Characterization and comparison of platform reef communities off the Texas coast
Abstract
From the Executive Summary: “Natural hard substrates are not abundant topographical features in the northern Gulf of Mexico. Consequently, offshore oil/gas production structures provide “islands of opportunity” for organisms that require hard surface substrates on which to settle, and eventually create dynamic artificial reefs that meet the habitat needs of mobile reef organisms, both invertebrate and vertebrate. Artificial reefs numerically increase opportunities that suitable habitat will be encountered by larval and pelagic organisms. As dynamic biological communities, artificial reefs impact the biology, ecology, and socioeconomics of the Gulf of México.
This report details new information on the biological dynamics of artificial reef communities on oil/gas production platform structures in the Gulf of México. Artificial reefs have a positive effect the biology and ecology of the Gulf of México on a local and regional scale. Off the Texas coast, artificial reefs support diverse biological communities, some of which are predominantly temperate in nature, others are tropical, and still other reefs are a mix of temperate and tropical. Artificial reefs meet the habitat needs of reef-restricted organisms and pelagic organisms. These communities enhance local and regional biodiversity.
Based on the results reported herein, to maximize biodiversity, primary and secondary production, and fisheries production, reef sites are most effective when concentrated between the 40 and 75 m depth contours. This zone seems to be equally effective at attracting and supporting strictly tropical organisms transported in offshore blue-water of the Gulf of México as well as those more temperate organisms found in shallow coastal waters. Seasonally clear waters exist in this area for at least six months of the year. Water depths are adequate to minimize bottom disturbances and seasonal meteorological conditions have less impact on water temperature than at shallow water sites. These water depths also keep a significant portion of the reef structure above the nepheloid layer.
Artificial reefs also create fisheries management challenges by making targeted fishery species more accessible to a greater number of fishers. A possible strategy to mitigate for easier accessibility of targeted fishes at artificial reef structures and to support increased biomass of targeted fish stocks would be to establish fish reserves (i.e. no take zones) around artificial reef structures. The strategy would be to set aside an area, perhaps 1 km2, in an ecologically and environmentally advantageous area in water depths between 40 and 75 m. Concentrate reef material, perhaps having a standing platform as a center point, in this area. Place the reef material in a manner to increase the density and complexity with as much vertical relief as possible. Extend the reef structure to the shallowest depth allowable by shipping safety guidelines.
The debate of whether or not artificial reefs contribute to the biological productivity of the Gulf of México inevitably is based on the productivity of fishery targeted fish populations. This is understandable since the socioeconomic demand for sustainable fisheries has substantial influence on the management of living marine resources. Based on targeted fishery species, the question of impact is unanswered. But based on the non-targeted fauna, particularly the sessile community, the answer is unequivocally yes – artificial reefs do contribute to the biological productivity of the Gulf of México ecosystem.
This report along with other reports just released and some research in progress significantly advances our understanding of the dynamics of artificial reefs. Yet, there remains a great deal of research to be done to fully understand the impact of artificial reefs upon the ecology and productivity of the Gulf of México.