Terms of Reference

Northern Cod Framework Review Meeting

Regional Peer Review – Newfoundland and Labrador Region

November 30 ‑ December 4, 2015
St. John’s, NL

Chairperson: Don Power

Context

The framework review meeting will focus on methodology for estimating the population size of the Northern Cod (NAFO Divs. 2J3KL) stock.

The most recent (2013) stock assessment utilized a survey-based model (SURBA) to determine stock status. This method relies only on DFO survey data, generating absolute estimates of total mortality rates (Z) and relative estimates of stock size. A drawback to this approach is that it cannot directly provide catch-based management advice. A Framework Review meeting on Northern Cod will review multiple models of population dynamics, and also discuss the utility of various data sets available for assessing this stock. For example, Cadigan (2015) describes a state-space population dynamics model which estimates stock size of Northern Cod by integrating input data from several sources (survey data, mark-recapture data and commercial fisheries data).

The goal of the Framework will be to determine which data sets and models will be considered at the March 2016 Regional Peer Review (RPR) as a basis for providing management advice. No provision of management advice will occur during the framework meeting, rather management advice will be provided through the 2016 RPR.

Objectives

The Framework meeting will address the following:

1. Evaluate the utility of data sources that may provide information on the stock status of Northern cod. If possible, examine the uncertainty in the data and the methods used to estimate measures of uncertainty.

In addition, for each model considered:

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2. Is the structure of the model and the estimation techniques employed sufficient (i.e. robust and reliable) to estimate the stock size of Northern cod?
3. Are proposed projection methods for evaluating future catch options sufficiently robust and reliable? Are any additions or modifications to methods or inputs required before providing advice to Fisheries Managers?
4. Recommend priority short- and medium-term research areas to improve data sources, assessment model formulation and estimation, and projection methods.
5. If reference points have not been estimated, provide direction for future work towards estimating Precautionary Approach reference points (both biomass and removal references).
6. Acoustic surveys have recently been conducted by the Centre for Fisheries Ecosystems Research at Marine Institute of Memorial University. (Data from these surveys are not currently available.) Consider extensions to the model structure that can incorporate these data as an index of stock size.
7. If time permits, discuss the extent to which the method (and underlying computer software) is amenable to conducting Management Strategy Evaluation (MSE).

In order to address the Terms of Reference and enable across-method comparison for each method considered, the following results should be available for review two weeks prior to the beginning of the meeting:

• Measures of Fit, including graphical display of residuals,
• All parameter estimates and/or random effects, with measures of uncertainty,
• Estimates of Total Abundance, Recruitment (at age 3), Biomass (Ages 3 and older), Mature Biomass, Fishing Mortality (averaged over both ages 4-6 and ages 7-9), Natural Mortality (if applicable), and Catchability Parameters, and
• Retrospective analysis (five years or greater).

External experts will participate and provide independent peer-review of the Framework Review. Identified reviewers will be required to provide a reviewer report on the final day of the meeting.

Expected Publication

• Proceedings (which shall include reports from the reviewers)

Participation¹

• Fisheries and Oceans Canada (DFO) - Science, NL Region
• Fisheries and Oceans Canada (DFO) - Fisheries Management and Policy & Economics, NL Region²
• Memorial University of Newfoundland and Labrador
• Fisheries Scientist, Fish Food and Allied Workers Union
• Other invited Regional, National and International Scientific Experts, including Academia
• Invited reviewers:
  • Dr. Joanna Mills-Flemming, Associate Professor of Statistics, Dalhousie University (Halifax, Canada)
  • Dr. Anders Nielsen, Senior Research Scientist, DTU Aqua (Copenhagen, Denmark)
  • Dr. Chris Legault, Supervisory Research Fishery Biologist, NMFS (Woods Hole, USA)
  • Dr. Doug Swain, Research Scientist, Fisheries and Oceans Canada (Moncton, Canada)

Reference

Cadigan, N.G. 2015. A state-space stock assessment model for northern cod, including under-reported catches and variable natural mortality rates. Canadian Journal of Fisheries and Aquatic Sciences, 10.1139/cjfas-2015-0047