Diving behavior of female loggerhead turtles (Caretta caretta) during their internesting interval and an evaluation of the risk of boat strikes

Abstract

New advantages in science and technology, such as time depth recorders, have allowed researchers to study the dive behavior of sea turtles in their natural habitat. Previous studies of dive behavior of internesting turtles have provided significant evidence on how to protect nesting turtles from human interactions. We examined the dive behavior of internesting loggerhead and green turtles and the risk of boat impacts at Casey Key, Florida during the 2007 nesting season. The Florida Sea Turtle Stranding Network makes it clear that new management plans need to be implemented because of the increasing trend of boat impacts. Relative boat draft, water temperature, and daily activity of nesting female loggerhead and green turtles were documented with the use of time depth recorders (TDRs). The objective of the TDR study was to assess the correlation between surface intervals and daily activities and evaluate whether there are periods of increased surface activity that might infer greater risks of boat strikes. The results show that female loggerhead turtles are most active during morning hours which overlays with boat launches and departures at local boat ramps. Protective measures, such as spatial and temporal boat restrictions, are reviewed in this report.