Tagging of Pacific Predators (TOPP)

A program using electronic tagging technologies that studied migration patterns of large open-ocean animals and the oceanographic factors controlling these patterns.

Barbara Block
Steven Bograd
Dan Costa

Project Leaders:

Barbara Block, Ph.D., Stanford University, Hopkins Marine Station, Department of Biological Sciences, Pacific Grove, California, USA

Steven Bograd, Ph.D., NOAA Pacific Fisheries Environmental Laboratory, Pacific Grove, CA, USA

Dan Costa, Ph.D., Center for Ocean Health, University of California, Santa Cruz, Santa Cruz, California, USA

Visit the TOPP website.


Although humans have pursued pelagic animals for hundreds - indeed thousands - of years, our understanding of their complex lives remains fragmentary. Historically, the tools available to study animals and their ocean environment have provided only a "snapshot" view of their lives. Recent technological advances, however, are revolutionizing such studies and will soon provide near-real time, narrative "motion picture" visualizations of these animals' lives.

The Tagging of Pacific Predators (TOPP) research program was a collaboration among scientists from the U.S., Australia, Canada, Mexico, Japan, France and the UK, that applied new technologies to understanding the environmental basis for movements and behaviors of large pelagic animals in the North Pacific. With new electronic tags, TOPP scientists followed the migrations of marine fishes, turtles, birds, pinnipeds, whales and Humboldt squid as they crisscrossed the Pacific basin. The results answered basic questions about the animals' biology, including where they feed and breed, and what migration corridors they use. By integrating these biological data with available oceanographic information, scientists began to explore how the dynamic ocean environment influences these basic life functions. By tagging a broad array of taxonomically diverse species, the scientists gained a broader understanding of how the North Pacific ecosystem functions.

In addition to providing information about the animals themselves, the data from the tags are invaluable to oceanographers. Although modern oceanographic sciences are aided by satellite-based observations, this view from space can only provide information about the oceans' surface. There is a dearth of information about the water column. This lack of data limits scientists' ability to describe ocean dynamics, and has hampered efforts to understand the coupling between the ocean, atmosphere and climate. Understanding of this coupling is a critical component of models that predict changes in the global climate. Since many of the TOPP organisms made repeated dives as they traveled, they were continually sampling the water column-effectively "profiling" the ocean along their path.

The goals of the TOPP program, to obtain both biological and oceanographic information for an array of species, required the development of new tools. Additional tags were designed that will expand the range of oceanographic parameters that can be measured. Also, tracking the movements of thousands of individuals required new software for the assimilation, storage, analysis and visualization of 3-D organismal and oceanographic data as it varied through time. The TOPP team worked with experts in computer sciences, oceanographic modeling, and data visualization to develop these tools.

The TOPP program provided a more complete understanding about how large open-ocean animals utilize the North Pacific ecosystem as well as about the North Pacific itself. We now know which areas are most critical for feeding, reproduction and migration and better understand the environmental mechanisms that shape these behaviors. This information both added to our current knowledge about these magnificent creatures, and may prove to be invaluable in establishing ecosystem-based management strategies to ensure the long-term health of populations.

Visit the Tagging of Pacific Predators website.