Aquaculture, Fish and Fisheries最新文献

{"title":"Multispecies Probiotics Relieve High Temperature–Induced Growth Obstruction and Stress on Rohu (Labeo rohita) by Activating GH/IGF Axis","authors":"Zannatul Ferdous,&nbsp;Joya Chakrabarty,&nbsp;Md. Rasel Mahomud,&nbsp;Rakib Hossain Shawon,&nbsp;Tamanna Ferdous,&nbsp;Md. Mahiuddin Zahangir,&nbsp;Md. Shahjahan","doi":"10.1002/aff2.70050","DOIUrl":"https://doi.org/10.1002/aff2.70050","url":null,"abstract":"<p>Global warming is upsetting for aquatic species, and probiotic treatment may help to diminish its impacts. In order to counter the negative consequences of elevated temperature on growth and well-being, rearing water of rohu (<i>Labeo rohita</i>) was supplemented with multispecies probiotics (1.0 mL/L). For 6 weeks, fingerlings weighing 10.08 ± 0.13 g were raised in triplicate at normal temperature (30°C) and higher temperatures (33°C and 36°C) with or without probiotics. Fish treated without probiotics showed substantial decreases in weight gain (WG) and specific growth rate (SGR) at 36°C in contrast to normal temperature (30°C). However, fish reared with probiotics showed enhanced WG and SGR at the highest temperature (36°C) compared to fish maintained without probiotics. In the group of fish supplemented with probiotics under high-temperature conditions, haemoglobin levels increased while glucose levels decreased. The number of irregularities in cells and nuclei of erythrocytes was dramatically reduced in probiotic-treated fish at 36°C. The relative mRNA level of three growth-relevant genes (growth hormone, <i>gh</i>, in the pituitary; insulin-like growth factor 1 and 2, <i>igf-1</i> and <i>igf-2</i>, in the liver) decreased with increasing temperature but rose after probiotic addition. Fish at 36°C revealed a notable upregulation regarding the expression of genes for stress-associated heat shock protein 70 and 90 (<i>hsp70</i> and <i>hsp90</i>), whereas their expressions were lowered following probiotics administration. Considering as a whole, the addition of probiotics to water improved blood biochemistry and cellular structure of blood and increased the expression levels of GH and IGF which consequently relieved growth retardation and stress in rohu.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70050","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Vitamin C on Growth, Haemato-Immunological Characteristics and Stress Tolerance Capability of Climbing Perch, Anabas testudineus (Bloch, 1792)","authors":"Tanwi Dey,&nbsp;Md. Sakhawat Hossain,&nbsp;Md. Mostufa Kamal,&nbsp;Piash Kumer Ghosh,&nbsp;Md. Shahab Uddin,&nbsp;Md. Tariqul Alam,&nbsp;Sohel Mian,&nbsp;Md. Jakiul Islam","doi":"10.1002/aff2.70048","DOIUrl":"https://doi.org/10.1002/aff2.70048","url":null,"abstract":"<p>Climbing perch, <i>Anabas testudineus</i>, were fed four diets: D0, D500, D1000 and D1500, containing 0, 500, 1000 and 1500 mg of vitamin C per kg of basal diet, respectively, over 70 days. After the growth trial, significantly higher final weight, percent body weight (%WG) and specific growth rate (SGR) were observed in fish fed D1000 followed by D500 and D0 diets. However, D1500 diet-fed fish had a significantly lower growth performance among all diet groups. The best feed conversion ratio and protein efficiency ratio were observed in fish fed D1000, followed by D500, with no significant difference between D0 and D1500 groups. Blood parameters were significantly influenced by vitamin C dosages. Fish fed on the D1000 diet exhibited significantly higher white blood cell (WBC), monocyte (MONO) and granulocyte (GRA) counts among all dietary groups. Vitamin C supplementation significantly increased platelet count in the D1000 group. Haemoglobin, haematocrit and red blood cell (RBC) counts showed an increasing trend with higher vitamin C levels, with the highest values in fish fed D1500 followed by D1000 diet. Total immunoglobulin (Ig) content was significantly higher in fish fed D1000 and D1500 diets compared to others, while peroxidase and catalase activity remained unaffected by the vitamin C levels. Vitamin C supplementation enhanced the salinity stress tolerance of fish, with the highest lethal time of 50% mortality (LT50) observed in the D1000 group, while other groups showed intermediate values. The polynomial regression analysis of %WG, LT50, WBC and Ig revealed that the optimum vitamin C supplementation levels were 773.75, 866.67, 934.71 and 1062.5 mg/kg diet, respectively, for climbing perch; these values are also in line with most of the growth and health performance parameters of the fish.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Dietary Protein Levels on Growth, Body Composition, and Haematology of Tilapia in Biofloc Without Solid Management System","authors":"Sudip Debnath,&nbsp;Md. Shahin Parvez,&nbsp;Sayma Sadia,&nbsp;K. M. Rakibur Hossain,&nbsp;Md. Nazmul Ahsan","doi":"10.1002/aff2.70046","DOIUrl":"https://doi.org/10.1002/aff2.70046","url":null,"abstract":"<p>This study investigated the effects of varying dietary protein levels on the performance of tilapia reared in biofloc culture system without solid management. Five experimental diets containing crude protein (CP) levels of 32, 28, 24, 20, and 16% were tested in a completely randomized design in triplicate. Tilapia fingerlings (mean initial weight of 40.82 ± 0.38 g) were randomly stocked in biofloc tanks (effective water volume of 300 L) at a stocking density of 65 fish m⁻³. After 13 weeks of feeding trial, significant differences were observed in final weight (g), daily growth (g day⁻¹), feed conversion ratio, and yield (kg m⁻³) (<i>p</i> <i>&lt;</i> 0.05). Water quality parameters remained unaffected by dietary treatments (<i>p</i> <i>&gt;</i> 0.5). Notably, fish fed with diets containing 32%, 28%, and 24% CP demonstrated similar growth performance. Based on weight gain, a linear response plateau model estimated the minimal dietary CP level of 24.5%. Dietary CP levels altered visceral index (<i>p</i> <i>&lt;</i> 0.05), but not visceral fat index, hepatosomatic index, or spleen somatic index (<i>p</i> <i>&gt;</i> 0.05). Similarly, dietary CP levels did not significantly affect the fish composition (<i>p</i> <i>&gt;</i> 0.05) and the haematological parameters of the experimental fish (<i>p</i> <i>&gt;</i> 0.05). These results suggest that dietary protein in a small-scale biofloc system can be reduced from 32% to 24.5% without compromising fish health. However, appropriate solid management in biofloc systems is recommended to ensure optimal growth of fish.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Otolith and Pectoral Fin Spine Ages of Black Bullhead Ameiurus melas","authors":"Glenn T. Schumacher,&nbsp;Logan W. Sikora,&nbsp;Joshua K. Raabe,&nbsp;Justin A. VanDeHey,&nbsp;Greg G. Sass","doi":"10.1002/aff2.70047","DOIUrl":"https://doi.org/10.1002/aff2.70047","url":null,"abstract":"<p>Black bullhead <i>Ameiurus melas</i> are an environmentally tolerant fish that are often the target of population-level management efforts due to overabundance and potential negative influences on sport fishes. Descriptions of black bullhead growth and life history have been limited in part due to challenges in age estimation. Pectoral fin spines have been validated as age estimation structures for other ictalurids, but not black bullhead. We evaluated the precision of black bullhead pectoral fin spine and whole otolith age estimates from a northern Wisconsin lake. Age bias of pectoral fin spines was evaluated relative to whole otoliths using age estimates from two readers. Age estimates from both structures were applied to produce von Bertalanffy growth models. Precision of both structures was similar for both readers (66% and 58% agreement, 89% and 87% within 1 year). Pectoral fin spine age estimates showed higher between-reader agreement (59%, 95% within 1 year, CV = 9.2) than whole otolith age estimates (45%, 91% within 1 year, CV = 15.1). Pectoral fin spines may underestimate age relative to whole otoliths, particularly in older fish. von Bertalanffy growth model parameters were similar using both structures. Our findings suggest pectoral fin spine and whole otolith age estimates provide utility for age estimation in black bullhead, but modified methods of otolith processing and known age fish are needed to evaluate the accuracy of each structure.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143466180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aligning Fishing Gear Selectivity With Harvest Slot Limits for Ballan Wrasse Labrus bergylta","authors":"Calum J. Pritchard,&nbsp;Marthe M. R. Stendal,&nbsp;Kim T. Halvorsen,&nbsp;Lauren Stewart,&nbsp;Nabeil K. G. Salama,&nbsp;Iain Berrill,&nbsp;Samuel A. M. Martin,&nbsp;C. Tara Marshall","doi":"10.1002/aff2.70044","DOIUrl":"https://doi.org/10.1002/aff2.70044","url":null,"abstract":"<p>Selectivity is an important parameter used to identify the portion of a stock caught by a fishing gear. In principle, fisheries management aligns the length at which 50% of individuals are selected for (<span></span><math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mn>50</mn>\u0000 </msub>\u0000 <annotation>${L_{50}}$</annotation>\u0000 </semantics></math>) with minimum landing sizes. Harvest slot limits (the implementation of minimum landing sizes alongside maximum landing sizes) are in place for ballan wrasse, a sequential hermaphrodite commercially exploited in northern Europe. The selectivity of fishing gears used has yet to be investigated for this fishery. Two fishing gears were dismantled into their selective apertures, and fall-through experiments were used to determine the selectivity of each aperture, alternative escape panels and alternative entrances. Binomial logistic models were fit to estimate the relationships between selectivity, fish length and condition factor for each aperture. Linear models were used to investigate the relationships between <span></span><math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mn>50</mn>\u0000 </msub>\u0000 <annotation>${L_{50}}$</annotation>\u0000 </semantics></math>, escape panel width and entrance diameter. Both commercial fishing gears retained fish both smaller and larger than the size-based harvest slot limits. Empirical relationships were developed to estimate escape panel widths and entrance diameters to align the <span></span><math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mn>50</mn>\u0000 </msub>\u0000 <annotation>${L_{50}}$</annotation>\u0000 </semantics></math> with harvest slot limits. Fisheries managers may use these relationships to propose modifications to fishing gear that align their selectivity with harvest slot limits. However, it should be considered that these relationships were based on morphology and do not account for behaviour within the estimation of selectivity.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Soft-Shell Mud Crab (Scylla olivacea) Farming Trend in the Southwest Coastal Region of Bangladesh","authors":"Md. Masudul Haque,&nbsp;Anirban Sarker,&nbsp;Shilpi Saha,&nbsp;Akond Mohammad Rafiqul Islam,&nbsp;Shaikh Nazrul Islam,&nbsp;Mohammad Abdul Baki","doi":"10.1002/aff2.70045","DOIUrl":"https://doi.org/10.1002/aff2.70045","url":null,"abstract":"<p>Soft-shell crab aquaculture practices emerged as a profitable livelihood option in the study area due to its lower vulnerability to changing climatic conditions and high demand in the international market. Therefore, this study aims to identify the current growth of soft-shell mud crab farming to develop strategies to cope with future challenges. Random sampling was applied to collect primary empirical data from different stakeholders of the crab sub-sector based on structured and semi-structured questionnaires. In addition, focus group discussions (FGDs) and key informant interviews (KII) were arranged to collect information from a wide range of expert people to cross-validate the obtained information during the interviews. The study results indicated that the southwest region of Bangladesh has more than 380 farms having 5.55 ± 0.42 million seed crabs in demand in each cycle which is entirely dependent on wild stock. However, the wild crab harvesting amount has declined from 10.35 ± 2.07 to 4.38 ± 0.83 kg/day/person which represented a highly positive relationship with the active percentage of plastic cages that reduced from 99.43 ± 2.12% to 67.04 ± 4.75% during the investigated years. Farm mortality of stocking crabs has also increased by more than 8% in the last 9 years due to a lack of quality seed crabs. The soft-shell crab farmers preferred small stocking sizes to get quick moulting, ranging from 30.35 ± 2.59 to 43.50 ± 3.59 g. Most of the crab farmers used only tilapia fish as feed items leading to the increase in unit price from BDT 30.30 ± 1.98 to BDT 80.00 ± 2.46. The feeding demand and cost also increased many folds over the years with an increase in farm numbers and feed prices. So, crab hatchery development and formulated feed supply are inevitable for the sustainable growth of this sector.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Designing Digital Tools in Fisheries: What Fisherfolks Want in Malawi","authors":"Patrick Kawaye Chimseu,&nbsp;Samson Pilanazo Katengeza,&nbsp;Emmanuel Kaunda,&nbsp;Joseph Dzanja,&nbsp;Abigail Bennett","doi":"10.1002/aff2.70043","DOIUrl":"https://doi.org/10.1002/aff2.70043","url":null,"abstract":"<p>Use of digital tools is rapidly transforming the world, and Information and Communications Technology (ICT) integration in fisheries presents great opportunities for enhancing fishing-dependent livelihoods. This article employed latent class analysis and a multinomial logistic regression to explore preferred digital tools for fish traders to address the problem of lack of access to market information. Results from a sample of 548 participants show heterogeneous preferences among fish traders who can be classified into three subgroups: digital-wise (70%), phone-wise (24%) and digital-local (6%) across different platforms and prefer the use of all platforms (USSD, calls, apps, radio and television [TV] programmes). On the basis of platform ranking, traders prefer calls more, followed by app, USSD, radio and TV, respectively. Results further show that social demographic characteristics, including marital status, gender, age and trust among players, influence class membership in different subgroups. To address the diverse needs of traders, there is a need for a free, cross-platform digital system, call centre/USSD service for convenience, data quality checks, endorsements, the provision of digital credit and stakeholder collaboration to exploit digital fish trade opportunities for Malawi to benefit from the African Continental Free Trade Agreement and not to be left behind in the fourth industrial revolution.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143248849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Food Sources for Juvenile and Adult Penaeus monodon in Tanzania Coastal Waters","authors":"Ambakisye P. Simtoe,&nbsp;Blandina R. Lugendo,&nbsp;Yunus D. Mgaya","doi":"10.1002/aff2.70041","DOIUrl":"https://doi.org/10.1002/aff2.70041","url":null,"abstract":"<p>To investigate the food sources for juvenile and adult <i>Penaeus monodon</i> and reconstruct its diet, samples of potential food sources were collected from the nursery areas of Kondo, Mbegani and Kitame, as well as from the fishing grounds of Mwambakuni and Saadani, located in the Bagamoyo coastal waters of Tanzania in the Western Indian Ocean. The carbon and nitrogen isotopic ratios of both <i>P. monodon</i> muscle tissues and their respective potential food sources were determined from samples collected during the Northeast Monsoon (NEM, September–October) and Southeast Monsoon (SEM, April–May), representing the dry and wet seasons, respectively. <i>P. monodon</i> muscles exhibited a wide range of δ¹³C values from −20.87‰ to −12.22‰ (average of −16.23‰, <i>n</i> = 6) during NEM, alongside a narrower range of δ¹⁵N values from 5.32‰ to 8.86‰ (average of 6.63, <i>n</i> = 6). Similarly, during SEM, δ¹³C values ranged from −20.68‰ to −15.59‰ (average of −17.47‰, <i>n</i> = 6), while δ¹⁵N values ranged from 5.32‰ to 8.55‰ (average of 7.05‰, <i>n</i> = 6). Different size classes displayed distinct δ¹³C with a range of −8.27‰ but were closely related in δ¹⁵N, exhibiting an average range of only 2.66‰. The contributions of carbon and nitrogen from mangrove and terrestrial sources were found to be negligible as food sources for <i>P. monodon</i> across both seasons. However, both juvenile and adult <i>P. monodon</i> significantly relied on seagrass ecosystems for their food, with minimal connectivity (<i>p </i>˂ 0.05) between the nursery and fishing grounds. Furthermore, it was observed that the primary carbon sources for <i>P. monodon</i> included shellfish (prawns), sergestid shrimps, plankton and algae during the SEM, with a slight shift towards algae and polychaetes during the NEM. Notably, <i>P. monodon</i> specialized in a specific food source during NEM, with juveniles showing significantly higher levels of cannibalism compared to adults.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parasites of Farmed and Wild Tilapine Fishes From Selected Farms and Lake Jipe in Taita Taveta County, Kenya","authors":"Finnan O. Ageng'o,&nbsp;Robert M. Waruiru,&nbsp;Daniel W. Wanja,&nbsp;Philip N. Nyaga,&nbsp;Mercy M. Hamisi,&nbsp;Joseph M. Ndegwa,&nbsp;Shimaa E. Ali,&nbsp;Mohan V. Chadag,&nbsp;Paul G. Mbuthia","doi":"10.1002/aff2.70042","DOIUrl":"https://doi.org/10.1002/aff2.70042","url":null,"abstract":"<p>Parasitic infections threaten the endangered <i>Oreochromis jipe</i> and other ichthyic populations in Lake Jipe, thereby hindering conservation efforts. Initiatives have been made to farm <i>O. jipe</i> as a conservation strategy. To develop effective conservation approaches and ensure the species' survival in its natural habitat and aquaculture systems, it is imperative to understand the diverse parasites in these habitats. Consequently, this cross-sectional study was conducted to determine parasitic loads in tilapias from selected farms and Lake Jipe. A total of 111 fishes were collected (76 farmed, 35 from the lake), comprising 66 <i>O. jipe</i>, 34 <i>Oreochromis niloticus</i> and 11 hybrids of <i>O. jipe</i> and <i>O. niloticus</i>. The fish were euthanized, necropsied and examined for parasitic infections via visual inspection and light microscopy. Out of 111 fishes examined, 58 (52.3%) were infected with 212 parasites, including 135 (63.7%) and 77 (36.3%) from farm and lake habitats, respectively. The prevalence of parasitic infections in fish from the lake and farm habitats was 68.6% and 44.7%, respectively. The most frequently occurring parasite genera identified were <i>Diplostomum</i> (30.63%), <i>Acanthocephalus</i> (20.7%), <i>Dactylogyrus</i> (9.9%) and <i>Contracaecum</i> (2.7%), with mean intensities of 2.9, 3.7, 1.9 and 1.7, respectively<i>. Contracaecum</i> and <i>Camallanus</i> were exclusively found in fish from Lake Jipe, while <i>Euclinostomum</i> and <i>Gyrodactylus</i> were only observed in farmed fish. <i>O. jipe</i> had the highest prevalence of parasitic infections (59.1%), followed by <i>O. niloticus</i> (44.1%) and hybrids (36.4%) (<i>p</i> &gt; 0.05). In conclusion, the examined fishes were infected with diverse parasites, which have both public health concerns (<i>Euclinostomum</i> and <i>Acanthocephalus</i>) and economic significance (<i>Dactylogyrus</i> and <i>Gyrodactylus</i>). Consequently, it is imperative to enhance public awareness and enforce biosecurity measures to mitigate potential health risks and to improve the productivity of the pond culture system and lake ecosystem. These measures will help reduce parasite dissemination and promote sustainable fish production and populations.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Length-Based Stock Assessment of the Mackerel Scad, Decapterus macarellus (Cuvier, 1833) From the Tanzanian Coastal Waters","authors":"Joseph Salawa Sululu,&nbsp;Blandina Robert Lugendo,&nbsp;Paul Tuda,&nbsp;Benaiah Lameck Benno","doi":"10.1002/aff2.70039","DOIUrl":"https://doi.org/10.1002/aff2.70039","url":null,"abstract":"<p>This study aimed to conduct a stock assessment of <i>Decapterus macarellus</i> from Tanzanian coastal waters to determine its current stock status and provide appropriate management recommendations. We used a suite of length-based methods, including the Electronic Length Frequency Analysis (ELEFAN) programme to estimate growth parameters and catch curves to evaluate exploitation fishing and mortality parameters; Length-Based Spawning Potential Ratio (LBSPR) to calculate the spawning potential ratio (SPR), length-based indicators (LBI) to assess sustainable fishing levels and length-based reference point (LBRP) to determine the target reference point (RP) for stock spawning biomass (SB). The results indicated that this small pelagic species grows fast, with a growth rate (<i>K</i>) of 0.74 year⁻¹ and a growth performance index (Ф′) of 2.88. However, the stock is currently at risk of overfishing due to high fishing pressure (<i>F</i>/<i>M</i> &gt; 1) and an elevated exploitation rate (<i>E</i> = 0.71), which resulted in a very low SPR (SPR = 0.11) and SB below the target RP. Yield-per-recruit analysis revealed that the current fishing effort (<i>F</i>_curr = 2.57) far exceeded the precautionary limit (<i>F</i>_0.1) and surpassed the fishing mortality rate that maximizes yield per recruit (<i>F</i>_max = 1.73). This excessive effort largely impacted mega-spawners, reducing their proportion in the catch to a critically low percentage (9%). On the basis of these findings, the study recommends reducing the current fishing effort to <i>F</i>_0.1 (0.84) by limiting the number of ring nets, implementing seasonal closures during peak spawning periods and operating in deeper waters (40–200 m) to protect juveniles and minimize mega-spawner capture.</p>","PeriodicalId":100114,"journal":{"name":"Aquaculture, Fish and Fisheries","volume":"5 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/aff2.70039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}