Perspectives:Gene expression in fisheries management

Functional genes and gene expression have been connected to physiological traits linked to effective production and broodstock selection in aquaculture, selective implications of commercial fish harvest, and adaptive changes reflected in non-commercial fish populations subject to human disturbance and climate change. Gene mapping using single nucleotide polymorphisms （SNPs） to identify functional genes, gene expression （analogue microarrays and real-time PCR）, and digital sequencing technologies looking at RNA transcripts present new concepts and opportunities in support of effective and sustainable fisheries. Genomic tools have been rapidly growing in aquaculture research addressing aspects of fish health, toxicology, and early development. Genomic technologies linking effects in functional genes involved in growth, maturation and life history development have been tied to selection resulting from harvest practices. Incorporating new and ever-increasing knowledge of fish gehomes is opening a different perspective on local adaptation that will prove invaluable in wild fish conservation and management. Conservation of fish stocks is rapidly incorporating research on critical adaptive responses directed at the effects of human dis- turbance and climate change through gene expression studies. Genomic studies of fish populations can be generally grouped into three broad categories： l） evolutionary genomics and biodiversity; 2） adaptive physiological responses to a changing environment; and 3） adaptive behavioral genomics and life history diversity. We review current genomic research in fisheries focusing on those that use microarrays to explore differences in gene expression among phenotypes and within or across populations, information that is critically important to the conservation of fish and their relationship to humans [Current Zoology 56 （1）： 157-174, 2010].

Impacts of species depletion on the food web structure of a marine ecosystem based on topological network analysis

Single-species management ignores the interactions between species,and ecosystem-based fisheries management(EBFM)has become a main method to fisheries management.Understanding food web structures and species interactions is essential for the implementation of EBFM and maintenance of ecosystem functions.Overfishing is one of the main reasons behind the depletion,which could even lead to the depletion of some target species in local areas.So understanding the impacts of species depletion on food web structures is important for the implementation of EBFM.The impacts of species depletion can be transmitted through the food web and cause the local extinction of both target and non-target species.In this study,topological network analysis was applied to examine the impacts of species depletion on the food web structure of Haizhou Bay.Results showed that fine crayfish Leptochela gracilis,squid Loligo sp.,and Japanese snapping shrimp Alpheus japonicus have the highest numbers of outgoing links(48,32 and 31 respectively);thus,these species may be considered key prey species.Whitespotted conger Conger myriaster,fat greenling Hexagrammos otakii,and bluefin gurnard Chelidonichthys kumu were key predators with the highest number of incoming links(37,36 and 35 respectively).The competition graphs derived from the Haizhou Bay food web were highly connected(more than 40%predators sharing over 10 common prey species),and showed close trophic interaction between high trophic level fishes.Simulation analysis showed that the food web structure has small changes to the depletion of species in a highly complex food web.The most-connected target species did not necessarily indicate high structural importance;however,some species with low connectivity may demonstrate stronger trophic interactions and play important ecological roles in the food web.But most species were more sensitive to the depletion of the most-connected target species than other target species(for instance,for zooplankton,closeness centrality 13.876 in D6,but closeness centrality 82.143 in original food web).Therefore,EBFM should focus on the most-connected target species,but also on those species with few but strong links and feeding relationships in the food web.

Estimating the total allowable catch and management of Threadfin porgy(Evynnis cardinalis)fisheries in the northern South China Sea based on sampling surveys conducted at fishing ports

In order to develop a method that apply sampling survey data randomly obtained at fishing ports to fish stock assessments,based on fish landing surveys conducted at fishing ports in the northern South China Sea(SCS),19 Threadfin porgy(Evynnis cardinalis)catch per unit effort(CPUE)datasets were collected for fishing vessels with different gear types and engine powers and incorporated into surplus production models.Considering only the fitting performance,the Schaefer model had the best overall goodness of fit,followed by the Fox,CYP,W-H,and Schnute models.Among fishing vessels with different gears and engine powers,the data were best fitted for single-trawl vessels powered by 301-400-kW engines and for gillnet vessels powered by>200-kW engines.Eight model expressions were superior and selected for subsequent analyses based on their goodness of fit and relative residuals.The Kobe plot analysis results showed an optimistic fish stock status when using the four model expressions,required more caution when using three model expressions and output pessimistic estimations using one model expression.Considering the incomplete information acquired,a compromising decision-making method was used to derive a 2017 northern SCS E.cardinalis total allowed catch(TAC)of 44,691.21 t.The different conclusions drawn from estimations using CPUEs reflect variable exploitation and utilization fish stock statuses among fishing vessels with different gears and engine powers.Hence,the fishing operations were grouped according to their CPUE relationship,and recommendations regarding optimum fishing efforts were assigned to the groups following a fundamental principle:to improve fishery TAC management,fishing efforts should be reduced if the fish stock assessment is pessimistic and maintained if the assessment is optimistic.This study providing a feasible technical method for the TAC management of China’s offshore fisheries.

Constructing a raster-based spatio-temporal hierarchical data model for marine fisheries application

Marine information has been increasing quickly. The traditional database technologies have disadvantages in manipulating large amounts of marine information which relates to the position in 3-D with the time. Recently, greater emphasis has been placed on GIS （geographical information system）to deal with the marine information. The GIS has shown great success for terrestrial applications in the last decades, but its use in marine fields has been far more restricted. One of the main reasons is that most of the GIS systems or their data models are designed for land applications. They cannot do well with the nature of the marine environment and for the marine information. And this becomes a fundamental challenge to the traditional GIS and its data structure. This work designed a data model, the raster-based spatio-temporal hierarchical data model （RSHDM）, for the marine information system, or for the knowledge discovery fi＇om spatio-temporal data, which bases itself on the nature of the marine data and overcomes the shortages of the current spatio-temporal models when they are used in the field. As an experiment, the marine fishery data warehouse （FDW） for marine fishery management was set up, which was based on the RSHDM. The experiment proved that the RSHDM can do well with the data and can extract easily the aggregations that the management needs at different levels.

The impact of natural mortality variations on the performance of management procedures for Spanish mackerel(Scomberomorus niphonius) in the Yellow Sea, China

Natural mortality rate（M） is one of the essential parameters in fishery stock assessment, however, the estimation of M is commonly rough and the changes of M due to natural and anthropogenic impacts have long been ignored.The simplification of M estimation and the influence of M variations on the assessment and management of fisheries stocks have been less well understood. This study evaluated the impacts of the changes in natural mortality of Spanish mackerel（Scomberomorus niphonius） on their management strategies with data-limited methods. We tested the performances of a variety of management procedures（MPs） with the variations of M in mackerel stock using diverse estimation methods. The results of management strategies evaluation showed that four management procedures DCAC, SPMSY, cur E75 and minlen Lopt1 were more robust to the changes of M than others; however, their performance were substantially influenced by the significant decrease of M from the 1970s to 2017. Relative population biomass（measure as the probability of B〉0.5 BMSY） increased significantly with the decrease of M, whereas the possibility of overfishing showed remarkable variations across MPs. The decrease of M had minor effects on the long-term yield of cur E75 and minlen Lopt1, and reduced the fluctuation of yield（measure as the probability of AAVY〈15%） for DCAC, SPMSY. In general, the different methods for M estimation showed minor effects on the performance of MPs, whereas the temporal changes of M showed substantial influences. Considering the fishery status of Spanish mackerel in China, we recommended that cur E75 has the best trade-off between fishery resources exploitation and conservation, and we also proposed the potentials and issues in their implementations.

Evaluation of Three Harvest Control Rules for Bigeye Tuna(Thunnus obesus) Fisheries in the Indian Ocean

The stock of Bigeye tuna(Thunnus obesus) in the Indian Ocean supports an important international fishery and is considered to be fully exploited. The responsible management agency, the Indian Ocean Tuna Commission(IOTC), does not have an explicit management decision-making framework in place to prevent over-fishing. In this study, we evaluated three harvest control rules, i) constant fishing mortality(CF), from 0.2 to 0.6, ii) constant catch(CC), from 60000 to 140000 t, and iii) constant escapement(CE), from 0.3 to 0.7. The population dynamics simulated by the operating model was based on the most recent stock assessment using Stock Synthesis version Ⅲ(SS3). Three simulation scenarios(low, medium and high productivity) were designed to cover possible uncertainty in the stock assessment and biological parameters. Performances of three harvest control rules were compared on the basis of three management objectives(over 3, 10 and 25 years): i) the probability of maintaining spawning stock biomass above a level that can sustain maximum sustainable yield(MSY) on average, ii) the probability of achieving average catches between 0.8 MSY and 1.0 MSY, and iii) inter-annual variability in catches. The constant escapement strategy(CE=0.5), constant fishing mortality strategy(F=0.4) and constant catch(CC=80000) were the most rational among the respective management scenarios. It is concluded that the short-term annual catch is suggested at 80000 t, and the potential total allowable catch for a stable yield could be set at 120000 t once the stock had recovered successfully. All the strategies considered in this study to achieve a ‘tolerable' balance between resource conservation and utilization have been based around the management objectives of the IOTC.

Geospatial Mapping of Fisheries Profile of West Bengal of India through GIS

In the age of information and technological advancements, location-awareness is becoming a key feature in management of natural resources. Geospatial mapping is a location based study and is a part of intelligence GIS which is expected to be useful tool for fisheries scientists, aquatic resource managers and policy planners in developing and planning strategies for fisheries resources of the country. In this context, a study was performed where mapping of fisheries profile of West Bengal was carried out using GIS tool having critical geographic dimensions. For this purpose, at the core of the system fisheries data of West Bengal were accessed and integrated from different sources at district level. Data were tabulated using Microsoft Excel and then joined to digitize Map of West Bengal to enable mapping using Arc info 9.3 GIS software. This was further synchronized and integrated to generate four thematic maps based on different criteria. The map dealing with fisher folk population and their occupation contains the searchable criteria as regards to the fishermen population as well as their classified categories according to their occupation. The map dealing with West Bengal fish production contains fish production, fish seed production district-wise and growth rate for 2004-2008. The third map contains district-wise water resources and reservoir areas along with brackish water. With this mapped information, planners and various stakeholders will have readily accessible district level data on various components of fisheries of West Bengal, thereby facilitating better planning, management and development of the fisheries sector.

Using data-limited approaches to assess data-rich Indian Ocean bigeye tuna:Data quantity evaluation and critical information for management implications

The majority of fishery stocks in the world are data limited,which limits formal stock assessments.Identifying the impacts of input data on stock assessment is critical for improving stock assessment and developing precautionary management strategies.We compare catch advice obtained from applications of various datalimited methods(DLMs)with forecasted catch advice from existing data-rich stock assessment models for the Indian Ocean bigeye tuna(Thunnus obesus).Our goal was to evaluate the consistency of catch advice derived from data-rich methods and data-limited approaches when only a subset of data is available.The Stock Synthesis(SS)results were treated as benchmarks for comparison because they reflect the most comprehensive and best possible scientific information of the stock.This study indicated that although the DLMs examined appeared robust for the Indian Ocean bigeye tuna,the implied catch advice differed between data-limited approaches and the current assessment,due to different data inputs and model assumptions.Most DLMs tended to provide more optimistic catch advice compared with the SS,which was mostly influenced by historical catches,current abundance and depletion estimates,and natural mortality,but was less sensitive to life-history parameters(particularly those related to growth).This study highlights the utility of DLMs and their implications on catch advice for the management of tuna stocks.

Preliminary Analysis of the Jimo Coastal Ecosystem with the Ecopath Model

The Jimo coast encompasses an area of 2157 km^2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting of 15 functional ecological groups was developed for the coastal ecosystem using the Ecopath model in Ecopath with Ecosim(Ew E) software(version 6.4.3). The results of the model simulations indicated that the trophic levels of the functional groups varied between 1.0 and 3.76, and the total production of the system was estimated to be 5112.733 t km^(-2) yr^(-1) with a total energy transfer efficiency of 17.6%. The proportion of the total flow originating from detritus was estimated to be 48%, whereas that from primary producers was 52%, indicating that the grazing food chain dominated the energy flow. The ratio of total primary productivity to total respiration in the system was 3.78, and the connectivity index was 0.4. The fin cycling index and the mean path length of the energy flow were 4.92% and 2.57%, respectively, which indicated that the ecosystem exhibits relatively low maturity and stability. The mixed trophic impact(MTI) procedure suggested that the ecological groups at lower trophic levels dominated the feeding dynamics in the Jimo coastal ecosystem. Overfishing is thought to be the primary reason for the degeneration of the Jimo coastal ecosystem, resulting in a decline in the abundance of pelagic and demersal fish species and a subsequent shift to the predominance of lower-trophic-level functional groups. Finally, we offered some recommendations for improving current fishery management practices.

Study on the Prediction System of Shrimp Field Distribution in the East China Sea Based on Big Data Analysis of Fishing Trajectories

In recent years,China has paid more and more attention to the development of marine economy and the management and protection of fishery resources.The management departments at all levels regulate and manage the fishing behavior of fishing vessels through the data of fishing trajectories.In this paper,the distribution of shrimp farms in the East China Sea is predicted by studying the trajectories and behavior patterns of shrimp boats in the system of fishing trajectories.At the same time,a set of shrimp farm distribution management system based on Back Propagation algorithm is established.It can monitor the trajectories of fishing boats and the distribution of shrimp groups in real time,which effectively improves the work efficiency and management mode of the management department.It also plays a positive role in regulating the behavior of fishing boats at sea.

Japanese Aquatic Resources Management and Its Enlightenment to China

This article briefly reviewed the history of fishery resource management,especially the basic laws,concepts and basic techniques of aquatic resource management in Japan. It was concluded that the experience of management systems,basic methods,etc. in Japan,as a county that has earlier protected and managed aquatic resources,is worth learning by the establishment of China's aquatic resource management system.

Study on Due Procedure of Local Legislation of Marine Fishery Management

Based on the local legislation of marine fishery management, this paper takes the process of local legislation of marine fishery management in Liaoning Province as the main object of study, to explore the advantages and existing problems of the process of local marine fishery management. From the perspective of theory and practice, this paper analyzes the local legislative process deeply and discloses some problems, especially analyzes the main steps deeply in order to discover problems in the whole process from drafting to acting and proposes the corresponding solutions.

Lobster Fishery Connectivity and Management In Indonesia Waters

The distribution of lobsters in Indonesian waters is very wide,even lobster species in Indonesia are also scattered in the tropical waters of the western Pacific Ocean,the Indian Ocean,Africa to Japanese waters.Indonesian waters are divided into 11(eleven)Fishery Management Zone(FMZ).Lobsters in Indonesia may come from various water areas,both national and regional water zones,and they’re called the sink population.Its spread is influenced by the movement of the current.Lobster seed is nurtured by nature through ocean currents from Australia,East Indonesia,Japan,then back to Australia.Lobsters have a complex life cycle,where adult lobsters inhabit coral reefs as a place to lay eggs,then hatch into planktonic larvae,and grow up in open seas and carry out diurnal and ontogenetic vertical migrations before returning to nurseries in shallow coastal areas and reefs,coral,as well as habitat by the type of species.Literature research had used at least two methodologies to estimate the distribution and connection sensitivity matrices of marine organism larvae.The two most common approaches are using genetic markers and numerical biophysical modeling.Thus,this research uses molecular genetic techniques to explain the ge­netic structure of lobster populations using a biophysical model approach that can explain the genetic structure of lobsters,as well as the distribution based on regional oceanographic synthesis data and lobster biology known in Indonesian waters.This model has four components,namely:1)a ben­thic module based on a Geographical Information System(GIS)which is a lobster habitat in the spawning and recruitment process,2)a physical oceanography module containing daily velocity in the form of a three-di­mensional hydrodynamic model,3)a larva biology module that describes larval life history characteristics,and 4)a Lagrangian Stochastic module that tracks the individual trajectories of larvae.

Fishing Dynamic and Stock Status of Endeavour Shrimp(Metapenaeus ensis de Haan)in Bombana Waters,South-East Celebes

The high market demand for endeavour shrimp(Metapenaeus ensis de Haan)has caused intensive fishing for this resource and tends to threaten their sustainability.Assessment of fishing dynamic and stock status of fisheries resource is the main point to formulate its proper sustainable management in the future.The purpose of this study was to determine the stock status of endeavour shrimp in the Bombana and its surrounding waters.The study was conducted from April to November 2021 using a survey method to analyze the length at first capture(L_(c)),length at first maturity(L_(m)),growth rate(K),maximum theoretical carapace length(Loo),and mortality rate such as total mortality rate(Z),fishing mortality rate(F)and natural mortality rate(M).The study results revealed that the endeavour shrimp growth pattern in Bombana was negative allometric and that the ratio of males and females was not balanced.The length at first capture(L_(c))was 29.83 mm(carapace length)and the length at first maturity(L_(m))was at a total carapace length of 31.67 mm.The growth rate(K)was 1.0 per year and maximum theoretical length(L_(∞))was 46.2 mm.The estimate total mortality rate(Z)was 2.52 per year,the fishing mortality rate(F)and natural mortality rate(M)were 0.91 per year and 1.61 per year respectively.The exploitation rate(E)was 0.36 per year,therefore the stock status is not categorized overfishing.In order to ensure the sustainability of the endeavour shrimp,then the effort must be increased by about 28%of the current effort.

Dilemma of total allowable catch(TACs)allocated as shareable quotas:Applying a bio-economic game-theoretical approach to euro-mauritanian fisheries agreements

The recent fisheries management approach by Mauritania recommends that Total Allowable Catch(TAC)quotas,identified as essential for maintaining fish stocks,be shared(allocated)among fishing fleets operating in Mauritanian waters.However,the efficiency of such management regulations is debated.This issue can be identified as the typical dilemma between distant-fishing countries and coastal countries.We developed a theoretical model to determine how to allocate TAC quotas between the fishing fleets of Mauritania(RIM)and the European Union(EU).We discuss the various procedures and conditions for optimizing the allocation of fishing quotas(by country)in context of the Nash equilibrium.We found that both equilibria are characterized by strategic interactions of the exploitation that influence both the supply of TAC quotas available on the market and the cost of externalities due to RIM’s dependence on financial compensation by the EU and available TAC quotas.

The hits and misses of Namibia’s attempt to implement the Ecosystem Approach to Fisheries(EAF)Management

Ecosystem Approach to Fisheries(EAF)management is a concept aimed at the conservation and sustainable use of the entire ecosystem.While EAF is a noble approach,its implementation has been challenging.Although Namibia has committed to the implementation of EAF,only limited assessment has been done of Namibian fisheries management processes and instruments concerning EAF.A qualitative assesment was done to ascertain if the Namibian fisheries management processes and instruments conform to the EAF principles.Namibian fisheries management processes and instruments largely conform to the EAF principles,although there are notable areas needing improvements.The conformities were pronounced in the total allowable catch setting,rebuilding depleted stocks,minimizing bycatch,and fishing impact minimization.The polluter pays,and user pays principles were also applied.Areas that were found lacking in this study included setting the indicators for EAF and ecosystem integrity.The assessment also noted the absence of guidelines for the precautionary approach principle and a transparent policy for quota and right allocation processes.The strategies for managing transboundary fish species are also not formulated.Overall,this assessment showed the complexities and challenges that Namibia and other countries need to overcome to implement EAF successfully.

Hydroacoustic estimates of fish biomass and spatial distributions in shallow lakes

We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of the Changjiang(Yangtze) River in November 2013. Both lakes are subject to active fish management with annual stocking and removal of large fish. The purpose of the study was to compare hydroacoustic horizontal beam estimates with fish landings. The preliminary results show that the fish distribution patterns dif fered in the two lakes and were af fected by water depth and macrophyte coverage. The hydroacoustically estimated fish biomass matched the commercial catch very well in Niushan Lake, but it was two times higher in Kuilei Lake. However, acoustic estimates included all fish, whereas the catch included only fish >45 cm(smaller ones were released). We were unable to determine the proper regression between acoustic target strength and fish length for the dominant fish species in the two lakes.

Significant Effects of Fishing Gear Selectivity on Fish Life History

Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual's traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectivity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. According to the existing tend of exploited fish individual's life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.

Management of China's capture fisheries:Review and prospect

Management of capture fisheries has been a perpetual problem facing all fisheries countries worldwide.This study first analyzes the features of China's capture fisheries,and points out that its management tends to be more complex and difficult than any other country in the world.It goes on to describe the history of China's fisheries management and the development process of China's fisheries policies,recognizing the role of fisheries policies in guiding and promoting industrial production during the whole development process.With Fisheries Law of the People's Republic of China as the basic framework,China is thought to have initially formed a fisheries management system with a complete structure and powerful measures for constant improvement and reinforcement.Major systems and measures of China's fisheries management are summarized,with their corresponding effects being evaluated to a certain extent.China's continuous introduction of advanced fisheries management philosophies over the past decades,especially since the reform and opening up,plays an active role in securing the prosperity of the following five industries:aquaculture,capture fisheries,processing and logistics,enhancement,and recreational fisheries;more effort has been put into fisheries ecological environment restoration;and lawbased governance capacity in fisheries has been significantly improved.However,due to the characteristics of China's fisheries,as well as the complex and uncertain nature of fisheries itself,certain prominent problems still remain in its capture fisheries.With reference to relevant fisheries development planning,the study concludes with a prospect that China's capture fisheries management will be steered towards the total catch control of fisheries resources and the intensification of resource conservation and ecological restoration.

Stock assessment for Atlantic yellowfin tuna based on extended surplus production model considering life history

The modern fishery stock assessment could be conducted by various models,such as Stock Synthesis model with high data requirement and complicated model structure,and the basic surplus production model,which fails to incorporate individual growth,maturity,and fishery selectivity,etc.In this study,the Just Another Bayesian Biomass Assessment(JABBA)Select which is relatively balanced between complex and simple models,was used to conduct stock assessment for yellowfin tuna(Thunnus albacares)in the Atlantic Ocean.Its population dynamics was evaluated,considering the influence of selectivity patterns and different catch per unit effort(CPUE)indices on the stock assessment results.The model with three joint longline standardized CPUE indices and logistic selectivity pattern performed well,without significant retrospective pattern.The results indicated that the stock is not overfished and not subject to overfishing in 2018.Sensitivity analyses indicated that stock assessment results are robust to natural mortality but sensitive to steepness of the stock-recruitment relationship and fishing selectivity.High steepness was revealed to be more appropriate for this stock,while the fishing selectivity has greater influence to the assessment results than life history parameters.Overall,JABBA-Select is suitable for the stock assessment of Atlantic yellowfin tuna with different selectivity patterns,and the assumptions of natural mortality and selectivity pattern should be improved to reduce uncertainties.