scholarly journals Using the LBB Method for the Assessments of Seven Fish Stocks From the Yangtze Estuary and Its Adjacent Waters

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuanchao Wang ◽  
Cui Liang ◽  
Weiwei Xian ◽  
Yibang Wang
Keyword(s):  
Fishery Management ◽  
Management Strategies ◽  
Yangtze Estuary ◽  
Reference Points ◽  
The Yangtze Estuary ◽  
Fish Stocks ◽  
Effective Implementation ◽  
Stock Biomass ◽  
The Status ◽  
Growth Features

The status of fishery resources in the Yangtze estuary and its adjacent waters is still unclear for the effective implementation of fishery management strategies. To help address this gap, a new method especially for data-limited fish stocks (LBB) was applied to assess seven commercially and ecotrophically important fish stocks. Fish specimens were collected in the estuary by bottom trawling quarterly from May 2018 to February 2019. Two historical datasets were collected with the same method in the same area for Indian perch (Jaydia lineata) and sickle pomfret (Pampus echinogaster). To explore the growth features and resilience of fish stocks, auximetric plots and growth performance indices (Φ′) were used. Results showed that common hairfin anchovy (Setipinna tenuifilis) in 2018 and Indian perch in 2018 showed a healthy stock biomass status with complete length structures under a sustainable fishing pressure. The others were outside of safe biological limits or overfished. The Lmean/Lopt < 0.9 in six (67%) of nine LBB models for seven fish stocks suggested that most of the stocks were truncated in length structures. This contribution provides the main fishery reference points regarding stock status that can inform managers and form the basis for various management strategies.

scholarly journals Reproductive hyperallometry and managing the world’s fisheries

2021 ◽  
Vol 118 (34) ◽  
pp. e2100695118
Author(s):  
Dustin J. Marshall ◽  
Michael Bode ◽  
Marc Mangel ◽  
Robert Arlinghaus ◽  
E. J. Dick
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Reference Points ◽  
Target Level ◽  
Fish Stocks ◽  
Global Food Security ◽  
Common Reference ◽  
Future Assessment ◽  
Traditional Approaches ◽  
Global Food

Marine fisheries are an essential component of global food security, but many are close to their limits and some are overfished. The models that guide the management of these fisheries almost always assume reproduction is proportional to mass (isometry), when fecundity generally increases disproportionately to mass (hyperallometry). Judged against several management reference points, we show that assuming isometry overestimates the replenishment potential of exploited fish stocks by 22% (range: 2% to 78%) for 32 of the world’s largest fisheries, risking systematic overharvesting. We calculate that target catches based on assumptions of isometry are more than double those based on assumptions of hyperallometry for most species, such that common reference points are set twice as high as they should be to maintain the target level of replenishment. We also show that hyperallometric reproduction provides opportunities for increasing the efficacy of tools that are underused in standard fisheries management, such as protected areas or harvest slot limits. Adopting management strategies that conserve large, hyperfecund fish may, in some instances, result in higher yields relative to traditional approaches. We recommend that future assessment of reference points and quotas include reproductive hyperallometry unless there is clear evidence that it does not occur in that species.

Island in the Stream: Oceanography and Fisheries of the Charleston Bump

2001 ◽  
Keyword(s):  
North Atlantic ◽  
Fishery Management ◽  
Population Analysis ◽  
Mortality Rates ◽  
Fishing Mortality ◽  
Stock Biomass ◽  
The Status ◽  
Eastern North Atlantic ◽  
Charleston Bump ◽  
Definition Of

<em> Abstract.</em>—The status of the wreckfish <em> Polyprion americanus </em>stock caught on the Blake Plateau in the southeastern United States Atlantic was analyzed by calibrated virtual population analysis (VPA) to estimate trends in fishing mortality and population (or stock) biomass. Calibration of the FADAPT VPA program was to fishery-dependent catch-per-unit effort (CPUE) for a range in assumed values for natural mortality (M). Age-length keys were developed from two aging studies of wreckfish (1988– 1992 and 1995–1998). Keys were developed annually (pooled across seasons to create three “annual” age-length keys to represent 1988–1990, 1991–1993, and 1994–1998) and seasonally (pooled across years to create three seasonal age-length keys to represent April–June, July–September, and October to end of fishing year on 15 January). Analyses based on both annual and seasonal catch matrices showed similar patterns and values, with the seasonal catch matrix producing slightly lower estimates of fishing mortality rates (F) and higher estimates of biological reference points based on F. Fishing mortality rates peaked in 1989, as did the maximum annual U.S. landings (4.2 million pounds). Subsequently, both landings and fishing mortality rates have generally declined. Although stock biomass has generally declined over the study period, recruitment at age 7 has risen since about 1994. Meanwhile, annual estimates of static spawning potential ratio (SPR), which are inversely related to F, have risen since 1994. Fishing mortality rates from recent low landings are at or near the South Atlantic Fishery Management Council’s threshold definition of overfishing (static SPR of 30%), while the process of rebuilding with improving recruitment appears to be underway. Concern persists because the assessment is based on the underlying assumption that wreckfish from the Blake Plateau form a single stock separate from the eastern North Atlantic and genetic evidence suggests the stock encompasses the entire North Atlantic.

The Angler in the Environment: Social, Economic, Biological, and Ethical Dimensions

2011 ◽  
Keyword(s):  
United States ◽  
Fishery Management ◽  
Management Strategies ◽  
Stakeholder Involvement ◽  
The United States ◽  
Shared Vision ◽  
Integrated Process ◽  
Analysis Model ◽  
The Status ◽  
King Mackerel

<i>Abstract</i> .—Despite widespread recognition of the importance of including stakeholders in management decisions for fisheries, an integrated process for broadening stakeholder involvement in the management of marine fisheries in the United States is lacking. Many marine recreational fishery stakeholders feel frustrated by a perceived lack of inclusion in the management process. Here, we describe a collaborative, integrated process between scientists and stakeholders, called “FishSmart,” which complements current management by informing fishery managers of stakeholder preferences for alternative management strategies. Strategies were designed by the stakeholders to improve the status of the king mackerel <i>Scomberomorus cavalla </i> fishery off the southeastern coast of the United States, relative to their shared vision of an improved fishery. Over the course of four facilitated workshops, stakeholders explored and compared the consequences of voluntary and regulatory fishery management strategies, using a decision analysis model developed by project scientists. Goals identified by stakeholders included maintaining high and stable catches and retaining year-round access and the ability to catch large fish. Options modeled included both voluntary changes in fishing practices and mandatory regulations. Stakeholders agreed that status quo management options were not sufficient to ensure sustainability in the Atlantic king mackerel fishery and developed a suite of 18 consensus recommendations of how to best meet their shared vision of a quality fishery.

scholarly journals Fisheries management under climate and environmental uncertainty: control rules and performance simulation

2013 ◽  
Vol 71 (8) ◽  
pp. 2208-2220 ◽  
Author(s):  
André E. Punt ◽  
Teresa A'mar ◽  
Nicholas A. Bond ◽  
Douglas S. Butterworth ◽  
Carryn L. de Moor ◽  
...  
Keyword(s):  
Fishery Management ◽  
Climate Models ◽  
Global Climate ◽  
Management Strategies ◽  
Environmental Variation ◽  
Global Climate Models ◽  
Reference Points ◽  
Environmental Data ◽  
And Performance ◽  
The Impact

Abstract The ability of management strategies to achieve the fishery management goals are impacted by environmental variation and, therefore, also by global climate change. Management strategies can be modified to use environmental data using the “dynamic B0” concept, and changing the set of years used to define biomass reference points. Two approaches have been developed to apply management strategy evaluation to evaluate the impact of environmental variation on the performance of management strategies. The “mechanistic approach” estimates the relationship between the environment and elements of the population dynamics of the fished species and makes predictions for population trends using the outputs from global climate models. In contrast, the “empirical approach” examines possible broad scenarios without explicitly identifying mechanisms. Many reviewed studies have found that modifying management strategies to include environmental factors does not improve the ability to achieve management goals much, if at all, and only if the manner in which these factors drive the system is well known. As such, until the skill of stock projection models improves, it seems more appropriate to consider the implications of plausible broad forecasts related to how biological parameters may change in the future as a way to assess the robustness of management strategies, rather than attempting specific predictions per se.

scholarly journals Human dimensions information needs of fishery managers in the Laurentian Great Lakes

2018 ◽  
Author(s):  
Nadine Heck ◽  
Richard C. Stedman ◽  
Marc Gaden
Keyword(s):  
Great Lakes ◽  
Cultural Values ◽  
Information Needs ◽  
Fishery Management ◽  
Supply And Demand ◽  
Management Strategies ◽  
Relevant Information ◽  
Human Dimensions ◽  
Interdisciplinary Studies ◽  
The Status

Fishery management is increasingly moving towards ecosystem-based approaches that integrate ecological and human dimensions of fisheries. Studies on the human dimensions (HD) of fisheries have increased in recent years. A gap, however, remains between the nature of available information and the information needed by fishery managers. Our paper addresses this gap for the Great Lakes fisheries. We explicitly explored information needs of fishery managers to better reconcile the supply and demand of HD information. Our study finds that managers need HD information in particular to demonstrate the achievements of management goals and to address management issues. In addition, understanding the purpose and timing of information is important in order to provide timely and relevant information as fishery managers identify distinct information needs for planning, decision-making, and evaluation of management. Fishery managers in our study were particularly interested in direct and indirect economic values of the fisheries as well as values, beliefs, attitudes, and behaviors of users. Interviewed managers were not only interested in the status quo of these factors but also wanted to understand what influences and shapes them. In addition, fishery managers would like to understand the contribution of fisheries to ecosystem services in the basin including cultural values. Our interviews did not detect interest in information on long-term HD trends or the explicit need for interdisciplinary studies. Such information, however, would be critical to understand and predict changes in the human dimensions of the fisheries and to develop management strategies to cope with these changes.

scholarly journals Environmental Preferences and Fish Handling Practice among European Freshwater Anglers with Different Fishing Specialization Profiles

2021 ◽  
Vol 13 (23) ◽  
pp. 13167
Author(s):  
Emil Andrzej Karpiński ◽  
Andrzej Robert Skrzypczak
Keyword(s):  
Fishery Management ◽  
Management Strategies ◽  
Predatory Fish ◽  
Environmental Preferences ◽  
Fish Stocks ◽  
Recreational Specialization ◽  
Negative Environmental Impact ◽  
Engagement Factors ◽  
Important Form ◽  
Insight Into

Recreational specialization is characteristic of many activities, including recreational fishing, which is a popular and important form of recreation throughout the world. The pressure on the environmental resources used by anglers is increasing. It is becoming crucial to understand the preferences and behaviors of anglers, which can accumulate and multiply the risk of damage to fish stocks and aquatic habitats. The main objective of the study was to comprehensively analyze the differences between anglers with diverse specialization profiles. By investigating the fishing preferences within the context of the socioeconomic, demographic and engagement factors, three groups of anglers were identified: anglers who specialize in predatory fish, anglers who specialize in non-predatory fish and unspecialized anglers. Specialized anglers, regardless of type, were found to be more supportive of releasing caught fish (71% on average) and were less likely to keep them (16%) than unspecialized anglers (55% and 27%, respectively). Unspecialized anglers (26.5% of the surveyed population) show less commitment to ethical values. The potential negative environmental impact of the least specialized anglers is an accumulation of the preferences for the use of ground bait, artificial lures, and live fish as bait. Anglers specializing in predatory fish are the most critical in their evaluation of fish resources and water quality and are least attached to specific fisheries. This work provides insight into angler experience and it may help to better identify anglers who are disrespectful towards the fishing laws in place. The results of this work may be incorporated into fishery management strategies, including strategies to reduce naïve anglers and deter disrespectful anglers, which are lucrative in the fishing process.

Comparative performance of data-poor CMSY and data-moderate SPiCT stock assessment methods when applied to data-rich, real-world stocks

2020 ◽  
Author(s):  
Paul Bouch ◽  
Cóilín Minto ◽  
Dave G Reid
Keyword(s):  
Stock Assessment ◽  
Assessment Methods ◽  
Production Model ◽  
Fishing Mortality ◽  
Comparative Performance ◽  
Fish Stocks ◽  
Surplus Production ◽  
Stock Biomass ◽  
Surplus Production Model ◽  
The Status

Abstract All fish stocks should be managed sustainably, yet for the majority of stocks, data are often limited and different stock assessment methods are required. Two popular and widely used methods are Catch-MSY (CMSY) and Surplus Production Model in Continuous Time (SPiCT). We apply these methods to 17 data-rich stocks and compare the status estimates to the accepted International Council for the Exploration of the Sea (ICES) age-based assessments. Comparison statistics and receiver operator analysis showed that both methods often differed considerably from the ICES assessment, with CMSY showing a tendency to overestimate relative fishing mortality and underestimate relative stock biomass, whilst SPiCT showed the opposite. CMSY assessments were poor when the default depletion prior ranges differed from the ICES assessments, particularly towards the end of the time series, where some stocks showed signs of recovery. SPiCT assessments showed better correlation with the ICES assessment but often failed to correctly estimate the scale of either F/FMSY of B/BMSY, with the indices lacking the contrast to be informative about catchability and either the intrinsic growth rate or carrying capacity. Results highlight the importance of understanding model tendencies relative to data-rich approaches and warrant caution when adopting these models.

scholarly journals Seasonal Variation and Assessment of Fish Resources in the Yangtze Estuary Based on Environmental DNA

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2874
Author(s):  
Hui Jia ◽  
Yibang Wang ◽  
Susumu Yoshizawa ◽  
Wataru Iwasaki ◽  
Yuquan Li ◽  
...  
Keyword(s):  
Environmental Dna ◽  
Yangtze Estuary ◽  
The Yangtze Estuary ◽  
Annual Fish ◽  
Fish Stocks ◽  
Marine Communities ◽  
Fish Resources ◽  
The Past ◽  
Fishery Resources ◽  
Four Seasons

In the past few years, environmental DNA (eDNA) techniques have been used to monitor marine communities. Research indicates that eDNA is an effective tool for monitoring fishery resources. This study analyzed the seasonal variations in fish resources in the Yangtze Estuary, China, using eDNA. A total of 103 water samples were collected from the Yangtze Estuary across the four seasons in 2019—20 samples in February, 28 in May, 28 in August and 27 in November. Our research successfully detected the fishery resources of the Yangtze Estuary. We found significant differences according to the season. The results showed that 59 species were identified in 2019 (20 in February, 16 in May, 5 in August and 45 in November) and fish species varied widely over the four seasons. Furthermore, our samples revealed significant differences in annual fish stocks in the Yangtze Estuary, compared with eDNA data from 2018 and with traditional surveys from past years. Overall, eDNA is a useful emerging tool to assist with monitoring and protecting fish resources for the Yangtze Estuary.

Use and abuse of fishery models

2001 ◽  
Vol 58 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Jon T Schnute ◽  
Laura J Richards
Keyword(s):  
World Literature ◽  
Fishery Management ◽  
Stock Assessment ◽  
Management Practice ◽  
Fish Stock ◽  
Fish Stocks ◽  
Creative Thought ◽  
Modeling Process ◽  
Stock Biomass ◽  
Fish Stock Assessment

Recent failures of important fish stocks give mathematical models a poor reputation as tools for fishery management. This paper examines the role of models in fish stock assessment and identifies reasons why they can fail. Starting with laws of arithmetic, models attempt to relate observed data to unknown quantities, such as the stock biomass and abundance. Typically, the number of unknowns greatly exceeds the number of observations, and models must impose hypothetical constraints to give useful estimates. We use the word "fishmetic" (rhymes with arithmetic) to represent uncertainty in the conversion of arithmetic to practical fishery models. Arbitrary assumptions cannot be avoided, even though different choices can greatly influence the outcome of the analysis. We compare the modeling process in fisheries with that in other sciences. World literature also offers useful analogies. Potential reasons for failure suggest possible improvements to the application of fishery models. We recommend that modelers remain skeptical, expand their knowledge base, apply common sense, and implement robust strategies for fishery management. Particularly creative thought must be applied to the problem of translating scientific knowledge into management practice. Comparisons between fish stocks and financial stocks illustrate some possibilities.

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