RECORDING BENTHIC AND DEMERSAL FISH IN DENSE VEGETATIVE COVER

In temperate marine waters seagrass (Zostera spp.) meadows and kelp (Laminaria spp.) forests commonly form dense stands of vegetation. The importance of seagrass beds as nursery areas for fish is widely accepted although exceptions are reported (Jenkins & Wheatley, 1998 and references therein). Kelps commonly dominate hard substrata, in both sheltered and exposed
locations. They are found from the intertidal zone down to 30 m (although kelp forests are generally found in shallower water) and, as such, form an important part of many marine biotopes. Sampling in dense vegetation is technically difficult (Kuslan, 1984) and should only be undertaken when an assessment of the fish population in the vegetation is specifically required. If
alternatives are available they are to be recommended, for example, an estimate of fish abundance within dense vegetation can be made by sampling fish outside the vegetated zone (Baelde, 1990).
If the kelp density does not preclude the use of divers or traps then these techniques should be used as discussed in the procedural guidelines for ‘Sampling Benthic and Demersal Fish Populations In Subtidal Rock Habitats’. Additional methods for sampling fish specifically within kelp or other dense algal communities are not widely reported in the literature and for this reason
only one method is described here.