By Hannah Bernard and Cheryl King, for the Hawai’i Wildlife Fund

The most remote high islands on earth, located in the middle of the world’s largest ocean, the Hawaiian archipelago is home to one of the highest percentages of endangered species in the world. Because of this remoteness, some of Hawai’i’s endangered marine species, such as the hawksbill sea turtle (Eretmochelys imbricata), do not migrate away from the archipelago. This isolation leads to no known interchange with other hawksbill populations — leading to an isolated population wholly dependent upon the health of Hawai’i’s marine ecosystem.

You might ask: How do we know so much about a species that spends so much time in the sea? Largely through the application of high technology satellite tracking and geospatial mapping. In fact, this particular technological tool has proven invaluable in assisting researchers and wildlife managers in understanding key pieces of many species’ life cycle puzzles. This is especially true for endangered hawksbill sea turtles in Hawai’i, who are very difficult to study since they only come ashore to nest - in the dead of night.

Geospatial technology provides scientists with a unique research technique that opens a window into a world very different from our own. The ability to assess this world and evaluate its status is essential to the long-term survival of species such as hawksbills because we cannot adequately protect them and their habitat until we first identify and characterize this habitat. A multi-agency collaboration using high technology and community involvement has been and will continue to be essential for protecting this small population from dangers caused by human disturbance, coastal lighting, non-native vegetation, predators, and vehicular traffic.

About the Project

Our organization currently participates in a cooperative research project with a number of government agencies tasked with the management of Hawaiian sea turtles, including the National Marine Fisheries Service, the Fish and Wildlife Service, and the Hawai’i Department of Land & Natural Resources.

This group of researchers safely adhere transmitters to the backs of female hawksbill sea turtle shells after the turtles turtles lay their eggs and are on their way back to the ocean. The transmitters then enable researchers to monitor sea turtle activity at sea - when the turtles come to the surface to breathe, a signal is sent to an orbiting satellite.

The project requires deep technological integration - the satellites that receives the signals transmitted from the turtles are NOAA Polar-orbiting Operational Environmental Satellites (POES), the data aggregated on the turtles are managed through the ARGOS program, and the coordinates for the turtle’s location when the signal is received are plotted on a map by scientists from the National Marine Fisheries Service and then made available to the larger community of researchers.

The time-depth recorders (TDRs), VHF radio, satellite transmitters, and geospatial information systems used in this project are already revealing the turtles’ behavior and habitats, especially as they relate to reproduction. Before these studies, the marine habitat in Hawai’i used by these endangered sea turtles before and after nesting (hawksbills may lay up to five egg clutches in a season, with each clutch containing nearly 200 eggs) was completely unknown. Scientists had to spend many nights walking the beaches and waiting for turtle activity in the hope that they could sneak a peek at the turtles while they were nesting. Research was limited to the land - beyond the beach the turtles were simply out of our reach. No one knew where these turtles went or what they did during the ~18 days after laying each nest.

Now, thanks to the technology, the world of the turtle at sea is much better understood. While each turtle is different of course, the research indicates:

Hawksbills typically choose an offshore location within a few miles of their nesting beach to rest between nesting events and they do not appear to forage during this time.

The turtles’ otherwise predictable dive times change once they swim back to the nesting beach to lay another nest.

The turtles return to their original offshore resting location until their eggs have developed and it’s time to nest again.

Once a turtle has laid all of her clutches for the season, it will immediately leave the nesting beach and swim in a directed way towards her foraging grounds.

The migratory pathways of the turtles appear to route through nearshore waters around the islands, except for when they have to cross offshore channels to reach their home island.

The turtles’ foraging grounds have been shown to be within the main Hawaiian Islands.

This valuable information is enabling the government and the community to take action to protect the turtles. The research enables Hawai’i residents to be better informed on how to mitigate offshore human use of marine resources, thereby minimizing potential conflicts with sea turtles. The research also sheds light on shoreline management, especially given the fact that the nesting beaches are in close proximity to human dwellings and beach activities. Along with the state and federal agencies tasked with the protection of sea turtles, we are using the research to encourage community-based management of the lands where sea turtles nest in Hawai’i and to assist in protecting nests and hatchlings. Even though much of the nesting habitat is degraded, we see that a large community-led effort to rejuvenate and protect these beaches on the island of Maui during the last twelve years has made an impact.

About the Authors

Hannah Bernard is the President and cofounder of Hawai’i Wildlife Fund. She is an award-winning marine biologist with 25 years of experience in conducting research, education and community outreach programs on protected marine life.

Cheryl King holds a Master’s of Science in marine biology from Nova Southeastern University Oceanographic Center. She has been working on the HWF Hawksbill Sea Turtle Recovery Project (researching and protecting nesting hawksbills and hatchlings) since 2000, and the Makai Watch Project (studying human usage patterns) since 2001. She is also an Ocean Resources Specialist for the Kaho‘olawe Island Reserve Commission.