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Deployment performance review of the 2015 North Pacific Groundfish and Halibut Observer Program
  • Published Date:
    2016
Filetype[PDF - 1.78 MB]


Details:
  • Corporate Authors:
    Alaska Fisheries Science Center (U.S.)
  • Series:
    NOAA technical memorandum NMFS-AFSC ; 322
  • Document Type:
  • Description:
    This report contains the analyses and findings of the Alaska Fisheries Science Center's Fisheries Monitoring and Analysis Division s Observer Science Committee on the efficiency and effectiveness of observer deployment following the 2015 Annual Deployment Plan (ADP). Responses to comments by the North Pacific Fishery Management Council s Science and Statistical Committee from the 2014 version of this report are also included. In 2015, observers were deployed and collected data for 5,318 days - 3.6% fewer days than were budgeted for and predicted in the 2015 ADP. In total, 4,859 trips (39.1%) were observed on 498 vessels belonging to five strata (two trip-selection strata - a "t" stratum comprised of fixed gear catcher vessels 40-57.5 feet in length and a "T" stratum defined by larger catcher vessels, an EM voluntary stratum, a full-coverage stratum, and a zero-coverage stratum). All partial coverage strata had coverage rates within expected ranges with the exception of the new EM Voluntary (EM) stratum that had two observed trips although the selection rate was zero. Overall selection rates in the Observer Declare and Deploy System (ODDS) were as expected for each trip-selection stratum. The proportion of trips selected computed using the initial observer-status (selected or not selected for coverage) of logged trips differed from the proportion selected using the final observer-status after trips are cancelled or dates have been changed. Trips that were selected to be observed were cancelled at a higher rate than unselected trips. Despite this behavior, a temporal bias was not evident in the trips belonging to either trip-selection strata. Spatial bias was evident in the t stratum with coverage rates lower than expected in four NMFS areas. There was some evidence of an observer effect in the partial coverage category. In particular, observed trips were 8 - 14% shorter in both trip-selection strata and landed catch was 1% less diverse in the T stratum than unobserved trips. Observers monitor deliveries of trawl-caught walleye pollock (Gadus chalcogrammus) at Shoreside processing plants and collect genetic tissue samples from salmon bycatch. Although all pollock deliveries were monitored in the full coverage pollock fishery, coverage rates were below expected in the partial coverage category due to tendering activity at King Cove. Tendered trips were found to have different trip characteristics than non-tendered trips. There was some evidence of an observer effect within partial coverage tendered trips. Tendered trips landed 33-101% fewer fish, by weight, when observed and landed catch with 25% less species in the t stratum than unobserved tendered trips. In the T stratum, observed tendered trips were also 51% shorter than unobserved tendered trips. Similarly, for nontendered trips, observed trips were 3-5% shorter and fishing occurred in 3% fewer areas in the t stratum and were 1% less diverse in the T stratum. We examined the probability of having no observer coverage as a function of how many trips were in a NMFS area for each partial coverage stratum. The probability of having no data from a NMFS area decreased as total effort and sampling rate increased. While this result is not surprising, it highlights that the smaller the population of interest (e.g., fishing activities in a NMFS area), the higher the overall coverage rate needs to be in order to meet observer coverage goals and to obtain data that are representative of all fishing activities. Based on these combined results, we support the continued implementation and expansion of tLandings to document unobserved tendered deliveries, and make four recommendations to improve the 2017 ADP. The recommendations are: 1) tendered vessels should be evaluated as separate strata, 2) the treatment of partial coverage catcher processors should be evaluated as separate strata, 3) sampling rates should be high enough that the probability of achieving three observed trips in each NMFS Area is low, and 4) NMFS should work with its partial coverage contractor to explore the possibility of eliminating trip cancellations in ODDS. [doi:10.7289/V5/TM-AFSC-322 (http://dx.doi.org/10.7289/V5/TM-AFSC-322)]

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