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Priority 8 Call for Proposals Task 2: Understanding the mechanisms of stock recovery

Priority 8 Call for Proposals Task 2: Understanding the mechanisms of stock recovery. Objective: ”The objective of this task is to apply all available and relevant data in order to identify changes experienced during the stock decline and the consequences for the prospects of stock

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Priority 8 Call for Proposals Task 2: Understanding the mechanisms of stock recovery

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  1. Priority 8 Call for ProposalsTask 2: Understanding the mechanisms of stock recovery Objective: ”The objective of this task is to apply all available and relevant data in order to identify changes experienced during the stock decline and the consequences for the prospects of stock recovery. The task should focus on relevant case studies but not necessarily limited to stocks where recovery plans have already been implemented. Strategies for rebuilding Should also be outlined…”

  2. WP2: Impact of exogenous processes on recruitment dynamics • Objectives: • Increase understanding of processes affecting recruitment of target • fish species. • Describe and quantify links between historical variations in • recruitment, egg production, spawner demographics and environmental • Variability. • Evaluate using process knowledge the sensitivity of recruitment to • variations in egg production, spawner demographics and environmental • variability.

  3. WP2 Subtasks 2.1 Identification of Critical Life stages and Processes. 2.2 Develop Process Understanding and Models. 2.3 Implement Process Knowledge in Biological-Physical Individual-based Oceanographic models. 2.4 Scenario Modelling Variations in Biological and Physical Forcing to Develop Predictive Capacities with Respect to Stock Recovery.

  4. Participants and Months

  5. Role of Participants

  6. WP2 Deliverables

  7. WP2 Milestones

  8. CS1 (Barents/Norwegian Sea) contributions to WP2

  9. CS2 (North Sea) Contributions to WP2

  10. CS3 (Baltic Sea) Contributions to WP2

  11. CS4 (Bay of Biscay) Contributions to WP2

  12. Links to other WPs Input from WP1 and WP3 re. egg production and predators Input from WP4 re. datasets and process requirements Output to WP4 re. process knowledge, hypotheses and data for FEMS ”operating model” Output to WP4 re. Level 1 and 2 questions Output to WP6 re. Synthesis (esp. Objective 6.2: Identification of changes in the ecosystem that affect recruitment [e. g., hydrographic conditions, interactions among recruits] during periods of stock decline and recovery based on results from WP2).

  13. Project Structure

  14. Project Time Plan

  15. WP2 Discussion, March 29, 2006 Participants: Wolfgang, Thomas, Hans-Harald, Myron, Jens R., Laurie, Leire, Brian Reviewed subtasks, deliverables, milestones and deadlines Participants asked to identify colleagues responsible for deliverables and milestones for completion of activity table. Discussed inputs/outputs to WP4.

  16. WP2 Links to WP4 Key product required by WP4 is improved stock-recruitment models -presentation by Laurie showed sensitivity of reference points to alpha and beta in Ricker curve -S-R relationship is fundamental for various aspects of management and recovery plans (recovery times, expected biomass levels in future, etc…. -new S-R models can be used in WP4 where FEMS outputs can be compared with those obtained using existing S-R models Models can be based on complex process information from WP1-2-3. -e. g. improved estimates of egg production, spawning location/time, egg/larval survival, transport, food conditions, predator abundances, abiotic variables. -process information can be used in IBMs to produce recruit estimates If no S-R relationship can be derived, then period-specific R estimates can be used in FEMS. -high/low recruitment periods can be identifed from historical analysis of time series and processes.

  17. WP2 Links to WP4 Level 1 and Level 2 questions -level 1 can perhaps be addressed by comparing across stocks and species within Uncover (herring x 2, sprat x 2, cod x 3). Are not able to do more analyses of recruitment variations for stocks and species outside of project. This may be done in Reclaim, where responses of recruitment to climate change by species with different lifehistories (pelagic vs. demersal, short-lived vs. long-lived) will be investigated. -level 2 questions can potentially be addressed in Case Studies for target species.

  18. Approach: Start from endproduct and work backwards: What is it we want to achieve? (Main objective:identify changes experienced during the stock decline and the consequences for the prospects of stock recovery. Strategies for rebuilding should be outlined.) How do we get there? – tools, datasets, analyses,? How can our work be structured to achieve the objective? What hypotheses can we test?

  19. DIFRES Contributions to Topic 2 1. Habitat utilisation by juvenile gadoids and herring in North Sea, including frontal utilisation by pelagic stages and benthic habitats by demersal stages. 2. Habitat modelling for cod eggs in Baltic Sea (via 3D-NPZD models), processes causing variability (together with IOW & Kiel) 3. Multi-decadal changes in species productivity and species distributions (e. g., cod, herring, haddock, in North Sea, cod in Baltic Sea, etc.) 4. Large-scale stock-enhancement releases of Baltic cod larvae. Can be used for recruitment process studies. 5. Recruitment modelling - cod in North, Baltic Sea, herring in North Sea

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