Ecosystems and Oceanography Division

The Ecosystems and Oceanography Division (EOD) conducts research to advance our understanding of the structure and dynamics of Pacific basin marine ecosystems. In particular, EOD seeks to understand how marine populations change directly in response to changes in their predators and prey and indirectly as a result of broader habitat-based changes in the ocean climate, including El Niño, La Niña, and other interannual or decadal events.

EOD research covers topics on many different spatial scales ranging from fine-scale habitat characterization to basin-scale oceanography, and various temporal scales from short-term individual foraging behavior to long-term ecosystem changes and population trends. Accordingly, a variety of approaches are necessary, including collaborations with scientists in other PIFSC divisions, other government agencies, academic departments, industry, nongovernmental organizations, and foreign institutions.

The EOD has three major research themes:

• Insular Habitat and Ecology focuses on understanding the dynamics of island-associated species and processes.
• Pelagic Habitat and Ecology considers the ocean from the perspective of large pelagic animals.
• Ecosystem Oceanography identifies changes in the ocean that may affect the marine ecosystem.

EOD provides scientific advice in support of improved stock assessment and fisheries management, develops indicators of ecosystem changes, and publishes scientific findings related to effects of habitat and environment on individuals, populations, ecosystems, and fisheries. To accomplish these goals, EOD researchers use a variety of platforms including deep diving submersibles, remotely operated vehicles, and SCUBA, both small and large research vessels and commercial vessels. EOD employs a broad spectrum of advanced technologies and tools, including pop-up satellite archival tags, animal-borne instruments such as crittercam, shipboard and moored echo sounders, satellite remotely sensed oceanographic and atmospheric data products, ocean circulation models, and ecosystem models.

EOD has 11 staff, including 6 federal employees and 5 JIMAR employees. Salaries and benefits made up the largest share of expenditures in the EOD budget.

The EOD Chief also serves as Principal Investigator for NESDIS-funded Central Pacific OceanWatch Node managed by a JIMAR oceanographer. This program archives and distributes a suite of satellite remotely sensed oceanographic data to a diverse group of users in government agencies and the private sector.

Key 2007 Accomplishments

• Completed a paper on abundance and movements of jacks (giant trevally) at Midway Atoll based on tag-and-recapture data from a recreational fishery.
• Completed a paper on the expansion of oligotrophic gyres in the world's oceans.
• Completed a revised ECOPATH model to describe energy flow in the French Frigate Shoals ecosystem.
• Completed a paper on movement of opakapaka (Hawaiian pink snapper) based on conventional tagging data.
• Developed a method to estimate and map loggerhead turtle habitat in waters north of Hawaii and distributed the product to Hawaii longline fishermen in a weekly TurtleWatch bulletin. The information, available in both English and Vietnamese versions, helps fishers reduce incidental interactions with the protected turtles.
• Conducted a research cruise to Cross Seamount to estimate biomass of tuna using shipboard acoustic instruments.

Challenges, Problems, and Limitations

Noise contamination in the acoustic data collected by the NOAA Ship Oscar Elton Sette continues to be a problem for research surveys of tunas and their forage. Due to funding limitations at the Pacific Marine Center (NOAA), the problem has yet to be resolved. Storage and handling of the massive data sets produced by passive and active acoustic recorders, satellite-borne sensors, and coupled physical-biological ocean models remain significant challenges.

Future Focus and Direction

In collaboration with the Protected Species Division, we are continuing to deploy passive acoustic recorders on the seafloor to collect information on the occurrence of cetaceans at various locations in the central North Pacific. The Division also plans to expand studies to describe climate-induced changes in the subtropical gyre marine ecosystem using remotely sensed oceanographic data, longline and observer fishery data and ecosystem models.

Satellite Data Key to Describing Habitat of North Pacific Loggerhead Turtles

PIFSC scientists led an international project to collect data on movements of loggerhead sea turtles in the North Pacific and analyzed the data in combination with environmental measurements to describe the loggerhead's oceanic habitat. The turtles nest on beaches in Japan and spend most of their lives foraging in a broad expanse of the ocean from Baja California, Mexico, to the East China Sea. Their population has been severely reduced by human activity and they are listed as threatened under the U.S. Endangered Species Act.

Wild loggerheads, including many captured in fishing gear, and other turtles reared in captivity, were outfitted with geolocation transmitters and released at locations in mid-ocean and off Baja California, Japan and Taiwan. Satellite tracking data showed the turtles occupying surface waters of the North Pacific Transition Zone where fishing fleets from several countries pursue tunas, billfishes and other species. Turtle location data were analyzed along with concurrent environmental information. Temperature and chlorophyll-a concentration at the sea surface, measured by sensors on satellites, were identified as two key environmental predictors of loggerhead habitat, along with a trio of geomagnetic variables that could influence turtle migration. Sea surface temperature and chlorophyll-a are considered proxies for availability and abundance of turtle forage.

Habitat maps for pelagic loggerheads were created using a habitat selection model driven by the five predictor variables. The maps indicate where loggerheads are most likely to be encountered at different times of the year, and therefore provide valuable guidance for international efforts to avoid or mitigate incidental turtle interactions with fishing gear. Such encounters may not only be detrimental to recovery of the loggerhead turtle population, but to economic returns of the fisheries, which may be closed if turtle interactions exceed allowable limits.

The loggerhead habitat research was recently published by PIFSC scientist Donald Kobayashi and several colleagues in a special sea turtle issue of the Journal of Experimental Marine Biology and Ecology.

Location data collected from 186 loggerhead sea turtles released with transmitters attached and tracked by satellite have provided information on the oceanic habitat of this protected species. Red dots show turtle locations determined by satellite, and black stars indicate points of release. The research is vital to assessing and reducing risks of mortality to turtles caused by their incidental interactions with fisheries across the North Pacific Transition Zone, ranging from Baja California, Mexico, to coastal waters of Japan, Taiwan, and the East China Sea.

NOAA Pacific Islands Fisheries Science Center