The development and dynamics of a small artificial reef community

Abstract

1. The development of the community of a small artificial reef built from car tyres was investigated by SCUBA diving over a 12 month period. It was sited on a sandy bottom at a depth of 20 m on the coast of north-eastern New Zealand. 2. Seasonal settlement by sessile organisms occurred in a number of well defined stages (serpulid tubeworms, barnacles, bryozoans, Lithothamnion, hydroids). The reef was colonised by small mobile invertebrates - notably gastropods, hermit crabs, mysids and shrimps - as well as by fishes. 3. Wave action was the most important single factor affecting the community. Severe water movement and sand scouring caused extensive sloughing of the epifauna, and a pattern of settlement-growth-catastrophic mortality which limited biotic succession. Wave action was important also in the colonisation by mobile organisms and many of the invertebrates and small fishes were probably carried to the reef associated with drift weed and other storm flotsam. 4. Seven species of fish were more or less permanent residents. There was little seasonal change in the number of fish species but fluctuation in the numbers of individuals occurred, brought about mainly by the effects of storms, and in some cases also by predation and the availability of food. 5. Standing crop estimates of the fishes were 1.458 and 1.075 kg/m2, or about 10-14 times greater than that of nearby natural reefs. the bulk of the fish biomass, however, was contributed by a single species (Upeneichthys porosus) which inhabited the adjacent sand and was not directly supported by the reef itself. © 1975 Biologischen Anstalt Helgoland.