Marine Mammals

Marine mammals are among the more visible and engaging components of the marine ecosystem and are often considered to be sentinels of how an ecosystem is functioning. Top predators in the marine ecosystem, the 26 marine mammal species found in Alaska waters also provide important subsistence resources to many Alaska communities.

This cultural and ecological role makes it important for us to understand how these species interact with other ecosystem components and how overlap with commercial fisheries and other human activities impact marine mammal populations.

Based on recommendations from the National Research Council and NPRB's enabling legislation to address both pressing fisheries management needs and marine ecosystem information needs, the Board has funded marine mammal research under the following six categories:

• foraging success
• marine habitat use
• population dynamics
• fisheries interactions
• other human-related impacts
• long-term climate change

The Board funds a mix of long and short-term marine mammal research, focusing on species that may be at greatest risk from interactions with major commercial fisheries of the Bering Sea, Aleutian Islands, and Gulf of Alaska.

Marine mammal research funded by NPRB

From 2002-2008, the Board has supported 33 marine mammal studies for a total of just under $5.3 million. Studies focus on a variety of baleen and toothed whale species, northern fur seals, Steller sea lions, harbor seals, ice seals, Pacific walrus, and sea otters. Twenty studies have been completed with 13 currently ongoing. Of these, 26 are process studies, two are monitoring, three are modeling, and two are retrospective studies, most focused predominantly in the Bering Sea and Gulf of Alaska, with only a few in the Arctic.

Research Highlights

Project 719: Analysis of acoustic and oceanographic data from the Bering Sea

(December 2008) The murkiness of the Bering Sea -- as well as its large size -- makes detecting undersea mammals difficult. For researchers at sea, sometimes hearing animals can be the next best thing to actually seeing them.

In the winter and spring of 2006-07, scientists doing research for NPRB Project 719 deployed hydrophones to record the under-ice sounds of bowhead whales, bearded seals and walrus.

The three locations chosen for this work correspond to long-term oceanographic mooring sites in place since 1995. The resulting acoustic data provide an unprecedented survey of the current status of North Pacific right whales and other endangered marine mammals in the Bering Sea.

When collated with oceanographic data, they will also let scientists include large whales in Bering Sea ecosystem models.

Follow the bouncing spectrogram

A spectrogram (right) is a visual representation of sound. Brighter colors mean louder sounds. Here's how it works:

1. LOOK at a larger image of the spectrogram.
2. LISTEN to the three-species "concert" to "follow along" with the sound. For example, the tapping sounds of walrus can be seen as vertical lines in the spectrogram.