Screening and Validation: Sargasso Sea Case Study

Laurence Kell & Brian Luckhurst 4th May 2020

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Review the progress on developing an Ecosystem Report Card for ICCAT including the development of status and pressure indicators and reference levels

  • Review adequacy of existing indicators against proposed new ones, and progress on the development of methods for screening and validation
  • Review development of case studies and ecoregions

Sargasso Sea Case Study

  • Indicators for assessed and unassessed stocks

  • Link to habitat

  • Extend to Endangered, Threatened and Protected Species

Habitat

Arrizabalaga, H., Dufour, F., Kell, L., Merino, G., Ibaibarriaga, L., Chust, G., Irigoien, X., Santiago, J., Murua, H., Fraile, I. and Chifflet, M., 2015. Global habitat preferences of commercially valuable tuna. Deep Sea Research Part II: Topical Studies in Oceanography, 113, pp.102-112.

Indicators

Non-stationarity

Kell,L.T., Sharma,R., Winker, H., Kitakado4,T., and Mosqueira,I. 2021. NON-STATIONARITY IN PRODUCTIVITY OF TROPICAL TUNA AND THE IMPLICATIONS FOR ECOSYSTEM BASED FISHERIES MANAGEMENT. Collect. Vol. Sci. Pap.

Tropical Tunas

Surplus Production

\(B_t+1\) = \(B_t\) - \(C_t\) + \(SP\)

Process Error

\(B_t+1\) = \(B_t\) - \(C_t\) + \(SP\)

Yellowfin and Indian Ocean Dipole

Risk Base Approaches

Risk is an uncertainty that matters, what matters are management objectives.

  • Risk based approaches, e.g.
    • NAFO objectice driven, depends on the identification of ecosystem-based management units, and takes an hierarchical approach to addresses the effects of the ecosystem plus fishing on the target stocks by defining sustainable harvest rates by sequentially considering sustainability at the ecosystem, multispecies and stock levels.
    • Australia Ecological Risk Assessment a hierarchical approach that depends on the level of data and knowledge
    • ICES, stocks are assigned a category depending on quality of data available, i.e. from
      • Full quantitative assessment,
      • Trends based on CPUE
      • Length Based Indicators (LBIs)

Unassessed Stocks

  • A variety of data poor methods are available i.e.
    • Catch Only
    • Length Based Indicators
    • Productivity Susceptibility Analysis
  • Test using data rich stocks

Catch Only Methods

Kell, L.T., and Sharma, R., 2021. AN EVALUATION OF DATA POOR APPROACHES FOR THE EVALUATION OF STOCK STATUS IN LARGE ECOSYSTEMS USING ONLY LANDINGS DATA.xxxx. Collect. Vol. Sci. Pap. ICCAT, 77(x), pp.xx-xxx.

Kell, L.T., Sharma, R., and Winker, H., 2021. EVALUATION OF DATA POOR APPROACHES FOR EVALUATING STOCK STATUS AND TRENDS: CROSS TESTING USING INTEGRATED ASSESSMENT MODELS. Collect. Vol. Sci. Pap. ICCAT, 77(x), pp.xx-xxx.

Kell, L.T., Sharma, R., and Winker, H., 2021. EVALUATION OF DATA POOR APPROACHES FOR EVALUATING STOCK STATUS AND TRENDS: SELF TESTING USING BIOMASS BASED ASSESSMENT MODELS. Collect. Vol. Sci. Pap. ICCAT, 77(x), pp.xx-xxx.

Self Test

Cross Test

Length Base Indicators

Kell, L.T., and Sharma, R., 2021. NON-STATIONARITY IN PRODUCTIVITY. Collect. Vol. Sci. Pap. ICCAT, 77(x), pp.xx-xxx.

DEVELOPMENT OF QUANTITATIVE ASSESSMENT METHODOLOGIES BASED ON LIFE-HISTORY TRAITS, …

Length Base Indicators: Mean Length and \(L_{opt}\)

Proxy for \(MSY\)

Length Based Indicators \(25^{th}\): Percentile and \(L_{mat}\)

Proxy for growth overfishng

Length Based Indicators: Blue Marlin

Productivity Analysis

Used in ERA as part of Productivity Susceptibility Analysis, or to derive priors

Productivity Susceptibility Analysis

Kell, L.T., Taylor, N., and Palma C., 2021. VALIDATION OF PRODUCTIVITY ANALYSIS FOR DATA LIMITED STOCKS. Collect. Vol. Sci. Pap. ICCAT, 77(x), pp.xx-xxx. Length Based Indicators

Sargasso Sea Case Study

  • Indicators for assessed and unassessed stocks
  • Link to habitat
  • Extend to Endangered, Threatened and Protected Species

Scale

Remote Sensing: Surface Temperature

Turtles

Electronic Tags

Tunas

Atlantic

Fishing

AIS data

What if?

You could integrate satellite ocean data for a range of environmental parameters, animal telemetry data for various species from IMOS, IOOS-ATN RFMOs and fisheries catch/effort data by species, and AIS

Acknowledgements

This work was supported by the Sargasso Sea Commission (SSC)

2020-04-30