Marine Ecological Field Methods. A Guide for Marine Biologists and Fisheries Scientists

  • ID: 4226294
  • Book
  • 240 Pages
  • John Wiley and Sons Ltd
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A comprehensive, clear, and detailed guide to procedures for conducting marine ecological field studies

Marine Ecological Field Methods is a comprehensive resource that offers the most relevant sampling methodologies for quantitative and qualitative studies of mesopelagic, demersal, littoral, and soft–bottom organisms, as well as relevant physical parameters. The authors describe how various sampling gears work, how to operate them, their limitations, guides on sorting and measuring collected organisms, and how to deal with subsamples of large catches. The text also explains how to use acoustic equipment for monitoring aggregations of organisms, for example fish shoals, as well as the use of sensors for registering environmental variables such as salinity, temperature, oxygen, and light.

The text contains cutting–edge research techniques that are in their final stages of development for use in research surveys. Marine Ecological Field Methods is designed to help with the entire procedure for conducting a field study, including the generation of hypotheses, planning field collection of data, conducting field work, data exploration and statistical analysis with the use of R, and presentation of results in a final report. This essential resource:

  • Covers a wide range of techniques and methods for the marine environment
  • Includes tried and trusted methodologies and techniques from a team of noted experts in the field
  • Contains information on sampling equipment ranging from those that are useful in the littoral zone to shallow nearshore areas, including bottles, secchi discs, and gillnets, and finally large trawls, benthic sleds, ROV and advanced technologies for remote sensing in the open ocean
  • Explores the step–by–step procedures for conducting a field study, from formulating hypotheses to the process of registering and reporting results

Written for students and professionals in the field, this vital resource describes marine ecological sampling equipment, methods and analysis, ranging from physical parameters to fish, microalgae, zooplankton, benthos and macroalgae.

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List of Contributors xi

Foreword xiii

Acknowledgements xv

1 The Marine Environment 1
Jon Thomassen Hestetun∗, Kjersti Sjøtun∗, Dag L. Aksnes, Lars Asplin, Jennifer Devine, Tone Falkenhaug, Henrik Glenner, Knut Helge Jensen and Anne Gro Vea Salvanes∗ Lead authors; co–authors in alphabetical order

1.1 Marine Habitats 4

1.1.1 The Pelagic and Benthic Realms 4

1.2 The Coastal and Fjord Biotopes 5

1.2.1 The Littoral and Sublittoral Habitats 6

1.2.2 The Continental Shelf and Slope 8

1.2.3 The Deep Ocean 9

1.3 Physical Characteristics of the Pelagic System 10

1.3.1 The Light Environment 15 Inherent Optical Properties: Scattering and Absorption Coefficients 15 Visibility, Sighting Distance, and the Beam Attenuation Coefficient 16 Light Penetration and the Attenuation Coefficient of Diffuse Light 16 Photosynthetically Active Radiation (PAR) 17

1.4 Temperate Marine Communities Environment and Organisms 18

1.4.1 Littoral Organisms 18 Species, Zonation, and Communities 18

1.4.2 Sublittoral Organisms 20

1.4.3 Demersal and Benthic Organisms 21 Bottom ]associated Organisms 21 Continental Shelf and Slope Benthos 22 Benthic Fish of the Continental Shelf and Slope 23 Deep Bottom Fish of Fjords and the Norwegian Deeps 24

1.4.4 Pelagic Organisms 24 Plankton and Micronekton 24 Pelagic Fish 28 Mesopelagic Organisms 29 Deep ]pelagic Fish 30

References 30

2 Planning Marine Field Studies 33
Jennifer Devine∗, Keno Ferter, Henrik Glenner, Jon Thomassen Hestetun, Knut Helge Jensen, Leif Nøttestad, Michael Pennington, David John Rees, Anne Gro Vea Salvanes, Kjersti Sjøtun and Arved Staby ∗ Lead author; co–authors in alphabetical order

2.1 Survey and Sampling Design 33

2.1.1 Survey Design 35

2.1.2 Sampling at a Station 36

2.2 Littoral Survey Design 38

2.2.1 Sampling Methods 40

2.3 Benthos Survey Design 40

2.3.1 Mapping the Biodiversity of Sognefjord An Example of a Multi ]sampling Approach 42 The Objectives of the Project 43 Sampling Strategy and Sampling Design 43 Methods and Sampling Activities 44

2.4 Oceanic Survey Design 44

2.4.1 Pelagic Trawl Survey for Abundance Estimation of Mackerel 45 Background 45 Primary Objectives 45 Survey Design 46 Equipment 47 Sampling 47 Assumptions 47 Computations 47 Results 48 Potential Uncertainties and Bias 48 What are the Data Used for? 48

2.4.2 Bottom Trawl Surveys to Monitor Demersal Fish 49 Background 49 Primary Objectives 49 Survey Design 50 Equipment 51 Assumptions 52 Computations 53 What are the Data Used for? 53

2.5 Ecological Process Studies 54

2.5.1 Studying Diel Vertical Migration (DVM) of Mesopelagic Organisms Using Acoustics 54 Background 54 Primary Objectives 55 Survey Design 56 Equipment 56 Sampling 57 Assumptions 58 Computations 59 Results 61 Potential Uncertainties and Bias 61 What are the Data Used for? 63

2.5.2 Studying Barotrauma Impacts in Physoclistous Fish Species 63 Background 63 Primary Objectives 64 Survey Design 64 Equipment 66 Assumptions 66 Computations 66 Results 66 What are the Data Used for? 67

References 69

Further Reading 73

3 Sampling Gears and Equipment 75
Anne Gro Vea Salvanes∗, Henrik Glenner∗, Dag L. Aksnes, Lars Asplin, Martin Dahl, Jennifer Devine, Arill Engås, Svein Rune Erga, Tone Falkenhaug, Keno Ferter, Jon Thomassen Hestetun, Knut Helge Jensen, Egil Ona, Shale Rosen and Kjersti Sjøtun ∗ Lead authors; co–authors in alphabetical order

3.1 Sampling Organisms 75

3.1.1 Direct Observations 75 Littoral Zone Methods 75 ROV Sampling 78 Video/image ]based Methods 79 Manned Submersibles 79 Scuba Diving 79

3.1.2 Active Gears 79 Sampling Trawls (Midwater and Bottom) 79 Beach Seine 85 Plankton Nets 86 Multiple Nets 89 Sledges and Dredges 91 Grabs and Corers 94 Water Samplers 95

3.1.3 Passive Gears 98 Gillnets and Entangling Nets 98 Pots 99 Fyke Nets 100 Hook ]and ]line 101

3.1.4 Remote Sensing 101 Acoustics 101 AUVs 107 Satellite or Infrared Light 107

3.2 Sampling the Physical Environment 110

3.2.1 Conductivity, Salinity, Temperature, Oxygen 110 CTD 110 Weather Station 111

3.2.2 Light 111 Secchi Disc 111 Transmission Meters 112 PAR Sensors 112 Spectroradiometers 113

3.2.3 Currents (Direction, Speed) 113 ADCP (Acoustic Doppler Current Profiler) 113 LADCP (Lowered Acoustic Doppler Current Profiler) 116 Small Handheld ADCPs 116 Moorings with ADCPs 117

3.2.4 Sediment 117

3.3 Suitability of Equipment in Given Habitat Types 118

References 118

4 Sorting Specimens and Preserving Materials 121
Anne Gro Vea Salvanes∗, Henrik Glenner∗, Jennifer Devine, Jon Thomassen Hestetun, Mette Hordnes, Knut Helge Jensen, Frank Midtøy and Kjersti Sjøtun ∗ Lead authors; co–authors in alphabetical order

4.1 Sampling Diary 121

4.2 Sorting and Preserving Littoral Collections 121

4.3 Sorting Zooplankton 122

4.3.1 Procedure for Processing Small Zooplankton Samples for Total Biomass 124

4.4 Sieving and Sorting Benthic Samples 125

4.5 Fish and Nekton 126

4.5.1 Trawl Samples 126 Sorting a Codend Sample and Subsampling 129

4.5.2 Sorting Hook ]and ]Line Samples 137

4.6 Data Records 137

4.6.1 Station Records and Species Composition 138

4.6.2 Detailed Individual Measurements 142

4.6.3 Information Transfer to Data Files 142

4.7 Samples for Storage 144

4.7.1 Fixatives 145

4.7.2 Health and Security When Using Fixatives 147

References 149

5 Data Analysis 151
Knut Helge Jensen∗, Jennifer Devine, Henrik Glenner, Jon Thomassen Hestetun, Anne Gro Vea Salvanes and Kjersti Sjøtun ∗ Lead authors; co–authors in alphabetical order

5.1 Scripts 151

5.2 Setting the Working Directory 152

5.3 Importing Data 153

5.4 Working with Data 155

5.4.1 Error Checking 155

5.4.2 Saving Data 159

5.5 Data Exploration and Statistical Testing 160

5.5.1 Analysis of Marine Communities 160 The Bray ]Curtis Dissimilarity Index 163

5.5.2 Physical Environment 167

5.5.3 Zooplankton Samples 170

5.5.4 Fish and Nekton 175 Hook ]and ]line 175 Trawls 175

5.5.5 Mapping 200 Making Maps with R 200

References 206

Index 209

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About the Editors
University of Bergen, Norway

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