New study analyzes the risk to endangered whales from ships in southern California

March 25, 2013
NOAA research vessels are used to conduct marine mammal and ecosystem surveys, as shown here. Credit: Cornelia Oedekoven NOAA, Southwest Fisheries Science Center

Researchers have identified areas off southern California with high numbers of whales and assessed their risk from potentially deadly collisions with commercial ship traffic in a study published in the scientific journal Conservation Biology.

Scientists from NOAA Fisheries, the Marine Mammal Commission and Cascadia Research Collective analyzed data collected over seven years by NOAA on marine mammal and ecosystem research surveys in the Southern California Bight. Maps predicting the density of endangered humpback, fin and were developed by merging the observed whale sightings with oceanographic conditions to identify the habitat preferred by the different .

"We know several endangered species of occur in the waters off southern California," said Jessica Redfern, a NOAA Fisheries marine mammal biologist and lead author of the paper. "What we didn't know, and what this study helps provide, is an understanding of the areas with the highest numbers of whales."

Knowing where whales are more likely to be found in the ocean environment is vitally important to reduce human impacts. Although this information could be used to assess any number of human impacts, the study specifically looked at current and alternative to and from the Ports of Los Angeles and Long Beach and the risk to humpback, fin and blue whales from ship strikes.

These are the routes considering in analyses of the risk to endangered whales from ships transiting to and from the Ports of Los Angeles and Long Beach. Credit: Redfern et al. 2013. Conservation Biology.

Researchers selected four routes to study; the shipping route in the Santa Barbara Channel, which is the current shipping route; a Central route south of the northern Channel Islands; a Central Fan route, or just the eastern part of the Central route; and a Southern route, a course south of the Central route and constrained by the protected areas around Santa Barbara, Santa Catalina, and San Nicolas Islands. (See figure 1)

By overlaying the routes with the predicted whale densities, researchers found the route with the lowest risk for (Southern ) had the highest risk for fin whales and vice versa. However, risk may be ameliorated for both species in one of the Central routes.

Researchers have identified areas off southern California with high numbers of whales and assessed their risk from potentially deadly collisions with commercial ship traffic. Credit: John Calambokidis/Cascadia Research

Blue whales, however, were at approximately equal risk in all routes considered because of their more even distribution throughout the study area. The authors' estimate of the number of blue whales likely killed by ships exceeds levels established by the Protection Act to ensure sustainable populations. This result suggests that it is important to find ways to reduce the risk of ships striking blue whales.

"The Southern California Bight is an incredibly complex system with a diverse set of users, including the military, shipping industry and fishing industry. All users have specific needs and their input is necessary to plan the best and safest uses of these waters," said Redfern, "This paper helps to incorporate whale habitat use in the planning process so that their needs can be considered as well."

Explore further: Marine scientists monitor longest mammal migration

Related Stories

Marine scientists monitor longest mammal migration

April 10, 2007

Marine scientists recently published a research paper in the science journal, Biology Letters, that found humpback whales migrate over 5,100 miles from Central America to their feeding grounds off Antarctica; a record distance ...

Blue whales returning to former Alaska waters

May 18, 2009

(AP) -- Blue whales are returning to Alaska in search of food and could be re-establishing an old migration route several decades after they were nearly wiped out by commercial whalers, scientists say.

Jump in whale deaths blamed on krill, ship traffic

October 11, 2010

(AP) -- An increase in the population of a tiny crustacean and busy shipping lanes are being blamed for a jump in the number of whale deaths in Northern California waters this year.

Recommended for you

New insights into the production of antibiotics by bacteria

July 31, 2015

Bacteria use antibiotics as a weapon and even produce more antibiotics if there are competing strains nearby. This is a fundamental insight that can help find new antibiotics. Leiden scientists Daniel Rozen and Gilles van ...

Out of the lamplight

July 31, 2015

The human body is governed by complex biochemical circuits. Chemical inputs spur chain reactions that generate new outputs. Understanding how these circuits work—how their components interact to enable life—is critical ...

Cell aging slowed by putting brakes on noisy transcription

July 30, 2015

Working with yeast and worms, researchers found that incorrect gene expression is a hallmark of aged cells and that reducing such "noise" extends lifespan in these organisms. The team published their findings this month in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.