Wednesday, July 18, 2018

Whales and New Jersey: Blue Whales

In reaction to the decline of various whale species, the first international agreement to halt whale hunting was reached in the mid-1930s. All six species that I have written about here are listed by the U.S. federal government as endangered as of 1970.

Because of that federal status, all 6 were automatically added to the New Jersey endangered species list following enactment of the New Jersey Endangered and Nongame Species Conservation Act in 1973.

Currently, only Japan and Norway are still engaged in commercial whaling.

Size of blue whale compared to an average human scuba diver

Our sixth and final species from our endangered in New Jersey list to consider in this series is the blue whale. Last but certainly not least, the blue whale is the largest animal alive and probably the largest animal that has ever existed!

The blue whale has reached lengths greater than 30.5 meters (100 ft.) and has reached weights of about 178,000 kg (196 tons). Typically, it averages 23-27 m (70 to 90 ft.) and weighs about 90,000 to 135,000 kg (100 to 150 tons).

The blue whale model in the Museum of Natural History in New York City was my first childhood whale encounter. It makes the dinosaurs seem pretty small. I have yet to see a blue whale in the ocean, but I am sure that will fill me with that same childhood wonder.

Blue whale in the Museum of Natural History, NYC - via https://www.flickr.com/photos/zokuga/6226644368

The blue whale's skin is light-bluish gray and mottled with gray or grayish-white. It appears distinctly blue when seen through the water.

Underneath, the belly sometimes has a yellowish tinge as a result of diatoms that have attached themselves in cold water. That gives this whale the nickname "Sulphur Bottom Whale."

The pectoral flippers are long and thin, while the dorsal fin is very small and far back.

When this whale spots through its blowhole it is high and columnar. Like the fin whale and unlike the sei whale, the blowholes appear before (not with) the dorsal fin as the whale surfaces.

Blue whale - Balaenoptera musculus - NOAA photo via Wikimedia

Blue whales were abundant in nearly all the oceans on Earth until the beginning of the twentieth century. For over a century, they were hunted almost to extinction by whalers until protected by the international community in 1966.

A 2002 report estimated there were 5,000 to 12,000 blue whales worldwide in at least five groups. An encouraging IUCN report estimates that there are probably between 10,000 and 25,000 blue whales worldwide today.

Before whaling, the largest population was in the Antarctic, but now there are only much smaller (around 2,000 whales) concentrations in each of the eastern North Pacific, Antarctic, and Indian Ocean groups. There are two more groups in the North Atlantic, and at least two in the Southern Hemisphere. As of 2014, the Eastern North Pacific blue whale population had rebounded to nearly its pre-hunting population.  A 1987 report on the blue whale population in the Gulf of St. Lawrence catalogued 308 individuals.



Whale, North Atlantic right**Eubalaena glacialis**
Whale, blue**Balaenoptera musculus**
Whale, fin**Balaenoptera physalus**
Whale, humpback**Megaptera novaeangliae**
Whale, sei**Balaenoptera borealis**
Whale,sperm**Physeter macrocephalus**
**Federally Endangered

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