Table 1 Common invertebrate sampling techniques.

Benthic core

Animals buried in the sediments

Destructive as habitat is removed in sampling. More mobile animals escape. Time consuming to collect and process samples. Specimens usually damaged during collection

Grab sample

Dredge

Specimens at and just below surface

Quadrat scraping

Sessile animals on solid surface

Suction sampler

Benthic organisms

Destructive. Expensive equipment and labour intensive

Plankton net or pump

Free floating and slow moving organisms

Cannot sample in structurally complex areas. Specimens can be damaged by net. More mobile taxa escape

Visual including photography

Observe larger mobile fauna and sessile and sedentary macrobiota

Mobile macrofauna not sampled

Baited traps

Larger mobile macrofauna

Limited to scavenging species and will attract megafauna that predate smaller species

Artificial substrata

Sessile, sedentary and nestling biota

Have to be left in situ for weeks to months to be colonised

Emergence and sediment traps

Select benthic animals that move up or down in water column

Need to be large to capture sufficient number of animals and/or left in place for days