Fishery Resources Research Articles

Evaluation of the efficacy of implementing Ecosystem-Based Management (EBM) strategies within fisheries across the middle and lower Yangtze River basin lakes in China

To mitigate the decline of fishery resources and the exacerbation of water pollution in Chinese lakes and to enhance the potential and sustainable use of lake fisheries, the Chinese government has actively implemented principles and models of ecosystem-based lake fishery management. This includes promoting ecological aquaculture techniques and the “retiring pens to restore lakes” policy. To assess the effects of ecosystem-based management on Chinese lake fisheries, data from 2007 to 2020 were collected for the Qiandao Lake, Tai Lake, Hongze Lake, Luoma Lake, and Gaobao Lake in the middle and lower reaches of the Yangtze River. The study employed Data Envelopment Analysis (DEA) to assess fishing efficiency through a static input-output efficiency model. Additionally, the Malmquist index and distance functions were used for a dynamic comparison of total factor productivity (TFP) across the five lake management models. The results indicate that trends in technological progress, scale efficiency, and TFP were consistent across the lakes from 2013 to 2020. Qiandao Lake, Tai Lake, and Hongze Lake showed a positive average annual growth rate in TFP, with Qiandao Lake having the highest average annual growth rate of 13.2%. In contrast, Gaobao and Luoma Lakes experienced a negative growth rate in TFP. Furthermore, Qiandao Lake exhibited significantly higher technical efficiency than the other four lakes, effectively achieving an efficient state, followed by Hongze Lake. The study demonstrates that technological progress and variations in scale efficiency are the primary factors driving the increase in TFP in fisheries. Promoting ecosystem-based “fishing for water conservation” aquaculture techniques and restricting aquaculture scale through the “retiring pens to restore lakes” policy contribute to enhancing TFP in ecological fisheries.

Population characteristic of torpedo scad (Megalaspis cordyla Linnaeus, 1758) in the Lampung Bay: Size structure, growth type, and condition factor

Megalaspis cordyla, locally known as ikan bekre, stands as a crucial economic species commonly consumed by the people of Lampung. The escalating demand for this fish has significant implications for increased fishing activities, potentially impacting its population. This research aimed to explore the biological characteristics of M. cordyla landed at the Lempasing Fishing Port, Bandar Lampung, providing fundamental insights for fisheries resource management in the waters of Lampung Bay. Using a quantitative descriptive method, the sampled fish has been analyzed to get size structure, growth type, and fish condition factors based on length and weight data collected from M. cordyla landed weekly. Between April and June 2022, a total of 300 samples were collected, with length ranging from 230 to 430 mm TL, with the largest count (77 individuals) in the 314-334 mm interval. M. cordyla has an allometric negative growth pattern in Lampung Bay, with a growth coefficient (b) value of 2.47. Fish condition factor values ranged from 0.71 to 1.33, with June having the highest average value of 1.03. This information contributes greatly to a better understanding and long-term planning for the management of this fish population.Keywords: Allometric; Condition Factor; Length-Weight Relationship; Pelagic Fish; Aquatic Resources Management

Genetic diversity of the Ruditapes decussatus and evidence of its hybridization with the alien R. philippinarum in the Western Mediterranean Sea

The introduction of alien species in marine ecosystems is often driven by the increasing demand of fishery resources. This is the case of the Manila clam (R. philippinarum), imported in Europe from Japan since the 1970s, to meet the growing demand for clams that the native species, the grooved carpet shell clam (Ruditapes decussatus), could not satisfy. Alien species introduction could threaten the genetic diversity and integrity of the native clam, also causing hybridization (i.e., gene flow from one species into the gene pool of another). Since R. philippinarum recently spread in a few important Mediterranean coastal areas, a combined approach based on morphological characteristics, length differences of two nuclear species-specific markers (ITS2, 5SrDNA) and the sequence of the mitochondrial gene cytochrome c oxidase subunit I (COI), was used to investigate the presence of hybrids in six Mediterranean wetlands (Sardinia, Italy). Eight individuals morphologically identified as R. decussatus were hybrids, having sequences specific to both R. decussatus and R. philippinarum in their nuclear DNA (ITS2 and 5SrDNA). Most of these individuals were found to be post-first generation (F1) hybrids indicating that F1-hybrids may be fertile. Secondly, to study the genetic diversity of R. decussatus in the Sardinian wetlands as well as in its whole distribution area, >380 new COI sequences from the eastern Atlantic Ocean and Mediterranean Sea were analysed along with those available from public databases. Mitochondrial COI data revealed variable haplotype and nucleotide diversities in different areas, which were not dependent on sample sizes. The aquaculture breeding activities and clam transplantation between different countries, along with the long pelagic larval dispersal and the commercial import of other bivalve species might have promoted gene exchange between different sites and thus higher diversity levels in a few wild populations. Our research, evaluating the genetic makeup of wild and hatchery stocks and clarifying the degree of hybridization, can contribute to develop further recommendations for conserving the genetic integrity of R. decussatus.

Impacts of polluted water discharged by the fishing-related industry on fisheries resources and economic development in an R&D-based growth model

Impacts of polluted water discharged by the fishing-related industry on fisheries resources and economic development in an R&D-based growth model

The complete mitochondrial genome of Mya japonica (Jay, 1857 Myida:myidae)

The soft-shell clam Mya japonica (Jay, 1857) is a commercially important fishery resource. In this study, we identified the complete mitochondrial genome of M. japonica and performed a phylogenetic analysis to explore its genetic relationship with Mya arenaria. The genome is 21,396 bp in length and contains 13 protein-coding genes (PCGs), 23 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and 5 D-Loop control regions. The atp8 gene was annotated in Myidae for the first time. Notably, the genome contains an additional trnM, consistent with M. arenaria. The length of the cox2 gene is 1,947 bp, which is 513 bp longer than that in M. arenaria. Its base composition is 29.14% A, 37.26% T, 10.89% C, and 22.71% G. Phylogenetic analysis based on 12 PCGs and 2 rRNAs indicates that M. japonica and M. arenaria form a sister group. In this study, the identification and phylogenetic analysis of the complete mitochondrial genome of M. japonica provide significant information for future taxonomic and evolutionary research of the genus Mya.

DNA metabarcoding unveils the hidden species composition in fish surimi: Implications for the management of unlabeled and mixed seafood products

Fish surimi products are traditional foods primarily made from fish meat and may contain a complex species composition. In Taiwan, the abundant fishery resources and diverse fish species lead to local catches being widely used as ingredients in fish surimi products. However, due to growing market demand and increasingly scarce resources, some surimi products contain sensitive species, such as sharks, posing potential threats to the ecological environment and biodiversity. In this study, by applying metabarcoding techniques, we analyzed 120 fish surimi product samples from different brands and types throughout the four seasons in Taiwan's market. The main fish species identified included milkfish (Chanos chanos), dolphinfish (Coryphaena hippurus), Pomfret (Taractes rubescens), swordfish (Istiophorus spp.) and cartilaginous. Moreover, at least 37 species of cartilaginous fish, including 26 endangered species, were found. Through comprehensive and accurate species identification of surimi product ingredients, we unveiled the usage of sensitive species in products on the market. This finding is important for the surimi industry's quality control and market supervision. Furthermore, it can promote the sustainable use of Taiwan's fishery resources and protect biodiversity.

The complete mitogenome reveals genetic diversity and differentiation among wild and farmed black carp (Mylopharyngodon piceus) populations

Black carp (Mylopharyngodon piceus) is an important freshwater fish species in China, and fishery resources have been severely depleted for decades. Understanding the population genetic background is a prerequisite for conservation of black carp genetic resources. Complete mitogenome was analyzed for the first time to study the population genetic diversity and structure of black carp across China. The complete mitochondrial genomes obtained from six wild and three farmed populations ranged from 16,598 to 16,614 base pairs. Black carp populations across China are characterized by moderate to high genetic differentiation (0.08 ≤ FST ≤ 0.55, P ＜ 0.05), with a low overall degree of gene flow (0.34 ≤ Nm ≤ 2.61) individuals per generation. The nucleotide diversity (Pi) ranged from 0.0010 to 0.0024 and the average number of pairwise nucleotide differences (K) ranged from 17.4 to 40.2, with the minimum Pi and K values (0.0010 and 17.4) observed in the Foshan population. Compared to farmed populations, wild populations exhibited high average genetic diversity. Neighbor-joining phylogenetic reconstructions revealed two main genetic lineages, one represented by wild populations from the middle reaches of the Yangtze River and the other by populations from the lower reaches of the Yangtze River and farmed populations. The results of Tajima's D and Fu's F neutrality tests and the nucleotide mismatch distribution indicated that wild populations expanded rapidly after undergoing a historic genetic bottleneck. Demographic decline over recent generations has resulted in a bottleneck effect upon black carp populations and genetic connectivity across its distribution has become limited. Poorly designed artificial propagation, long-term inbreeding and random genetic drift probably were the main causes of low genetic diversity in cultured populations. Our results provide baseline information crucial for conservation of black carp genetic resources in China.

The first report of digenean infecting short mackerel (Rastrelliger brachysoma) from Chon Buri Province, the Gulf of Thailand

Rastrelliger brachysoma (Bleeker, 1851), the short mackerel, is a dietary staple and of significant economic demand in Southeast Asia and Thailand. However, the demand for short mackerel has precipitated an overfishing crisis, leading to a depletion of fish stocks. Overfishing, coupled with parasitism, may result in a decline in the population of R. brachysoma. Digenetic trematode infection is prevalent in marine fish and has a considerable impact on the overall health of the fish. Here, to identify digenetic trematodes infecting R. brachysoma, we aim to determine the identity, prevalence, and intensity of digenean infections in R. brachysoma from the Gulf of Thailand. A total of 194 short mackerel were obtained from Chon Buri Province, where digeneans were isolated and identified. The molecular identity of the digeneans was confirmed using the nuclear 28S rRNA gene. Of the 194 short mackerel, 100% were found to be infected with digeneans, comprising of Lecithocladium, Prodistomum, Opechona, and Aphanurus. Lecithocladium was the most prevalent (98%) and had the highest intensity of infection (37 mean intensity), followed by Prodistomum (75% prevalence and 17 mean intensity). Our study thus presents the first evidence of digeneans infecting the economically important short mackerel from the Gulf of Thailand. The high infection rate of digenetic trematodes may have implications on the health of R. brachysoma, further driving their population decline. These data underscore the importance of safeguarding fisheries resources in the Gulf of Thailand, and downstream conservation efforts are crucial for evidence-based management decisions to safeguard the long-term sustainability of fish resources.

Offshore windfarm construction elevates metabolic rate and increases predation vulnerability of a key marine invertebrate

A global increase in offshore windfarm development is critical to our renewable energy future. Yet, widespread construction plans have generated substantial concern for impacts to co-occurring organisms and the communities they form. Pile driving construction, prominent in offshore windfarm development, produces among the highest amplitude sounds in the ocean creating widespread concern for a diverse array of taxa. However, studies addressing ecologically key species are generally lacking and most research is disparate, failing to integrate across response types (e.g., behavior, physiology, and ecological interactions), particularly in situ. The lack of integrative field studies presents major challenges to understand or mitigate actual impacts of offshore wind development. Here, we examined critical behavioral, physiological, and antipredator impacts of actual pile driving construction on the giant sea scallop (Placopecten magellanicus). Benthic taxa including bivalves are of particular concern because they are sound-sensitive, cannot move appreciable distances away from the stressor, and support livelihoods as one of the world's most economically and socially important fisheries. Overall, pile driving sound impacted scallops across a series of behavioral and physiological assays. Sound-exposed scallops consistently reduced their valve opening (22%), resulting in lowered mantle water oxygen levels available to the gills. Repeated and rapid valve adductions led to a 56% increase in metabolic rates relative to pre-exposure baselines. Consequently, in response to predator stimuli, sound-exposed scallops displayed a suite of significantly weaker antipredator behaviors including fewer swimming events and shorter time-to-exhaustion. These results show aquatic construction activities can induce metabolic and ecologically relevant changes in a key benthic animal. As offshore windfarm construction accelerates globally, our field-based study highlights that spatial overlap with benthic taxa may cause substantial metabolic changes, alter important fisheries resources, and ultimately could lead to increased predation.

Sustainable Development Perspective: Analysis of Capture Fisheries in Muncar District Banyuwangi

Capture fisheries resources in Muncar Regency have enormous potential to support the lives of the community, especially fishermen. However, in these conditions, the volume of capture fisheries production in Muncar Regency has decreased. This research aims to direct sustainable development efforts in the capture fisheries subsector so that it can improve the welfare of fishermen. This is done by optimizing the use of fishery resources without ignoring economic, ecological (environmental), and social aspects. This research uses descriptive analysis methods. The results of measuring the level of sustainability of capture fisheries resources in Muncar District show that the average value is still low. From each dimension (economic, social, and environmental) several criteria have medium (M) and high (H) scores. This means that each dimension requires alternative recommendations to support sustainable capture fisheries development. It takes synergy from all levels of society to maintain the balance of the marine ecosystem. Increasing awareness of coastal communities is needed to maintain the balance of the capture fisheries resource ecosystem. Apart from that improving the quality of human resources in fishing communities is an important thing that the government can do to support the sustainable development of capture fisheries resources. Keywords: sustainable development, capture fisheries, Muncar

Age Estimation in Sepia officinalis Using Beaks and Statoliths.

Establishing the age of cephalopods is crucial for understanding their life history, which can then be used for assessment and management. This is particularly true for the common cuttlefish Sepia officinalis (Linnaeus, 1758), one of the most important resources for coastal fisheries. For this reason, an age analysis of S. officinalis was performed for the first time in the Mediterranean, using beaks and statoliths from 158 wild specimens (55-222 mm mantle length; 23-1382 g total weight) at different maturity stages (immature to mature). Growth increments were counted in the lateral wall of the upper beaks and the lateral dome of statoliths. In both cases, a good relationship was found between the counts and the sizes of the animals. The low values of coefficients of variation between the readings obtained for beaks (3.96 ± 1.87%) and statoliths (4.00 ± 1.89%) showed a high level of precision and accuracy in the readings. However, the analysis was simpler for beaks, which were all successfully analyzed, while it was more complex for statoliths, with 69% being lost due to rejection or overgrinding. Based on daily increments previously validated in statoliths, the beaks were cross-verified by comparing their counts with those from statoliths extracted from the same 83 specimens, obtaining a statistically significant relationship between the two counts, confirmed by the ANOVA test. Absolute growth rates that were assessed using both beaks and statoliths indicated that the two sexes had a higher growth rate at 122 and 182 days, which subsequently declined in older specimens. Due to the relative simplicity of its processing method, the beak was finally proposed as a suitable hard structure to study the age of S. officinalis. We also confirmed the good readability of increments in the lateral wall of the beak, which could be considered a valid alternative to the rostrum surface.

S-BESE: Strategy for Improving the Quality of Life for Coastal Area Communities in West Kalimantan

The coastal area of West Kalimantan has a wealth of marine and river fishery resources that have the potential to be utilized optimally, including fishing, conservation, port activities, marine cultivation, coastal tourism, and water. Various problems in coastal areas that need to be prioritized to provide solutions include the occurrence of illegal fishing, damage to coral reef ecosystems and mangroves, coastal abrasion, not yet optimal development of ponds where utilization only reaches 40% of their potential, natural disasters which result in increased poverty and ecosystem damage, as well as the growth of corruption and injustice. The number of people living in poverty has been steadily increasing at an average rate of 6.86% over the past three years, reaching 353,350 individuals in 2023. This research aims to develop coastal areas, creating local economic development innovations to reduce poverty, unemployment, and inequality and preserve natural resources. The method developed in this study was carried out descriptively and qualitatively by developing an in-depth analysis through SWOT. The results provide solutions for improvements and innovations, which include implementing a blue economy by utilizing the modernization of fishing gear, developing a paradigm shift from land to water resources, and producing garbage filters in rivers so they do not wash away into the sea. This study will improve the quality of life economically and socially while maintaining the ecology in coastal areas.

ASSESSMENT OF THE RESOURCES SUSTAINABILITY USING RESOURCE UTILISATION AND CATCH PROJECTION APPROACH: CASE OF PRIGI GULF INDONESIA

Utilisation of fisheries resources requires good management to maintain the sustainability of fish resources. Based on these conditions, this study aims to analyse the status of fish resource utilisation and estimate fish catches in the following year. The data collection is secondary data from Prigi Fishery Port, East Java, from June to September 2023. This study evaluates biological surplus production relationships. Next, due to the time series data, the forecasting performance uses Holt-Winter’s exponential smoothing. The modelling shows that the best estimation value in the Fox model is based on the highest R2 (0,614) and the effort coefficient (0.000034). The maximum sustainable yield (CMSY) and the optimum catch effort (EMSY) values were 10.006 tonnes/year and 29,425 trips/year, respectively. It shows that biological overfishing has yet to occur. The average production forecasting results in 2021-2023 decreased 8.5% from the previous year. Forecasting fish catches in 2021 exceeds CMSY, but in 2022 and 2023, production is still below CMSY. The circumstance indicates that fishing operations are inefficient because the catch obtained is projected to be smaller with fixed effort. Possible management strategies, therefore, include creating sustainable fisheries management through improved work variation for fishers in the off-season.

Diversity and ecological drivers of fish in Singkil Swamp Wildlife Reserve, Aceh, Indonesia

Abstract. Rohim N, Sulistiono, Yulianda F, Muhtadi A. 2024. Diversity and ecological drivers of fish in Singkil Swamp Wildlife Reserve, Aceh, Indonesia. Biodiversitas 25: 2849-2856. Singkil Swamp Wildlife Reserve (SSWR) is a conservation area in Aceh Singkil District, Aceh, Indonesia, that has an important role in maintaining the sustainability of fisheries resources on the Singkil coast. This study analyzes fish biodiversity and ecological factors influencing fish distribution in SSWR waters. The data were collected at five stations (Station I and II in the watershed area while Station III, IV, and V in peat swamp area) every month from April to October 2021 (7 months), consisting of fish biodiversity and aquatic ecological characteristics. The data obtained were analyzed using an index of diversity, evenness, dominance, frequency of presence, and Canonical Correspondence Analysis (CCA). Fish biodiversity in the SSWR utilization area consists of 26 species, including 14 families and 19 genera. Station I (in the Alas-Singkil River) has a higher diversity value and is dominated by the white fish group compared to Stations II, III, IV, and V (in the Lae-Treup River), which the black fish group dominates. Based on ecological characteristics, the distribution of fish species in SSWR is divided into four groups. The first and second groups of fish were positively correlated with high pH and DO, while the third and fourth groups tended to have negative correlation values.

Hazardous Elements in the Edible Portion of Perna perna Mussels: Relation with the COVID-19 Pandemic Period and Assessment of the Risk to Human Health.

In this work, the concentrations of hazardous elements (As, Cd and Pb) in the edible portion of the Perna perna mussel from Southeast Brazil were analyzed to understand the effects of the COVID-19 pandemic on the coastal environment and to evaluate the quality of this fishery resource. Decreases in anthropogenic chemical outputs to the environment were expected to occur during the COVID-19 pandemic, with decreases in element concentrations in mussels. The ranges of median concentrations (µgg-1dw) in the pre- and pandemic periods were 5.4-16.1 and 2.2-10.6 for As; 0.2-0.6 and 0.1-0.5 for Cd; and 1.2-3.2 and 0.7-1.8 for Pb, respectively. Temporal variations (prepandemic x pandemic) were more significant than spatial variations (five sampling sites). The relationships between the concentrations of hazardous elements and isotopic ratios (δ15N and δ13C) suggested that food sources were more diverse across the sampling sites during the pandemic period, when individuals exhibited less efficient trophic transfer. The concentrations of Cd and Pb were below the tolerable maximum limit, whereas for As, they were above the limit; however, these concentrations are not a risk to human health, as most As was present in the least toxic organic form. The intake estimates were below the tolerable intake limits, and only Pb concentrations are at risk of causing concern if the intake of mussels increases. This is the first study in Brazil that presents a spatial-temporal comparison of hazardous elements in marine fauna considering COVID-19 as a temporal landmark. The results are of interest for both public health and environmental health management in a post-COVID-19 scenario.

Strategic Model for Mangrove Forest Resource Management in Boalemo District, Gorontalo Province

Mangrove forest destruction in Boalemo Regency has increased significantly over the past decade. The condition of mangrove forests has been degraded due to the pressure of population growth, especially in coastal areas. Damage to mangrove forest resources is certainly very dangerous to the ecosystem of fisheries resources, biodiversity and destroys the stability of coastal forests that support the protection of inland and rural agricultural crops. The purpose of this research is to design a model of sustainable mangrove forest resource management strategy in Boalemo District, Gorontalo Province, so that it can be applied as a policy in improving and optimizing mangrove forest resource management efforts in Gorontalo Province. The method used is Interpretive Structural Modeling (ISM). The results showed that there are thirteen sub-elements of program requirements needed to build the model, of the thirteen elements of program requirements there are no sub-elements that occupy quadrant I, in quadrant II there are two sub-elements and in quadrant III there are six sub-elements, in quadrant IV is occupied by five sub-elements which are key elements to build a mangrove forest resource management strategy model.

Dynamics of Coral Fish Biomass in The Coastal Waters of Spelman Strait, Central Buton Regency, Southeast Sulawesi

The coastal waters of the Spelman Strait are rich in reef fish resources. Small-scale fishers also use coral fishing in the coastal waters of the Spelman Strait in meeting household needs and improving their welfare. The purpose of this research is to analyze how coral fish biomass in two fishing seasons, namely the west and east seasons. The coastal waters of the Spelman Strait are rich in reef fish resources. Small-scale fishers also use coral fishing in the coastal waters of the Spelman Strait in meeting household needs and improving their welfare. The purpose of this research is to analyze how coral fish biomass in two fishing seasons, namely the west and east seasons. The results of the study, reef fish biomass in the two seasons is relatively different. The difference between the two is due to different fishing patterns, wherein the wet season, the reef fish that are targeted by fishermen are the Serranidae and Lutjanidae families, and the size of the fish is relatively large by using hooks number 5, 6, 7 and 8. In contrast, in the east season, the target fish fishers are all reef fishes and are relatively small in size using hooks 15, 16 and 17. The problem is that some fishermen still use explosives in catching reef fish. Muis et al. (2019) reported the condition of live coral cover in the coastal waters of the Spelman Strait in moderate condition (37.71) and dead coral (33.71). Community participation in the management of fisheries resources is significant to note because the community is the user of these resources. Community participation in the management of fisheries resources is crucial to do because of fishermen as users of resources. Muis et al. (2019) reported the condition of live coral cover in the coastal waters of the Spelman Strait in moderate condition (37.71) and dead coral (33.71).

Redescription of the commercially harvested jellyfish, Crambionella orsini and Lobonemoides gracilis (Cnidaria: Scyphozoa) from Sri Lanka

ABSTRACT Two types of edible jellyfish, namely ‘ball-type’ and ‘white-type’, were reported to be commercially harvested respectively from the southeast and northwest coasts of Sri Lanka, but their taxonomic identity was unknown. Therefore, medusae collected in the ‘Waya-jel-Survey’, together with specimens from museums, were examined, comparing their morphomeristic data with information from the literature. As per results, the ‘ball-type’ and ‘white-type’ jellyfish species were recognized respectively as Crambionella orsini (Vanhöffen 1888) and Lobonemoides gracilis Light 1914 for the first time from Sri Lanka, with a detailed account of morphological features. Among the four valid species of the genus Crambionella, C. orsini is distinguished by the presence of 16 velar lappets per octant, without tubercles. The two congeners of L. gracilis, namely L. robustus Stiasny 1920 and L. sewelli Rao 1931, were synonymized to L. gracilis, making Lobonemoides monospecific, thus L. gracilis is recognized by the presence of papillae on the exumbrella; 1–6 elongated velar lappets between two successive rhopalia; and the window-like openings and long, spindle-shaped appendages on the oral arms. Likewise, the present study re-describes C. orsini and L. gracilis providing a basic component for efficient management of jellyfish fishery resources in Sri Lanka as well as in other Asian countries.

Role of Mangroves as Fishery Resource: A Systematic Review

Mangroves are valuable for their fishery resources, coastline stabilization abilities, water quality and clarity benefits, provision of habitat to economically profitable and ecologically important species, carbon sequestration services, and climate regulation capabilities. For centuries, mangroves have contributed significantly to the socioeconomic lives of coastal dwellers; especially in coastal fishery by providing nursery grounds for finfishes. Fishery resource services provided by mangrove ecosystem play an important role as the habitat, nursery ground, feeding ground, and spawning ground for various marine fish species. Despite their enormous socio-economic value and ecological significance, mangrove ecosystems are under severe threat such as large scale clearing, small scale harvesting and grazing, and industrial threats. The productivity of mangrove ecosystems has been linked to the well-being of valuable fisheries because of the role mangroves play as nursery habitat for a variety of marine and estuarine species. Many species of mangrove-related fish and crab have served the coastal communities as a natural, cheap and balanced nutritional source. Mangroves provide vital ecosystem services to coastal fishing communities through the enhancement of fisheries production. Due to their economic and ecologic significance, it is important to look to the future of these systems in the face of ‘fishery resource’ so that policy makers may act quickly to preserve and protect these ecosystems. Present review provides recent information on role of mangroves as fishery resource by studying the updated published literature and the threats faced by the mangroves. It is suggested that strategies should be prepared and rigorously implemented for the conservation and restoration of mangrove ecosystem.

Temporal and spatial variations in squid jigging catch efficiency in the Oyashio Extension region

AbstractThe abundance of fishery resources significantly impacts the ratio of fishing effort to harvest. However, traditional statistics of fishery catches or commonly used catch per unit effort (CPUE) metrics cannot accurately capture the complexity of resource abundance in the ocean. To address this issue, we propose here a novel approach that integrates the actual fishery catch from vessel logs with fishing duration obtained through automatic identification system (AIS) positioning. This combined analysis eliminates confounding factors and introduces a novel metric called “catch efficiency (CE)” to evaluate fishing operations more accurately, thereby reflecting resource abundance in a more reasonable way. In this study, we focus on the CE of squid in the Oyashio Extension region in the Northwestern Pacific. Our analysis reveals significant temporal and spatial variations of CE, manifesting in both intensity and distribution patterns. Moreover, our findings establish a close relationship between CE and background water mass distribution, chlorophyll‐a concentration, and micronekton biomass. This implies that the resource abundance of squid can be inferred by considering the varying environmental factors within the fishing area.