Commercial Fisheries Research Articles

Impacts of Reef Degradation on Commercial Fisheries

Impacts of Reef Degradation on Commercial Fisheries

Morphometric Characterization and Fillet Yield of Two Commercial Fish Species from Panyam Fish Farm Plateau State

A total of 50 individual samples of Parachanna obscura and Clarias gariepinus were collected fresh from Panyam fish farm with the aid of crush ice for preservation until assessment was carried out to determine the fillet yield of Parachanna obscura in comparism with Clarias gariepinus. The whole fresh fish samples were taken to the department of Fisheries and Aquaculture laboratory of the Federal University, of Agriculture, Makurdi for assessment. Their Total and Standard Lengths were recorded (in cm) using a Measuring Rule, while Total Body Weights were recorded (in grams) using an electronic weighing balance. Data were collected on: the Total Weight (g), Total Length (cm), Standard Length (cm), Visceral Weight (g), Head Length (cm), Weight of Bones (g), Weight of Fins (g) and Weight of Fillet (g) in comparism between the two fish species. Descriptive statistics for morphometric data were determined using Minitab 18® (Minitab 2017). Regression and correlation of variables was carried out in R (R Core Team 2020). Results of the mean measured parameters of Parachana obscura and Clarias gariepinus from Panyam Fish Farm Jos, showed that Total Length (42.66 ± 0.58cm), Standard Length (38.56 ± 0.29cm), Fin Weight (15.51 ± 0.37g), Visceral Weight (11.04 ± 0.17g), Head Weight (1.49 ± 4.01g), Bone weight (39.84 ± 0.80g) and Weight of fillet (89.02 ± 2.38g) of Parachana obscura were higher than the mean measured parameters of Clarias gariepinus. There was a significant difference (p= .05) among the measured parameters between P. obscura and C. gariepinus. The higher fillet percentage per body weight of P. obscura in comparism to C. gariepinus is a pointer to a relatively higher economic value for commercial purposes of this species. This assessment also provides information for further studies on this species to be built on, as there is obvious need for Nigeria’s aquaculture system to diversify from the prevalent catfish culture.

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean: Suppl. Fig. 3

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean: Suppl. Fig. 3

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean: Suppl. Fig. 2

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean: Suppl. Fig. 2

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean: Suppl. Fig. 1

Postrelease survival of undersized swordfish (Xiphias gladius) caught on pelagic longline gear in a U.S. commercial fishery in the western North Atlantic Ocean: Suppl. Fig. 1

Species-specific trends of plutonium, radiocesium, and potassium-40 levels in three fish species of the Yenisei river (Siberia, Russia)

The Yenisei is the largest river in the Northern Hemisphere receiving controlled radioactive discharges from nuclear facilities. The paper presents a comparative study of temporal trends of artificial radionuclides plutonium (239,240Pu) and radiocesium (137Cs), and a natural isotope of the essential macronutrient potassium (40K) in samples of three commercial fish species (Northern pike, Baikal grayling, and Siberian dace) occupying different positions in a trophic network in the Yenisei River (Siberia, Russia). Samples of fish were caught in the Yenisei in 2011–2020 during a period of significant changes in controlled radioactive releases into the river. The study has shown no increase in plutonium concentration in fish samples within two years after the upsurge in controlled Pu discharge into the river (2018–2020). Average activity concentration of 239,240Pu (mBq∙kg−1 d.w., range, mean ± sd) in muscle of grayling (0.6–31.8, 10.9 ± 8.6) was higher (p < 0.01) than in muscle of dace (1.0–4.4, 2.4 ± 1.2) and pike (1.1–11, 3.8 ± 2.9). This can be attributed to the feeding of grayling on benthic invertebrates rich in Pu. The concentration of Pu tended to increase in muscle of pike with the increasing size of the fish. Average activity concentration of 137Cs (Bq∙kg−1 d.w., range, mean ± sd) in muscle of pike, a piscivorous fish (1.8–23.4, 7.7 ± 5.1), was significantly higher (p < 0.001) than the average activity concentration of 137Cs in muscle of dace (0.7–5.7, 2.7 ± 1.6) and grayling (1.3–7.2, 2.5 ± 1.7). A similar effect was revealed for 40K. This can be attributed to biomagnification of 137Cs and 40K in food chains. The results will draw a baseline for assessment of dose-dependent ecological risks for wild fish itself and fish consumers, add field-based facts to the fundamental knowledge of behavior of artificial radionuclides in freshwater food chains, and suggests a hypothesis for consequent experimental studies.

Can commercial aquafeeds improve the nutritional value of brine shrimp? Proximal composition and lipid profile of alternative enhancers

Artemia, commonly known as brine shrimp, holds a significant role as live prey in ornamental and commercial fish aquaculture. This study addressed the nutritional deficiency in adult Artemia biomass, exploring alternative enrichers available in Brazil. Evaluating a commercial aquafeed (Polinutre Poli Camarão 400PL) and a lipid emulsion (BioViv HUFA Continum), adult Artemia were subjected to different enrichment protocols, including periods of 1, 12, and 24 hours with each enricher, as well as a test group raised 100% on the commercial feed. Protein content for Artemia exclusively fed the commercial aquafeed (CF100) reached values very similar to those provided by the main commercial products available worldwide and other commonly used live prey. Enrichment time effects were observed from 12 h onwards, showing positive impacts on protein accumulation. Lipid content peaked at 12 h, followed by a decrease at 24 h. Further studies are needed to assess whether the combination of feed-based protocols followed by 12-h lipid emulsion enrichment can surpass the current results, providing high levels of protein content while maintaining a complete lipid profile.

A critical review on heavy metal contamination in aquatic food webs by edible fish species: a special case concerning Bangladesh.

Heavy metals (HMs) are ubiquitous in terrestrial and aquatic environments due to unplanned industrial waste discharge, the release of untreated wastewater, and improper mining activities. In particular, the concentrations of HMs are found to be higher in aquatic environments. As a result, the aquatic biota was heavily affected by HM contamination. This critical review aims to understand the sources and toxicity of HMs in commercial fish species, explore their ecological exchange, and examine the related human health challenges in Bangladesh. A modified PRISMA review technique is used in this paper to analyze the current status and research limitations of HM studies in Bangladesh fish species and their toxicity within aquatic food webs. Briefly, we searched several keywords to explore the research trend of HM concentrations and toxicity in fish species. Furthermore, potential toxicity and risk assessment of HMs through the aquatic food chain in Bangladesh were explored. On the other hand, a cross-tabulation approach was used to process the toxicity findings of HMs. Previous studies indicate that fish species can possess comparatively higher HMs than river water due to ecological exchange factors, including bioaccumulation and biotransformation. This review focuses on Bangladesh, highlighting areas for improvements and the need for further study to achieve a transparent understanding of HM deposition in fish species and the sustainable management of aquatic food chain toxicity.

Mediterranean Islands as Refugia for Elasmobranch and Threatened Fishes

ABSTRACTAimThe Mediterranean Sea is one of the most anthropized seas in the world but also a marine biodiversity hotspot with many fish species under threat. The main goal of the study is to test whether on the heavily fished and anthropized Mediterranean coast, the less impacted Corsica and Balearic Islands, can be considered as refugia for threatened and elasmobranch fishes independently of protection by marine reserves.LocationThe French Mediterranean coast and three north‐western Mediterranean islands: Corsica and also Mallorca and Minorca from the Balearic archipelago.MethodsWe performed 187 fish surveys using environmental DNA metabarcoding on three islands and 109 along the continental coast. Of the 78 surveys on islands 22 correspond to no‐take marine reserves and of the 109 continental surveys 26 were carried out within reserves. After eDNA filtration, extraction, amplification, and sequencing we estimated the number of fish species but also the number commercial, threatened and elasmobranch fish species on each sample. We then performed an ANOVA by permutation to test the effect of insularity and protection on these four biodiversity metrics. We also modelled these four biodiversity metrics as a function of protection and human pressure but also environmental, habitat and sampling conditions. We also built species accumulation curves to obtain asymptotes representing the potential regional pools for each species category on both island and continental coasts.ResultsWe obtained a total of 175,982,610 reads over the 187 eDNA samples that were assigned to 153 fish species including 17 elasmobranch species among which 7 were only detected on islands. We observed a higher total fish richness on continental than island surveys regardless of protection but a higher threatened and elasmobranch fish richness on the island than on continental surveys. We obtained a significant, negative and predominant human gravity impact on the diversity of elasmobranch species. The modelled asymptote reached 148 teleostean fish species on islands and 196 on the continental coastline with a very similar rate of diversity increase with sampling effort but the shape of the species accumulation curves differed markedly for elasmobranchs with a stronger increase in diversity with sampling effort on islands.Main ConclusionsOur findings highlight that Mediterranean islands can be refugia for sharks and rays but also threatened fishes in this overexploited region. Our results also suggest that reducing or banning trawling activities may play a key role for conserving vulnerable fishes, beyond the benefits of no‐take marine reserves, which appear limited on these large home‐range species.

Chromosome-level reference genome for the Jonah crab, Cancer borealis.

The Jonah crab, Cancer borealis, is integral to marine ecosystems and supports a rapidly growing commercial fishery in the northwest Atlantic Ocean. This species also has a long history as a model for neuroscience that has expanded our understanding of central pattern generators, neuromodulation, synaptic plasticity, and the connectivity of neural circuits. Here we present a highly contiguous reference genome for the Jonah crab that will provide an essential resource to advance fisheries, conservation, and biomedical research. Using a combination of PacBio long-read sequencing and Omni-C scaffolding, we generated a final genome assembly spanning 691 Mb covering 51 chromosome-length scaffolds and 106 additional contigs. Benchmarking Universal Single-Copy Ortholog (BUSCO) analysis indicated a high-quality assembly with a completeness score of 90.8%. Repeat annotation identified 1,649 repeat families making up 48.27% of the Jonah crab genome. Gene model predictions annotated 24,830 protein coding genes with a 92.3% BUSCO score. Gene family evolution analysis revealed the expansion of gene families associated with nervous system function, and targeted analysis revealed an extensive repertoire of neural genes. The Jonah crab genome will not only provide a resource for neuroscience research but will also serve as a foundation to investigate adaptation to stress and population structure to support sustainable fisheries management during this time of rapidly changing environmental conditions in the northwest Atlantic Ocean.

Socio-Economic Profile and Vulnerabilities Assessment in Small-Scale Fisheries of Lower Gangetic Flood Plain Wetland: An Initiative Towards Achieving Wetland Ecosystem Sustainability and Community Well-Being

ICAR-CIFRI has been continuously working to develop wetland fisheries in a transdisciplinary knowledge-to-action mode to upscale the livelihood of vulnerable small-scale fishermen communities. The integrated development approach was initiated in different lower Gangetic floodplain wetlands of North 24 Parganas, West Bengal, India, to increase the fish production and socio-economic development of small-scale fishermen communities of the wetlands. Duma is one of the most extensive horseshoe-shaped wetlands in Asia. To augment the fish production from this wetland, the pen culture system was adopted by the fishers under the supervision of ICAR-CIFRI in 2021. Within a year, they received 15 tons of commercial fish, valued at around 30 lakhs apart from the small indigenous fish. It has recently been advised that auto-stocked, high-value minor carp in the wetland be adopted to improve income and conserve small indigenous species. In this article, SDG 14 (Life below water) addresses sustainable ecosystem management and livelihood enhancement for the wellbeing of the local people (SDG 3). Nutritional security of the local people is maintained through the small indigenous fish species which is crucial for addressing ‘No hunger’ as per SDG-2. The research also proves that women can play a crucial role in small-scale fisheries and they can economically stand alone, which is the main aim of SDG-5 (gender equality). However, significant issues such as lack of jurisdictional coordination, ecological changes, inequitable distribution of benefits, and income reduction persist in wetland management. The need for urgent reformation of policy and resource management systems is crucial to boost the economic efficiency of the SSF in the wetland. Training for more knowledge on fishing and fish farming, acquiring alternative livelihood and education on financial management should be brought to the fishermen’s communities. These could develop a resilient community that is more equipped to respond to future crises.

Macrophytes Used as Multifaceted Benefits Including Feeding, Bioremediation, and Symbiosis in Freshwater Aquaculture—A Review

ABSTRACTThe utility of macrophytes in freshwater aquaculture is diverse. We review the benefits of macrophytes in aquaculture into broadly three useful perspectives: (i) Feeding, (ii) Bioremediation, and (iii) Symbiosis. Macrophytes are used as direct food by herbivores for their potential nutrient values with a maximal protein content of 35% (D/W basis) and as ingredients for fish feed preparation with optimal 50% protein inclusion to reduce feed cost in commercial aquaculture. Macrophytes are used for wastewater treatments to eliminate contaminants, including As, Cu, Cd, Cr, Hg, and Pb, to 99.9%, and to reduce BOD (Biological Oxygen Demand) to improve water quality. Intake of remedied wastewater into aquaculture enhances water productivity through phytoplankton growth. An estimate is that 1.0 L of remedied wastewater, particularly sewage effluent adds an average of 0.05 g N &amp; P and 0.99‐L freshwater into aquaculture to yield an average of 0.309 g fish. Macrophytes are integrated with fish in commercial aqua‐farming. Plants and fish are farmed together in aquaponics. They are used as substrates for some commercial fish species to lay eggs in farming. They are raised with ornamental fish for benefits in aquariums. Nevertheless, extensive studies are required to harness more benefits from macrophytes.

Fabulous but Forgotten Fucoid Forests.

Fucoid forests are areas dominated by marine brown seaweed in the taxonomic order Fucales that, like the better-known marine foundation species-corals, kelps, seagrasses, salt marshes, and mangroves-are threatened by anthropogenic stressors. Fucoid forests are fabulous and important because they, like the better-known marine foundation species (i) span large areas, bioregions, and ecosystems, (ii) provide ecological functions such as high productivity, biodiversity, and habitat for iconic and endemic species, and (iii) support a variety of ecosystem services, like commercial fisheries, regulation of nutrients and carbon, and cultural values. Fucoid forests are, based on a new citation analysis, forgotten worldwide, because they are described orders of magnitude less than the better-known marine foundation species, in ecology and marine biology textbooks, in Google Scholar and Scopus databases over scientific literature, and in recent reports and reviews about seaweed forests. Fucoid forests would be less forgotten if more people acknowledge their biological importance and societal value more often and equate their importance to that of the better-known marine foundation species. To decrease the knowledge gap between fucoids and the better-known foundation species, researchers and science communicators could join forces under a broad "fucoid umbrella," establish stronger online presences, coordinate and collaborate on publications, and produce free eye-catching non-technical materials for teachers, managers, politicians, grass-root organizations, philanthropists, and funding agencies.

Stability and reliability of regional cumulative impact mapping: A Canadian Pacific case study

Cumulative impact mapping is a commonly applied spatial representation of the impacts of human activities on the ocean. This spatial model has been applied at varying scales around the world, in part due to its ability to visually communicate complicated information in a simple way. The application of the model to decision-making processes requires an understanding of the reliability and stability of its outputs. This paper represents both an updated regional application in Pacific Canada and an evaluation of the tool over two iterations, 2015 and 2023. The regional application utilised higher model resolution and new and improved data inputs including 38 habitats and 46 activities across five sectors. High impact hotspots were found around major population centres and ports, as well as in fishing and shipping areas along the continental shelf. Commercial fishing, shipping, and climate change (sea surface temperature change) remained the major drivers of cumulative impacts in the region, and cumulative impacts per unit area continued to be highest in kelp and seagrass. Results suggest evidence of decreased impacts where improved protection for sponge reefs were implemented but show an overall increase in cumulative impacts for the region. Results showed consistency and reliability in the location of cumulative impact hotspots. Refinements in data quality and resolution of spatial data inputs contributed towards increasing the spatial precision of hot spot areas identified. Confidence in the cumulative impact mapping outputs and applications for marine spatial planning, marine protected area designation and management, research, and decision support are discussed.

Abundance and ecological risk of microplastics in commercial fish species from Northeastern Mediterranean Sea

Microplastic pollution in marine environment has attracted the attention of scientists and policy makers. A substantial number of studies have examined the microplastic content in the gastrointestinal tract (GIT) of fish to monitor microplastic (MP) pollution levels in the ambient environment. The aim of the study was to access the microplastic abundance in the commonly consumed fish species and associated ecological risk assessment for consumers. To that end, microplastic presence in the gills and GIT of Boops boops, Mullus barbatus Mullus surmuletus, Saurida undosquamis, Sardina pilchardus, Trachurus mediterraneus, Pagellus erythrinus, Oblada melanurus, Diplous annularis was investigated. The polymer analysis of extracted MPs were done using Fourier transform infrared (FTIR) spectroscopy. Including all examined specimens, mean MP abundance in the GIT and gills were found as 0.8±1.2 MPs/ind and 0.3±0,7 MPs/ind, respectively. Consistent with the global picture, mainly detected MPs were fiber in shape (79%), black (39%) and blue (37%) in color, and less than 500 μm in size (63%). Polyethylene (21%), polyethylene derivatives (33%) and polypropylene (26%) were the most frequently detected polymers. Ecological risk assessment was calculated by employing polymer risk index, and varied between 4,6 to 27 indicating low to medium hazard risk for examined species. Hazard risk score showed that demersal and bentopelagic fish species were more prone to MP toxicity depending on the toxicity levels of identified polymers. Results indicated that polymer distribution in the marine environment is as significant as the habitat preferences of fish in determining the ecological risk posed by microplastic toxicity.

Spatial multi-criteria analysis based on food web model results: application to a marine conservation area

Effective marine management requires balancing conservation and sustainable use of resources. Food web models are useful for simulating direct and indirect effects of management scenarios on ecosystem functioning by using multiple indicators. However, a key challenge is consolidating these indicators into a single, comprehensive, measure, which is often required to guide management decisions, such as in Strategic Environmental Assessment. This study applies spatial multi-criteria analysis to food web model outputs to develop a single index for different marine management applications. We applied this framework to the case of the “Tegnùe di Chioggia”, a Special Area of Conservation (SAC; IT3250047) under the Natura 2000 European network, located in the northern Adriatic Sea (Italy). This area, characterised by the presence of biogenic rocky outcrops, currently lacks a formal management plan. Using the Ecospace module of the Ecopath with Ecosim software, we simulated three management scenarios: 1) SAC expansion; 2) winter artisanal fishing in the SAC; 3) a combination of both. In line with ecosystem-based management, we focused on economically important trophic groups in the region, such as the Mediterranean mussel, Mytilus galloprovincialis, and striped venus clam, Chamelea gallina, which are present near the SAC. We also considered the efforts of the local fishing fleets. Ecosystem structure and functioning indicators, generated by the spatial food-web model, were linked to three criteria aligned with the management priorities of the area: nature conservation, aquaculture productivity, and fishing productivity. These criteria were aggregated into a final score to compare the management scenarios. The results showed that none of the scenarios would significantly alter community composition or ecosystem functioning compared to the current situation. However, they did show contrasting responses in the food web model. The SAC expansion scenario notably increased total biomass and commercial fish biomass, especially pectinids and cephalopods. The fishing scenario had a minimal impact on trophic groups. Ecosystem resilience and structure indicators were less sensitive to management scenarios than biomass indicators. However, the multi-criteria analysis revealed that the fishing scenario limited the benefits of expanding the SAC, due to reduced catches. The final score effectively ranked proposed scenarios, highlighting key indicators that influenced these variations. The proposed approach shows potential for supporting participatory modelling and engaging stakeholders in developing management scenarios.

Mathematical approaches to fisheries quota management: ensuring sustainable practices in U.S. commercial fishing

Fisheries quota management plays a critical role in ensuring the sustainability of commercial fishing practices, particularly in the United States, where overfishing and resource depletion pose significant challenges to marine ecosystems. This review explores the mathematical approaches utilized to manage fisheries quotas effectively and sustainably. The paper examines key mathematical models, including population dynamics, bioeconomic models, game theory, and Catch-per-Unit-Effort (CPUE) models, highlighting their role in maintaining fish stock levels and regulating fishing activities. Through case studies from U.S. fisheries, such as the New England groundfish and Alaska pollock fisheries, the review assesses the effectiveness of these models in real-world applications. Additionally, it explores how advances in technology, such as satellite tracking, big data, and artificial intelligence, are enhancing the accuracy and adaptability of fisheries management models. The review concludes with insights into future directions for mathematical approaches in fisheries management, emphasizing the need for continuous innovation to support sustainable commercial fishing practices. By integrating advanced mathematical techniques and data-driven models, this paper aims to provide a pathway for policymakers and fisheries managers to achieve long-term sustainability in U.S. commercial fisheries.

Age-Dependent Enhancement in Fecundity and Ova Diameter of &lt;i&gt;Schizopyge niger&lt;/i&gt; (Heckel, 1838) in Dal Lake, Kashmir

Understanding the reproduction and recruitment pattern is essential for successful conservation of a species. Accurate estimates of fecundity plays acrucial role in comprehending fish population dynamics. The snowtrout, Schizopyge niger, is a Cyprinid fish widely distributed throughout the lakes of Kashmir valley and is one of the most important commercial fish species. In this study, we examined the age-dependent reproductive perfor-mance of female S. niger, aiming to gain insights into its breeding characteristics for the development of an optimal brood-stock management plan. The study involved 78 female S. niger specimens collected from Dal Lake during the spawning season, representing age groups of 2+, 3+, 4+, 5+, and 6+ years. Fecundity and ova diameter showed an increasing trend from age 2+ (3,971 eggs; 1.45 mm) to age 6+ (10,501 eggs; 2.00 mm). Total fecundity exhibited positive correlations with age, total weight, ovary weight, and ova diameter. Additionally, there was a positive correlation between ova diameter and fish age, with the highest fecundity and largest ova diameter observed in the 6+ years age group. Among each age group, fecundity and ova diameter varied significantly (p &lt;0.05). Based onthese findings, for optimal broodstock management of S. niger, it is recommended to use females of the6+ years age group after assessing the quality of eggs.

Spatial Distribution and Growth Variability of Juveniles of Two Myctophid Species (Myctophum asperum and Symbolophorus evermanni) in Relation to Environmental Factors in the Kuroshio Current System in Winter

ABSTRACTThe distribution and growth rate of juveniles of two myctophid species (Myctophum asperum and Symbolophorus evermanni) were examined in relation to environmental factors, based on samples collected in the Kuroshio Current system during winter from 2020 to 2022. The growth rate of juveniles was compared among three oceanic regions: the inshore side of the Kuroshio axis, the Kuroshio axis, and the offshore side of the Kuroshio axis in relation to sea surface temperature (SST), sea surface salinity (SSS), chlorophyll‐a concentration (CHL), and biomass of zooplankton (ZPB). M. asperum juveniles were distributed mainly in the inshore region and the Kuroshio axis of higher CHL and ZPB, whereas S. evermanni juveniles were distributed mainly in the Kuroshio axis and in the offshore regions of higher SST and SSS. No significant difference in growth rate was found among the three regions for M. asperum juveniles, whereas the growth rate of S. evermanni juveniles in the Kuroshio axis was higher than in the offshore regions. No environmental factors were selected for growth rate of M. asperum in the GLMM, whereas SST was selected for S. evermanni. M. asperum juveniles can be considered to have a higher tolerance for variability in environmental factors, whereas water temperature could be the driver for the distribution and growth rate of S. evermanni. Lastly, we discuss possible interspecific interactions among noncommercial fish (myctophids) and commercial fish (Pacific saury Cololabis saira).