Patterns of Shrimp Fishing Intensity in Relation to Offshore Oil and Gas Platforms and Artificial Reefs in the Gulf of Mexico

The National Marine Fisheries Service has maintained an Electronic Logbook (ELB) data collection program for the Gulf of Mexico penaeid shrimp fishery between 2004 and present.  The ELB uses a GPS unit connected to a small computer to collect location data at 10-min intervals.  Algorithms have been developed to delineate actual trawling versus other activities.  We used these data in conjunction with offshore platform and artificial reef location data to determine patterns of fishing intensity around these artificial reefs.  Random samples were taken from the artificial reef and oil and gas platform files and the distribution of trawling around these sites was evaluated to determine zones of avoidance.  We also defined areas of no trawling in areas where trawling intensity in adjacent areas was high.  These areas suggest bottom obstructions, natural or artificial are likely present.  ArcGIS was utilized in our study to conduct spatial analyses on the ELB data around the artificial reefs and the oil and gas platforms. Density analyses were combined with the known structural material of individual reefs in order to determine if spatial patterns of trawling effort differed by reef type.