Clocking 48kmh (30mph) or more is pretty impressive for the ninth largest living animal, and handy if some orcas come a-chomping.  And while it’s not quite as effective at escaping humans, the sei whale has some red tape on its 20 metre (66 ft) side. Funnily enough, that’s also how it feeds.

By swimming sideways on the surface with one fin up, it can scoop up prey as it goes, and if you can forgive the baffling Titanic music over the top, you can watch one here. When surfacing, it blows air and water about 4 metres (13 feet) up, but unlike its bigger relatives, it doesn’t arch its back or flash its tail when diving. You still might catch a glimpse of its crescent-shaped dorsal fin, though.

Like the blue, the sei whale is both a rorqual and a baleen whale, so it has throat grooves and mouth plates for filtering food. It takes in huge amounts of water, then pushes its tongue upwards, forcing the liquid out through said plates before swallowing any unfortunate thing left behind. Within reason, of course – mainly krill, copepod crustaceans, squid and small fish rather than errant swimmers, which is fortunate since it’s five times faster than an Olympic one. In fact its name comes from the Norwegian for pollack, “seje”, and can be pronounced “say” or “sigh”, so feel free to adjust depending on whatever terrible joke you’re telling.

While the sei doesn’t use echo-location to find food, powerful sonic pulses have been recorded, with those near Hawai’i different to those in the southern seas. At a range of 20-35 hertz, the Hawai’ian visitors sound like the local fin whales, and being similar to other species can be problematic.

When blue and fin whale populations plummeted in the 50s and 60s, whalers switched to the sei, and it wasn’t until the 1980s that commercial whaling was banned. However, Japan can kill up to 100 a year for “scientific research”. Reading that made me sigh about 4 metres of air, especially since most of the resulting meat seems to have been sold commercially. But knuckles may still get rapped.

Almost unanimously, CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, agreed killing most of the whales for commercial rather than scientific reasons was a violation of said convention. In response, Japan has agreed to delay their “research vessels”, and not to authorise any more hunting in the high seas in the northern Pacific until the next CITES meeting in May 2019. In the meantime, they need to come up with a remediation plan or risk being hit with sanctions from the other 182 governments. Unfortunately algae hasn’t been behaving itself either, and this time it can’t be reasoned with.

In 2015, presumably due to El Niño shoving warm water where it shouldn’t, a “hostile algal bloom” occurred, and up to 300 dead sei whales were found stranded in Chilean Patagonia, covered in toxic algae. Being a “goldilocks” species, the sei whale prefers sub-tropical and sub-polar waters while making its yearly feed-and-breed migration, so increasing temperatures are about as welcome as harpoons and could be just as deadly. That’s before we even get to ocean noise, boat strikes and net entanglement, which are the top three sigh-worthy things on a sei whale’s list (sorry).

Will there come a day when we say its name without a “sigh”? For the sake of conservation and good humour, let’s hope so.


LatinBalaenoptera borealis

What? One of the fastest whales in the ocean

Where? Subtropical, temperate, and sub-polar waters worldwide

How big? 13-20 metres / 45-66 feet long

Endangered? Yes, due to last century’s whaling, and this century’s climate change, increased ocean noise and boat strikes.

Probable motto: I like feeding sideways, but everything else is going that way too.

They sound sweet. Do they need my help at all?

Yes. Despite the commercial whaling ban, an increase in ocean noise – which can baffle and disorientate them – and collisions with boats are causing a problem. More and more shipping lanes are opening up due to ice melt as well, and increasing ocean temperatures can affect both their feeding grounds and toxic algae.

WWF have an “adopt a whale” programme, and also work with the International Whaling Commission to help reduce threats to the animals (other than the regulated harpooning, obviously).

The Whale and Dolphin Conservation Society also has a campaign to end whaling full stop.

Just to prove I’m not fibbing

Balaenoptera borealis“. No date. IUCN Red List of Threatened Species.

CITES annual meeting sees States stepping up action against the overexploitation of precious timber and other species“. 2018.

CITES censures Japan for trading in whale products from an endangered species“. 2018. Animal Welfare Institute.

Geib, Claudia. 2017. “Death by killer algae“. Hakai Magazine.

Glum, Julia. 2017. “Shark week 2017 will see Michael Phelps race a great white, because why not?Newsweek.

Häussermann, Verena et al. 2013. “Killer whales in Chilean Patagonia: additional sightings, behavioural observations, and individual identifications“. Revista de Biología Marina y Oceanografía 48(1):73-85.

Rankin, Shannon, and Barlow, Jay. 2007. “Vocalisations of the sei whale Balaenoptera borealis off the Hawaiian Islands“. Bioacoustics 16(2):137-145.

Sei whale“. No date. Australian Government: Department of the Environment and Energy: Australian Antarctic Division.

Sei whale“. No date. National Oceanic and Atmospheric Administration.

Sei whale“. No date. WWF.

Sei whale“. No date.

Sei Whale – Balaenoptera borealis“. No date. Marine Conservation Society.

Sei whale: balaenoptera borealis“. No date. Whale and Dolphin Conservation Society.

Featured image credit: “Sei whale” by merch313.