North American Toothed Whales

On October 22, 2008, The National Marine Fisheries Service (NMFS) formally listed the Cook Inlet beluga whale, as an endangered species under the Endangered Species Act.

The listing took effect on December 22, 2008.

Beluga Whales (Delphinapterus leucas) are the white, toothed whales that inhabit cold waters in and around the Arctic Ocean and sub arctic areas of Russian, Norway, Greenland, Canada and the United States, including Alaska.

They are medium sized whales, with adults averaging about fifteen feet in length.

On October 22, 2008, The National Marine Fisheries Service (NMFS) formally listed the Cook Inlet beluga whale, as an endangered species under the Endangered Species Act.

The listing took effect on December 22, 2008.

Beluga Whales (Delphinapterus leucas) inhabit cold waters in and around the Arctic Ocean and sub-arctic areas of Russian, Norway, Greenland, Canada and the United States, including Alaska.

Whie in color and medium sized, the average adult Beluga whale grows to approximately fifteen feet in length.

Cook Inlet beluga whales constitute one of five distinct stocks of Alaskan beluga whales. Little scientific information is known about the Cook Inlet population, and population estimates only began in earnest in the early 1990s. Since that time, population estimates have declined and reached a steady state, rather than increasing as earlier estimates projected.

  • 1994 estimate - 653
  • 1998 estimate - 347
  • 2005 estimate - 278
  • 2007 estimate - 375

Scientists hypothesize that multiple stress sources, such as anthropogenic noise, pollution, decreasing food supply, increased predation by Orcas, among others, have been suggested as investigative starting points (see Trustees for Alaska).

Currently the Cook Inlet beluga population is not subject to commercial whaling. Under the terms of the Marine Mammals Protection Act (MMPA) the population is co-managed by the NMFS and the Cook Inlet Marine Mammal Council, a group of native Alaskans with traditional subsistence fishing rights.

Subsistence hunting of the Cook Island beluga stock has been greatly curtailed in the past few years. A NOAA press release stated only five whales were taken between 1999 and 2006. The annual subsistence hunt was cancelled for 2007.

In their 2008 Status Review, NMFS officials stated,

"With the very limited hunt between 1999 and 2007, NMFS anticipated that the population would begin to recover at a rate of 2% to 6% per year. When only the 1999-2007 time series of abundance estimates is considered, the rate of decline is estimated at -2.75% per year."

Gulf of Mexico Sperm Whales

Research on the status of the Gulf of Mexico Sperm Whale population following the BP oil spill is currently under way.

Past research suggests that the roughly 1,100 Sperm Whales are a distinct population with a range from just south of Western Florida Panhandle to the South Coast of Texas.

A June 2006 report done for the Minerals Management Service by the Department of Oceanography at Texas A & M University provides an initial set of data that more clearly defines stock characteristics.

The report runs over three hundred pages, reviewing and offering tentative conclusions about the range of experiments and observations undertaken by a team of scientists. Sample populations were observed, photographed, and/or tagged with tracking devices to determine basic characteristics such as gender, age, size, communication and feeding behaviors. Biopsies were taken to begin building a genetic data base.

The following brief summary of results provide some of the more interesting tentative conclusions.

Satellite tracking done on 39 whales between 2001-2004 shows them to be a stay at home group of whales inhabiting an area just south of Western Florida Panhandle to the South Coast of Texas. Gender and age differences explained some basic range and movement activities within the sample group. For example, a group of females and juveniles appear to favor living and feeding in an area around Mississippi River Delta and Mississippi Canyon. Mature and maturing males displayed a tendency to extend both their horizontal and vertical ranges.

A sample of 52 sperm whales measured smaller on average than sperm whales found in the Gulf of California. Scientists hypothesize size as a function of environment and food sources. The smaller size of sperm whales in the Gulf of Mexico may be related to the relatively smaller size of the Gulf (compared to other sperm whale habitats) and the smaller food sources available.

Sperm whales are considered a social and chatty species of whales. When gathered as a group, they exhibit a specific type of vocalizing called a coda. The coda of a sample population of whales was taken, and initial results from a dendrogram (mathematical way to chart sounds) shows they use a distinct dialect compared to codas of sperm whales in the Azores, Caribbean and Mediterranean Seas.

Sperm whales use echolation, (their built in sonar) as a navigation and feeding tool. There is a growing body of evidence suggesting that anthropogenic noises harm whales, perhaps by knocking out their sonar. Since oil and gas drilling operations use sonar for generating seismic survey arrays of potential development areas, one series of studies sought to understand how noise from ongoing or potentially new oil and gas operations in the Gulf of Mexico might effect the sperm whale population.

The only solid conclusions reached in the study were that whale feeding habits were altered by initial sound experiments, and more research was needed (p 254(272).

"While these results should not be considered conclusive, this study does provide some evidence that air guns affect the foraging behavior of sperm whales, and should help define hypotheses about effect size and describe natural variability in these important behaviors..."

© 2013 Patricia A. Michaels