Fisheries Ecology Research Articles

Spatial distinction analysis on marine ranch development potential in coastal areas of China

According to the 14th Five-Year Plan and the outline of 2035 long-term goals, a modern marine industrial system should be built, the layout of green offshore aquaculture should be optimized, and marine ranching should be built. The research on the construction of marine ranching can provide new ideas for sustainable ecological fishery and inject new vitality into the development of marine industry. In the future, the construction of marine ranching will be a vast world. In this paper, from the perspective of geography, the GC-TOPSIS method combined with the entropy weight TOPSIS method and the grey correlation method were used to construct 22 evaluation index systems to estimate the development potential of marine ranching construction in ten coastal provinces and municipalities of China from 2011 to 2016. The results showed that the overall development potential of marine ranching in ten provinces and urban areas had regional differences (north, central and south), and the differences in the north and south regions were obvious. The regional differences in the central coastal areas of China were not significant, and the development potentials of marine ranching in ten provinces and urban areas were all medium. The development potential of four criteria layers of marine ranching in ten coastal provinces and regions of China is different in space, and the development potential of marine ranching in the same region is unbalanced in all aspects of the criteria layers. To estimate the development potential of marine ranching in China’s ten coastal provinces and regions provides scientific support for the sustainable development of ecological fisheries, and has practical application value for the scientific planning of marine ranching and the selection of demonstration areas.

Age, growth, mortality, and exploitation rate of blueline snapper, Lutjanus coeruleolineatus (Actinopterygii: Perciformes: Lutjanidae), from Dhofar Governorate, Sultanate of Oman

The blueline snapper, Lutjanus coeruleolineatus (Rüppell, 1838), is a significant commercial fish species harvested from the traditional fishery in the Sultanate of Oman. Deficient data on this species, however, make the management strategies challenging, especially in fisheries ecology. A total of 978 specimens were obtained from Dhofar Governorate off the coast of the Arabian Sea during the period between February 2015 and March 2016. In total, 296 sectioned otoliths were analyzed and growth was estimated from non-seasonal growth by using von Bertalanffy method. The parameters of von Bertalanffy growth function, total mortality (Z), natural mortality (M), fishing mortality (F), and exploitation rate (E) were determined and compared with those for Lutjanidae fishes elsewhere. The age structure of male fishes was between 1 and 14 years for males while the age of females ranged from 1 to 18 years. Growth rate (K) was 0.21 y–1 and 0.16 y–1 for males and females, respectively. The hypothetical length of female (L∞ = 46 cm) was relatively higher than that of male (L∞ = 42 cm). The natural mortality (M) was 0.296, total mortality (Z) was 0.372, fishing mortality was 0.076, and exploitation rate (E) was estimated as 0.2. The presently reported study is conducted to examine this fish in relation to growth parameters by analyzing otolith structure. The results of the presently reported study will contribute towards planning the regional fishery management policies in Oman.

Local Values and Data Empower Culturally Guided Ecosystem‐Based Fisheries Management of the Wuikinuxv Bear–Salmon–Human System

AbstractDespite numerous examples of ecosystem‐based fisheries management (EBFM) addressing tradeoffs between ecological and commercial fishery interests, local social and cultural concerns are less frequently considered. We illustrate how Indigenous fishery harvest goals and data from locally driven wildlife research can inform EBFM, guided by cultural values of respect for and reciprocity with wildlife. Grizzly bearsUrsus arctos horribilishold particular importance for the Wuikinuxv First Nation in Rivers Inlet, British Columbia, where people and bears have coexisted as consumers of Sockeye SalmonOncorhynchus nerkafor millennia. The region’s valuable commercial fishery, active since the late 1800s, has been closed since the Sockeye Salmon population collapsed in the mid‐1990s, but the Wuikinuxv maintain a modest food, social, and ceremonial (FSC) harvest. To address questions about balancing the needs of fishers and ecosystem recipients, we quantified tradeoffs between long‐term maximum sustainable fishery yield and ecosystem benefits (for which bear density served as a proxy). We fitted age‐structured state‐space spawner–recruitment models and estimated relationships among spawner abundance, long‐term fishery yields, and relative bear densities in time periods before and after the population collapse. We found that predicted maximum postcollapse bear density was 74% of maximum precollapse densities. We estimated a 94% decline in Sockeye Salmon equilibrium population size (from ˜3,115,000 to 200,000), resulting in a commensurate decline in maximum sustainable fishery yield. Despite this, we showed that Wuikinuxv FSC harvest goals are compatible with an EBFM target that seeks also to sustain relatively high bear densities, whereby relative fishery yield and bear density are reduced about 10% from their respective maxima, assuming that current Sockeye Salmon productivity and carrying capacity remain similar for the foreseeable future, although these estimates are highly uncertain. Collectively, our findings illustrate how EBFM can apply interdisciplinary approaches that draw not only on fisheries ecology but also local values to design sustainable harvest strategies for diverse beneficiaries.

Quantifying abundance trends and environmental effects on a population of queen scallop Aequipecten opercularis targeted by artisanal fishers in a coastal upwelling area (Ría de Arousa, NW Spain) using a Bayesian spatial model

Queen scallop Aequipecten opercularis, is exploited by small-scale trawlers in separated aggregations along the east Atlantic coast and the Mediterranean Sea. However, population performance is poorly known. Here, we combine official information and on-board observers’ data over two decades to study the fishery ecology of an aggregation occurring in a coastal upwelling system (Ría de Arousa, NW Spain). Annual landings fluctuated around a mean of 170 tons while beam trawlers declined at a rate of 11 vessels per decade. A hurdle Bayesian spatial model fitted to observers’ catch and effort data showed that the probability of occurrence and abundance of the species increased with fishing effort and decreased in sandy bottoms. Moreover, abundance increased with upwelling intensity and decreased with continental runoff and along the fishing season. Furthermore, occurrence was higher in the inner part of the embayment while abundance increased in the central channel. The predicted index of standardized abundance correlated with the trend in landings, and year-to-year fluctuations in abundance were negatively and positively related to upwelling intensity and net primary production, respectively, during the spawning and settlement period.

Progress on Research Regarding Ecology and Biodiversity of Coastal Fisheries and Nektonic Species and Their Habitats within Coastal Landscapes

This paper aims to highlight the new research and significant advances in our understanding of links between coastal habitat quality/quantity/diversity and the diversity of fisheries species and other mobile aquatic species (hereafter nekton) that use them within coastal landscapes. This topic is quite diverse owing to the myriad of habitat types found in coastal marine waters and the variety of life history strategies fisheries species and nekton use in these environments. Thus, we focus our review on five selective but relevant topics, habitat templates, essential fish habitat, habitat mosaics/habitat connectivity, transitory/ephemeral habitat, and the emerging/maturing approaches to the study of fish-habitat systems as a roadmap to its development. We have highlighted selected important contributions in the progress made on each topic to better identify and quantify landscape scale interactions between living biota and structured habitats set within a dynamic landscape.

Research on Development Status, Issues and Policy for Ecological Fishery of Large-scale Waters in China

China is rich in fishery resources of large-scale water such as lakes, reservoirs, and river ditch, and large-scale fisheries play an important role in freshwater fisheries. Its area and output account for 46% and 15.42% of the national freshwater fisheries respectively. Both theory and practice show that large-scale fisheries have obviously multiple ecological, economic and social functions. In China, large-scale fisheries can be divided into five types that are industry convergence development, water ranch, environmental cage, reservoir water quality protection, repair ecology in lake. However, in recent years, the back-out of “seine, block, cage” with environmental storm has caused serious negative impacts. Compared with 2016, in 2018, the area of all kinds of large-scale ecological fisheries in the country has decreased by 11%-34%, and it faces social cognition bias, partial or individual short-term economic behavior, insufficient integration and other issues. Focusing on problems and combining the development goals of the new era of fisheries, drawing on typical successful experiences, four countermeasures including adhering to ecological priorities, increasing publicity, innovating institutional mechanisms, optimizing support policies, and building internal motivation are proposed to promote sustainable development of large-scale ecological fisheries.

Morphology and composition of Goldeye (Hiodontidae; Hiodon alosoides) otoliths

We provide up-to-date morphological and compositional data on otoliths of the osteoglossomorph Goldeye (Hiodon alosoides). Using computed tomography (CT) X-ray, we documented the location of each of the three pairs of otoliths (lapilli, sagittae, and asterisci) in relation to the swim bladder, which extended forward in close proximity to the sagittae and asterisci. The lappili were the largest otoliths in terms of surface area and volume, but the sagittae were highly modified, appearing spiral in shape when viewed dorsally, with a surface area to volume ratio more than double that of the lapilli. Using scanning electron microscopy, the surface of each otolith was viewable in great detail, and small otoconia (~10.5 μm diameter) were observed on each, but were most numerous on the sagittae. On scanning electron micrographs, the sagittae appeared to be bi-lobed, with asymmetrical lobes each oriented in the same general direction. Using neutron and X-ray diffraction methods, we found three polymorphs of calcium carbonate crystals (aragonite, vaterite, and calcite), sometimes all within the same otolith. However, in general, lapilli and sagittae were composed predominately of aragonite whereas asterisci were composed chiefly of vaterite. With these results, we provide information on a unique species, whose inclusion in future studies would benefit our understanding of fish hearing, fish evolution, and fisheries ecology.

Deep neural network-based real time fish detection method in the scene of marine fishing supervision

Overfishing of marine fishery is a serious threat to fishery ecological security. Fishing supervision is one of the main ways to maintain marine fishery ecology. In order to improve the intelligence of fishing supervision system, a real time fish detection method based on YOLO-V3-Tiny-MobileNet was proposed. Aiming at the problems of shallow network layers and insufficient feature extraction ability in YOLO-V3-Tiny network, the proposed network takes YOLO-V3-Tiny as baseline and combines it with MobileNet. The proposed network is pre-trained by VOC2012 dataset, and then retrained and tested on Kaggle_ NCFM (The Nature Conservancy Fisheries Monitoring) dataset. The experimental results show that the proposed method has superior performance in parameters number, mean average precision and detection performance, compared with other methods. Compared with the monitoring method of fishing vessel detection on shore supervision, the real time monitoring method can give timely warning to the fishing vessel operators, which is more conducive to fishery ecological protection.

Sustainable Development Index of Marine Capture Fisheries in Indonesia

This study aims to compile a composite index from economic, social, ecology and institutional dimensions of sustainable capture fisheries. Use of primary and secondary data. Different methods of data analysis used in this study include priority analysis, key component analysis (PCA), analysis of structural equation modeling (SEM), and analysis of flag modeling. The results show that the main priorities in capturing fisheries development were determined by the social and ecology dimensions. The sensitivity analysis results indicate that all indicators on the institutional level have a higher sensitivity compared with other indicators. Thus, Indonesia's current development of catch fisheries is in the "moderate" sustainability status. In order to attain sustainable fisheries production in the future, it must take significant account of ecology and social indicators and issues.

Fish Diversity and Abundance Using Statistical Modelling in Hadejia-Nguru Wetlands (HNWs), Nigeria: An Adaptive Environmental Assessment

Fisheries and aquaculture plays a significant role in the Nigerian economy by providing employment, diversifying livelihoods, providing animal nutrition, and earning returns on foreign exchange. Fish is an important economic factor for many nations, as serves as a staple diet in many countries. As evident, in many developed nations, fishing is a crucial source of livelihood, particularly for low-income families in rural areas, where it offer local jobs in many communities and is a key source of food for millions. Over the past few decades, fish populations have deteriorated dramatically, and species at risk have experienced growing environmental challenges. Dams, overfishing, pollution, erosion, soil loss and other human activities are main threats to fisheries ecology. The presents study aimed to analyze the decline in diversity of the fish, adaptive management of artisanal fishermen in the wetlands of Hadejia-Nguru, Guri local government area of Jigawa State and to explore the correlation of environmental factors for the decline in fish diversity. In this study the data were collected through questionnaire interview (QI), focus group conversation (FGD), and field data collection (FDC), and the test objectives were accomplished via the analysis workflow. Geostatistical software was used to analyze the information obtained from QI, FGD and other sources while other auxiliary data and field data were collected using GPS receiver. The research findings can be considered as a tools for decision-making, policy-making, management plan development, fish conservation strategies plan and ultimately help to achieve the UN's Sustainable Development Goals (SDGs) 1, 2, 8, 14 and 15 of the 2030 agenda.

First estimates of metabolic rate in Atlantic bluefin tuna larvae.

Atlantic bluefin tuna is an iconic scombrid species with a high commercial and ecological value. Despite their importance, many physiological aspects, especially during the larval stages, are still unknown. Metabolic rates are one of the understudied aspects in scombrid larvae, likely due to challenges associated to larval handling before and during respirometry trials. Gaining reliable estimates of metabolic rates is essential to understand how larvae balance their high growth needs and activity and other physiological functions, which can be very useful for fisheries ecology and aquaculture. This is the first study to (a) estimate the relationship between routine metabolic rate (RMR) and larval dry weight (DW) (mass scaling exponent) at a constant temperature of 26°C, (b) measure the RMR under light and darkness and (c) test whether the interindividual differences in the RMR are related to larval nutritional status (RNA/DNA and DNA/DW). The RMR scaled nearly isometrically with body size (b = 0.99, 0.60-31.56 mg DW) in contrast to the allometric relationship observed in most fish larvae (average b = 0.87). The results show no significant differences in larval RMR under light and darkness, suggesting similar larval activity levels in both conditions. The size explained most of the variability in RMR (97%), and nutritional condition was unrelated to the interindividual differences in routine metabolism. This is the first study to report the metabolic rates of Atlantic bluefin tuna larvae and discuss the challenges of performing bioenergetic studies with early life stages of scombrids.

Beak morphological and growth characteristic of Sthenoteuthis oualaniensis in the northwest Indian Ocean in winter and spring

Beak is one of the most important hard tissues of cephalopods, and thus is widely used in the study of cephalopod fisheries ecology and fishery resource assessment. With 1009 Sthenoteuthis oualaniensis samples collected by Chinese light falling-net fishery during February to May in the northwest Indian Ocean, we examined the morphologic and growth characteristics of beak. Results of the principal component analysis showed that the upper hood length (UHL), the upper crest length (UCL), the upper lateral wall length (ULWL), the lower crest length (LCL), the lower wing length (LWL) and the lower lateral wall length (LLWL) could be used as the morphological cha-racteristic parameters to examine the morphological changes of the beak. Results of the analysis of covariance (ANCOVA) showed that there were significant differences in the relationships between all of the morphological characteristic parameters and mantel length (ML) for males and females except UCL. There were significant differences in the relationships between all of the morphological characteristic parameters and body weight (BW) for males and females. The relationships between LCL, UCL and ML were optimally described by the linear functions. Power functions were best for UHL, LWL and linear functions were best for ULWL, LLWL for females. The relationships between ULWL and ML were optimally described by power functions, while the logarithm functions were best for UHL, LLWL and LWL for males. The relationships between all of the morphological characteristic parameters and BW were optimally described by the power functions for females, while the logarithm functions for males except the power function for ULWL. Our results provided scientific basis for the research of the fisheries ecology and stock assessment for S. oualaniensis.

Population connectivity in a highly migratory fish, Japanese Spanish mackerel (Scomberomorus niphonius), along the Chinese coast, implications from otolith chemistry

Connectivity is a vital component of metapopulation and fishery ecology, influencing fundamental processes such as population dynamics, evolution, and community responses to climate change. The Japanese Spanish mackerel, Scomberomorus niphonius, is an economically important species in the temperate and subtropical waters of the Northwestern Pacific Ocean, especially in the China seas. As a highly migratory species, the population connectivity of S. niphonius is not only limited to dispersal in the pelagic larval stage but throughout the whole life history, and then determines the natal origin and population structure. However, knowledge about population connectivity is scarce and, at present, is no formal management strategy to ensure the long-term sustainability of the S. niphonius fishery in China. In this study, otolith chemistry was applied to investigate the connectivity among four spawning grounds along a latitudinal gradient spanning much of the known species range in the Yellow Sea and the East China Sea [Qingdao (QD), Lvsi (LS), Xiangshan (XS) and Fuzhou (FZ)]. Otoliths from age-1 spawning or spent individuals were analyzed from the core to the margin by using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). In each sampled life stage, otolith elements are similar among fish from different spawning grounds, but otolith chemical compositions vary greatly between life stages. Decreasing Ba:Ca ratio indicates ontogenetic migrations from relatively shallow coastal water during larval growth to relatively deep offshore waters with increasing age. The random forest classification and non-metric multi-dimensional scaling show a strong overlap in otolith elemental composition. The hereby results indicate a large-scale connectivity in the life history of S. niphonius: the immature fish mix to a large extent when they feed and overwinter in the extensive offshore waters; adults spawned in the same spawning ground have multiple natal origins and fish caught off QD may even be of FZ origin. Clustering of near core chemistry pointed to three sources, with southern grounds dominated by a single cluster while northern grounds dominated by two or three clusters. From these results, it was suggested that the local mackerel assemblages on which fisheries rely in the Yellow Sea are collectively influenced by the recruitment of all the spawning assemblages along China coastal waters instead of self-sustaining.

Engaging Recreational Salmon Anglers in Fisheries Ecology

Engaging Recreational Salmon Anglers in Fisheries Ecology

Behavioural diversity in fishing—Towards a next generation of fishery models

AbstractDespite improved knowledge and stricter regulations, numerous fish stocks remain overharvested. Previous research has shown that fisheries management may fail when the models and assessments used to inform management are based on unrealistic assumptions regarding fishers' decision‐making and responses to policies. Improving the understanding of fisher behaviour requires addressing its diversity and complexity through the integration of social science knowledge into modelling. In our paper, we review and synthesize state‐of‐the‐art research on both social science's understanding of fisher behaviour and the representation of fisher decision‐making in scientific models. We then develop and experiment with an agent‐based social–ecological fisheries model that formalizes three different fishing styles. Thereby we reflect on the implications of our incorporation of behavioural diversity and contrast it with the predominant assumption in fishery models: fishing practices being driven by rational profit maximizing. We envision a next generation of fisheries models and management that account for social scientific knowledge on individual and collective human behaviours. Through our agent‐based model, we demonstrate how such an integration is possible and propose a scientific approach for reducing uncertainty based on human behavioural diversity in fisheries. This study serves to lay the foundations for a next generation of social–ecological fishery models that account for human behavioural diversity and social and ecological complexity that are relevant for a realistic assessment and management of fishery sustainability problems.

Root Cause Analysis on Development of Sustainable Fisheries Business in Indonesia

The development of the capture fisheries sector is significant to improve the national economy, but the development of this sector needs to be regulated to create a sustainable business and ecology of capture fisheries. This study aims to examine the development of the sustainable fisheries sector in Indonesia. This research uses descriptive qualitative method by collecting data from literature studies and focus group discussions (FGD). This study was further analyzed using root cause analysis (RCA). Based on these results, the policy recommendation was obtained to realize sustainable fisheries in Indonesia. This policy recommendation also needs to be supported by government support, such as forming a fishery platform that serves as a mediator for stakeholders so that the policy that is created will positively impact the stakeholders from upstream to downstream. Keywords: capture fisheries, strategy, sustainability, root cause analysis (RCA)

An unseen synchrony or recurrent resource pulse opportunity? linking fisheries with aeroecology

AbstractUnderstanding insect and fish interactions from a spatial and temporal perspective can have implications on large‐scale phenology in freshwater systems, yet current information is limited. We employed a novel approach of combining information from acoustic telemetry for six freshwater fish species and weather radar to assess the phenology of mayfly emergence and foraging patterns of freshwater fish. We hypothesized that freshwater fish conduct synchronous movements with annual mayfly hatches as a pulse resource opportunity. Generalized additive models were developed to assess movement distance as a function of species and time; before, during, and after annual mayfly hatch events. A cross‐section abundance index was also employed to quantify dynamics of aerial mayflies. Hatch dynamics revealed nocturnal emergence behaviour with annual variations in intensity, spatial extent, and origin. We found that the hatch was likely a pulse resource feeding opportunity for channel catfish, common carp, freshwater drum, and walleye instead of a synchronized feeding event. Bigmouth buffalo and lake sturgeon utilized riverine habitat away from the hatch and did not likely forage on the emerging mayflies. Remote sensing of fishes and emergent insects using our approach is the first attempt at bridging the capabilities of fisheries ecology and aeroecology to advance movement ecology.

First annulus formation in the European anchovy; a two-stage approach for robust validation

The age determination in fast-growing short-living species, such as European anchovy (Engraulis encrasicolus), has been widely recognized as a difficult task and bias introduced by readers leads to bias in reconstructing the population age structure. In this context, it is worth to note that age structure of fish population represents key information in fishery ecology and for stock assessment models. The uncertainty in estimating the age of the European anchovy by otolith reading is linked to the number of false-growth increments (checks) laid down before the annulus formation. While direct validation methods (e.g. mark-recapture, rearing, radiochemical dating) are difficult to implement specially for this short living species, the use of different indirect methods, supported by a coherent statistical approach, represents a robust and easier validation tool. A statistical modeling approach has been here adopted to assess the coherence of two well-known methods, namely Edge Analysis and Marginal Increment Analysis, in order to validate the first annulus formation in European anchovy. Both methodologies in two different yearly cycles converged toward the same result, thus confirming the annulus identification for the first year class. In addition, the completion dates of the checks and the first annulus were computed in order to gain a better insight into otolith growth dynamic. According to the species spawning period, the completion date of the first annulus falls in the summer period, while the first and second checks completion dates were mostly found in summer and winter respectively. General additive models using marginal increments as dependent variable showed a significant effect of the month, highlighting the presence of only one clear minimum in July/August, as well as specific relationships with condition factor and gonadosomatic index. Modeling the otolith edge morphology, the probability to find a hyaline band displayed in both years a similar shape, characterized by a minimum in July/August and higher values between November and January. The obtained results evidenced temporally coherent patterns providing a better insight in the otolith growth dynamic as well as a more robust validation of the first annulus formation in the European anchovy.

Beak morphological growth characteristic of Gonatopsis borealis in the Northwestern Pacific Ocean

Beak is one of the most hard tissues in cephalopods, which is important in the study of fishery ecology. We analyzed the morphological growth characteristics of 268 beaks of Gonatopsis borealis collected in the Northwest Pacific Ocean from September to November of 2018 by Chinese jigging fishing fleets. Results from the principal component analysis showed that the upper hood length (UHL), upper crest length (UCL), upper rostrum length (URL), lower hood length (LHL), lower crest length (LCL) and lower rostrum length (LRL) could be used as the morphological characteristic parameters to study the morphological growth of beak. Results from the analysis of covariance (ANCOVA) showed that there was no significant difference both in the relationships between the morphological characteristic parameters versus mantle length (ML) or body weight (BW) for males and females. The relationships between ML and UHL, LHL were best described by power functions but by logarithm function for UCL, URL, LCL, and linear function for LRL respectively. The relationships between BW and UHL, UCL, URL, LCL, LRL were best described by logarithm functions but power function for LHL based on the result of the Akaike's information criterion. The results of growth models for the morphological parameters in this study provided scientific basis for the stock assessment in further research.

Study on Industrialization of Eco-fisheries and Benefit Mechanism of Migrants in Three Gorges Reservoir Area

In order to ensure the good water quality of the Three Gorges Reservoir, realize the sustainable development of the ecological fishery, and promote the protection and construction of the ecological environment in the reservoir area. This paper defines the concept and characteristics of ecological fishery and its industrialization, and analyses the present situation and problems of fishery development in the Three Gorges Reservoir on this basis, discusses the conditions for the industrialization of ecological fisheries in the Three Gorges Reservoir Area. The paper puts forward the restraint mechanism that needs to be constructed and some countermeasures to promote the healthy development of ecological fisheries in the Three Gorges Reservoir.