Fishery productivity and trophodynamics of platform artificial reefs in the northwestern Gulf of Mexico

Two petroleum platforms in the northwestern Gulf of Mexico were studied to characterize fouling community productivity and estimate energy flow between fouling-community elements and selected reef fishes.; Standing-stock energy levels of the fouling community ranged from 0.13 kcal/m2 for the amphipod Corophium biglovia to 24,000 kcal/m2 for the bivalve Isognomon bicolor. Annual production for amphipods ranged from 5.4 gDW/m 2 for Corophium biglovia to 43.8 gDW/m2 for Corophium louisiana.; Foraging and production of Paranthias furcifer, Epinephelus adscensionis and Balistes capriscus were examined. Paranthias furcifer populations and biomass varied seasonally and between platforms, ranging from 318 (mean weight 0.48 kg) during the winter at HI389A to 636 (mean weight 0.43 kg) at EB165A during summer. Populations of E. adscensionis and Balistes capriscus also varied between platforms. Population levels of E. adscensionis were 301 and 214 at EB165A and HI389A, respectively, whereas equivalent values for B. capriscus were 86 and 167.; E. adscensionis and B. capriscus fed almost exclusively on fouling-community, whereas P. furcifer fed primarily on planktonic organisms. Paranthias furcifer diets showed an increase in numbers of fouling community organisms consumed during winter. Consumption for P. furcifer ranged from 42.4 kcal/day to 24.9 kcal/day (465 g mean fish weight). Epinephelus adscensionis consumed 58.5 kcal/day (496 g mean fish weight), whereas Balistes capriscus consumed 78.7 kcal/day (646 g mean fish weight).; Models indicate P. furcifer used 42% of consumed energy for metabolism and 38% for growth during summer, and 59% for metabolism and 21% for growth during winter. Epinephelus adscensionis used 35% of consumed energy for metabolism and 45% for growth, whereas Balistes capriscus dedicated 35% to metabolism, and 45% to growth. Fish production rate from fouling community elements ranged from <0.1 g/(stock·m 2·day) for P. furcifer during winter to 0.7 g/(stock·m2·day) for B. capriscus.; This study indicates that the productive potential of platform artificial reefs lies in their ability to redirect energy flow. Filter-feeding organisms function to trap energy from the primary and secondary producers of the plankton community and redirect this energy making it available to predatory reef and pelagic fishes.