Maximum Sustainable Yield Assessment Methods
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Maximum Sustainable Yield Assessment Methods

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Questions and Answers

What does CMSY primarily estimate using catch data?

  • Species distribution and migration patterns
  • Environmental impacts on fish populations
  • Stock status and exploitation rates (correct)
  • Fishing gear efficiency

    • What is a necessary prior for the CMSY method?

  • Geographical distribution
  • Environmental stressors
  • Predation rates
  • Species-specific resilience (r) (correct)

    • Which of the following resilience categories has the widest range of values in CMSY?

  • High
  • Medium (correct)
  • Low
  • Very low

    • When should AMSY be used instead of CMSY?

    <p>When catch data are unreliable or unknown</p> Signup and view all the answers

    What does the Length-based Bayesian Biomass (LBB) method allow researchers to infer?

    <p>A proxy for relative biomass capable of producing maximum sustainable yield</p> Signup and view all the answers

    What percentage of assessed populations is deemed healthy in terms of biomass status according to LBB?

    <p>18%</p> Signup and view all the answers

    What is a common challenge associated with using catch-per-unit-of-effort (CPUE) data in AMSY?

    <p>Species catchability varies, leading to inconsistency</p> Signup and view all the answers

    What issue is highlighted regarding the reliability of LBB assessments?

    <p>The assessments are deemed too unreliable</p> Signup and view all the answers

    What is the relationship between Maximum Economic Yield (MEY) and Maximum Sustainable Yield (MSY)?

    <p>MEY is typically around 60-70% of MSY.</p> Signup and view all the answers

    Which of the following describes the Bayesian Schafer Model (BSM) in stock assessment?

    <p>It estimates stock status based on catch and abundance data.</p> Signup and view all the answers

    Which concept describes the issue where historical data for fish populations is often underrepresented in assessment?

    <p>Shifting Baseline Syndrome</p> Signup and view all the answers

    In terms of data quality, what challenge do developing countries face regarding fisheries assessments?

    <p>Developing countries typically have virtually no assessment data.</p> Signup and view all the answers

    What is a potential drawback of harmful or capacity-enhancing subsidies in the fishing industry?

    <p>They increase fishing effort and lead to overfishing.</p> Signup and view all the answers

    What does BMSY represent in fisheries management?

    <p>Biomass maximum sustainable yield</p> Signup and view all the answers

    Which of the following best describes overfished conditions?

    <p>High mortality and low spawning biomass</p> Signup and view all the answers

    What is a significant consequence of localised depletion in fisheries?

    <p>Decreased availability of fish near populations</p> Signup and view all the answers

    What is a primary difference in objectives between recreational and commercial fishers?

    <p>Recreational fishers seek varied fishing experiences.</p> Signup and view all the answers

    What does 'shifting baseline syndrome' refer to in fisheries management?

    <p>The changing perceptions of what is a healthy fish population over time.</p> Signup and view all the answers

    Which concept reflects the ability of a fish population to recover from fishing pressure?

    <p>Qualitative resilience</p> Signup and view all the answers

    Which of the following is a primary management lever for recreational fisheries?

    <p>Size limits</p> Signup and view all the answers

    What is the role of data quality in inland fisheries assessments?

    <p>To inform science-based decision making effectively.</p> Signup and view all the answers

    What is a formal document involved in stock assessment not required to specify?

    <p>Total financial budget allocated</p> Signup and view all the answers

    What factor contributes to an increase in recreational fishing participation?

    <p>Higher angler satisfaction levels with past catches</p> Signup and view all the answers

    What is the primary concept behind Bayesian statistics in fisheries science?

    <p>Combining prior beliefs with new data to revise knowledge.</p> Signup and view all the answers

    What does Shifting Baseline Syndrome illustrate in marine ecology?

    <p>A gradual decline in awareness of ecosystem changes over time.</p> Signup and view all the answers

    Why is understanding past marine animal populations important for modern fisheries?

    <p>To establish reference points for assessing current stocks.</p> Signup and view all the answers

    How does data quality in inland fisheries typically compare to marine fisheries?

    <p>Data quality is usually worse in inland fisheries.</p> Signup and view all the answers

    What role do priors play in estimating parameters like r(max) in fisheries?

    <p>They provide baseline values that can reduce uncertainty.</p> Signup and view all the answers

    What is a 'virgin stock' in the context of fisheries management?

    <p>A historical stock level before significant human impact.</p> Signup and view all the answers

    What was one of Daniel Pauly's significant contributions to fisheries science?

    <p>Highlighting the issue of global over-fishing through his research.</p> Signup and view all the answers

    What can affect the intrinsic rate of population increase r(max)?

    <p>Ecological factors and prior population conditions.</p> Signup and view all the answers

    What is a primary characteristic of commercial fisheries in inland waters?

    <p>Predominantly small-scale fishing operations.</p> Signup and view all the answers

    What impact did the introduction of larger species have on the traditional drying method of chichilds?

    <p>It required alternative preservation methods like smoking or freezing.</p> Signup and view all the answers

    Which factor contributed significantly to the underreporting of freshwater catch data?

    <p>Increased aquaculture activities.</p> Signup and view all the answers

    How did climate change affect ocean temperatures and species distribution?

    <p>It led to varying heating effects, impacting species differently.</p> Signup and view all the answers

    What is a primary consequence of dam construction on the Tana River Delta ecosystems?

    <p>It negatively impacts flood-dependent ecosystems.</p> Signup and view all the answers

    What was noted about the majority of fish catch reported from Lake Victoria?

    <p>A high percentage of it is from artisanal fishing.</p> Signup and view all the answers

    What aspect of climate change is impacting fish populations most critically?

    <p>Variations in oxygen content and acidification.</p> Signup and view all the answers

    What percentage of reported fish catch was determined to be from subsistence fishing practices?

    <p>20%</p> Signup and view all the answers

    Which of the following is a consequence of factoring in aquaculture data into fishing reports?

    <p>Misleading projections on freshwater resource management.</p> Signup and view all the answers

    What is one of the major environmental issues linked to firewood demand for fish preservation methods?

    <p>Deforestation leading to harmful runoff.</p> Signup and view all the answers

    How has climate change influenced the Arctic permafrost?

    <p>It poses a risk of methane release, intensifying global warming.</p> Signup and view all the answers

    What is a primary purpose of marine protected areas (MPAs)?

    <p>To protect marine biodiversity</p> Signup and view all the answers

    Which of the following statistics reflects the need for MPAs due to wildlife declines?

    <p>95% decline in turtle populations</p> Signup and view all the answers

    What percentage of fisheries is deemed unsustainable according to the provided data?

    <p>33%</p> Signup and view all the answers

    What is a secondary purpose of establishing marine protected areas?

    <p>To sequester blue carbon</p> Signup and view all the answers

    Under IUCN guidelines, which zone would allow for some form of exploitation?

    <p>IUCN III-VI</p> Signup and view all the answers

    What percentage of large fish in Australia has been lost over a decade?

    <p>30%</p> Signup and view all the answers

    What biodiversity outcome was recorded in no-take MPAs compared to pre-Park conditions?

    <p>Numbers increased by 166%</p> Signup and view all the answers

    What percentage range of Queensland sharks has disappeared over five decades?

    <p>74-92%</p> Signup and view all the answers

    Which of the following is NOT a factor contributing to the need for Marine Protected Areas (MPAs)?

    <p>Natural marine migrations</p> Signup and view all the answers

    What was noted as the fisheries outcome near the boundaries of no-take MPAs?

    <p>Revenue is highest</p> Signup and view all the answers

    What method is mentioned as a tool for gathering fish species data in various ecosystems?

    <p>Baited remote underwater video systems</p> Signup and view all the answers

    Which of the following topics is not used for building information on fish species?

    <p>Feeding habits</p> Signup and view all the answers

    What is a primary characteristic of the initial effort to create FishBase?

    <p>It involved 600 note cards documenting species.</p> Signup and view all the answers

    What type of access does FishBase aim to promote concerning fish data?

    <p>Equity and free access</p> Signup and view all the answers

    Which of the following factors is categorized under the information attributes in FishBase?

    <p>Family</p> Signup and view all the answers

    What is the equation representing the standardization of weight based on length?

    <p>Weight = a∙Length^b</p> Signup and view all the answers

    What does dynamic data management eliminate to maintain data accuracy?

    <p>Zombie data by deep-linking to other databases</p> Signup and view all the answers

    Which of the following statements reflects a philosophical thought concerning accuracy in data?

    <p>Trophic value should be 4.3, not 4.1, highlighting potential miscalculations.</p> Signup and view all the answers

    Thomas Bayes is known for contributing to which area relevant to predictive modeling?

    <p>Foundation of Bayesian probability methods</p> Signup and view all the answers

    What does the relationship 'Fork Length => Total Length' imply?

    <p>Fork Length can be converted into Total Length through specific ratios.</p> Signup and view all the answers

    Which statement most accurately describes the purpose of stock assessments in fisheries management?

    <p>Stock assessments deliver comprehensive information for regulating a fish stock.</p> Signup and view all the answers

    What aspect is NOT included in a formal harvest strategy document?

    <p>Detailed marketing strategies for fish distribution.</p> Signup and view all the answers

    In stock assessment methods, what role does statistical analysis primarily serve?

    <p>To make quantitative predictions about fish population responses.</p> Signup and view all the answers

    Which characteristic distinguishes ecosystem-based fisheries management (EBFM) from traditional stock assessment approaches?

    <p>EBFM integrates ecological interactions and cumulative impacts.</p> Signup and view all the answers

    What does the precautionary approach emphasize in the context of stock management?

    <p>It requires cost-effective measures even when scientific data is incomplete.</p> Signup and view all the answers

    What consequence level is described as having a level of depletion that is unacceptable but still does not affect recruitment levels of stock?

    <p>High</p> Signup and view all the answers

    Which option accurately defines the Maximum Acceptable Level of Depletion in the context of consequence levels?

    <p>Biomass between Threshold and Target</p> Signup and view all the answers

    In a risk-based approach, which level indicates a situation where the impacts on population are not detectable against background variability?

    <p>Minor</p> Signup and view all the answers

    What does the model fitted to CPUE and age data primarily account for when assessing fish populations?

    <p>Fishing efficiency changes over time</p> Signup and view all the answers

    Which assessment scenario leads to a lower current female spawning biomass when accounting for CPUE?

    <p>With CPUE influences</p> Signup and view all the answers

    Study Notes

    CMSY (Catch Maximum Sustainable Yield)

    • Estimates stock status (B) and exploitation using catch data and 'r' (population growth rate), which requires prior knowledge.
    • Qualitative resilience ranges available for all species.
      • Very low: 0.015-0.1
      • Low: 0.05-0.5
      • Medium: 0.2-0.8
      • High: 0.6-1.5

    AMSY (Abundance Maximum Sustainable Yield)

    • Estimates stock status (B) and exploitation using catch data and resilience, but relies on CPUE data when catch data is unreliable or stock boundaries unknown.
    • CPUE data is commonly available and useful for assessment.
    • No need to standardize CPUE units as long as consistency is maintained.
    • Account for catchability, as different species may have varying levels.
    • Provides reasonable uncertainty around B/B(msy), suitable for management advice, but high uncertainty around F/F(msy).

    LBB (Length-based Bayesian Biomass)

    • Serves as a proxy for biomass capable of producing maximum sustainable yield.
    • Reproduces simulated "true" parameter values.
    • Only 18% of assessed populations are deemed healthy in terms of biomass status.
    • Criticized as unreliable, but considered better than no data when other options are unavailable.

    Bayesian Statistics

    • Combines prior knowledge with data to create updated knowledge.
    • Estimates parameters 'r' and 'k' using a specific formula (not provided in the notes).
    • Requires prior information about the intrinsic rate of population increase (rmax), which can sometimes be found in FishBase or SeaLifeBase.

    Shifting Baseline Syndrome

    • Defined by Daniel Pauly in 1995.
    • Highlights overfishing since 1050.
    • Pauly's 1995 paper, "Fishing down marine food web," drew attention to global overfishing.
    • Emphasizes the importance of understanding human impacts on long timescales.

    Freshwater and Inland Fisheries

    • Data quality is generally worse than in marine fisheries.
    • Dominated by small-scale fisheries, except for a few exceptions with industrial freshwater fisheries.
    • Examples of data collection methods: Bi-annual phone diary, boat ramp surveys, and boat ramp cameras.
    • Key issues include:
      • Shark depredation, higher near boat ramps.
      • Localized depletion near populations, especially for recreational fishers.

    Recreational Fishers

    • Have different objectives than commercial fishers.
    • Focus on fishing experience, with a variety of contributing factors.
    • Management levers:
      • Commercial: Catch quota, effort quota.
      • Recreational: Bag limits, size limits, seasonal closures.

    WA Stock Assessment

    • Main data in WA:
      • Catch
      • SPUE data (catch rate)

    UN Convention on Law of the Sea (1982)

    • Supports science-based decision making.
    • Principles include:
      • Ecosystem based management (EBM)
      • Ecosystem based fisheries management (EBFM)
      • Single fishery management

    Stock Assessment

    • Uses statistical and mathematical calculations to predict fish population responses to management choices.
    • Identifies how fish populations change over time and the resulting management response.
    • Includes:
      • Objectives
      • Performance indicators and reference points
      • Monitoring and assessment strategy
      • Harvest decision rules

    Overfishing vs Overfished

    • Overfishing: High fishing mortality rate and high spawning biomass.
    • Overfished: High mortality rate and low spawning biomass.

    Resource Allocation

    • Concerns about allocation between recreational and commercial fishing interests.

    Risk-Based Approach

    • Classifies biomass status as:
      • Minor: Biomass > target
      • Moderate: Biomass between threshold and target
      • High: Biomass below threshold

    Climate Change and Fisheries

    • Climate change is happening faster than projected and caused by humans.
    • The 2015 Paris Agreement aims to keep global warming well below 2 degrees Celsius and pursue efforts to limit it to 1.5 degrees Celsius.
    • Arctic warming and thawing permafrost pose a risk of releasing significant amounts of methane into the atmosphere, creating a positive feedback loop.

    Impacts of Climate Change on Fisheries

    • Increased average water temperature, with variations in different regions.
    • Changes in oxygen content.
    • Ocean acidification.
    • Sea level rise.
    • Changes in ocean current regimes.

    Subsidies

    • Harmful or capacity-enhancing subsidies:
      • Increase fishing effort, worsen sustainability, and lead to more fish being caught.
    • Beneficial subsidies:
      • Promote sustainability.
    • Ambiguous subsidies:
      • Difficult to assess impact.

    MEY (Maximum Economic Yield)

    • Maximizes profit, not catch.
    • Generally found at lower fishing effort levels than MSY.
    • Typically around 60-70% of MSY.

    Data-Limited Stock Assessment Options

    • Many exploited stocks have insufficient data for traditional age-structured assessment.
    • Rainer Froese developed a simplified approach for developing countries.

    BSM (Bayesian Schaefer Model)

    • Estimates stock status (B) and exploitation (F) using catch and abundance data (CPUE).
    • Advantages:
      • Can utilize short and interrupted time series of CPUE data.
      • Estimates catchability (q).
      • Provides fisheries reference points: MSY, B(msy), and F(msy).
      • Provides ecological reference points: r(max) and k.
      • Determines stock size (B) and status (B/B(msy)).

    Marine Protected Areas (MPAs)

    • MPAs are marine areas designated for protection, with various levels of restrictions on human activities.
    • They can also be called marine parks, reserves, or sanctuaries.
    • Their primary purpose is to protect marine biodiversity and serve as natural experiments to study ecosystems.
    • Secondary benefits include rebuilding fisheries, providing climate resilience, and sequestering blue carbon.

    IUCN Zoning

    • The International Union for Conservation of Nature (IUCN) categorizes MPAs into six zones, ranging from strict protection (IUCN I and II) to various forms of exploitation (IUCN III-VI).

    Why MPAs are Needed

    • Wildlife Declines: Populations of various marine species have been declining significantly, including striped marlin, yellowfin tuna, shortfin mako, whale shark, blue shark, hammerhead shark, and turtles.
    • Fisheries Declines: Global fish catches peaked in 1996, with a subsequent decline of 694,000 kg per year between 1996 and 2018.
    • Nowhere to Hide: Fishing pressure has increased significantly, leaving fewer refuge areas for marine life.
    • Australian Seascape: Declines are observed in Australian waters, with over 30% of large fish gone in a decade and over 20% of fish populations managed by the Australian Government overfished or uncertain.
    • Warming Oceans: Ocean warming affects the distribution and abundance of marine species, altering ecosystem dynamics.
    • Industrialization: Oil and gas exploration and extraction, including seismic activity, platforms, vessel noise, and oil spills, impact marine ecosystems.

    Benefits of No-Take MPAs

    • Coastal Evidence: Studies have shown that no-take MPAs increase biodiversity, biomass, size, and abundance of species, including sharks, within their boundaries. They also contribute to higher revenue near boundaries due to increased fisheries yields, larval export, and larger prize fish outside their borders.
    • Resilience: No-take MPAs demonstrate increased resilience to disturbances like coral bleaching, with fewer crown of thorn starfish outbreaks and reduced coral disease.

    Carbon Sequestration

    • MPAs contribute to carbon sequestration, playing a role in mitigating climate change.

    The Rise of Large MPAs

    • There is growing momentum for establishing large MPAs, including initiatives like the "30 by 30" target (protecting 30% of the ocean by 2030) and high seas protection.

    Evidence of MPAs

    • The number of publications on marine protected areas has increased significantly, indicating a growing body of research and scientific understanding of their effectiveness.

    FishBase

    • FishBase was founded by Professor Daniel Pauly and Professor Rainer Froese
    • Founded 30 years ago
    • Started with 600 index cards
    • Aim was to improve the accessibility of fish ecology data
    • Fishbase provides data on fish species including size, habitat, diet, and human use.
    • The website uses a standard length–weight relationship formula: Weight = a∙Lengthb where a and b are constants.
    • The website uses data from a variety of sources, such as research papers, government reports, and citizen science projects.
    • The website is dynamic and continuously updated using data from the RedList, allowing for automatic data updates
    • Data for new fish species are added frequently to the database.
    • Website offers options for searching data by family, country/island, ecosystem, or topic.
    • The website is used to track data including:
      • Diet
      • Growth
      • Gill surface area
    • Website uses various tools to ensure data accuracy:
      • Baited Remote Underwater Video Systems (BRUVS)
      • Nutritional
      • Graphs

    FishBase Accuracy

    • Fishbase uses various prediction models to estimate data including the Bayes Model.
    • The website addresses inaccuracies by incorporating the limitations of estimations and data collection into the study.
    • The website acknowledges the possibility of error in estimated data including:
      • Trophic value
      • Length-weight relationships
      • Lifespan

    FishBase Data Analysis

    • FishBase can be used to analyse the data that it collects and provide information about communities of fish.
    • Can assess the ecological components of an area of study including
      • Species richness
      • Total abundance
      • Total biomass
    • Webpage tools can be used to determine trophic levels, vulnerability, and IUCN status of fish species.

    Using FishBase

    • users can extract data using R.
    • users can use the website to study topics relating to:
      • Aquamaps
      • BRUVS database
      • Species matrices
    • It’s is important to determine if researching single species or a group of species is needed for study.
    • It's important to conduct a "pub test" which evaluates whether the work done using FishBase data is of publishable quality.

    Precautionary Principle and Fisheries Management

    • The Rio Conference (1992) introduced the precautionary principle, which states that lack of scientific certainty should not be used to delay protective measures, especially regarding serious or irreversible environmental damage.
    • The FAO Code of Conduct for Responsible Fisheries (1992) promotes a voluntary approach to applying the precautionary principle in fisheries management.

    Ecosystem Based Management and Fisheries Management

    • Ecosystem Based Management (EBM) is a comprehensive approach to resource management that considers the interactions of different sectors, such as mining, marine parks, coastal development, aquaculture, and the environment.
    • Ecosystem Based Fisheries Management (EBFM) is a crucial component of EBM, focusing on sustainable fisheries management practices.

    Stock Assessment and Harvest Strategies

    • Stock assessment quantifies fish population responses to different management strategies, using statistical and mathematical calculations.
    • Harvest strategies are formal documents defining objectives, performance indicators, and monitoring strategies for fisheries management, aiming to achieve ecological and socio-economic sustainability.

    Risk-Based Approach to Fisheries Management

    • The risk-based approach evaluates consequences of different management choices based on likelihood and consequence levels.
    • Likelihood levels range from remote (unlikely to happen) to certain (highly likely to happen) and quantify the probability of specific consequences.
    • Consequence levels are classified as minor, moderate, high, and major, depending on the impact on fish population size, dynamics, and recruitment levels.

    Case Study: Western Australia (WA) Finfish and Invertebrate Species

    • The WA assessment approach for fisheries management incorporates a range of data types and approaches, including catch history, CPUE (catch per unit effort) data, age data, and risk assessment frameworks.
    • Catch history data tracks fishing activities over time, providing insights into trends and impact.
    • CPUE data measures catch rates relative to fishing effort, reflecting changes in fish abundance.
    • Age data reveals fish population structure and how fishing impacts different age groups.
    • Risk assessment frameworks, such as weight-of-evidence assessments, integrate various data sources to assess the risk of overfishing and inform management decisions.
    • L5 integrated model assessment uses a detailed age-based model to understand and predict the dynamics of fish populations.

    Key Western Australian Fisheries Management Considerations

    • Western Australian fisheries management acknowledges the data-limited nature of some fisheries, where data richness may decline following management interventions aimed at stock rebuilding.
    • The management approach prioritizes rapid stock rebuild through measures like reduced catches and spawning area closures.

    UN Convention on the Law of the Sea (UNCLOS)

    • UNCLOS (1982) emphasizes the responsibility of coastal states to ensure the sustainable management of living resources in their exclusive economic zones (EEZs).
    • Coastal states are obliged to implement conservation and management measures based on the best available scientific evidence to prevent overexploitation and ensure the long-term viability of fisheries.

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    Description

    This quiz explores various methods for assessing Maximum Sustainable Yield (MSY), including CMSY, AMSY, and LBB techniques. It delves into the principles of estimating stock status, exploitation metrics, and the role of catch and effort data. Test your knowledge on these important fisheries management strategies!

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