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 (TDRs), have allowed researchers to study the dive behavior of sea turtles in their natural habitats. Observing dive behavior of internesting turtles has provided significant evidence on how to protect nesting turtles from human interactions. One source of anthropogenic mortality on marine turtles is boat strikes. Trend data from the Florida Sea Turtle Stranding Network demonstrate that the annual proportions of boat-strike related mortality is increasing. Since 1980 boat strike injuries have tripled in Florida. This study, near Casey Key Beach in southwest Florida, examined the internesting dive behavior of loggerhead sea turtles using time-depth-recorders; National Geographic Crittercams tm , and satellitelinked location data to evaluate the risk of boat impacts based on the resulting dive data.When combined with 4 years of satellite telemetry data gathered prior to this study I revealed that loggerhead turtles are most vulnerable to boat strikes between 8 a.m. -12 p.m. on the day following a nesting or false crawl event and on the night before returning to the beach to nest. Potential mitigation measures, such as spatial and temporal boat restrictions, are reviewed by this study.

Habitat Use and Behavior of Multiple Species of Marine Turtles at a Foraging Area in the Northeastern Gulf of Mexico

“…Based on the behavioral patterns estimated in this study, most CM were distributed in shallow waters where there is potentially higher exposure to marine traffic, but those CM distributed in deeper waters (up to 12 m) are less exposed to marine traffic and have more room to avoid occasional vessels. LK and CC are likely to be more vulnerable to threats related to the presence of vessels (e.g., disturbance, behavioral changes, vessel strikes) (Sobin, 2008), as they move substantially across the region and spend slightly longer periods at the surface (>20 s) in consistently shallow waters. Future studies on the cumulative and synergistic effect of this and other potential threats (e.g., hook-and-line, pot fisheries, trawl fisheries, water quality, algal blooms) on the overall health of nearshore habitats and consequently their impact on marine turtle foraging ecology could enhance effective management of threats to the local marine turtle populations.…”

Quantifying sublethal Florida manatee-watercraft interactions by examining scars on manatee carcasses

“…Manatees share the waterways with hundreds of thousands of watercraft: registered watercraft (https: // www.flhsmv.gov/motor-vehicles-tags-titles/ vessels/ vessel-owner-statistics), unregistered watercraft, and watercraft visiting Florida from other states or countries (Wright et al 1995). Watercraft harm manatees and a variety of marine wildlife including ceta ceans (Wells & Scott 1997, Stone & Yoshinaga 2000, Fonnesbeck et al 2008, Wells et al 2008, Conn & Silber 2013, Christiansen et al 2016 and sea turtles (Hazel & Gyuris 2006, Hazel et al 2007, Singel et al 2008, Sobin & Eckert 2008. It has long been known that collisions with watercraft are a significant threat to the Florida manatee (Wright et al 1995, USFWS 2001, Lightsey et al 2006, FWC 2007, Runge et al 2017, and regulations regarding the operation and speed of motorized watercraft in specified areas are important aspects of protection efforts (Calleson & Frohlich 2007, Calleson 2014, Rycyk et al 2018, Udell et al 2019.…”

Brushes and Shelters as Low-Cost Environmental Enrichment Devices for Loggerhead Turtles (Caretta caretta) During Rehabilitation

“…To encourage expression of natural behavior, we tested 3 simple, low-cost EEDs for use with loggerhead turtles in rehabilitation centers: 1) a shelter to imitate corals and rocks that wild turtles have been observed resting under (Kirkden and Pajor 2006; Sobin and Tucker 2008), 2) brushes to allow scratching, 3) a pipe to allow assisted resting. The main objectives of this study were 1) to determine how much time loggerhead turtles interact with EEDs; and 2) to assess preferences in loggerhead resting behavior.…”