Whales' foraging strategies revealed by new technology

Marine biologists are beginning to understand the varied diving and foraging strategies of filter-feeding whales by analyzing data from multisensor tags attached to the animals with suction cups. Such tags, in combination with other techniques such as echolocation, are providing a wealth of fine detail about how the world's largest creatures find and trap their prey.

Recent studies on the behavior of baleen whales—which filter small fish or invertebrate animals from seawater—are described in the February issue of BioScience. Jeremy A. Goldbogen of the Cascadia Research Collective in Olympia, Washington, and his colleagues point out that tags can report not only the depth but also the acceleration of the animal carrying them, which reveals information on its pitch and rolling motion.

Together with special software, this can allow foraging dives to be visualized in three dimensions, along with the timing. Studying whale behavior is logistically challenging, as it may be necessary to coordinate the actions of several research vessels and large research teams. Yet despite the difficulties, patterns are becoming clear.

Right whales and bowhead whales have a very different feeding strategy from rorquals—the group that includes the biggest animal on earth, the blue whale. Right and bowhead whales filter-feed by swimming relatively slowly through prey patches, a mode called continuous ram feeding. This keeps their energy expenditure low and makes possible dives of 10 minutes or longer, but means they miss out on prey able to take evasive action.

Rorquals, in contrast, make high-speed lunges at prey patches that enable them to catch elusive species. They must then pause to filter water engulfed in their large mouths, however, and they have to surface more often to breathe than continuous ram feeders. The new tools available mean researchers can study the efficiency of diving and foraging in different whales and relate it to the availability of prey of different types. Because whales are considered keystone predators that structure oceanic food webs, such insights will shed important light on ocean ecology.

BioScience, published monthly, is the journal of the American Institute of Biological Sciences (AIBS; www.aibs.org). BioScience is a forum for integrating the life sciences that publishes commentary and peer-reviewed articles. The journal has been published since 1964. AIBS is a meta-level organization for professional scientific societies and organizations that are involved with biology. It represents nearly 160 member societies and organizations. The article by Goldbogen and colleagues can be accessed ahead of print at www.aibs.org/bioscience-press-releases/ until early February.

The complete list of peer-reviewed articles in the February, 2013, issue of BioScience is as follows. These are now published ahead of print.
Public Understanding of Synthetic Biology
Eleonore Pauwels
Integrative Approaches to the Study of Baleen Whale Diving Behavior, Feeding Performance, and Foraging Ecology

Jeremy A. Goldbogen, Ari S. Friedlaender, John Calambokidis, Megan F. McKenna, Malene Simon, and Douglas P. Nowacek

The Challenge of Lignocellulosic Bioenergy in a Water-Limited World
John S. King, Reinhart Ceulemans, Janine M. Albaugh, Sophie Y. Dillen, Jean-Christophe Domec, Regis Fichot, Milan Fischer, Zakiya Leggett, Eric Sucre, Mirek Trnka, and Terenzio Zenone
Defusing Ideological Defenses in Biology
Angela Potochnik
Navigating the “Noxious” and “invasive” Regulatory Landscape: Suggestions for Improved Regulation

Lauren D. Quinn, Jacob N. Barney, James S. N. McCubbins, and A. Bryan Endres

Implementing Policies to Control Invasive Plant Species
Edward B. Barbier, Duncan Knowler, Johnson Gwatipedza, Sarah H. Reichard, and Arianne Ransom-Hodges