Monday, February 23, 2009

Marine noise: Moving beyond sonar and whales

The furor over Navy sonar and its impacts on marine mammals may be doing a disservice to the larger issue of ocean noise.

(Research is increasingly looking at the impacts of marine noise on a range of sea creatures. Seen here, sea life on the reef at Molokini Crater in Hawai'i. Credit: Hawaii Department of Land and Natural Resources.)

Environmental groups and military lawyers fight over whether national security trumps environmental concerns. (It can, according to the Federal Register notice of the Navy's new authorization to conduct sonar training in Hawaii: Taking and Importing Marine Mammals; U.S. Navy Training in the Hawaii Range Complex.)

Meanwhile, there's the much larger issue of other kinds of human-caused noise on marine mammals and other kinds of marine life. Fortunately, there is increased interest in marine noise beyond the Navy and charismatic megafauna (big cuddly critters.)

One (admittedly partisan) resource for current research on this issue is the Acoustic Ecology Institute. It includes data on new studies as well as news reports, like the apparent shift in migratory routes of gray whales away from the oil fields off Russia's Sakhalin Island, and the concerns in Canada about the impact of increased tanker traffic on local nearshore whale populations.

Acoustic Ecology is also making the point that while deaths and strandings by marine mammals get big headlines, science is appropriately moving to the study of subtler effects of noise.

“Several studies released during 2008 all suggest that whales of many species may stop or reduce their feeding when moderate to loud human sounds enter their habitat, and this particular impact is likely to become a central focus of future research and regulatory consideration,” write Acoustic Ecology founder Jim Cummings, who serves as president of the American Society for Acoustic Ecology.

And then there's the impact of noise on non-mammals.

Does an angler's catch rate change in the presence of roaring jet skis? Is the rate different in the presence of paddle-powered outrigger canoes? (Thus is the issue the presence of a foreign object or its volume?)

“The possibility that noise causes stress responses in marine life is under increasing scrutiny, and could fundamentally alter the equation that is central to ocean noise regulation: if and how noise may contribute to long-term, population-level impacts,” Cummings wrote.

Scientists in and out of government are starting to look at those impacts. There are international efforts to develop technologies to quiet big ships. And increasingly, researchers are recognizing that mammals aren't the only creatures affected.

As an example, the Italian Ministry of Environment, Land and Sea, concerned about the impacts of shipping on marine life in the Mediterranean, issued a report that included this line:

“While most interest in anthropogenic noise and its mitigation has focused on marine mammals (mainly cetaceans and pinnipeds) and a few other vertebrates (such as sea turtles), there is increasing concern regarding the impact of such noise on fish, other vertebrates such as aquatic and diving birds, and marine invertebrates (including crabs and lobsters).”

©2009 Jan TenBruggencate

1 comment:

Keahi Pelayo said...

Let's by ear plugs for marine life.