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 rebuildingShould also be outlined…”

WP2: Impact of exogenous processes on recruitment dynamics

Objectives:

1. Increase understanding of processes affecting recruitment of targetfish species.

2. Describe and quantify links between historical variations in recruitment, egg production, spawner demographics and environmentalVariability.

3. Evaluate using process knowledge the sensitivity of recruitment to variations in egg production, spawner demographics and environmentalvariability.

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.

Participants and Months

Participant ID Months

AZTI 2 10

CEFAS 3 0.9

DIFRES 5 23

FRS-Aberdeen 6 0.8

IFM-GEOMAR 9 19

IFREMER 10 13

IMR 11 21

SFI 12 3.5

PINRO 13 12

RIVO 14 3.6

UiB 16 7

Uni-HH 17 15

Total 128.8

Role of Participants

WP2: Impact of exogenous processes on recruitment dynamics

This group represents institutes and key personnel with well documented expertise, specific skills and extensive experience in fish stock recruitment processes, time series analysis, individual-based modelling, physical oceanography, coupled hydrodynamic modelling, climate change.

Task 2.1 Identification of critical life stages and processes IFREMER (4), AZTI (4), DIFRES (2&3), FRS (2), IFM-GEOMAR (3), IMR(2), PINRO (1), RIVO (2), SFI (3), UiB (1) with LATFRA (3), IOW (3) and AtlantNIRO (3)

Task 2.2 Developing process understanding and models RIVO (2), DIFRES (2&3), FRS (2), IFM- GEOMAR (3), IFREMER (4), UNI-HH (3), PINRO (1) with LATFRA (3)

Task 2.3 Implementation of process models in coupled bio-physical models IFM-GEOMAR (3), CEFAS (2), DIFRES (2&3), FRS (2), IFREMER (4), RIVO (2), UiB (1), UNI-HH (2&3) with SWEM (2)

Task 2.4 Scenario modelling of recruitment dynamics relative to biological and physical forcing UNI-HH (2&3), AZTI (4), DIFRES (2&3), IFM- GEOMAR (3), IFREMER (4), IMR (1) with SWEM (2&3)

WP2 Deliverables

WP2 Milestones

No Respon-sible WP

Project Month

Milestone

1 All

(WP 7) 1

Kick-off meeting: Common goals and work plans with other WPs and CSs defined. Strategic questions formulated. Current status of knowledge summarised. Information requirements outlined.

6 WP 1-4;

6 8

Joint workshops with WPs 1-4 and 6. Modelling strategies and common goals defined.

7 WP 2 18 Hypotheses identified for recruitment variability of target species and case studies; initial datasets and proxy variables affecting recruitment compiled.

11 WP 1-4;

6 20

Joint workshops with WPs 1-4 and 6: Initial modules for each case-study specific or generic stock-

recovery evaluation evaluated and feedback provided.

12 WP 2 24

Initial analyses of existing field and experimental data conducted. Preliminary process knowledge from WP 2.1 and 2.2 implemented in biological-physical IBMs.

14 WP 1-4;

6 26

Joint workshops with WPs 1-4 and 6 concerning modelling. Further iteration process developed and defined.

17 WP 2 32 Revised analyses of historical variations in recruitment in relation to environmental variations ands spawning stock demographics.

20 WP 2 36 Final versions of proxy variables and datasets available, and time series analyses of recruitment variability conducted for target species in CS regions.

21 WP 1-7

CS 1-4 36

Joint workshop with all CSs and all WPs under participation of task coordinators to ensure testing and evaluation of findings in CS areas.

23 WP 2 42

Existing field and experimental data analysed and interpreted. Process knowledge from WP 2.1 and 2.2 implemented and operationalized in biological-physical IBMs for target species in CS regions.

26 WP 2 47 Historical recruitment patterns and variability estimated from IBM modelling for target species in CS regions.

CS1 (Barents/Norwegian Sea) contributions to WP2

Task Expected results Participating Institution* /Responsible Scientist

WP2 - Impact of exogenous processes on recruitment dynamics

Statistical analysis of the effect of water temperature and aeration, air temperature and the Barents Sea ice condition on the year-class strength of cod and herring

PINRO (O. Titov)

Life cycle strategy of cod PINRO (V. Tretyak)

2.1 – Identification of critical life-stages and processes

Compile data on growth of larval cod and larval and early juvenile herring growth, condition and survival from previously conducted laboratory (UiB) and mesocosm (Hyltro) experiments.

UiB (A. Folkvord)

2.2 – Develop process understanding and models

Develop statistical forecast model of cod recruitment based on climatic, hydrographic and biological parameters

PINRO (O. Titov)

2.3 – Implement process knowledge in coupled individual-based biological-physical oceanographic models

Calculate egg development times, feeding and growth of larval cod and herring using trajectories calculated in ECOBE.

UiB (Ø. Fiksen)

2.4 – Scenario modelling of variations in biological and physical forcing to develop predictive capacities with respect to stock recovery

Population dynamics (growth, mortality, drift) of pre-recruits (0-6 months) of cod and herring will be modelled, as well as cod spawning locations. The effect of climate change on those processes will be studied. Hindcasts of the number of recruits (at different life stages) for the period 1955-2005

IMR (S. Sundby)

CS2 (North Sea) Contributions to WP2Task Expected results Participating Institution

/Responsible Scientist

WP2 - Impact of exogenous processes on recruitment dynamics

Indication of evidence of critical-life stages of herring and plaice.

RIVO (M. Dickey-Collas), IMR (R. Nash), FRS (M. Heath)

Development of frontal-related proxy variables for use in cod and herring recruitment models

DIFRES (B. MacKenzie)

Statistical and modelling analyses of roles of hydrographic fronts and climatic variability on historical variations in cod and herring recruitment (analyses will also include spawner biomass and improved estimates of egg production as these become available)

DIFRES (P. Munk)

2.1 – Identification of critical life-stages and processes

Recovery of historical herring and cod data, analysis of long-term changes in herring and cod recruitment in relation to climate variability and spawner biomass

DIFRES (B. MacKenzie)

Highlight evidence for process drivers for North Sea herring and plaice

RIVO (M. Dickey-Collas),

Mapping of 0-group/juvenile cod and larval/0-group herring distributions relative to frontal regions

DIFRES (P. Munk)

Analysis of hydrographic processes affecting 0-group/juvenile cod and larval/0-group herring distributions

DIFRES (P. Munk)

2.2 – Develop process understanding and models

Resolve processes influencing recruitment dynamics of cod

FRS (M. Heath), DIFRES (B. MacKenzie)

2.3 – Implement process knowledge in coupled individual-based biological-physical oceanographic models

Implementation of early life-history stage biology in coupled hydrographic-biological oceanographic models

Uni-HH (M. Peck), SWEM (C. Schrum), DIFRES (A. Christensen), FRS (M. Heath), RIVO (M. Dickey-Collas), CEFAS (J. Metcalfe)

Interpretation of outputs of IBM model runs of egg-larval drift simulations for different hydrographic and egg production situations

DIFRES (A. Christensen), Uni-HH (M. Peck), SWEM (C. Schrum)

2.4 – Scenario modelling of variations in biological and physical forcing to develop predictive capacities with respect to stock recovery

Simulations of future cod and herring recruitment under different climate change scenarios and projections of future environmental variability

Uni-HH (M. Peck), DIFRES (B. MacKenzie), SWEM (C. Schrum)

CS3 (Baltic Sea) Contributions to WP2

Task Expected results Participating Institution /Responsible Scientist

WP2 – Impact of exogenous processes on recruitment dynamics

Updated time-series on spawning stock, recruitment, egg and larval production as well as environmental variables/proxies for cod and sprat

IFM-GEOMAR (G. Kraus), DIFRES (C. Möllmann), LATFRA (A. Macarchouk), AtlantNIRO (V. Feldman), SFI (W. Grygiel), IOW (W. Fennel)

2.1 – Identification of critical life-stages and processes

Identification of critical process/life-stages and causes for periods with high/low cod and sprat recruitment

DIFRES (B. MacKenzie), IFM-GEOMAR (C. Clemmesen, G. Kraus), AtlantNIRO (V. Feldman), SFI (W. Grygiel)

Process understanding and models on distribution, growth and survival of cod and sprat eggs, larvae and early juveniles

IFM-GEOMAR (R. Voss; C. Clemmesen), DIFRES (K. Andersen), LATFRA (A. Macarchouk)

2.2 – Develop process understanding and models

Process knowledge on hydrographic and trophodynamic processes affecting survival of cod larvae using direct field manipulation from a national project

DIFRES (J. Støttrup), IFM-GEOMAR (G. Kraus), Uni-HH (M. Peck)

2.3 – Implement process knowledge in coupled individual-based biological-physical oceanographic models

Enhanced coupled biophysical individual-based models to predict cod egg, larvae and early juvenile distribution, survival and growth dependent on abiotic and biotic environmental conditions

IFM-GEOMAR (H.H. Hinrichsen), DIFRES (B. MacKenzie), Uni-HH (M. Peck)

Evaluation of the sensitivity of cod and sprat recruitment to variable viable egg production and environmental impact on offspring distribution, production, growth and survival using enhanced coupled biophysical individual-based models

Uni-HH (M. Peck), DIFRES (F. Köster), IFM-GEOMAR (R. Voss)

2.4 – Scenario modelling of variations in biological and physical forcing to develop predictive capacities with respect to stock recovery

Time series on proxies of future cod and sprat recruitment for different climate change scenarios based on runs using enhanced coupled biophysical individual-based models

Uni-HH (M. Peck), DIFRES (C. Möllmann), IFM-GEOMAR (H.H. Hinrichsen), SWEM (C. Schrum)

CS4 (Bay of Biscay) Contributions to WP2

Task Expected results Participating Institution/

Responsible Scientist

WP2 – Impact of exogenous processes on recruitment dynamics

Time-series and statistical models linking environment to recruitment

IFREMER (B. Planque)

Spatial distribution of egg mortality of anchovy and its relation to environmental parameters

AZTI (L. Ibaibarriaga)

2.1 – Identification of critical life-stages and processes

Analysis of loophole mechanism in relation to recruitment of considered species

AZTI (X. Irigoien)

2.2 – Developing process understanding and models

Larval vertical behaviour to validate larval drift models

IFREMER (P. Petitgas)

2.3 – Implement process knowledge in coupled individual-based biological-physical oceanographic models

Probability of recruitment success/failure for each potential spawning ground will be estimated under different scenarios of population occupation and climate regime.

IFREMER (P. Petitgas)

2.4 – Scenario modelling of variations in biological and physical forcing to develop predictive capacities with respect to stock recovery

Application of an IBM model to anchovy (possibility to extend to hake) in the Bay of Biscay, comparing statistical vs. mechanistic models.

IFREMER (P. Petitgas), AZTI (X. Irigoien)

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).

Project Structure

Project Time Plan

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 forcompletion of activity table.

Discussed inputs/outputs to WP4.

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 betain 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/larvalsurvival, 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 timeseries and processes.

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 changeby 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.

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?

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-NPZDmodels), 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. Canbe used for recruitment process studies.

5. Recruitment modelling - cod in North, Baltic Sea, herring in North Sea