Pub Date : 2023-02-21DOI: 10.33997/j.afs.2023.36.1.003
Tô Văn Phương, R. Pomeroy
Vietnamese illegal fishing in foreign waters is a prominent issue that has led to a yellow card warning from the European Commission (EC) on 23 October 2017. Although Vietnam has made considerable efforts to halt illegal, unreported and unregulated (IUU) fishing and clear this yellow card, the results were insufficient to remove the yellow card as of the beginning of 2022. The present study analyses why addressing this issue has been so challenging. Specifically, the following questions are addressed: i) how do local fisheries authorities implement central regulation policies against IUU fishing and ii) what are the bottlenecks in legal enforcement for both fisheries agencies and fishers? The secondary data analysis and the findings from interviews with government officials and fishers are presented. The authorities have implemented various approaches to prevent illegal fishing in foreign waters. These include an improved policy framework, law enforcement, fishing vessel management and supervision with vessel monitoring system (VMS), and increased responsibilities attached to the local fisheries authorities. Despite the several measures taken, illegal fishing in foreign waters continues. There are several reasons for the failure to control illegal fishing, including exhausted local marine resources, too many fishing boats operating in the same areas, unclear responsibilities of stakeholders, and lack of coordination among implementing authorities. Several recommendations are suggested for addressing the problem of IUU fishing of Vietnamese vessels in foreign waters to meet the criteria set by the EC to remove the yellow card and ensure that the results are long-lasting and substantive.
{"title":"Addressing Illegal, Unreported and Unregulated Fishing of Vietnamese Fishing Vessels in Foreign Waters","authors":"Tô Văn Phương, R. Pomeroy","doi":"10.33997/j.afs.2023.36.1.003","DOIUrl":"https://doi.org/10.33997/j.afs.2023.36.1.003","url":null,"abstract":"Vietnamese illegal fishing in foreign waters is a prominent issue that has led to a yellow card warning from the European Commission (EC) on 23 October 2017. Although Vietnam has made considerable efforts to halt illegal, unreported and unregulated (IUU) fishing and clear this yellow card, the results were insufficient to remove the yellow card as of the beginning of 2022. The present study analyses why addressing this issue has been so challenging. Specifically, the following questions are addressed: i) how do local fisheries authorities implement central regulation policies against IUU fishing and ii) what are the bottlenecks in legal enforcement for both fisheries agencies and fishers? The secondary data analysis and the findings from interviews with government officials and fishers are presented. The authorities have implemented various approaches to prevent illegal fishing in foreign waters. These include an improved policy framework, law enforcement, fishing vessel management and supervision with vessel monitoring system (VMS), and increased responsibilities attached to the local fisheries authorities. Despite the several measures taken, illegal fishing in foreign waters continues. There are several reasons for the failure to control illegal fishing, including exhausted local marine resources, too many fishing boats operating in the same areas, unclear responsibilities of stakeholders, and lack of coordination among implementing authorities. Several recommendations are suggested for addressing the problem of IUU fishing of Vietnamese vessels in foreign waters to meet the criteria set by the EC to remove the yellow card and ensure that the results are long-lasting and substantive.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44869644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-29DOI: 10.33997/j.afs.2023.36.1.002
Md. Asadur Rahman, M. Islam, Aparna Barman, S. Khatun, Kazi Rumaiya Binta Monir, Md. Rakibul Islam, Makidul Islam Khan
The coronavirus disease (COVID-19) adversely impacted the fisheries sector of Bangladesh, particularly affecting the outcomes for women workers of the fish and shellfish processing plants (FSPPs). This study aimed to assess the impacts of COVID-19 on the women workers of the FSPPs by collecting data through 151 questionnaire surveys and two focus group discussions (FGDs) from September to December 2021. During COVID-19, 32.1 % of respondents’ food consumption decreased slightly, and 16.6 % reduced drastically. Children of 18.2 % of the respondents had no access, and 16.9 % had insufficient access to online class facilities. Increased livelihood costs and decreased household income posed adverse economic impacts on women. Formal paid hours and overtime job opportunities were reduced because foreign buyers cancelled orders during the pandemic. Gender-based violence and social insecurity increased. Respondents (13.2 %) reported increased mistreatment by their husbands during the pandemic. Women workers’ mental health deteriorated as their anxiety and insecurity about life increased during the pandemic. This study recommends overcoming the adverse effect of COVID-19 or COVID-like pandemics in the future. To ensure proper food consumption and reduce adverse economic impacts, the government should offer a special relief package, financial incentives and flexible low-interest loans. Related authorities should ensure that every child has the opportunity and access to participate in online classes during COVID-19 or COVID, like pandemics in the future.
{"title":"COVID-19 Induced Impacts on Women Workers of Fish and Shellfish Processing Plants in Bangladesh","authors":"Md. Asadur Rahman, M. Islam, Aparna Barman, S. Khatun, Kazi Rumaiya Binta Monir, Md. Rakibul Islam, Makidul Islam Khan","doi":"10.33997/j.afs.2023.36.1.002","DOIUrl":"https://doi.org/10.33997/j.afs.2023.36.1.002","url":null,"abstract":"The coronavirus disease (COVID-19) adversely impacted the fisheries sector of Bangladesh, particularly affecting the outcomes for women workers of the fish and shellfish processing plants (FSPPs). This study aimed to assess the impacts of COVID-19 on the women workers of the FSPPs by collecting data through 151 questionnaire surveys and two focus group discussions (FGDs) from September to December 2021. During COVID-19, 32.1 % of respondents’ food consumption decreased slightly, and 16.6 % reduced drastically. Children of 18.2 % of the respondents had no access, and 16.9 % had insufficient access to online class facilities. Increased livelihood costs and decreased household income posed adverse economic impacts on women. Formal paid hours and overtime job opportunities were reduced because foreign buyers cancelled orders during the pandemic. Gender-based violence and social insecurity increased. Respondents (13.2 %) reported increased mistreatment by their husbands during the pandemic. Women workers’ mental health deteriorated as their anxiety and insecurity about life increased during the pandemic. This study recommends overcoming the adverse effect of COVID-19 or COVID-like pandemics in the future. To ensure proper food consumption and reduce adverse economic impacts, the government should offer a special relief package, financial incentives and flexible low-interest loans. Related authorities should ensure that every child has the opportunity and access to participate in online classes during COVID-19 or COVID, like pandemics in the future.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47698518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-24DOI: 10.33997/j.afs.2023.36.1.001
M. Rajesh, B. Kamalam, M. Dubey, P. A. Ganie, K. Kunal
A field study evaluated the safe loading density for live transportation of rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), yearlings in plastic bags of super-oxygenated water. The experimental fish (197.5 ± 40 g) were starved for 72 h and mildly sedated with clove oil (40 µL.L-1 for 2–3 min) before packing. Three loading densities of live rainbow trout (120, 170, 230 g.L-1) were packed in plastic bags containing 6 L of stream water and 10–12 L of medical-grade oxygen gas. Six replicate bags per loading density were then subjected to 10 h of transportation by road at ~10 °C. On arrival at the destination, important water quality indicators and fish survival were recorded from each plastic bag. With increasing fish loading density, there was a corresponding increase in the concentrations of carbon dioxide (CO2), total ammonia nitrogen (TAN), free ammonia (NH3), total dissolved solids (TDS) concentrations and specific conductivity in the transport water, and a decrease in dissolved oxygen (DO, R2 = 0.91-0.99). These differences in vital water quality indicators were significantly more in the 230 g.L-1 group. However, there was no mortality even at the highest loading density, as the critical water quality parameters did not cross the acute lethal thresholds for rainbow trout. Based on the findings, it is recommended that a loading density of 230 g.L-1 is safe for live transportation of rainbow trout yearlings in plastic bags over a transport duration of 10 h at ~10 °C, following adequate starvation and mild sedation.
{"title":"Optimisation of Safe Loading Density for Live Transportation of Rainbow Trout, Oncorhynchus mykiss (Walbaum, 1792), Yearlings in Plastic Bags","authors":"M. Rajesh, B. Kamalam, M. Dubey, P. A. Ganie, K. Kunal","doi":"10.33997/j.afs.2023.36.1.001","DOIUrl":"https://doi.org/10.33997/j.afs.2023.36.1.001","url":null,"abstract":"A field study evaluated the safe loading density for live transportation of rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), yearlings in plastic bags of super-oxygenated water. The experimental fish (197.5 ± 40 g) were starved for 72 h and mildly sedated with clove oil (40 µL.L-1 for 2–3 min) before packing. Three loading densities of live rainbow trout (120, 170, 230 g.L-1) were packed in plastic bags containing 6 L of stream water and 10–12 L of medical-grade oxygen gas. Six replicate bags per loading density were then subjected to 10 h of transportation by road at ~10 °C. On arrival at the destination, important water quality indicators and fish survival were recorded from each plastic bag. With increasing fish loading density, there was a corresponding increase in the concentrations of carbon dioxide (CO2), total ammonia nitrogen (TAN), free ammonia (NH3), total dissolved solids (TDS) concentrations and specific conductivity in the transport water, and a decrease in dissolved oxygen (DO, R2 = 0.91-0.99). These differences in vital water quality indicators were significantly more in the 230 g.L-1 group. However, there was no mortality even at the highest loading density, as the critical water quality parameters did not cross the acute lethal thresholds for rainbow trout. Based on the findings, it is recommended that a loading density of 230 g.L-1 is safe for live transportation of rainbow trout yearlings in plastic bags over a transport duration of 10 h at ~10 °C, following adequate starvation and mild sedation.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42322368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-29DOI: 10.33997/j.afs.2022.35.4.005
Verakiat Supmee, Juthamas Suppapan
Genetic information is crucial to manage fish resources, and a good case in point is the population of silver croakers, Pennahia argentata (Houttuyn, 1782), which is economically important for Thailand. In the present study, 102 silver croaker samples were collected along the coast of the Gulf of Thailand and analysed for genetic variation based on nucleotide sequences in the cytochrome oxidase subunit I gene (510 bp). Of these, 33 haplotypes were examined, and 21 were singleton haplotypes, indicating a historical pattern of large female effective population sizes (female reproductive success). An analysis of molecular variance (AMOVA) and pairwise FST analysis showed that the geographic barrier did not affect the genetic structure of the silver croakers in the Gulf of Thailand. The minimum spanning network and phylogenetic tree revealed that the silver croaker population in the Gulf of Thailand separated into two haplogroups. Various methods to examine demographic history showed that the silver croaker population in the Gulf of Thailand had expanded. This study’s findings can guide the management of silver croaker populations in the Gulf of Thailand to conserve genetic diversity.
{"title":"Population Genetic Structure of Silver Croakers, Pennahia argentata (Houttuyn, 1782), in the Gulf of Thailand Based on Cytochrome Oxidase Subunit I Gene Sequences","authors":"Verakiat Supmee, Juthamas Suppapan","doi":"10.33997/j.afs.2022.35.4.005","DOIUrl":"https://doi.org/10.33997/j.afs.2022.35.4.005","url":null,"abstract":"Genetic information is crucial to manage fish resources, and a good case in point is the population of silver croakers, Pennahia argentata (Houttuyn, 1782), which is economically important for Thailand. In the present study, 102 silver croaker samples were collected along the coast of the Gulf of Thailand and analysed for genetic variation based on nucleotide sequences in the cytochrome oxidase subunit I gene (510 bp). Of these, 33 haplotypes were examined, and 21 were singleton haplotypes, indicating a historical pattern of large female effective population sizes (female reproductive success). An analysis of molecular variance (AMOVA) and pairwise FST analysis showed that the geographic barrier did not affect the genetic structure of the silver croakers in the Gulf of Thailand. The minimum spanning network and phylogenetic tree revealed that the silver croaker population in the Gulf of Thailand separated into two haplogroups. Various methods to examine demographic history showed that the silver croaker population in the Gulf of Thailand had expanded. This study’s findings can guide the management of silver croaker populations in the Gulf of Thailand to conserve genetic diversity.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43252780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-25DOI: 10.33997/j.afs.2022.35.4.004
Kiyar Jemal, Degsera Aemro
The age and growth rate of the fish species must be known since they are essential input variables that compose stock assessment models to assess the stock status and estimate the exploitable potential of the stock. The age and growth of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), in Koka Reservoir, Ethiopia, were studied based on 981 sagittal otoliths collected monthly from December 2017 to November 2018. Otoliths were grounded and examined under a stereoscopic microscope at 10–40× magnification for macrozones analysis using a reflected light source. The age of the fish was determined based on the number of translucent zones counted in the otoliths of O. niloticus by considering the time of translucent zone formation and median hatch date. Seasonal records on the macrozones at the edge of otoliths and relative marginal increments suggested that two translucent macrozones associated with biannuli were formed each year, one from January to February, and another one from June to July. The observed ages of O. niloticus from Koka Reservoir ranged from 1 to 6.5 years, and the most dominant classes were 2 and 3 years. Growth was determined using the von Bertalanffy growth function. The von Bertalanffy growth parameters (sexes combined) were; asymptotic length (total length), L∞ = 35.6 cm, growth rate constant, K = 0.37 year-1, theoretical age at zero-length, t0 = -0.42 years and the growth performance length, φ’ = 2.67. It could be concluded that the growth of O. niloticus in Koka Reservoir is within the range mentioned in Ethiopian lakes.
{"title":"Age and Growth of Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758), From Koka Reservoir, Ethiopia","authors":"Kiyar Jemal, Degsera Aemro","doi":"10.33997/j.afs.2022.35.4.004","DOIUrl":"https://doi.org/10.33997/j.afs.2022.35.4.004","url":null,"abstract":"The age and growth rate of the fish species must be known since they are essential input variables that compose stock assessment models to assess the stock status and estimate the exploitable potential of the stock. The age and growth of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), in Koka Reservoir, Ethiopia, were studied based on 981 sagittal otoliths collected monthly from December 2017 to November 2018. Otoliths were grounded and examined under a stereoscopic microscope at 10–40× magnification for macrozones analysis using a reflected light source. The age of the fish was determined based on the number of translucent zones counted in the otoliths of O. niloticus by considering the time of translucent zone formation and median hatch date. Seasonal records on the macrozones at the edge of otoliths and relative marginal increments suggested that two translucent macrozones associated with biannuli were formed each year, one from January to February, and another one from June to July. The observed ages of O. niloticus from Koka Reservoir ranged from 1 to 6.5 years, and the most dominant classes were 2 and 3 years. Growth was determined using the von Bertalanffy growth function. The von Bertalanffy growth parameters (sexes combined) were; asymptotic length (total length), L∞ = 35.6 cm, growth rate constant, K = 0.37 year-1, theoretical age at zero-length, t0 = -0.42 years and the growth performance length, φ’ = 2.67. It could be concluded that the growth of O. niloticus in Koka Reservoir is within the range mentioned in Ethiopian lakes.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44085878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.33997/j.afs.2022.35.4.003
Saila Rachma, M. Madihah, S. Sumarsono
Skeletal development is essential in supporting aquaculture success, as failure and deformities reduce fish viability and growth. Herein, the cartilage and bone formation in the larva and juvenile of the bonylip barb, Osteochilus vittatus (Valenciennes, 1842), is described in detail for the first time. Mature fish were injected with ovaprim at 0.5 mL.kg-1 body weight, followed by artificial spawning. After fertilisation, the embryos were reared in a glass container at 28 ± 1 °C. The first hatchling was observed at 26 h and 15 min post-fertilisation (pf), and the last was observed at 48 hpf. The cartilage and bone development were observed from 1 to 30 days post-hatching (dph) by alcian blue and alizarin red S staining. Freshly hatched fish larvae had not undergone either chondrification or ossification. The cartilage was observed at 1 dph, marked with Meckel’s cartilage, ethmoid plate, and pectoral fin, as the pre-larva had a standard length (SL) of 5 mm. At 5 dph (SL of 5.6 ± 0.55 mm), 3 to 4 pairs of basidorsal and basiventral were observed. The cartilaginous development ended at 26 dph as the SL reached 14.3 ± 0.57 mm. The ossification started at 20 dph (SL of 9.24 ± 0.68 mm) and was marked with opercle and cleithrum. At 26 dph, as the post-larvae length 14.3 ± 0.57 mm, dentary, pterotic, and parasphenoid were ossified. Juvenile fish at 30 dph (SL of 21.2 ± 3.9 mm) showed completed ossification processes in the cranium and vertebrae.
{"title":"Spatiotemporal Profile of Skeletal Development in Bonylip Barb, Osteochilus vittatus (Valenciennes, 1842)","authors":"Saila Rachma, M. Madihah, S. Sumarsono","doi":"10.33997/j.afs.2022.35.4.003","DOIUrl":"https://doi.org/10.33997/j.afs.2022.35.4.003","url":null,"abstract":"Skeletal development is essential in supporting aquaculture success, as failure and deformities reduce fish viability and growth. Herein, the cartilage and bone formation in the larva and juvenile of the bonylip barb, Osteochilus vittatus (Valenciennes, 1842), is described in detail for the first time. Mature fish were injected with ovaprim at 0.5 mL.kg-1 body weight, followed by artificial spawning. After fertilisation, the embryos were reared in a glass container at 28 ± 1 °C. The first hatchling was observed at 26 h and 15 min post-fertilisation (pf), and the last was observed at 48 hpf. The cartilage and bone development were observed from 1 to 30 days post-hatching (dph) by alcian blue and alizarin red S staining. Freshly hatched fish larvae had not undergone either chondrification or ossification. The cartilage was observed at 1 dph, marked with Meckel’s cartilage, ethmoid plate, and pectoral fin, as the pre-larva had a standard length (SL) of 5 mm. At 5 dph (SL of 5.6 ± 0.55 mm), 3 to 4 pairs of basidorsal and basiventral were observed. The cartilaginous development ended at 26 dph as the SL reached 14.3 ± 0.57 mm. The ossification started at 20 dph (SL of 9.24 ± 0.68 mm) and was marked with opercle and cleithrum. At 26 dph, as the post-larvae length 14.3 ± 0.57 mm, dentary, pterotic, and parasphenoid were ossified. Juvenile fish at 30 dph (SL of 21.2 ± 3.9 mm) showed completed ossification processes in the cranium and vertebrae.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41699392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-08DOI: 10.33997/j.afs.2022.35.4.002
Ivan Ndongo, Michel Thierry Onana Ngono, J. Tombi
Monogenea is a taxon containing flatworms that are primarily parasites of the skin and gills of fish. The African tetra, Brycinus kingsleyae (Günther, 1896), is a commercial fish species in artisanal fisheries in Southern Cameroon. Although the gill monogeneans of this fish species have been described, no ecological research has been carried out on this component community. The present study was conducted in the Nyong River to provide the first data about some factors that influence the structure of its infracommunities. In dry seasons, 70 fish specimens consisting of 27 males and 43 females of fork length between 9.5 and 14.1 cm were sampled.The analysis of their gill filament number indicated that the gill system of B. kingsleyae is heterogeneous because this factor varies with the length of the fish and depends on the gill arch. The studied guild consisted only of core species: Annulotrema combesi Birgi, 1988, Annulotrema maillardi Birgi, 1988, Annulotrema nyongensis Birgi, 1988, Annulotrema bouixi Birgi, 1988, and Characidotrema regia Birgi, 1988. The number of gill filaments and the parasitic load increased with the fish length, indicating that larger hosts provide a greater diversity of niches for parasites. Monogenean species exhibit various occupation patterns of gill arches, sectors, zones and gender differences in parasitological indices. This study reveals that the host length and sex, filament number, gill arch, sector and zone are largely responsible for structuring the studied component community.
{"title":"Gill Monogeneans of African Tetra, Brycinus kingsleyae (Günther, 1896), From the Nyong River: Biotope, Distribution and Site Selection","authors":"Ivan Ndongo, Michel Thierry Onana Ngono, J. Tombi","doi":"10.33997/j.afs.2022.35.4.002","DOIUrl":"https://doi.org/10.33997/j.afs.2022.35.4.002","url":null,"abstract":"Monogenea is a taxon containing flatworms that are primarily parasites of the skin and gills of fish. The African tetra, Brycinus kingsleyae (Günther, 1896), is a commercial fish species in artisanal fisheries in Southern Cameroon. Although the gill monogeneans of this fish species have been described, no ecological research has been carried out on this component community. The present study was conducted in the Nyong River to provide the first data about some factors that influence the structure of its infracommunities. In dry seasons, 70 fish specimens consisting of 27 males and 43 females of fork length between 9.5 and 14.1 cm were sampled.The analysis of their gill filament number indicated that the gill system of B. kingsleyae is heterogeneous because this factor varies with the length of the fish and depends on the gill arch. The studied guild consisted only of core species: Annulotrema combesi Birgi, 1988, Annulotrema maillardi Birgi, 1988, Annulotrema nyongensis Birgi, 1988, Annulotrema bouixi Birgi, 1988, and Characidotrema regia Birgi, 1988. The number of gill filaments and the parasitic load increased with the fish length, indicating that larger hosts provide a greater diversity of niches for parasites. Monogenean species exhibit various occupation patterns of gill arches, sectors, zones and gender differences in parasitological indices. This study reveals that the host length and sex, filament number, gill arch, sector and zone are largely responsible for structuring the studied component community.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49007627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-05DOI: 10.33997/j.afs.2022.35.4.001
Mochamad Amiri, L. Musdalifah, M. Amin
Cannibalism causes severe losses and has been considered one of the most important challenges in lobster aquaculture. The present study aimed to assess the effects of artificial shelters on the survival rate and growth performances of the scalloped spiny lobster, Panulirus homarus (Linnaeus, 1758). Wild-caught 600 puerulus stage scalloped spiny lobsters (~0.18 g wet-weight and 7.16 cm total length) were randomly allocated into floating cages provided with four different shelters; i) polyvinyl chloride (PVC), ii) nylon net, iii) cement sack and iv) no shelter as a control and cultured for 10 weeks to measure mortality and growth. The result of the experiment done in triplicate indicated that artificial shelters significantly affected scalloped spiny lobsters' survival rate and growth performances. The survival rate of scalloped spiny lobster in the control group observed on week 2 was only 62 %, while the survival rate in all treatments (with shelter) was 76 to 82 %. After 10 weeks culture period, the mean survival rate was only 28 % in control, which was significantly lower than all treatments (53 %, 54 %, and 59 % for nylon net, cement sack, and PVC, respectively). Similarly, the absolute growth and specific growth rate of the spiny lobsters reared with the artificial shelters were significantly better than that of lobsters in the control group. The best growth was obtained from lobster reared with a nylon net, followed by cement sack and PVC pipe. This research finding can be used to select suitable shelters for cultivating spiny lobsters.
{"title":"Effects of Artificial Shelters on Survival Rates and Growth Performances of Scalloped Spiny Lobster, Panulirus homarus (Linnaeus, 1758), Reared in Floating-Net Cages","authors":"Mochamad Amiri, L. Musdalifah, M. Amin","doi":"10.33997/j.afs.2022.35.4.001","DOIUrl":"https://doi.org/10.33997/j.afs.2022.35.4.001","url":null,"abstract":"Cannibalism causes severe losses and has been considered one of the most important challenges in lobster aquaculture. The present study aimed to assess the effects of artificial shelters on the survival rate and growth performances of the scalloped spiny lobster, Panulirus homarus (Linnaeus, 1758). Wild-caught 600 puerulus stage scalloped spiny lobsters (~0.18 g wet-weight and 7.16 cm total length) were randomly allocated into floating cages provided with four different shelters; i) polyvinyl chloride (PVC), ii) nylon net, iii) cement sack and iv) no shelter as a control and cultured for 10 weeks to measure mortality and growth. The result of the experiment done in triplicate indicated that artificial shelters significantly affected scalloped spiny lobsters' survival rate and growth performances. The survival rate of scalloped spiny lobster in the control group observed on week 2 was only 62 %, while the survival rate in all treatments (with shelter) was 76 to 82 %. After 10 weeks culture period, the mean survival rate was only 28 % in control, which was significantly lower than all treatments (53 %, 54 %, and 59 % for nylon net, cement sack, and PVC, respectively). Similarly, the absolute growth and specific growth rate of the spiny lobsters reared with the artificial shelters were significantly better than that of lobsters in the control group. The best growth was obtained from lobster reared with a nylon net, followed by cement sack and PVC pipe. This research finding can be used to select suitable shelters for cultivating spiny lobsters.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47600771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-27DOI: 10.33997/j.afs.2022.35.3.006
P. Coulson, N. Jarvis, G. Jackson
There is an increasing need to understand the interaction of marine fauna with line fishing, both recreational and commercial, particularly in regions where shark depredation has become an increasing issue. The dynamic nature of the fishing requires underwater filming techniques that can move with the fishing activity and capture high-resolution footage enabling the identification of fauna species. In the case of shark depredation, the development of deterrent devices specifically designed for use while line fishing will require underwater footage to determine the effectiveness of those devices designed to invoke avoidance behaviours in sharks that approach hooked fish. Two new and inexpensive mounting systems were developed, enabling a range of “action” cameras to be attached to fishing lines to capture underwater footage while line fishing. Using these mounting systems with GoProTM cameras, high-resolution video was obtained during line fishing trials in which the effectiveness of shark deterrents was investigated. The video footage enabled the identification of fish and shark species and recorded any avoidance behaviours of sharks, in response to the presence of deterrents.
{"title":"New Techniques for Underwater Video Photography of Line Fishing and Their Application in Shark Depredation Studies","authors":"P. Coulson, N. Jarvis, G. Jackson","doi":"10.33997/j.afs.2022.35.3.006","DOIUrl":"https://doi.org/10.33997/j.afs.2022.35.3.006","url":null,"abstract":"There is an increasing need to understand the interaction of marine fauna with line fishing, both recreational and commercial, particularly in regions where shark depredation has become an increasing issue. The dynamic nature of the fishing requires underwater filming techniques that can move with the fishing activity and capture high-resolution footage enabling the identification of fauna species. In the case of shark depredation, the development of deterrent devices specifically designed for use while line fishing will require underwater footage to determine the effectiveness of those devices designed to invoke avoidance behaviours in sharks that approach hooked fish. Two new and inexpensive mounting systems were developed, enabling a range of “action” cameras to be attached to fishing lines to capture underwater footage while line fishing. Using these mounting systems with GoProTM cameras, high-resolution video was obtained during line fishing trials in which the effectiveness of shark deterrents was investigated. The video footage enabled the identification of fish and shark species and recorded any avoidance behaviours of sharks, in response to the presence of deterrents.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47286151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-23DOI: 10.33997/j.afs.2022.35.3.005
M. Priyadarshana, C. Walpita, H. Ruwandeepika, M. Magamage
Inadequate availability and unreasonable prices made fish meal an unreliable feed ingredient in aquaculture. Consequently, researchers have tested different plant and animal-derived protein sources as an option over the fish meal. The black soldier fly, Hermetia illucens (Linnaeus, 1758), larva, has been identified as a reliable protein source for fish meal replacement. Many studies have revealed the growth and microbiological impacts of H. illucens larvae as a protein source in finfish culture. However, a review of knowledge on histopathology, haematology and microbial changes modulated by H. illucens larvae when incorporated as a feed ingredient in finfish aquaculture is not available. Therefore, this study reviews the effects on the histopathology, haematology and gut-microbial properties of finfish fed diet incorporated with H. illucens larvae. A review of different finfish species tested up to 100 % inclusion of H. illucens larvae meal in their diets revealed mixed results in blood chemistry, gut microbiota, and gut histology. Most studies stated common positive effects such as reduced plasma cholesterol levels, increased microbial diversity, and increased intestinal absorption up to 50 % incorporation level. Despite the possibility of incorporating H. illucens larvae meal without any negative impacts on some carnivore fish species, most studies disclosed adverse effects beyond 50 % fish meal replacement due to high chitin and crude fat levels in H. illucens larval diets.
{"title":"Effects of Black Soldier Fly, Hermetia illucens (Linnaeus, 1758), Larvae Incorporated Feed on Histomorphology, Gut Microbiota and Blood Chemistry of Cultured Fishes: A Review","authors":"M. Priyadarshana, C. Walpita, H. Ruwandeepika, M. Magamage","doi":"10.33997/j.afs.2022.35.3.005","DOIUrl":"https://doi.org/10.33997/j.afs.2022.35.3.005","url":null,"abstract":"Inadequate availability and unreasonable prices made fish meal an unreliable feed ingredient in aquaculture. Consequently, researchers have tested different plant and animal-derived protein sources as an option over the fish meal. The black soldier fly, Hermetia illucens (Linnaeus, 1758), larva, has been identified as a reliable protein source for fish meal replacement. Many studies have revealed the growth and microbiological impacts of H. illucens larvae as a protein source in finfish culture. However, a review of knowledge on histopathology, haematology and microbial changes modulated by H. illucens larvae when incorporated as a feed ingredient in finfish aquaculture is not available. Therefore, this study reviews the effects on the histopathology, haematology and gut-microbial properties of finfish fed diet incorporated with H. illucens larvae. A review of different finfish species tested up to 100 % inclusion of H. illucens larvae meal in their diets revealed mixed results in blood chemistry, gut microbiota, and gut histology. Most studies stated common positive effects such as reduced plasma cholesterol levels, increased microbial diversity, and increased intestinal absorption up to 50 % incorporation level. Despite the possibility of incorporating H. illucens larvae meal without any negative impacts on some carnivore fish species, most studies disclosed adverse effects beyond 50 % fish meal replacement due to high chitin and crude fat levels in H. illucens larval diets.","PeriodicalId":37296,"journal":{"name":"Asian Fisheries Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46190179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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