Whales and New Jersey: Sei Whales

Sei whale and calf

In this last post about whales that travel off the New Jersey coastline and that are federally endangered (and so protected while in our waters), we look at the sei whale.

Sei whales reach lengths of 18.9 meters (62 ft.). They have dark steel-gray body frequently looks galvanized. The body is frequently covered with small pit-like circular scars, which come from the bites of cookie-cutter sharks.

Sei is the Norwegian word for pollock, also referred to as coalfish, a close relative of codfish. Sei whales appeared off the coast of Norway at the same time as the pollock, both coming to feed on the abundant plankton. The specific name is the Latin word borealis, meaning northern.

The development of explosive harpoons and steam-powered whaling ships in the late nineteenth century brought previously unobtainable large whales like the Sei within reach of commercial whalers. Initially their speed and elusiveness, and later the comparatively small yield of oil and meat partially protected them. But once stocks of more profitable right whales, blue whales, fin whales, and humpback whales became depleted, sei whales were hunted in earnest, particularly from 1950 to 1980.

The right lower lip is gray and baleen plates are primarily grayish black. The whale's snout is barely arched, while its slightly pointed rostrum (the forward extension of the upper jaw) sports a single median dorsal ridge. Two-thirds of the body length back of the head is a tall curved, tall dorsal fin. The leading edges of the flukes are occasionally white.

When the sei whale spouts a blow it can be either bushy or columnar and it is usually quite tall.

The sei whale is a baleen whale, and the third-largest rorqual baleen whale after the blue whale and the fin whale.

It inhabits most oceans and adjoining seas, and prefers deep offshore waters. It avoids polar and tropical waters and semi-enclosed bodies of water.

The sei whale migrates annually from cool and subpolar waters in summer to winter in temperate and subtropical waters.

Sei whales have a lifespan of 70 years.

The total number of sei whales in U.S. waters is unknown. A old tag-and-recapture study from 1977 estimated the stock ranged between nearly 1,400 and 2,250 sei whales.

Mass death events for sei whales have been recorded for many years and evidence suggests endemic poisoning ("marea roja") causes may have caused mass deaths in prehistoric times.

In June 2015, scientists flying over southern Chile counted 337 dead sei whales, in what is regarded as the largest mass beaching ever documented. The cause is not yet known; however, toxic algae blooms caused by unprecedented warming in the Pacific Ocean, known as the Blob, may be implicated.

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

Endangered Whales Off The NJ Coast

There are nine mammals protected as endangered in NJ, and six of those are whales.

All six are also Federally Endangered, and so they are protected by Federal laws while off the coast of New Jersey.

Those 6 whale species are:

1. North Atlantic northern right whale (or Black right whale), balaena glacialis
2. Blue Whale, balaenoptera musculus
3. Fin Whale, balaenoptera physalus
4. Humpback Whale, megaptera novaeangliae
5. Sei Whale, balaenoptera borealis
6. Sperm whale, physeter macrocephalus

Cetaceans is the order that includes whales, dolphins and porpoises. It is then divided into two suborders: Odontoceti and Mysticeti.

Odonoceti have teeth and a single blowhole (nostril) at the top of the head. The sperm whale is well known, if only from pictures and movies, for being one that regularly produces a visible spout or blow.

(Photo of right whale skim feeding via The Whale Center of New England)

The Mysticetes are the baleen whales. The other 5 listed here are baleen whales. That means they have no teeth and filter their food through their baleen. They also have two blowholes.

Baleen is made of the same material as our fingernails and hair, and has been described to the touch as similar to thick plastic hair. The baleen plates overlap each other and hang from the upper jaw of the whale. (They are sometimes compared to vertical blinds.) Each plate is frayed on the bottom and edges so that they mat together and help trap food. Right whales have the longest baleen.

My childhood fascination with whales has never faded, so I will write more about each species here in the months to come. I also admit to listing Melville's Moby Dick in my five books list despite its portrayal of whale hunting.