Bryde's or Sei Whale, Sri Lanka (1 Viewer)

During a recent trip to Sri Lanka, I took three consecutive whale watching trips from Mirissa, mainly to see Blue Whales.

On the second trip, we found a fairly tight group of around 7 Blue Whales. Amongst them were two other whales, both described as Bryde's by the boat crew. The first was a definite Bryde's, with a typically falcate dorsal fin. At one point it raised it's head out of the water giving a clear view of the central and lateral head ridges.

The second, slightly larger whale was more interesting, showing a tall upright dorsal fin, which was typically the last thing on view when it submerged after each breath. Perhaps foolishly, I did not have my field guide with me (schoolboy error) and apart from the dorsal fin shape and number of head ridges, could not remember any other id features of Sei Whale. I was unable to get a clear view of the head on this second whale and can't be sure whether the rostrum and dorsal fin were on view at the same time each time it surfaced. We did not stay with these whales for very long as nearby Blue's were showing well, so I don't have many photos, but have attached a few below.

1st shot - Brydes showing typical falcate rear pointing dorsal fin.
2nd shot - head of Brydes showing central and lateral ridges
3rd shot - possible Sei tall upright dorsal fin
4th shot - possible Sei dorsal fin last thing on view as it submerged

I would appreciate any thoughts regarding the id of the second whale. Sei would be a rare find in Sri Lankan waters

Thanks
Martyn

I'm prepared to be shot down, but isn't the impression of verticality just a function of the angle from which the fin has been shot?

(Dons flak jacket, dives for trench)

John

No need for the flak jacket John.

You might be right, but it did give the "tall upright" impression in the field and did consistantly show the "sharks fin" on submerging, which the confirmed Brydes never did. I've seen Bryde's a few times before in South Africa, and was instantly uncomfortable about the larger of these two whales whilst perfectly happy with the other. Brydes/Sei Whales are a very difficult species pair to sort.

Just to add to the complexity, a third species may exist in Sri Lankan waters. Edens Whale has recently been described as a possible new species to science. This whale, very similar to Bryde's shows 5 ridges on the head.

Cheers
Martyn

Still unsure about the possible Sei either way. Still going through photos taken on my other camera body. I've found this shot of the same animal. It shows the dorsal fin appearing whilst the blow hole is still in view. I believe this is a good feature for Sei, but I'm not sure if this would be possible with a Bryde's. Anyone?

Thanks
Martyn

Two pictures I took of Sei Whales in the Azores last week. I've never seen Bryde's so can't help there.

TWM said:

Two pictures I took of Sei Whales in the Azores last week. I've never seen Bryde's so can't help there.

Click to expand...

Nice photos of Sei showing two of the key features, tall upright dorsal fin that is typically on view at the same time as the blow hole. Bryde's has a less upright, more curved dorsal that typically doesn't appear in view until after the blowhole submerges.

Of course, the diagnostic features are the head ridges, one on Sei, three on Bryde's and five on Eden's but these can be very difficult to see in the field (should I say "in the sea?"

Cheers
Martyn