The Endangered Blue Whale

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As you may know, blue whales are the largest mammal, not only in the ocean, but on the history of planet earth. These majestic aquatic creatures can weigh up to 330,000 lbs and reach up to 110 feet long when mature adults. For perspective, this is equivalent of the length of three school buses! Blue whales are found in every single ocean except the Arctic Ocean. There are five currently recognized subspecies of blue whales including the northern blue whale, the southern blue whale, the Indian ocean blue whale and the pygmy blue whale.

Unfortunately, the blue whale species is on the federally endangered species list and has been for many years. To answer why blue whales are endangered, we will cover a brief history of blue whale endangerment as well as the threats this species faces today.

When Did Blue Whales Become Endangered?

Blue whales became endangered in 1970. The blue whale was driven to extinction by commercial whaling in the 1800s and early 1900s. Whaling is the hunting and killing of whales for their usable products such as their meat and blubber that can actually be turned into a type of oil. This was particularly important during the Industrial Revolution. By the 16th century, the commercial whaling industry began in coastal regions in Spain and France and quickly spread throughout the world. The industry continued to grow well into the 20th century and was very profitable in terms of trade and resources.

It wasn’t until the mid to late 1960s when it became apparent that certain whale species were depleting to near extinction. This led many countries to start banning whaling in the early 1970s until worldwide cessation by 1980.

The blue whale species was protected from commercial whaling by the International Convention for the Regulation of Whaling in 1966. And in 1970, blue whales were officially listed as endangered under the Endangered Species Conservation Act, the predecessor to the Endangered Species Act (ESA).

Blue Whale Threats Today

Due to their enormous size and mass, blue whales have no natural predators on earth. They are only endangered through man-made causes. Although blue whales are legally protected today, they do continue to face some man-made threats in the form of entanglement, vessel strikes, and other threats.


Blue whales can become entangled in fishing gear including traps, pots, or gillnets. They can either swim off with the gear attached or becoming anchored. When entangled, whales may drag and swim with attached gear for long distances, ultimately resulting in fatigue, compromised feeding ability, or severe injury, which may lead to reduced reproductive success and death.

Vessel Strikes

Inadvertent vessel strikes can injure or kill blue whales. Vessel strikes have killed blue whales throughout their range, but the risk is much higher in some coastal areas with heavy ship traffic. More than 80% of global trade takes place by container at sea, making the international shipping industry a major and influential player in the global economy. Though this activity is great for our regional economy, it can also pose serious problems for blue whales when these shipping lanes intersect with feeding habitats, resulting in these fast-moving ships fatally striking and killing these endangered animals.

Other Threats

Other threats to blue whales include ocean noise, habitat degradation, ocean pollution, vessel disturbance, and drastic changes in climate that can happen over the years. That is why global warming is of particular concern. Global warming causes glaciers and permafrost to melt fast which allows a large amount of fresh water to flow into the oceans. There is concern that this can cause a disruption in saline levels and thermocline circulation. This disruption in thermocline circulation can affect blue whales’ migrations as they are based on ocean temperature. The change in ocean temperature can also affect the blue whale’s food supply. For instance, the increased warm temperatures and decreased saline levels can cause a significant shift in krill location and abundance.

The Harbor Breeze Whale Watching Experience

For an up close and personal experience with whales and dolphins in their natural habitat, we invite you to join us for an unforgettable whale watching experience with Harbor Breeze in Long Beach, California. Our experienced and enthusiastic naturalists are on board each and every trip to provide exciting narration about all marine life you may see. Contact us for ticket information to book your trip today!

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