Resource Assessment & Conservation Engineering (RACE) Division

Midwater Assessment & Conservation Engineering (MACE) Program

Acoustic Data Collection Aboard Commercial Fishing Vessels

In January 2005, representatives from the Center’s RACE and REFM Divisions and the North Pacific Groundfish Observer Program agreed to form a working group to discuss ongoing and proposed work to collect quantitative acoustic data aboard commercial fishing vessels. Discussion focused on four main topics: 1) development of acoustic data logging protocols for commercial vessels, including fishing vessels conducting acoustic surveys, chartered fishing vessels (e.g., for groundfish bottom trawl surveys), and those involved in commercial fishing operations; 2) methods for archiving raw acoustic data, and techniques to reduce the amount of logged data without compromising data quality; 3) software development for automated processing of the acoustic data; and 4) acoustic system calibration and inter-vessel comparisons.

Subgroups were formed to address each of the topics, and additional meetings were held throughout spring 2005. The acoustic data logging protocols, including a detailed section providing instructions for calibrating commercial fishing vessels, was completed in time to be used during the summer 2005 Bering Sea and Gulf of Alaska groundfish surveys. A conceptual flowchart has been developed for the automated acoustic processing software, and the first two stages are beta coded. A retrospective analysis has been initiated to examine feasibility of comparing whole water column acoustic backscatter from annual bottom trawl surveys in the Bering Sea to pollock backscatter identified from biennial acoustic trawl surveys.

By Taina Honkalehto
 

Workshop on Survey Design and Data Analysis

Paul Walline was among the 21 scientists from 13 countries who attended the second meeting of the International Council for the Exploration of the Sea (ICES) Working Group on Survey Design and Analysis, held in Sete, France, on 9-13 May. Part of the meeting dealt with alternate methods for analyzing survey data (acoustic or trawl) to estimate fish abundance and its associated precision. Participants analyzed surveys of the same simulated fish population to compare methods and presented results from several real survey datasets. Walline presented results from analysis of the simulated survey using geostatistical methods, and results from analysis of a set of repeated surveys made near Kodiak Island, Alaska, using a variety of methods.

Other subjects at the meeting included: a) potential gains and losses from reducing the duration of research trawls, b) the possible use of covariate data to improve survey design or analysis, c) methods for combining surveys, and d) the effective sample size to determine biological parameters such as a length distribution. Workshop participants summarized some of the discussions in the form of a "decision tree" providing a guide as to the best survey design for obtaining abundance estimates with as much precision as possible. The decision tree and a summary of the meeting presentations and discussions will be available as an ICES report.

By Paul Walline
 

Working Group on Fisheries Acoustics Science and Technology

Chris Wilson and Alex De Robertis attended the 2005 meeting of the ICES Fisheries Acoustics Science and Technology working group held at the Food and Agriculture Organization in Rome, Italy on 18-22 April. Wilson presented a paper describing ongoing field experiments designed to evaluate the effects of fishing activity on walleye pollock abundance and distribution. De Robertis presented a paper describing the use of hull-mounted hydrophones to measure the self-noise of NOAA’s new research vessel Oscar Dyson and served as meeting rapporteur. Major topics of discussion at the meeting included the use of alternate platforms such as fishing vessels for acoustic data collection, methods for remote species classification, fish reactions to survey vessels, and the effectiveness of noise-reduced research vessels.

By Alex De Robertis
 

Oscar Dyson Field Trials and Gulf of Alaska Survey

NOAA’s new fisheries survey vessel Oscar Dyson arrived at the Pacific Marine Center in Seattle in early March 2005. After a period of dockside equipment installation and testing, the vessel underwent field trials in Puget Sound on 9-13 May followed by more formal acceptance trials off the coast of Washington on 14-16 May. This phase of acceptance trials focused on demonstrating the capabilities of the vessel’s trawl, hydrographic and oceanographic winch systems along with the trawl net sounder systems. The vessel departed Seattle on 21 May enroute to its homeport in Kodiak, Alaska. A public commissioning ceremony was held in Kodiak on 28 May. The first leg of the Gulf of Alaska acoustic-trawl survey, which was scheduled for 1 June – 30 July, was suspended on 3 June because of generator problems. Repairs were completed by late June, and the survey resumed on 1 July. Survey objectives were modified to accommodate the shortened field season.

By Neal Williamson and Mike Guttormse


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AFSC Quarterly Research Reports April-June 2005