Sea Turtle Nesting Report 1994-1999

Nicholas, Mark

This report is a summary of the National Park Service's efforts to document sea turtle nesting activity in Gulf Islands National Seashore in Northwest Florida from 1994-1999. While this program has been ongoing for ten years, it was not until 1994 that a daily documentation ofsea turtle nesting activity occurred. Each year the accuracy and efficiency of the patrols hasincreased, particularly in 1998 when a Student Conservation Associate (SCA) and a seasonalbiological technician (bio-tech) were added to the staff. The 1999 season had two moreadditional bio-techs on hand, bringing available resource management staff to a total of 5. Themonitoring program relies on volunteers to do the majority of beach patrolling, with a typicalyear involving 20 or more volunteers patrolling over 35.7 km of beach daily. During this sixyear period, 243 nests were documented, 221 were loggerhead (Caretta caretta), 12 were green (Chelonia mydas), one was a Kemp's ridley (Lepidochelys kempi) and 9 were listed as unknown. Nesting typically occurs from mid-May until mid-August; the most active period is late June through early July. Incubation times range from a mean of73 days (n=16, SD = 7.7) in 1994 to 59 days in 1999 (n=46, SD = 5). There is a general trend of shorter incubation times over the last 5 years. Hatching success also varies depending on several factors such as predation, nest site location, tropical weather and above normal tides. Several nests were lost in 1995 from Tropical Storm Dean and Hurricanes Allison, Erin and Opal. Due to morphological changes brought on by Opal, several nests were inundated by water in 1996. Others were relocated to higher ground within 12 hours of being laid. Hatching success rates for these relocated nests averaged 83%. There were also an unusually high number of false crawls in 1996 on these hurricane-impacted beaches, up 287% from previous years. Nests are impacted by predators, with the number one predator the exotic red fox (Vulpes vulpes). Fox depredated 30% of the nests in 1994, 57% in 1995, 13% in 1996,54% in 1997 and 17% in 1998. No depredation occurred in 1999. When a nest does successfully hatch, a large portion of the hatchlings are disoriented due to direct and indirect lighting sources from developed areas, such as the City of Pensacola, Pensacola Naval Air Station, Pensacola Beach and Perdido Key. Efforts are directed towards nest sitting at hatch time, but this is unpredictable and very time consuming. In 1996, an increase in efforts to prevent disorientation met with mixed results. There were 13 nest hatches observed by park staff and volunteers, and 1215 hatchlings were observed entering the Gulf of Mexico. Some hatches were missed by just hours and others by as much as a day. By 1999, 3499 hatchlings were observed by staff or volunteers entering the Gulf of Mexico from the park beaches. An additional 868 hatchlings were observed entering the water on Pensacola Beach. Without this increased effort, disorientation would have been allowed to continue on numerous nests with high levels of hatchling mortality almost certainly being the end result. This problem will most likely continue as dune regeneration is a slow process and urban development in the area around OulfIslands National Seashore's (OUIS) Florida District shows no signs of abating.