The Blue Whale

The Blue Whale (Balaenoptera Musculus)

By Salvador Lopez

Photo by National Geographic

The Blue Whale is a fascinating titan of a species. As of July 28th 1998, it was enlisted as an endangered species which includes all of its subspecies. It is crucial to understand the blue whale before they are all gone, and we must acknowledge why they are endangered and what we can do to help them survive so that they do not perish from this earth.

About the Blue Whale

The blue whale, or balaenoptera musculus, is the largest known animal that has ever lived on Earth. This animal can reach a length of up to 33 meters (approx. 108 ft.) and a weight of up to 150,000 kg (over 33,000 lbs.), but blue whales in the Southern Hemisphere tend to be larger than those in the Northern Hemisphere, and females are usually larger than males (NOAA). There are three subspecies, one in the north Atlantic, one in the Antarctic, and one in the southern Indian Ocean and southwestern Pacific Ocean. Because of the three subspecies, it can be difficult to determine the conservation status of blue whales (ECOS).

Habitat

To expand a bit more on where blue whales are located, figure one below shows the ranges where they live on the Earth. As you can see, it ranges in about every ocean. 

Figure 1: Blue Whale Range
Figure by National Oceanic and Atmospheric Administration

Migration & Young

During the winter blue whales tend to be in warm, low latitude tropical waters, which is where they mate and breed. During the summer, they tend to be in cooler, high latitude polar waters, which is where they go for their feeding grounds in which they feed for about 3 to 4 months. Blue whales migrate back to the tropics segregated by sex and age, the older and pregnant whales migrate first, and the sexually immature whales migrate last. During migration, the whales basically eat nothing at all and live off of body reserves (WhaleRoute).
The young calves are born at about 7 meters long in the tropical waters during the winter, after the mothers are pregnant for about 10 to 12 months. They wean after the spring migration, which they do with their mothers and takes approximately 7 months, and then they begin to follow the normal migration cycle on their own (WhaleRoute).

Photo by National Geographic

Main Threats

For all subspecies, the causes of this listing are the following human impacts: vessel interactions that include collisions with ships and disturbance by vessels; entrapment and entanglement in fishing gear (but the large size of the species makes entrapment rare); habitat degradation, as many whales tested in the late ‘90s were found to have large amounts of chemical contaminants like DDT; military operations, but there is currently no evidence for this; and hunting, but most whaling operations do not take on blues. These are all substantial threats but the largest one continues to be collisions from large vessels (ECOS).

Recovery Plan

The goal of the following recovery plan is to recover blue whales from endangered status to threatened status and eventually from the ESA’s Endangered and Threatened Wildlife list. It is worth noting that blue whales move freely along international borders, so the recovery plan is not confined simply to U.S. territory. Thus, the recovery plan is as follows: to assess the structure of blue whales using genetic analysis and determine daily movement and seasonal migration patterns using telemetry; to monitor trends in populations and conduct photo-identification of blue whales; to improve knowledge of blue whale feeding and learn about the habitats of blue whales and how they use their habitats; to significantly decline or eliminate human-induced mortality and injury and implement studies of pollution that affect blue whale habitats and groups; to gain knowledge of effects of whale watching on blue whales and conduct appropriate protection, and; to create a criteria for deciding to delist whales (U.S Fish & Wildlife, Environmental Conservation Online System). A majority of these goals are currently active and many are partially complete.

Personal Action

My personal action is to increase awareness and understanding of the migration pattern of the blue whales, so that there will be a prevention of collisions with ships. Ships do not purposely collide with whales as they are always accidental, so the only thing we can do is learn more about the paths that these animals take. Every time I go out to fish, I like to inform people about the interesting studies I've made in my wildlife conservation class, so you can do your part as well and go inform those who are unaware of how the species they see often are actually endangered.

Source: National Geographic

Works Cited

Blue Whale (Balaenoptera musculus).  National Oceanic and Atmospheric Administration (n.d.). Web. November 20, 2015,  http://www.fisheries.noaa.gov/pr/species/mammals/whales/blue-whale.html

Recovery Plan Action Status for the Blue Whale. U.S Fish & Wildlife Service (1998, July 28). Web. November 22, 2015, http://ecos.fws.gov/roar/pub/planImplementationStatus.action?documentId=1004591&entityId=3199

Reeves, R., Clapham, P., Brownell Jr., R., & Silber, G. Environmental Conservation Online System (1998, July 28). Recovery Plan for the Blue Whale. Web. November 20, 2015, http://ecos.fws.gov/docs/recovery_plan/whale_blue.pdf

Species and populations with recovery plans. ECOS (1998, June 28). Web. November 20, 2015, http://ecos.fws.gov/tess_public/pub/speciesRecovery.jsp?sort=2

Whale Migration. (n.d.). Web. November 20, 2015, http://whaleroute.com/migrate/