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

FAO Fisheries and Aquaculture Circular. No. 1059

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







Download Full Report pdf file -2MB



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


The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products of manufacturers, whether or not these have been patented, does not imply that these have been endorsed or recommended by FAO in preference to others of a similar nature that are not mentioned.
The views expressed in this information product are those of the author(s) and do not necessarily reflect the views of FAO.

ISBN 978-92-5-107105-2

All rights reserved. FAO encourages reproduction and dissemination of material in this information product. Non-commercial uses will be authorized free of charge, upon request. Reproduction for resale or other commercial purposes, including educational purposes, may incur fees. Applications for permission to reproduce or disseminate FAO copyright materials, and all other queries concerning rights and licences, should be addressed by e-mail to:

Chief
Publishing Policy and Support Branch
Office of Knowledge Exchange, Research and Extension - FAO
Viale delle Terme di Caracalla, 00153 Rome, Italy
or by e-mail to: copyright@fao.org

© FAO