Marine animal entanglements in mussel aquaculture gear

121 Pages·2015·6.01 MB·English

by  Madeline Young

Master‘s thesis

Marine animal entanglements in mussel
aquaculture gear
Documented cases from mussel farming regions of the
world including first-hand accounts from Iceland

Madeline Olivia Young

Advisors: Halldór P. Halldórsson and Scott Lindell

University of Akureyri
Faculty of Business and Science
University Centre of the Westfjords
Master of Resource Management: Coastal and Marine Management
Ísafjörður, May 2015
Supervisory Committee

Advisors:
Halldór P. Halldórsson, Ph.D.
Scott Lindell, MSc.

Reader:
Áslaug Ásgeirsdóttir, Ph.D.

Program Director:
Dagný Arnarsdóttir, MSc.

Madeline Olivia Young
Marine animal entanglements in mussel aquaculture gear: Documented cases from
mussel farming regions of the world including first-hand accounts from Iceland
45 ECTS thesis submitted in partial fulfilment of a Master of Resource Management
degree in Coastal and Marine Management at the University Centre of the Westfjords,
Suðurgata 12, 400 Ísafjörður, Iceland
Degree accredited by the University of Akureyri, Faculty of Business and Science,
Borgir, 600 Akureyri, Iceland

Copyright © 2015 Madeline Olivia Young
All rights reserved

Printing: Háskólaprent, Reykjavík, May 2015
Declaration

I hereby confirm that I am the sole author of this thesis and it is a product of my own
academic research.

___________________________________
Student‘s name

Abstract
Mussel aquaculture utilizes various ropes in the water column that may pose an
entanglement risk to cetaceans and sea turtles. In contrast to fishing gear, however, there
are far fewer documented entanglement cases in mussel aquaculture gear. With that being
said, there has been little data collected on this issue to date. Due to the growing demand
for aquaculture and potential expansion into offshore areas, interactions with cetaceans and
sea turtles are likely to continue and even increase into the future. In Iceland, the mussel
aquaculture industry is currently small and largely experimental, but there is potential for
expansion. The development of a successful management plan is dependent on
understanding what type and part of the gear poses the greatest entanglement risk, as well
as the location and timing of events in relation to cetacean feeding and migration patterns.
The objective of this thesis is to lay the foundation for future studies regarding cetacean
and sea turtle entanglements in mussel aquaculture gear. Documented entanglement cases
were collected from mussel farming regions of the world via media outlets, academic
articles, secondary sources, and informal interviews. Primary data collection was then
undertaken in Iceland using online surveys and semi-structured interviews with mussel
operators. In total, seven entanglement reports were collected, including four baleen
whales, one harbour porpoise, and two leatherback turtles. A majority of cases involved
mussel spat collecting ropes, which suggests this part of the gear may pose the greatest
entanglement risk. Two entanglement reports were from Iceland, where there is likely
proximity between cetacean distributions and mussel farming sites. Summer spat collection
also coincides with the highest densities of cetaceans in Icelandic waters. Management
suggestions for Iceland may include the implementation of a reporting system for
entanglements in aquaculture gear and studies looking into areas where spat collection can
occur with low likelihood of encountering cetaceans.
Keywords: Cetaceans, entanglement, Iceland, mussel aquaculture, mussel farming, sea
turtles.

This thesis is dedicated to Oliver, Lisa, Alex, and Lucy.

Table of Contents
List of Figures ..................................................................................................................... xi

List of Tables ..................................................................................................................... xiii

Acknowledgements ............................................................................................................ xv

1
  Introduction ................................................................................................................... 17

1.1
  Research ................................................................................................................. 18

1.1.1
  Objective ...................................................................................................... 18

1.1.2
  Research questions ....................................................................................... 18

1.1.3
  Methods ........................................................................................................ 19

1.1.4
  Scope ............................................................................................................ 19

1.2
  Thesis organization ................................................................................................ 20

2
  Literature overview ...................................................................................................... 21

2.1
  Aquaculture ............................................................................................................ 21

2.2
  Mussel aquaculture ................................................................................................ 21

2.2.1
  Global production ........................................................................................ 22

2.2.2
  Mussel aquaculture techniques and gear ...................................................... 22

2.2.3
  Mussel farming in Iceland ........................................................................... 27

2.3
  Marine megafauna interactions .............................................................................. 31

2.3.1
  Species groups discussed ............................................................................. 31

2.3.2
  Interactions with aquaculture ....................................................................... 33

2.3.3
  Entanglement ............................................................................................... 34

2.3.4
  Entanglement reports of cetaceans and sea turtles in mussel gear ............... 41

2.3.5
  Changing species distributions and abundances .......................................... 45

2.4
  Management and mitigation .................................................................................. 46

2.4.1
  Fishing gear vs. aquaculture gear ................................................................. 47

2.4.2
  Fixed fisheries .............................................................................................. 48

2.4.3
  Shellfish aquaculture .................................................................................... 52

2.5
  Cetaceans in Icelandic waters ................................................................................ 54

2.5.1
  Species abundances and distributions .......................................................... 55

2.5.2
  Bycatch ........................................................................................................ 62

2.5.3
  Attitudes towards cetaceans in Iceland ........................................................ 63

3
  Methods .......................................................................................................................... 65

3.1
  Surveys and interviews .......................................................................................... 67

3.1.1
  Selection of participants ............................................................................... 67

3.1.2
  Survey design ............................................................................................... 67

3.1.3
  Survey limitations ........................................................................................ 70

3.1.4
  Interview design and process ....................................................................... 71

3.1.5
  Interview limitations .................................................................................... 72

3.2
  Site locations .......................................................................................................... 73

ix
4
  Results ............................................................................................................................. 75

4.1
  Surveys ................................................................................................................... 75

4.2
  Interviews ............................................................................................................... 80

4.3
  Site locations ........................................................................................................... 84

5
  Discussion ....................................................................................................................... 85

5.1
  Summary of entanglement reports .......................................................................... 85

5.2
  Iceland .................................................................................................................... 86

6
  Conclusions ..................................................................................................................... 91

7
  Future research and management recommendations ................................................ 92

References ........................................................................................................................... 95

Appendix A: Online survey ............................................................................................. 105

Appendix B: Interview guides ......................................................................................... 117

Appendix C: Mussel operations in Iceland .................................................................... 119

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