West Coast
Map of endangered whale strandings caused by vessel collisions between 2000 and 2018 along the California coast.JESS MORTEN / NOAA

New Technology Will Listen For Underwater Whale Traffic In An Effort To Reduce Ship Strikes

Scientists from the Benioff Ocean Initiative and Woods Hole Oceanographic Institution have deployed a a hydrophone, or underwater microphone, to listen for whale traffic in the Santa Barbara Channel. They hope to use the microphone to help prevent collisions between whales and boats - which are often deadly to whales.

Given how intelligent whales are, it might be surprising that they are hit by ships at all – but busy shipping channels are far from natural to a whale.

“It’s not something they’re evolved to deal with,” explains John Calambokidis, a researcher at Cascadia Research Collective. “It’s also something there’s very little opportunity to learn from. It’s not like you can get struck two or three times and then you know you should avoid them.”

A whale off the California coast passing through a heavily-trafficked shipping lane.JOHN CALAMBOKIDIS / CASCADIA RESEARCH COLLECTIVE

Sound travels much faster underwater than in the air, which is great for whales like humpbacks that use vocalizations to communicate and navigate underwater. However, the tones created by ships can overlap with the audio frequencies humpbacks use for communication, making it much harder for the whales to both talk to each other and navigate.

In addition to the humpback whale, endangered blue and fin whales migrate seasonally long the West Coast of the United States, overlapping with heavily used shipping channels, making these whales particularly vulnerable to collisions with ships.

“We’re basically making roadkill of them,” explains Dr. Douglas McCauley, director of the Benioff Ocean Initiative and associate professor at the University of California Santa Barbara. “The mortality is way more than it ought to be.”

A necropsy of a beached gray whale in Tiburon, California in April of 2019.JUSTINE SULLIVAN / GETTY IMAGES

Efforts to reduce ship strikes have been underway for years. In 2013, NOAA and the International Maritime Organization (IMO) changed the boundary of the Santa Barbara Channel by one nautical mile to move the channel away from whale feeding ‘hotspots’ in the Channel Islands.

NOAA has also implemented an ‘Incentive-Based Vessel Speed Reduction Program’. The program provides financial rewards to companies that reduce vessel speeds to 10 knots (11.5 mph), or less between July and mid-November in specific zones off the coast of Santa Barbara and San Francisco Bay. Similar speed reductions have been shown to reduce the chance of ship strikes and reduce underwater noise.

The program has expanded greatly in recent years, from just 7 companies and 14 vessels participating in 2014 to 12 companies and 280 vessels in 2018 – a 20-fold increase in participating vessels.

Despite the program’s success, many whales are still being killed by ships. According to a 2017 report by Point Blue Conservation Science, ship strikes alone kill more than 80 whales every year off of the West Coast, with most occurring off of California.

With information from this new hydrophone, scientists hope to further incentivize slowing down by letting ships know when whales are heard in the area. “It’s telling you that they’re there and the risk of ship strike is elevated,” explains Dr. Mark Baumgartner, who led the design of the hydrophone system.

Still, the new information provided by the hydrophone is not expected to remove the problem of ship strikes altogether.

“We definitely think that mandatory ship speeds are overdue,” said Catherine Kilduff, an attorney for the Center for Biological Diversity, which has previously asked NOAA to establish a mandatory 10-knot speed limit.
Source: Forbes

Liz Allen - Marine biologist with a background in Antarctic fish, coral reefs, and seagrass microbes. Fascinated by the role of bacteria and viruses in the marine realm. Avid tide pool investigator.

See Forbes article . . .