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Estimated Discard and Discard Rates in the Coastal Washington Arrowtooth Flounder Fishery In 2001

Category: Fish/Shellfish Research and Management - Fish/Shellfish Research

Date Published: December 2002

Number of Pages: 60

Publication Number: FPT 02-13

Author(s): Farron Wallace

EXECUTIVE SUMMARY:

Overview
In 2001, WDFW began a 2-year cooperative industry at-sea data collection program in an effort to facilitate directed Arrowtooth flounder fishing and to establish an objective basis for estimation of canary rockfish discard in that fishery. The program was approved by the Pacific Fishery Management Council (PFMC) and National Marine Fisheries Service (NMFS) and administered under an Exempted Fishing Permit. This report provides a review of the 2001 (year 1) observer data and an estimate of discarded catch for the participating vessels. A final report will be produced in 2003 summarizing results of the entire program.

All participating vessels were required to carried observers throughout the study period and retain all rockfish species (Sebastes and Sebastelobus) caught. Shoreside, rockfish catch was sorted into marketable, unmarketable, and forfeited. Unmarketable catch was typically made up of small fish of no value and rockfish landings exceeding monthly cumulative trip limits were forfeited. Rockfish discard estimates in this study are assumed equal to the sum of forfeited and unmarketable, because this catch would have ordinarily been discarded at-sea under normal fishing operations. Observers also monitored fishing strategies and collected data to estimate total catch, discard and bycatch rates of incidental catch of non-rockfish species.

Results
Participating vessels landed approximately 810 mt of arrowtooth flounder that would not have been possible without the EFP fishery. The estimated bycatch rate for canary rockfish in the north coastal Washington arrowtooth fishery is significantly lower than that used to set current regulations for the arrowtooth fishery in 2002. In arrowtooth directed tows, the ratio of canary to arrowtooth was 0.07% compared to an assumed rate of 2.0% to 3.0%. Among the 7 vessels participating in the study, the highest canary discard rate for a single vessel was 1.9%. Two vessels caught no canary. This questions the ability for at least some vessels to avoid canary rockfish in directed arrowtooth tows. This also suggests that predicting bycatch may be highly prone to error.

Although the relative volume of catch was low, the percent discard within rockfish market category was much higher.

Total estimated rockfish catch and discard

Total Estimated
(lbs)
Discard Rate
Species/Market Category Catch Discard
Canary 5,226 2,574 49.3%
Darkblotched 4,359 22 0.5%
POP 28,099 4,528 16.1%
Shortspine Thornyhead 14,893 3,838 25.8%
Shelf 21,656 12,193 56.3%
Slope 15,851 5,922 37.4%
Widow 632 - 0.0%
Yellowtail 41,975 10,014 23.9%
Sub-Total 132,691 39,091 29.5%

Data Limitation
Analysis in this study is based on data collected from seven volunteer vessels and does not represent a random sampling of the fleet. Because this study is limited in scope, results should not be widely applied to other fisheries. Furthermore, vessels participating in this study actively attempted to minimize canary bycatch and discard rates may not be representative of other vessels targeting arrowtooth.