The early life history of reef fish can be extremely important in the subsequent determination of year class strength. These early stages are probably the most susceptible life stages to any oil spill effects, especially considering the timing overlap between peak reef fish recruitment and the oil spill. This timing overlap would suggest that the reef fish larval and juvenile stages (e.g. red snapper) may have suffered higher mortalities from the recent Gulf oil spill resulting in subsequent year-class failures. However, there are few data available to provide valid assessment of this prediction.
This study will address this question of possible year-class failures based on prior work on the early life history of reef fishes in the northern Gulf of Mexico. For over 10 years reef fish recruitment to reef structure was examined as juvenile fish just after settlement from the pelagic environment and these previous studies provide a data base for valid comparisons to present conditions that may result from the oil spill. The study area is approximately 20-50 km south of Mobile Bay, Alabama, U.S.A., at depths of 20 to 40 m.
Small reef habitats (0.3 x 1.2 x 1.2 m) will be constructed and secured to the substrate with ground anchors. Reefs will be surveyed for abundance and size estimates of associated reef fish communities with SCUBA visual, video and digital camera surveys. Reefs will be built (n=30) in July 2011, and surveyed in August-September 2011, and in October-November 2011. We will measure temperature, salinity, and DO depth profiles (5 m intervals) during all reef fish surveys. We measure surface sediment samples and water samples for hydrocarbon analyses at each reef site. Environmental parameters will then be compared to fish recruitment patterns (densities, species communities, sizes). These patterns will then be compared our past reef fish surveys to test for possible oil contamination effects.