Fisheries Management Measures Research Articles

Biometric Indices and Condition factors of Pomadasys jubelini (Cuvier, 1830) from Obuama Creek, Nigeria

Biometric indices of Pomadasys jubelini from Obuama Creek, Rivers state, Nigeria were investigated using length frequency distributions (LFDs), length-weight relationships (LWRs), length-length relationships (LLRs), condition factors (allometric, KA, Fulton’s, KF and relative, KR). Specimens were captured in a stretch of the creek from March to September 2019. A total of 229 specimens were examined with the total length (TL) and weight (W) ranging from 8.7 to 50.4 cm and 8.7 to 834.5 g respectively. The standard length (SL) ranged from 5.3 to 46.8 cm, fork length (FL) was between 6.5 to 48.7 cm and the girth length (GL) varied from 4.7 to 38.7 cm. The relationships of weight-length showed a negative allometric growth pattern with a value of "b" of 2,666. Fulton's condition factor (KF) ranged from 0.10 to 5.45, with an average of 1.21±0.66 indicating perfect wellbeing for the species. The LLR's allometric coefficient ' b ' between TL vs. FL and TL vs. GL showed positive allometric growth, while SL vs. FL, SL vs. TL, SL vs. GL, and GL vs. TL showed negative allometric growth, although the values were close to 1. These findings also provided some new and updated information on some of the morphometric characters of Pomadasys jubelini in Obuama Creek that could be useful for fisheries management and fish species protection measures in the creek and adjacent habitats.

Assessing potential protection effects on commercial fish species in a Cuban MPA

Cuba has been leading marine protected area (MPA) designation in the Caribbean region to ensure conservation of its valuable marine ecosystems. Yet, an efficient monitoring program for MPAs is still to be implemented and will benefit from pre-existing information. The highly regulated MPA of Punta Francés National Park is one of the first Cuban MPAs and was established mainly to protect species and ecosystems for tourism purposes. Monitoring of protection effects on commercial fish species was lacking in this MPA. This study aimed at increasing local scientific knowledge by providing a baseline study about the most commercially fished families (Haemulidae, Lutjanidae and Serranidae) around Punta Francés MPA. Data collected represent only a limited period but can be used as a base point to support future monitoring. Fish abundance in number and biomass, and size were collected to test for differences between inside and adjacent areas outside the Punta Francés MPA, in different coral reef types. The main result of this study was the significantly larger size and biomass of snappers and groupers outside the MPA where intense fisheries occur. An observation consistent with a large spawning aggregation was also recorded outside the MPA. Even with a limited set of data, these results suggest that, at least temporarily, the most targeted species [and sizes] are still highly vulnerable to fisheries. Relevant habitats in the adjacent area, that are apparently missing within the MPA, may support some of the results found. Extending the limits of the Punta Francés MPA to include those habitats outside may be critical to ensure the effectiveness of this MPA in contributing to protect the most commercial species of the region. This should be done together with efficient fisheries management measures in the region, such as the significantly increase of minimum legal sizes and temporal closures during spawning migrations.

Evaluating the effectiveness of a large multi‐use MPA in protecting Key Biodiversity Areas for marine predators

AbstractAimMarine protected areas can serve to regulate harvesting and conserve biodiversity. Within large multi‐use MPAs, it is often unclear to what degree critical sites of biodiversity are afforded protection against commercial activities. Addressing this issue is a prerequisite if we are to appropriately assess sites against conservation targets. We evaluated whether the management regime of a large MPA conserved sites (Key Biodiversity Areas, KBAs) supporting the global persistence of top marine predators.LocationSouthwest Atlantic Ocean.MethodWe collated population and tracking data (1,418 tracks) from 14 marine predator species (Procellariiformes, Sphenisciformes, Pinnipedia) that breed at South Georgia and the South Sandwich Islands, and identified hotspots for their conservation under the recently developed KBA framework. We then evaluated the spatiotemporal overlap of these sites and the different management regimes of krill, demersal longline and pelagic trawl fisheries operating within a large MPA, which was created with the intention to protect marine predator species.ResultsWe identified 12 new global marine KBAs that are important for this community of top predators, both within and beyond the focal MPA. Only three species consistently used marine areas at a time when a potentially higher‐risk fishery was allowed to operate in that area, while other interactions between fisheries and our target species were mostly precluded by MPA management plans.Main conclusionsWe show that current fishery management measures within the MPA contribute to protecting top predators considered in this study and that resource harvesting within the MPA does not pose a major threat—under current climate conditions. Unregulated fisheries beyond the MPA, however, pose a likely threat to identified KBAs. Our approach demonstrates the utility of the KBA guidelines and multispecies tracking data to assess the contributing role of well‐designed MPAs in achieving local and internationally agreed conservation targets.

Trophic overlap between marine mammals and fisheries in subtropical waters in the western South Atlantic

Marine mammals and humans are apex predators and both may compete for fish in ecosystems under continuous fishing pressure. We assessed the degree of trophic overlap between prey species found in the diet of 5 marine mammals (39 specimens of sea lion Otaria flavescens, 61 fur seals Arctocephalus australis, 76 franciscana dolphins Pontoporia blainvillei, 25 bottlenose dolphins Tursiops truncatus and 28 Lahille’s bottlenose dolphins T. gephyreus) and the catches of the 6 main commercial fishing gears used in southern Brazil (coastal gillnets, oceanic gillnets, purse seine, demersal pair trawling, bottom [single] trawl and double-rig trawling) between 1993 and 2016. An adjusted general overlap index indicated an overall moderate to high overlap. Specific overlap analysis showed that O. flavescens and T. truncatus presented high trophic relationships with fisheries, followed by T. gephyreus. Smaller interactions were observed for A. australis and P. blainvillei, even though they also exploit commercial fishing resources. Coastal gillnet and pair bottom trawling are the fisheries that most target the fish species favoured by O. flavescens, T. gephyreus and T. truncatus. The information presented in this study on trophic interactions may assist decision making for both fishery management and conservation measures for these apex predators. Commercial fishing activities are a major threat to marine mammals both regionally and globally. Current levels of fishing or its intensification may lead to dramatic changes in the coastal marine food web, including additional threats to coastal marine mammal populations in southern Brazil.

Input versus output controls as instruments for fisheries management with a focus on Mediterranean fisheries

Article 4 of EU Regulation 1380/2013 on the Common Fisheries Policy (CFP) define ‘technical measure’ as “a measure that regulates the composition of catches by species and size and the impacts on components of the ecosystems resulting from fishing activities by establishing conditions for the use and structure of fishing gear and restrictions on access to fishing areas.” Thus, these are a set of rules that govern where, when and how fishing can take place. Most of the fisheries management systems in place worldwide employ technical measures based on control of inputs and outputs. For Europe, the European Commission is reforming the CFP legislative framework and has updated and amended the rules for technical measures (EU Regulation 2019/1241). This is particularly important for management systems in the European parts of the Mediterranean, where input measures play a major role, in contrast to management systems in the North East Atlantic, which uses mainly output measures (catch quota).We discuss here the main advantages and disadvantages of these instruments with a particular focus on the European part of the Mediterranean Sea, our main aim being to foster a debate on the best measures for fisheries management.

Parturition time for the Blacktip shark, Carcharhinus limbatus (Carcharhiniformes: Carcharhinidae), in Southwestern Atlantic

Abstract The determination of the period of parturition and identification of nursery areas are fundamental for the management and conservation of a fishing resource. Through combination of monthly abundance, length measurements, and development time of embryos we inferred about parturition time of the Blacktip sharks, Carcharhinus limbatus, from Southwestern Atlantic. Specimens of C. limbatus were caught from 2002 and 2008 by artisanal fleets from three different locations along the Brazilian coast using gillnets (mesh width ranging between 30 and 120 mm between opposite knots and operating from 9 to 120 m in depth), handlines (19 to 140 m depth) and longlines (6 to 90 m depth). Through a comparative analysis of fisheries landing data collected, we have verified neonatal (< 90 cm) catch peaks at specific times of the year in different locations and, matching with birth prediction of embryos, propose that C. limbatuspresents a well-defined parturition time in late spring-early summer in Southwestern Atlantic. Moreover, we indicate supposed nursery grounds for the species along the Brazilian coast. This information will be crucial for stock assessments of the species and may serve as a basis for determining fisheries management measures.

Bioeconomic Modelling of Coastal Cod and Kelp Forest Interactions: Co-benefits of Habitat Services, Fisheries and Carbon Sinks

Ecosystem-based fisheries management seeks to expand upon the traditional one-stock fisheries management measures by internalizing the effects of fishing on marine ecosystems, and accounting for biological interactions among marine resources. The fact that marine resources provide multiple, often competing benefits, makes the accomplishment of these ecosystem-based fisheries management objectives highly complex. In this paper, we develop a dynamic bioeconomic model to analyze the ecological and economic interactions between fisheries and renewable habitat where the habitat provides multiple ecosystem services. Specifically, a single resource manager seeks to maximize co-benefits of fishery-habitat interactions when the habitat is an exploitable marine resource, but also a dwelling place for commercial fish, enhancing the growth of the fish stock and providing regulating ecosystem services in the form of carbon sink for climate change mitigation. The optimal management rules for both fishery and habitat are derived and discussed. We also present an application of the model to analyze an integrated management of coastal cod and kelp forests in Norway, where regulations on commercial harvesting of kelp forests seek to protect fisheries. Both the theoretical model and the Norwegian application suggest substantial potential increases for both coastal cod and kelp forest stocks, with an attendant 8% increase in cod harvests, and about 1% reduction in kelp harvests. In addition, an optimal management regime that internalizes carbon sink co-benefits of kelp forests stores additional 300,000 tonnes of carbon.

The Sofia Ministerial Declaration on Black Sea Fisheries and Aquaculture

Abstract The General Fisheries Commission for the Mediterranean (GFCM), established in 1949 has always included Black Sea fisheries and in 1976 its constitutive agreement was amended to expressly include the Black Sea. A working group on the Black Sea (WGBS) established in 2011 was instrumental in adopting the first GFCM management measures for Black Sea fisheries. On 7 June 2018, the GFCM organized a High-Level Conference on Black Sea Fisheries and Aquaculture in Sofia which culminated with the signature of a ministerial declaration on Black Sea fisheries and aquaculture. This marked a milestone in the history of cooperation for fisheries among the Black Sea riparian countries.

Assessment of fish vulnerability to climate change in the Yellow Sea and Bohai Sea

Vulnerability assessments provide a feasible yet infrequently used approach to expanding our understanding and evaluating the effects of climate change on fish assemblages. Here, we first used a fuzzy-logic expert system to quantitatively estimate the vulnerability and potential impact risks of climate change for fish species in the Bohai Sea and Yellow Sea (BSYS). The mean (±s.d.) vulnerability and the impact-risk indices for 25 dominant fish species were 51±22 and 62±12 respectively (with the highest possible value being 100 under the Representative Concentration Pathway 8.5 scenario). Miiuy croaker (Miichthys miiuy) was found to have the highest impact risk, whereas the glowbelly (Acropoma japonicum) had the lowest. Demersal fishes tended to be more vulnerable than pelagic fishes, whereas the opposite was found for impact risks. No significant correlation was found between species biomass and vulnerability (P>0.05). The assessment provided a comprehensive framework for evaluating climate effects in the BSYS and suggested that interspecific and habitat group differences should be considered when developing future climate-adaptive fishery policies and management measures in this region, as well as similar systems elsewhere in the world.

Decadal variations in the community status of economically important invertebrates in the Bohai Sea

With the decline of fish stocks, the proportions of economically important invertebrates like crustaceans and cephalopods have increased in the Bohai Sea. The community structure and trophic level of economically important invertebrates were analyzed using the bottom trawl survey data collected by the Yellow Sea Fisheries Research Institute in the Bohai Sea in May and August of 1958–1959, 1982, 1992–1993, 2004, 2009 and 2015. A total of 37 species of economically important invertebrates, belonging to 5 orders, 24 families, were captured. The biomass densities of economically important invertebrates in the Bohai Sea displayed an overall downward trend from 1982 to 2015. Oratosquilla oratoria and Loligo spp. were the most dominant species in the past 30 years, the biomass proportion of O. oratoria increased gradually in both May and August from 1982 to 2015. Moreover, biodiversity indices of economically important invertebrates in the Bohai Sea appeared to decline from 1982 to 2004 and then increased in 2015. Similarly, the mean trophic level of economically important invertebrates declined from 1982 to 2004 and increased slightly in 2015. Overall, although the proportions of invertebrates have increased, the biomass densities in the Bohai Sea have displayed an overall downward trend from 1982 to 2015. The increases in the biodiversity and trophic level of economically important invertebrates after the 2000s, possibly benefit from stock enhancement projects implemented by governments at different levels and national fishery management measures such as the “double-control” of the total number and engine power of fishing vessels and summer moratorium of fishing.

Sex related differences in density, selectivity and vulnerability of the Atlantic blue crab, Callinectes sapidus (Rathbun, 1896), in the southern Gulf of Mexico

The density, selectivity and vulnerability by sex of Atlantic blue crab (Callinectes sapidus) in the Yucatan coast were estimated using a Jolly–Seber mark–recapture model. A total of 614 individuals of C. sapidus were captured, of which 336 were marked and of these 20 were recaptured. Overall male:female ratio was 1:3.78. The selectivity of fishing gear (L50) was estimated at 143.9 and 141.4 mm carapace width for females and males, respectively. Catch per unit effort (CPUE) was estimated at 0.41 (males) and 1.55 (females) individuals trap−1. With the model of Jolly–Seber density was estimated at 39 males ha−1 and 323 females ha−1. The average catchability (q) of the males was 0.0340 and 0.0243 for the females, and the relative vulnerability was higher for males of small sizes and females of large sizes. Our results indicated that sex related demographic variations should be considered in further design and application of fishery management measures since differences in density, selectivity, catchability and vulnerability by sex were found.

The neglected complexities of shark fisheries, and priorities for holistic risk-based management

Sharks and their cartilaginous relatives (Class Chondrichthyes, herein ‘sharks’) are one of the world's most threatened species groups. Their slow life history traits and vulnerability to capture make them particularly susceptible to overfishing, and they are widely caught in both target and by-catch fisheries. Fisheries management measures that can effectively reduce shark fishing mortality are urgently required to halt population declines and species extinctions. We provide an overview of typical measures for understanding and managing risks to sharks, and highlight critical gaps relating to incorporating socio-economic factors in to research and management. We argue that neglecting these factors hinders effective shark conservation, and has negative consequences for people. We emphasise the importance of a holistic approach, which explicitly considers socio-economic factors in decision-making. Based on this, we propose the first framework for assessing feasibility in a shark management context, which could be integrated with traditional fisheries risk assessments in order to bridge this gap. This framework considers key dimensions of the costs, benefits and overall enabling environment for shark management in a given fishery. Overall, managers and policy makers must consider socio-economic factors in shark conservation efforts to deliver better outcomes for sharks and people. Our simple feasibility framework can support this by enabling costs, benefits and context to be explicitly considered in planning and policy-making, alongside the typical biological and technical risks to sharks in fisheries.

Reproductive Biology of Three Important Threatened/Near-Threatened Groupers (Plectropomus leopardus, Epinephelus polyphekadion and Plectropomus areolatus) in Eastern Indonesia and Implications for Management.

Simple SummaryIndonesia needs basic data on the reproductive dynamics of economically important fishery species, including groupers, in order to support sustainable fisheries management. Data from the histological examination of grouper gonad samples were combined with data from: participatory mapping and interviews with fishermen, monitoring data from known spawning aggregation sites, and analyzed descriptively to provide basic data on the size at first maturity and seasonal reproductive patterns of three economically important groupers. We suggest management measures including size limits, temporal spatial closures, and a trading ban during the peak spawning season (November–December).The three grouper species most heavily fished for the live reef fish trade (LRFT) in Indonesia are Plectopomus leopardus (greatest catch volume), and two species classified as Vulnerable on the International Union for Conservation of Nature (IUCN) Red List: Plectropomus areolatus and Epinephelus polyphekadion. Understanding the reproductive biology of these fishes is essential for sustainable management, but relevant data are limited. This study aimed to determine reproductive dynamics, so as to inform management measures to maintain the reproductive capacity of these groupers. Grouper gonad samples collected from fish caught for the LRFT were analyzed histologically. Data were also collected from participatory mapping and interviews with fishermen, and underwater monitoring of three known spawning aggregation sites in the Wakatobi National Park, Eastern Indonesia. Based on observed gonad development, the respective lengths and weights at first maturity were: 37.7 cm and 759 g (P. leopardus); 36.65 cm and 771.2 g (P. areolatus); 36.95 cm and 889.9 g (E. polyphekadion). The mean weight of the groupers market-based sampled was higher than the size at first sexual maturity. Sex transition was observed in P. leopardus; sex reversal was not observed in E. polyphekadion, and the sex pattern of P. areolatus was unresolved. Based on the fisher surveys and spawning aggregation monitoring, spawning occurs around the new moon from September to April, with reproductive peaks in November and December. Fisheries management measures that are suggested to sustain grouper stocks include enforcing appropriate size limits, temporal spatial closures (spawning aggregation sites), and a trading ban during the peak spawning season (November–December).

Morphometric characteristic and growth patterns of climbing perch (anabas testudineus) from sungai batang river, Indonesi

This study provides scientific evidence on the length-weight relationship, condition factor and growth patterns of the Climbing perch (Anabas testudineus) from Sungai Batang River, Indonesia. The fish were obtained from local fishermen. A total of 156 individuals of A. testudineus consisted of 77 males and 79 females (55-125mm total length and 3-47g weight) were analyzed using SPSS-16 software. There were no statistically significance differences in the total length (TL), body depth (BD), and body weight (W) between male and female, as well as the W/TL and BD/TL ratio values of the fish (P>0.05). Most of total catch falls within the range of 80 and 89mm total length and more than 40% of total catch weighed between 10 and 19g. The W/TL ratio value of A. testudineus in the present study was more or less identical to that of A. testudineus from other different geographical areas. The fish samples were in good condition and grew negatively allometric (b=2.7766-2.8791). Outcomes of this study could be useful for fisheries management and conservation measures in this river.

First Central Mediterranean Scientific Field Study on Recreational Fishing Targeting the Ecosystem Approach to Sustainability

The Maltese Islands have a very active recreational fishing community which may affect the coastal marine ecosystem. Despite this, studies to scientifically document the effects of this activity have been lacking prior to works between July 2012 and June 2017 presented here as a case study. This project, with the aim of collecting long-term data on the characteristics, trends, catches and impacts to fish populations of the recreational shore sport fishery at the national level also involved a pilot study on hobby shore angling. 2589 roving-access creel surveys conducted during 132 sport fishing events and 159 catches from hobby fishers were documented with the methodology used also applicable to shore fishing taking place in the Mediterranean and elsewhere. 90 species belonging to 29 families were documented with the most common being the Sparidae and Labridae. Catch per unit effort was higher for sport fishers with hobby fishers targeting larger fish. Results from this case study go to augment the limited and necessary knowledge on this fishing sector in the Mediterranean. Findings also indicate that recreational fisheries need to be taken into account when considering conservation measures for national, regional and global fisheries management.

Identifying the distribution of Atlantic cod spawning using multiple fixed and glider-mounted acoustic technologies

Abstract Effective fishery management measures to protect fish spawning aggregations require reliable information on the spatio-temporal distribution of spawning. Spawning closures have been part of a suite of fishery management actions to rebuild the Gulf of Maine stock of Atlantic cod (Gadus morhua), but difficulties remain with managing rebuilding. The objective of this study was to identify the spatial and temporal distribution of cod spawning during winter in Massachusetts Bay to improve our understanding of cod spawning dynamics and inform fisheries management. Spawning was investigated in collaboration with commercial fishermen during three winter spawning seasons (October 2013–March 2016) using acoustic telemetry and passive acoustic monitoring equipment deployed in fixed-station arrays and mounted on mobile autonomous gliders. Tagged cod exhibited spawning site fidelity and spawning primarily occurred from early November through January with a mid-December peak and some inter-annual variability. The spatial distribution of spawning was generally consistent among years with multiple hotspots in areas >50 m depth. Current closures encompass most of spawning, but important areas are recommended for potential modifications. Utilizing multiple complementary technologies and deployment strategies in collaboration with commercial fishermen enabled a comprehensive description of spawning and provides a valuable model for future studies.

Small-scale fishers' perceptions about the performance of seasonal closures in the commonwealth of Puerto Rico

The targeting of spawning aggregations is one of the most significant pressures facing coral reef ecosystems. The use of seasonal closures has been advanced for protecting aggregating fisheries for which managers have limited information on the location and timing of their reproductive events; however, few studies have examined the performance of these types of closures. This study assesses the perceptions of 150 fishers regarding the performance of seasonal closures in the Commonwealth of Puerto Rico.Our results show that most fishers perceived that seasonal closures are effective fishery management measures. Across the six seasonal closures examined, fishers reported that these closures protected spawning aggregations and, to a lesser degree, increased fish abundance. These measures, however, did not always improve fishers' livelihoods nor result in their support for the seasonal closures. The loss of resource and market access during periods of high consumer demand and overlapping seasonal closures were the main causes of financial distress.Fishers indicated that the performance of the seasonal closures could be improved by increasing investments in monitoring, control, and surveillance capabilities, and adjusting their timing to accommodate economic and local ecological considerations. Fishers argued that revisions were necessary because some species spawned year-round or outside closure windows. Some fishers also called for replacing seasonal closures with alternative management measures (e.g., area-time closures, marine protected areas, gear restrictions), conducting additional scientific research, and improving fisher education. This work underscores that beliefs about conservation and livelihood outcomes are closely linked to the quality of management, the importance of conducting periodic assessments, and engaging fishers in decision-making to increase accountability, transparency, and support for management interventions.

Fishermen's perceptions of coastal fisheries management regulations: Key factors to rebuilding coastal fishery resources in Taiwan

Although Taiwan has taken conservation measures for coastal and offshore fishery resources in recent years, the effectiveness of resources rebuilding is unclear. Many initiatives, such as marine protected areas (MPAs), are frequently opposed by fishermen. This research reviewed management measures and interviewed 313 fishermen by purposive stratification and snowball sampling. Data were analyzed by fishery, age, and vessel size to address the attitudes and perceptions of fishermen toward twelve fisheries management measures. Descriptive statistics, as well as chi-squared tests and independent t-tests, were used for basic analysis and differences comparison between groups. The results showed that illegal fishing vessels from China (71%), overfishing (69.5%), and ghost fishing (64%) are considered as major threats to Taiwan marine resources. The measures from voyage data recorders, larval anchovy, precious coral, and shark management result in higher satisfaction because of strict monitoring. The satisfaction measures for three net-type measures, i.e., trawler area closure, torch-light limitation, and gillnet limitation, were low. Line-type and small-scale vessel fishermen are more concerned with “small mesh size” and “ghost fishing”. Net-type, large-scale vessels and young fishermen were concerned about “climate change” and “inappropriate measures”. In conclusion, the priorities are to (1) establish a comprehensive scientific research framework; (2) strengthen enforcement to ensure resources rebuilding, especially for large-scale net fisheries; (3) promote public awareness and build communication between stakeholders to obtain support; and (4) communicate among policymakers and fishermen to increase mutual understanding.

Boom‐bust like dynamics of invasive black bullhead (Ameiurus melas) in Lake Sava (Serbia)

AbstractThe life‐history traits and population dynamics of the black bullhead Ameiurus melas (Rafinesque) were studied monthly from August 2009 to December 2012 in Lake Sava in Belgrade (Serbia). This period included a mass mortality event in May 2011 and subsequent population recovery during 2012. Available evidence suggests the mass mortality was caused by European catfish virus that only affected the black bullhead. Changes in key life‐history traits and the recovery potential (increase in catch‐per‐unit‐effort, doubling of young‐of‐the‐year to adult ratio, earlier maturation and increased fecundity) following the mass mortality event suggest population resilience typical of a recurring boom‐bust pattern and demonstrate the species’ capacity to recover rapidly and re‐establish following disturbance. Repeated systematic mass removals of both juveniles and adults (using fyke nets) will be required if future fishery management measures aimed at limiting the population size are to be effective.

Effects of prolonging the trawl net summer fishing moratorium period in the East China Sea on the conservation of fishery resources

PDF HTML阅读 XML下载 导出引用 引用提醒 延长拖网伏季休渔期的渔业资源养护效应 DOI: 作者: 作者单位: 中国水产科学研究院东海水产研究所, 农业农村部东海渔业资源开发利用重点实验室, 上海 200090 作者简介: 严利平(1964-),男,研究员,研究方向为渔业资源评估和管理.E-mail:yanlp@ecsf.ac.cn 通讯作者: 中图分类号: S932 基金项目: 公益性行业（农业）科研专项经费项目（201303047）；农业部财政项目（2014-2018，2014-2017，2017-2018）. Effects of prolonging the trawl net summer fishing moratorium period in the East China Sea on the conservation of fishery resources Author: Affiliation: Key Laboratory of East China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs;East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:海洋伏季休渔制度是当前中国最主要的渔业资源管理制度之一，并在实践中得到不断调整与完善，新的海洋伏季休渔制度已于2017年发布实施。为论证新制度延长拖网休渔期的渔业资源养护效应，本研究依据2015—2017年每年5月东海区拖网大面定点调查资料，利用Ricker动态综合模型，从拖网的渔获结构特征和带鱼（Larimichthys polyactis），带鱼和小黄鱼的性成熟比例分别为92.04%~95.57%和13.82%~29.55%，幼鱼比例分别为74.94%~88.90%和0.03%~4.19%；带鱼种群经过4.5个月的休渔，其单位补充量资源量、单位补充量渔获量和平均渔获质量与3.5个月休渔期相比较，分别增加了7.04%、8.96%和20.78%。以上结果表明，提前并延长拖网休渔期，东、黄海主要经济渔业资源带鱼与小黄鱼的产卵群体和幼鱼得到进一步保护，资源增殖效果随着休渔期的不断延长而增加，新制度的休渔时间设置更趋合理。但由于开捕后的带鱼与小黄鱼渔获仍主要以当龄鱼为主，有必要同时配套执行现已颁布的最小网目尺寸和开捕标准等其他渔业资源管理措施，以确保伏季休渔制度主导下的渔业资源养护效果能真正得到巩固，渔业资源的种群结构能够得到切实好转与不断合理化。 Abstract:The summer fishing moratorium system, the main fishing management system in China, has been continuously adjusted and perfected in practice. In order to evaluate the conservation effects of prolonging the trawl net summer fishing moratorium period, which is contained in the new summer fishing moratorium system and promulgated in 2017, on the fishery resources, the data from the bottom trawl surveys in May during 2015-2017 and the dynamic integrated Ricker model were used to quantitatively analyze the structural characteristics of trawl catches and the dynamics of fish species such as the hairtail (). The results showed that the hairtail and the small yellow croaker () were the main organisms that were trawled in May, and their sex maturity ratios were 92.04%-95.57% and 13.82%-29.55%, respectively, while the proportion of juvenile fish for the two species were 74.94%-88.90% and 0.03%-4.19%, respectively. Compared with that from the previous 3.5 month fishing moratorium period, the biomass per recruit, yield per recruit, and the average catch weight of hairtail increased 7.04%, 8.96%, and 20.78%, respectively, after the newly enforced 4.5 month fishing moratorium period. According to our study, advancing and prolonging the trawl net moratorium period could further protect the spawning groups and juveniles of the hairtail and the small yellow croaker, which were the main economic fishery resources in the East China Sea and the Yellow Sea. The resource enhancement effect was more significant with the longer moratorium period, so the time setting of the new summer fishing moratorium system was reasonable. However, after the newly enforced summer fishing moratorium period, the main hairtail and little yellow croaker catch were still dominated by 1-year-old fish. Thus, it is necessary to support the implementation of other fishery resource management measures in addition to the new summer fishing moratorium system, such as the minimum mesh size and the open capture standard, to ensure that the conservation effects are firmly established and that the population structure of the fishery resources can continuously improve. 参考文献 相似文献 引证文献