BIOMASS EXPORTATION FROM OFFSHORE PRODUCTION PLATFORMS IN EAST TEXAS

Abstract

ABSTRACT Studies of the structure and development of the fouling community on active offshore production platforms in the Buccaneer Field, Texas, indicated that energy accumulated within this community was exported to components of the adjacent marine ecosystem along three major pathways. The most apparent pathway was through grazing fish. Gut content analyses of 191 fish representing 27 species indicated that the spadefish (Chaetodipterus faber), sheepshead (Archosargus probatocephalus), crested blenny (Hypleurochilus geminatus), cocoa damselfish (Pomacentrus variabilis), and cubbyu (Equetus acuminatus) feed extensively on fouling organisms. A second pathway linked the fouling community to the benthic fauna living beneath the platforms, which was apparently enriched by consumption of barnacles and other invertebrates dislodged from the platform legs by wave and current stresses, abrasion by boats, and foraging fish. Several fouling species, which did not occur on the structures themselves, were found on dislodged barnacle shells and gastropod shells occupied by hermit crabs. Thus, accumulation of biomass beneath the structures is apparently increased by the presence of these shells. The third pathway linked the fouling community to planktivorous fish and invertebrates through the release of planktonic larvae by fouling organisms. A significant difference (p < 0.05) was found in the proportion of these larvae in the total plankton between stations within Buccaneer Field and those at a control site 8 kilometers east of the field.