Fishing vessels execution of acoustic surveys for deep-sea species: main issues and way forward

FAO Fisheries and Aquaculture Circular. No. 1059

Food and Agriculture Organization of the United Nations
Rome 2012

ABSTRACT

FAO. 2012.
Fishing vessel execution of acoustic surveys of deep-sea species: main issues and way forward.
FAO Fisheries and Aquaculture Circular. No. 1059. Rome. 91 pp.

This Food and Agriculture Organization Fisheries and Aquaculture Circular is based on the Workshop on Fishing-vessel Execution of Acoustic Surveys for Deep-sea Species: Main Issues and Way Forward, held in Rome, Italy, from 9 to 11 December 2009. The report synthesizes current knowledge and practice for engaging the fishing industry in the management of the resources they target, highlights the main challenges that arise, and discusses how analysts and decision-makers can use this experience in undertaking aggregation-based fishing-vessel executed acoustic surveys.

The topics considered by this workshop included the conditions required at sea for successful fishing-vessel deep-water acoustics surveys, the equipment to be used and its maintenance, processing of data, the problems arising from uncertainty in the backscattering cross section–biomass relation, survey methods, the estimation of biomass abundance and the associated uncertainties, the nature of supplementary biological data that are required for interpretation of acoustic information, use of the results, funding of survey programmes and recommendations for considerations in implementation of fishing-vessel executed deep-water acoustic surveys.

The circular documents the meeting summary and the main recommendations with respect to general considerations, institutional and organization issues, applications at sea and operational challenges, vessels and equipment, survey methods, acoustic data processing and backscattering cross-section values, estimation of abundances, uncertainty of results, importance of collection of biological data, incorporating industry survey results into assessments and management process, funding of cost of acoustic surveys and discussions.

Table of Contents

Preparation of this document Abstract
1.	INTRODUCTION AND BACKGROUND
	1.1	Introduction
	1.2	Background
2.	INSTITUTIONAL AND ORGANIZATIONAL ISSUES
	2.1	Who is this report intended for
	2.2	Why there is an issue
	2.3	Strategic and technical considerations
	2.4	Requirements that must be met for stock assessment
3.	APPLICATIONS AT SEA AND OPERATIONAL CHALLENGES
	3.1	Operational characteristics
	3.2	Role of incentives/disincentives
	3.3	Integrating surveys with commercial fishing activities
	3.4	Echo mark identification
4.	VESSELS AND EQUIPMENT
	4.1	Introduction
	4.2	The echosounder
	4.3	Frequency considerations
	4.4	Choice of vessel
	4.5	Location of transducers
	4.6	Calibration
	4.7	Opportunities for introduction of new technologies
5.	SURVEY METHODS
	5.1	Strategic considerations
	5.2	Aggregation-based surveys
		5.2.1	Introduction
		5.2.2	Spaced parallel transects
		5.2.3	Star transects
		5.2.4	Protocol for aggregation-based surveys
	5.3	Area-based surveys
		5.3.1	Example of a protocol for area-based surveys
	5.4	Multiple surveys
	5.5	Deciding which data to use for estimation of abundance
6.	ACOUSTIC DATA PROCESSING
7.	ACOUSTIC BACKSCATTERING CROSS SECTION VALUES
	7.1	Importance of proper specification
	7.2	Problems associated with use of σb and sv values
8.	ACOUSTIC BACKSCATTERING CROSS SECTION VALUES
	8.1	Introduction
	8.2	Area-based surveys
		8.2.1	Application of area-based surveys
		8.2.2	Design-based estimation in area-based surveys
		8.2.3	Model-based inference in area-based surveys
	8.3	Aggregation-based surveys
		8.3.1	Application of aggregation-based surveys
		8.3.2	Design-based estimation in aggregation-based surveys
		8.3.3	Model-based estimation in aggregation-based surveys
	8.4	Comparison of estimators
		8.4.1	Methods
		8.4.2	Comparative results from applying different analysis methods to orange roughy South Western Indian Ocean (SWIO) 2008 data
9.	UNCERTAINTY OF RESULTS
	9.1	Sources of uncertainty
	9.2	Sampling error
	9.3	Determination of species composition
	9.4	Backscattering cross-section
	9.5	Fish distribution and behaviour
	9.6	Weather
	9.7	Seafloor acoustics "dead-zone"
	9.8	Calibration error
	9.9	Other errors
10.	IMPORTANCE OF COLLECTION OF BIOLOGICAL DATA
	10.1	Data to be collected
	10.2	Species composition of the catch
	10.3	Length and weight frequency data
	10.4	Records of bycatch
	10.5	Sex composition and status of gonads
	11.6	Otoliths
11.	INCORPORATING INDUSTRY SURVEY RESULTS INTO THE ASSESSMENT AND MANAGEMENT PROCESS
	11.1	Stock assessment
	11.2	Indices of abundance
	11.3	Fishing vessel data and stock assessments
12.	FUNDING OF ACOUSTIC SURVEYS
	12.1	Funding considerations
	12.2	Cost items
	12.3	National applications
		12.3.1	Australia
		12.3.2	Canada
		12.3.3	Namibia
		12.3.4	New Zealand
		12.3.5	Chile
13.	DISCUSSION
	13.1	Common views
	13.2	Communication with vessel crews
	13.3	Research strategies
14.	WORKSHOP RECOMMENDATIONS
	14.1	General recommendations
	14.2	Applications at sea and operational challenges
	14.3	Vessels and equipment
	14.4	Operational protocols
	14.5	Collection of biological data
	14.6	Acoustic data processing
	14.7	Estimating and estimates of acoustic backscattering values of deepwater species
	14.8	Estimation of abundance
	14.9	Uncertainty (error in estimates)
	14.10	Costs involved in commercial vessel stock assessment and funding issues
15.	REFERENCES
APPENDIXES
A.	List of participants
B.	Agenda
C.	Examples of Trip Survey Summary Report and Echo Mark Encounter Log
D.	Example of a Joint Project Agreement: Support for conducting Atlantic herring spawning ground acoustic surveys in Scots Bay and other spawning areas of Southwest Nova Scoti
E.	Example of Agreement for Fishing Vessel – Management Authority – New Zealand
F.	Case studies – Summary overview of experiences with industry-based acoustic surveys for deep-sea fisheries

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