Navy Seeks Reasons for Whale Strandings

It used to be there was a debate between the U.S. Navy and the scientific community about the adverse effect Navy sonar had on marine mammals.

The Navy maintained that there was no direct evidence that sonar caused harm to whales and other sea creatures while scientist cited several instances of cause and effect. Besides, the Navy could always site National Security as a reason to not be overly concerned about marine mammals off our coast. 

That debate is a thing of the past as both sides now agree that loud underwater sounds have some effect on these animals and more than likely a harmful one. There have been too many examples of mass whale standings in the exact location of where Navy sonar was being used.

That’s why a team of marine mammal specialists, engineers, acousticians, and biologists were placing suction cup tags on whales and dolphins from the Santa Monica Bay to the Orange County Coast these past few days.

The tags gather a plethora of information including how deep the whales dive, their exact route and location and their response to loud underwater noises.

This is the second year of this Navy funded study called SOCAL-11 and it seeks to determine how different species in different scenarios react to sonar. 

Of course the overall goal is help the Navy become environmentally compliant.

“The Navy has been wonderful as they really want to discover where and when they should not be using sonar,” said senior scientist Brandon Southall from SEA and the University of California at Santa Cruz.

This team effort seeks to provide a better scientific basis for estimating risk and minimizing effects of active sonar for the U.S. Navy and regulatory agencies.

Whale strandings have occurred during previous Navy exercises and the clearest response from many whales when a sound is played is that they move in the opposite direction.

“If you can imagine multiple sources sending out sounds during a Navy exercise and those sounds bouncing around these animals; well it’s not hard to understand how they become disoriented,” said research biologist John Calambokidis from the Cascadia Research Collective.

The operational area includes both “in-shore” areas along southern California from Morro Bay to San Diego and an offshore area that includes the U.S. Navy’s SCORE range near San Clemente Island. The team uses a variety of vessels, equipment and personnel to gather mountains of data.

The source vessel is the logistical hub of operations. On board, marine mammal experts observe and monitor tagged animals. There are also two, 18-20 foot rigid hull boats that operate independently from the sources vessel. There job is to locate and tag focal animals with suction cup acoustic and position‐ monitoring tags.

The tags provide a wealth of information and measure the animal’s response to sonar. Watching these teams place the tags on these leviathans is a work of art. Using 14-foot long poles, the boats must arrive at exactly the right time and place to get the tags attached properly. NOAA’s National Marine Fishery Service, Southwest Fishery Science Center is developing methods for real-time detection, localization, identification, and tracking of beaked whales.  

You can follow a daily blog from the tagging teams and stay right up to date with their efforts at www.SoCal-BRS.org . Here is its most recent entry.

“Yesterday, we attached one of the new generation DTags on a Risso's dolphin for almost nine hours and conducted a perfect CEE (controlled exposure experiment).  This was the longest successful attachment to date with the new version tags on offshore odontocetes and the first on a Risso's. Below is a shot of the tag riding on the back of the animal who was in a group of about 20 that we followed most of the day.”

So it looks as though the U.S. Navy is not beyond becoming “green” in the 21st century. It’s a move that many animal rights groups and scientists applaud. The study will continue through 2014.