Underwater measurements of fish
Brief description
Photography, stereo-photography, videography,
and stereo-videography have become popular sub-tidal sampling techniques.
These photographic or video sampling techniques have the advantage
of being non-destructive, rapid and repeatable and can record information
on the growth and competition of species without destroying the
communities. They can also record data across broad spatial scales,
which have proven useful in documenting large spatial scale differences
between reefs, areas and regions. More recently underwater video
has been widely used for recording epibenthic communities on temperate
and coral reefs, in rocky shore intertidal areas, soft sediment
and deep-sea environments.
The use of underwater photography and video to measure fish
Accurate and precise information on length, density and
diversity of fish facilitates estimates of recruitment,
fishing intensity and rates of recovery from fishing or
other disturbances. Such information is vital for the process
of planning management strategies, e.g. the design of Marine
Protected Areas (MPA's), to protect vulnerable fish species
and their associated habitat. The more accurate
and precise the information is, the more easily
changes in the populations can be detected leading to informed
decisions on their management. When measuring a single fish’s
length, accuracy is defined as the ‘closeness’
of the estimate to the actual length while precision is
defined as the closeness of repeated measures to this fish’s
length.
A review of techniques used for assessing changes in fish assemblages
by Dianne Watson, BSc (Hon's), PhD Candidate (Marine Science), School of Plant Biology,Faculty of Natural and Agricultural Sciences, The University of Western Australia. Contains a short review of current literature on the advantages and disadvantages of currently used sampling techniques and their ability to effectively measure changes in fish assemblages. Where relevant, suggestions for improvements in design and implementation are made.
Underwater video
Stereo camera fish measurements:
Quicktime
video
(0.2 MB MOV)
(Apple QuickTime format)
- Interactive habitat extent & distribution mapping interface
- Portal to the Coastal Habitat Resources Information System (CHRIS)
- Coastal water habitat mapping toolkit
- Introduction
- Bethic habitat mapping
- Techniques
- Introduction
- Broad-scale acoustic sensors
- Airborne electro-optical sensors
- Fine-scale physical sampling
- Geophysical
- Grab sampling
- Gravity drop and piston coring
- Sediment vibrocoring
- Underwater electro-optical sensors
- Sediment profile imaging
- Underwater photography
- Underwater video imaging
- Laser line imaging
- Underwater fish measurements
- Position Fixing
- Differential GPS and subsea tracking
- Case studies
- Decision tree
- Useful links
- Reports and publications
- Photo and video gallery
- Acknowledgements
- NSW marine habitat mapping
- Interactive 3D models
- Glossary
