1. General concepts and requirements Scott Large
ICES stock assessment
General concepts and requirements
Scott Large
@NucellaGrande
#TCOM
27 January 2016

2. ICES stock assessments - overview
ICES provides advice on the sustainable use of living marine resources and protection of the marine environment.
In 2015, ICES provided advice on fishing opportunities for 225 fish stocks across the northeast Atlantic

3. ICES stock assessments - data
225 ”ICES” stocks
~ 90 stocks: quantitative assessments
Catch data - InterCatch
Survey data - DATRAS
~ 90 stocks: survey trend-based assessments
~ 40 stocks: data-poor assessments
Nominal catch - Catch Statistics
Explanation of data categories: ICES 2012

4. ICES Stock assessments - methods
ICES scientists use a suite of common stock assesment methods (with varying complexity and computational needs)
Virtual Population Analysis
Extended Survivors Analysis (XSA; Shepherd, 1999)
Time Series Analysis (TSA; Gudmundsson, 1994)
State Space Stock Assessment Model (SAM; Nielsen and Berg, 2014)
Stock synthesis
SS3; Methot and Wetzel, 2013
Ecosystem, Mixed-fsheries, and multi-species models
Globally applicable Area Disaggregated General Ecosystem Toolbox (Gadget)
Size-structured, multi-species (Thorpe et al. 2015)
Mixed-Fisheries (Fcube; Ulrich et al 2011)
Survey-based model
SURBAR; Cook, 1997

5. Linking ICES and BlueBridge
ICES uses “simple” models
ICES has robust databases that handle catch and survey data
Increasing need for high powered computing:
Ecosystem models
Mixed-fisheries models
Single-stock forecasts
Management strategy evaluations

6. Test Case – Ensemble Model
Purpose – Length-based, multi-species and multi-fleet model for the Irish Sea
Complexity - High
Improvements – Current version is for North Sea. It is being rewritten for the Irish Sea. Takes a few hours to run – increasing computing power will enable broader resampling of models.
Stage in development – Agreement with author. Will initiate code review/ discussion by 15 February.
Contact/ Author: Robert Thorpe (CEFAS)

7. Test Case – Mixed-Fisheries assessment model
Purpose – Multi-fleet model, used for ICES advice
Complexity - Medium
Improvements – ”Optimizer” uses a genetic algorithm and takes several hours to run. BlueBridge will allow deeper model exporation.
Stage in development – Agreement with author. Will initiate code review/ discussion by 15 February.
Contact/ Author: Youen Vermard (IFREMER)

8. Test Case – Management Strategy Evaluation
Purpose – MSE for western horse mackerel
Complexity - Medium
Improvements – Simple test-case that will be a good point for further development.
Stage in development – Agreement with author. Will initiate code review/ discussion by 15 February.
Contact/ Author: José De Oliveira (CEFAS)

9. Test Case - eqSim
Purpose - Simulates equilibrium results for a population from stock assessment output
Complexity - low
Improvements - Currently eqSim is not computationally limited, but it could be drastically enhanced to become more useful with BlueBridge development.
Stage in development – Came up with the idea on the airplane. Will cut ticket ASAP.
Contact/ Author: Colin Millar (Marine Scotland Science)

10. Overview
ICES scientists are becoming very curious about how BlueBridge can help them.
Single-species stock assessments – simple but can be improved
eqSim, MSE, etc.
Good place to start with 4 test cases of varying complexity.
eqSim, Mixed-fisheries, and the MSE could also link directly into ICES training courses #BlueSkillz #bonus

11. Scott.large@ices.dk @nucellagrande