METHODS OF SAMPLINU THE BENTHOS
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A. Sampling the epifauna
Members of the epifauna which cannot actively move out of the
way are, of course, taken by all instruments which sample the burrowing
fauna. The are in addition certain techniques only suitable for sampling
the epifauna :
1. Qualitative instruments
Rectangular dredge
Otter, beam and Agassiz trawls
2. Quantitative instruments and techniques
Petersen’s sampler for epifauna (Petersen, 1918, p. 4)
Baird’s sampler (primarily designed for epifauna sampling,
but since found to sample the infauna quite successfully)
Underwater cameras
Underwater television
Free-diving
Since many of these techniques enable much larger areas to be
covered than iu possible with the grab, it is very desirable that one
or more should be employed in addition to the grab in order to sample
or record scarcer members of the epifauna.
B. Sampliw the shallow-burrowing fauna
The estimated depths of digging on hard-packed sand are shown.
Those samplers penetrating less than 4 cm will generally not sample
the fauna adequately ; those penetrating between 4 and 10 cm probably
get a reasonable sample for comparative purposes.
1. Qualitative iwtrumente
Dredges, with oval or bowed frame
U p t o 5 c m
Conical dredge
U p t o 5 c m
Anchor-dredge as used by Holme (1961) m. 10-15 cm
Robertson bucket-dredge
? 5-10 cm
2. Quantitative instruments
Petersen grab
0.1 m2
1-2 cm (Thamdrup, 1938)
Petersen grab
0.2 ma
3 cm (Umin, 1954)
van Veen grab
0.1 m2
3-5 cm (Thamdrup, 1938;
Smith and McIntyre,
1964)
van Veen grab
0.2 ma
5-7 cm (Umin, 1964)