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Assessment Summary

ISRP Assessment 2008-115-00-ISRP-20120215
Assessment Number: 2008-115-00-ISRP-20120215
Project: 2008-115-00 - Lake Roosevelt Burbot Population Assessment
Review: Resident Fish, Regional Coordination, and Data Management Category Review
Proposal Number: RESCAT-2008-115-00
Completed Date: 4/17/2012
Final Round ISRP Date: 4/3/2012
Final Round ISRP Rating: Meets Scientific Review Criteria - In Part
Final Round ISRP Comment:
Qualification #1 - Qualification #1
In Part - The full proposal is not yet justified. Deliverable 1 should proceed. Previous and ongoing burbot data collection in Lake Roosevelt from WDFW Fall Walleye Index Netting (FWIN) should be fully examined and analyzed to determine if it is adequate for evaluating the status of burbot before exerting significant additional sampling effort in the lake. Evaluation based on Deliverable 1 should be used to design field sampling efforts, if needed, beyond existing efforts as a means to meet project goals. The ISRP should review a subsequent revised proposal that builds on results from Deliverable 1. The design should consider other ISRP comments noted below.
First Round ISRP Date: 2/8/2012
First Round ISRP Rating: Meets Scientific Review Criteria - In Part
First Round ISRP Comment:

1. Purpose: Significance to Regional Programs, Technical Background, and Objectives

Significance to Regional Programs: The sponsor refers to several regional programs, including the Spokane Subbasin plan, the Columbia River Basin Research Plan, the Lake Roosevelt Guiding Document, MERR, and the NPPC Fish and Wildlife Program 2009. The declining status of burbot in many southerly portions of their range is a valid concern to resident fish managers. 

Technical Background: The proposal provides decent technical background information on sampling and status of burbot, although additional gray literature might be available on burbot sampling. 

Key information involving the ultimate goal of the proposal was missing until the presentation by the sponsor. During the presentation, the sponsor noted that current harvest levels of burbot are low because fishing gear is now limited to hook and line since set lines were banned in 2006. No sport or subsistence catch data was provided. According to WDFW regulations, the daily bag limit for burbot is currently five fish, but the state also recommends that women of child bearing years and children not consume more than one meal of burbot per week because the fish are contaminated. The sponsor cited a 10-year old WDFW report suggesting the Lake Roosevelt burbot population was “healthy” based on stable electrofishing and catch per effort sampling. Given the reportedly low catch rates of burbot by fishermen and the apparent healthy status of the population, the ultimate goal of this project seems to be whether the population of burbot could withstand a higher harvest rate, possibly through changes in gear regulation. If so, this would be a potential benefit to subsistence and recreational anglers. If changing harvest and gear regulations is an ultimate goal of this effort, then metrics and benchmarks for making this decision should be developed. 

Objectives: The goal is reasonable: a healthy and harvestable burbot population. The objective is reasonable: to monitor and facilitate management to achieve the goal. Specific target levels to define “healthy population” and harvest levels are needed.

2. History: Accomplishments, Results, and Adaptive Management (ISRP Review of Results)

This is a new project so no accomplishments, adaptive management, or results. 

However, the ISRP thought the sponsor should have analyzed the existing Fall Walleye Index Netting data (FWIN) prior to developing this proposal to conduct extensive field effort. Analysis of the existing FWIN data may be sufficient to evaluate status of burbot relative to previous sampling efforts (e.g., Bonar study), and this analysis could be used to inform the sampling design if it was determined that an extensive field effort was needed in addition to ongoing FWIN sampling and creel survey efforts.

3. Project Relationships, Emerging Limiting Factors, and Tailored Questions for Type of Work (hatchery, RME, tagging)

Project Relationships: The proposal described how this project was related to four other projects: Lake Roosevelt Data Collection Project, Kootenai River Resident Fish Mitigation, CCT Chief Joseph Kokanee, and CCT White Sturgeon Enhancement Project. Four BPA projects are listed that this project will coordinate with and share data.

Emerging limiting factors: Climate change, chemical contamination, and potential impacts by non-native predators are discussed.

Tailored questions: The sponsor addressed the PIT tag study to develop population estimates. They plan to tag and release all viable burbot, approximately 2200 fish per year based on assumptions. The sponsor notes that they do not know if the proposed sample size is adequate for estimating burbot population size, but they suggest this is not needed since the project is a pilot study. The ISRP notes that prior to the proposed field effort, the sponsor should examine “what if” scenarios to determine whether tagging of 1100 fish twice per year might be sufficient to detect population trends over time in this very large reservoir. Also, the sponsor should develop criteria for determining whether captured burbot are suitable for tag and release even though previous studies suggested mortality in trammel nets was low. Tagging of burbot that die from capture and tagging operations would significantly bias population estimates if not properly accounted for. The sponsor did describe how they would classify the health of burbot captured in traps. The sponsor notes that a biometrician would be consulted. 

4. Deliverables, Work Elements, Metrics, and Methods

Deliverables are adequate.

The sponsor did a good job describing methods in MonitoringMethods.org. However, presenting methods on separate web pages makes it difficult to evaluate how the overall sampling program fits together.

Additional information on metrics should have been provided. Age and year class strength are key metrics when assessing population status of fishes, yet it was not clear how age of burbot captured in traps, trammel nets, or gillnets (FWIN) will be assessed and incorporated into the analysis. Burbot are relatively long-lived (up to ~15 years) and could be susceptible to high harvest rates. Each gear type will have its own selectivity for size and age of burbot; how will selectivity be evaluated?

4a. Specific comments on protocols and methods described in MonitoringMethods.org

The sponsor did a good job describing methods in MonitoringMethods.org. Estimates of growth will be based on recaptured burbot, but growth estimates may be few. Were other approaches considered and excluded for estimating growth?

Modified by Dal Marsters on 4/17/2012 2:56:41 PM.
Documentation Links:
Proponent Response: