber species in Fiji, and other regions involved in the global BDM trade. While preliminary insights into the genetic structure and connectivity of sandfish in Fiji have been obtained, further local, regional and distribution-wide investigations are required to better inform conservation efforts, wild stock management and hatchery-based restocking interventions for this valuable invertebrate.

The importance of the cold chain in the medical biology laboratory: Experience of the central laboratory of CHU Mohammed VI of Oujda

The laboratory's activities lead to the storage of chemicals, analysis kits, biological samples, single-use material, etc. Depending on the storage conditions of certain products, it is necessary to create storage areas at different temperatures. The objective of our work is to underline the importance of the cold chain in the medical biology laboratory by presenting the experience of the Central Laboratory of CHU Mohammed VI of Oujda. The equipment for the preservation of biological collections must be placed in lockable rooms, with air conditioning and effective alarm systems, to ensure that the required temperatures are maintained. Access to the premises and collections is regulated and restricted to authorized and trained persons, a list of whom is established and regularly updated. The equipment is regularly maintained, defrosted, and the proper functioning of alarms is tested. Temperature control is ensured continuously, recorded, checked and the recording documents kept, in order to ensure the continuous traceability of the cold chain. All cold systems and cold measurement devices are subject to regular metrological checks. The results of these controls are archived. An emergency equipment must be maintained in working order to be able to receive samples in case of technical failure. Emergency response procedures should be posted near the equipment. Product storage rooms are ideally located according to the following parameters: on an exit accessible to delivery vehicles, which can sometimes carry several pallets of products per delivery, in close proximity to the technical rooms, to limit the movement of dangerous products and the creation of “wild stocks” in technical rooms that are too far away.

A sustainability assessment framework for genome-edited salmon

In this paper we present a suggestion for a sustainability assessment framework using genome editing of salmon as a case study. The salmon farming industry is facing several challenges hindering sustainable production. Genome editing has entered as a tool that can improve selective breeding and feed ingredients in aquaculture, hence providing solutions such as resistance to salmon lice and other pathogens, and sterility reducing interbreeding with wild, threatened stocks. As a goal for aquaculture is that its practices and products contribute to sustainability, the use of genome editing needs to be assessed with regards to sustainability, too. In our work, we draw on three sources of information; strategy and policy documents published by governmental offices and industry organizations; relevant GMO regulations and operationalization reports; and qualitative empirical data from 19 semi-structured interviews with Norwegian key stakeholders, and four semi-structured citizen groups. The findings from our analyses are discussed in relation to a Wedding cake-model for sustainability developed at the Stockholm Resilience Centre based on the UN SDGs and the three pillars of sustainability: biosphere, society, and economy. Analysis of document and interview data shows three main findings, one within each of the sustainability pillars. First, we identified that the biosphere pillar, including protection of the environment and the wild salmon, is the major sustainability issue and therefore important for the assessment of sustainability in the aquaculture industry and for the potential introduction of genome-edited salmon. Second, in the pillar for society the preservation of cultural and natural resources should be included, and in the Norwegian context this includes preserving the Sámi culture reliance on the wild salmon stocks. Third, in the economy pillar animal welfare needs to be included both for efficiency and ethical responsibility in farming. With some adoption to local and national conditions and the fish species in question, the same framework can be used for sustainability assessment of genome edited finfish in general.

Issues on the inclusion of Puntius denisonii (Day), a freshwater ornamental fish of global value, as Schedule-I species under the Wild Life (Protection) Amendment Act, 2021 of India

Puntius denisoniiis popularly known as Miss Kerala in India or Denison barb or Red line torpedo barb in the global ornamental fish trade. The species is endemic to fast-flowing rivers and streams of the Western Ghats of India. The species was not very popular earlier in aquatic trade but has been in great demand in global aquarium trade since it was exhibited at AQARAMA 1997 in Singapore and ranked third under the new species category. The export of the species from India started in 1996–1997, which increased progressively and constituted about 60%–65% of a total of 1.44 million US$ worth of ornamental fish exported from India in 2007–2008. Thereafter, it started declining and presently became negligible. It was attributed to depleting stocks ofP. denisoniiin rivers and streams of Western Ghats. The species was recommended to be listed as endangered on the IUCN red list in a CAMP workshop held at NBFGR, Lucknow, India in September 1997, owing to habitat degradation and the declining number of mature individuals in the wild. It was categorized as Vulnerable in 2009 and Endangered in 2015 under the IUCN red list. The Department of Fisheries, Government of Kerala has restricted the collection of smaller size fish from natural water bodies since 2008 to revive wild stocks. The Ministry of Environment, Forest and Climate Change, Government of India has now proposed to includeP. denisoniialong with two other freshwater fish species,Semiplotus semiplotus(Assamese kingfish) andOsteobrama belangeri(Manipur osteobrama), as Schedule-I species under the Wild Life (Protection) Amendment Act, 2021 of India. The species listed under this Schedule are prohibited to be hunted throughout the country. The captive breeding technology ofP. denisoniihas already been developed in the country more than a decade back, and fish is being produced commercially at several farms presently including hatcheries of the Kerala Government. The species is also being cultured and produced on a commercial scale by many ornamental fish farmers of Indonesia and supplied to the global ornamental fish trade at cheaper rates, and more color strains. The major factors that are responsible for the depletion of the stocks ofP. denisoniiand the overall fish biodiversity of Western Ghat regions are discussed in detail. The conflicts and repercussions that will arise because of the inclusion of Denison Barb or any other freshwater fish as Schedule-I species under the Wild Life (Protection) Amendment Act, 2021 of India are also discussed.

Eco-Friendly Fish Farming: Responsibly-Sustainable Aquaculture Among ASEAN Countries

Oceans were regarded as limitless source of fish and surmised that their supply was enough for the growing population. However, the fish sustenance of the seas was transcended by the increasing population's demands. Through the decade, wild fish stocks progressively depleted. Thus, aquaculture has emerged to address capture fisheries insufficiency. This research study aimed to assess aquaculture through its sustainability and effects on the ecosystem of ASEAN countries. This study utilized a Descriptive-Quantitative research design which gathers quantifiable information to describe the object of the study and how it could improve. It also employed data mining techniques. It is determined that Vietnam has the largest aquaculture farm while Indonesia boasts the highest fish production. Most of the ASEAN countries' employment rates in aquaculture-agriculture only amount to less than 15%. The majority of the countries have good aquaculture economies, while some are dependent on the importation of aquaculture products. The five leading ASEAN countries in aquaculture are Indonesia, Vietnam, Thailand, Philippines, and Myanmar, respectively. Aquaculture reduces fishing pressure on wild stocks but uses lots of shared resources that may hinder environment. “Responsible Aquaculture Standards in Vietnam" is the proposed action plan to minimize the negative outcomes of aquaculture in the Philippines.&#x0D; Keywords: Aquaculture, Sustainability, Ecosystem

Control of parasitic diseases in aquaculture.

Finfish aquaculture in freshwater and marine environments is continuously expanding globally, and the potential for a substantial further increase is well documented. The industry is supplying fish products for human consumption to the same extent as capture fisheries, and new fish species for domestication are still being selected by the industry. The challenge faced by all aquacultured species, classical and novel, is the range of pathogens associated with each new fish type. A fish host in its natural environment carries a series of more or less specific parasites (specialists and generalists). Some of these show a marked ability to propagate in aquaculture settings. They may then elicit disease when infection intensities in the confined aquaculture environment reach high levels. In addition, the risk of transmission of parasites from aquaculture enterprises to wild fish stocks adds to the parasitic challenge. Control programmes of various kinds are needed and these may include chemotherapeutants and medicines as the farmer's first and convenient choice, but mechanical, biological, immunological and genetic control methods are available solutions. New methods are still to be developed by scrutinizing the life cycle of each particular parasite species and pin-pointing the vulnerable stage to be targeted. As parasites exhibit a huge potential for adaptation to environmental changes, one must realize that only one approach rarely is sufficient. The present work therefore elaborates on and advocates for implementation of integrated control strategies for diseases caused by protozoan and metazoan parasites.

The Continued Spread of a Wild Population of American Chestnuts

We monitored the reproduction, dispersal, and regeneration of a wild population of Castanea dentata (American Chestnut), established from 4 seed-bearing trees planted in a western Maine forest in 1982. The 40-year-old parent trees, sourced from wild stock of a relict population in northern Michigan, show no obvious signs of blight and have been producing viable seeds now for >20 years. Over the course of 2 surveys conducted in 2019 and 2020, we mapped and measured 1348 offspring, varying in size from seedlings to nearly mature trees. As of October 2020, the natural spread of this population had expanded to at least 370 m from the parent trees, with an average dispersal distance of 124 m. While previous publications have focused on the scatter-hoarding behavior that gave rise to this expanding wild population, we report on possible factors affecting their spread, their fate, and prognosis for the future. Given the absence of other reproductive populations of American Chestnut in the immediate vicinity, our data provide rare insights into natural seed dispersal from a known point of origin while documenting the return of a functionally extinct species to a northern hardwood forest ecosystem.

Assessing Genetic Diversity of Wild Populations and Different Color Varieties for Genetic Improvement of Siamese Fighting Fish Betta splendens in Thailand.

To establish sustainable resources and founder populations for genetic improvement of the Siamese fighting fish Betta splendens, genetic diversity in wild and hatchery stocks was examined using mitochondrial (mt) DNA genes cytochrome b (cytb), 16S ribosomal DNA (16S rDNA), and cytochrome oxidase subunit I (COI), and eight microsatellite loci. Based on mtDNA sequences, restrictive levels of polymorphism (0, 3, and 1 substitutions) were observed in this study. For analysis of microsatellites, fluorescent multiplex PCR was developed, and subsequently identifying moderate levels of observed (Ho = 0.4488) and expected (He = 0.6627) heterozygosities and a high number of alleles per locus (15.125 alleles) for overall samples. Comparison of Siamese fighting fish from different sources revealed large genetic differences between pairs of farmed fish (eight groups) and between wild (three geographic locations) and farmed fish (P < 0.0031 following Bonferroni correction). This suggested limited exchanges of genetic resources between commercial farms. When different color varieties of B. splendens were compared, large genetic distances and significant FST estimates and genetic heterogeneity were found (P < 0.0031). Effective population sizes (Ne) were estimated and two farms (NP2-2BS and BK1-4BS) showed Ne greater than 10. Among color varieties, Multi-colors and Blue revealed reasonable Ne (large and 27.9), but lower Ne values (3.6-8.4) were found for the remaining color varieties. These results indicate an urgent need for the establishment of gene pool resources of B. splendens for effective genetic improvement of Siamese fighting fish in Thailand.