Humpback Whales in Tonga 2010

It's been a relatively slow period since my last update. The weather has been somewhat unpleasant (mild understatement), with the wind hitting 20 knots on most days, and gusting upward of 30 knots on a regular basis. It hasn't rained much, though there have been intermittent showers on some days.

Despite the relatively difficult conditions, we've managed to have some interesting encounters, the most memorable of which for me was a run-in with this escort:

Psychotic escort whale with Kowai (18th ID-ed calf)

It was another case of a mother and calf being assaulted by four males. As I noted in earlier posts, the instances of multiple male humpback whales fighting over females with babies this season started early, and the trend seems to have continued unabated.

In this instance, the mother and calf were originally with two relatively calm escorts. Once a separate pair of males in the vicinity joined them however, all heck broke loose, with the mom and calf running as fast as they could to stay away from the testosterone-crazed boys.

The escort pictured above was the craziest of the lot, choosing on one occasion to stay behind and swim circles around Takaji and me instead of following the other whales. It had a deranged, almost psychotic look in its eye. If I didn't know better, I would've said the whale was high on crack.

We named the calf involved in this encounter "Kowai", which means "scary" in Japanese, a reference to how scared the baby must've been with four big boys pounding and thrashing in the water while chasing the mom and calf. Kowai is the 18th calf we've ID-ed so far this season.

Given the relatively slow start to the season and generally uncooperative mood of the whales, I didn't expect to reach a count of 18 this year. If I have to be wrong, it's certainly nice to be wrong in a good way. I'm confident now that we'll cross the 20-calf mark by the time we're all said and done.

Kowai (18th ID-ed calf of the season) and mother

One Quick Note
I want to devote most of this update to a discussion about ID-ing baby whales, but before diving into that, I'd like to make one quick point.

In the past few days, I've received separate and corroborating reports of more whales than usual in Tahiti and the Cook Islands, with Niue reporting fewer whales than normal. I received a short message from Australia early in the season saying there were fewer whales than normal; and I also received another note today saying that humpback whale feeding in Australia has started early this season. I just got a note yesterday from Ha'apai letting me know that they have had about the same number of whales as usual. The general concensus in Vava'u among people who've been here for a while is that there are fewer whales overall, and they're less cooperative than usual.

The point I'd like to make is that given how little we know about the overall social structure, migration patterns and and interactions among humpback whales, it's dangerous and irresponsible to draw conclusions from a single season of observation.

For example, each year, the conditions in Vava'u change. And each year, people who are in Vava'u and have little to zero experience with whales make broad, sweeping statements about the plight of humpback whales based upon a couple of casual sightings and hearsay.

Inevitably, such statements tend to proclaim doom and gloom, with boats and people in the water being responsible for the downfall of the whale population. The really zealous and self-righteous usually throw in a jab at the Japanese people, even if they don't actually know any Japanese people, much less have any facts about the whaling situation (which is mostly about money, power and corruption…not whales).

My point is that the whales are doing what they want and need to do. They are incredibly intelligent animals with highly evolved, complex social structures.

Meanwhile, humanity knows next to nothing about these animals, so instead of trying to invent new and different ways to condemn other people, we should be investing our energy in sharing information to try to understand what the whales are doing.

One of the escorts that was with Kowai (18th ID-ed calf) and mom

Baby Whales
I wrote about Ikumi (calf #5), the undisputed star of the season, in Part 5 of my notes from Tonga this year. Between our first sighting of this female calf on 17 August through our final encounter on 31 August, we swam with Ikumi and mom on ten occasions…a record-breaking streak for us.

When I spent a night on Mounu Island last week, Allan and Liz there reported seeing Ikumi on multiple occasions as well, so I know that we're not the only ones that the sociable little calf has befriended and impressed.

We recently discovered another calf that has been in the area for an extended period, one that we first marked as an unknown calf, and later confirmed with in-water photographs as Lele, the 8th ID-ed calf this season.

I first photographed the dorsal fins of this calf and its mother on 22 August and labelled the pair as Unknown 08. The pair was in water with terrible visibility, and they were highly unsettled. It wasn't possible to get in-water photos of them at the time, though I did get a reasonably good look at the mom. I noted in my records: "Mom has unusually shaped dorsal fin, with white on trailing edge. The ends of her pectoral fins are quite white."

On 25 August, I photographed a mother and calf that was again quite skittish, in the area outside Hunga. Just as the pair seemed to be growing accustomed to me and were about to settle down, they took off at high speed into the blue…probably because the pilot whales, oceanic whitetip sharks and striped marlin showed up (See Part 5).

I immediately recognised the pair, and later confirmed that the calf was the one I marked as Unknown 08 a few days earlier.

And finally, Takaji ID-ed Lele again on 1 September, this time with two escorts, in an area that was close to where I first spotted Lele and mom on 22 August.

So that means Lele was around for at least 11 days, not quite as long as Ikumi, but a close second, and far longer than we've recorded for other baby whales in previous seasons.

I'm not sure if there's any meaning in these long-term sightings (we haven't confirmed any other long-term stayers this season, and we haven't re-sighted Ikumi or Lele for a while), but I'm inclined to think that with fewer whales than normal in the area to compete for territory, both Ikumi's and Lele's moms were able to relax for a longer period than normal before being beset upon by other whales.

One contributing factor to the long-term sightings might be that I'm keeping better records of calf encounters I label as "Unknown" this season than in previous seasons. Lele was initially marked as an Unknown, but I was later able to match the topside photos I took on that first sighting with photos I took in the water later, when I was able to make a firm ID of the mother and calf.

Keeping records of "Unknown" sightings adds a lot of work to my daily routine (and also to the final process of reviewing and reconciling all the photos when I get to that point), but it's underscored a point that I've believed for a long time…fluke images are not necessarily the best way to ID humpback whales in the southern hemisphere.

To Fluke or Not to Fluke
Most cetcean ID programs rely on photographs of flukes, because the patterns on the ventral surface of cetacean flukes (and sometimes the shape of the flukes themselves) are unique to each individual.

I'm not disputing the utility of fluke shots, nor the fact that fluke patterns are unique. My belief, however, is that…at least in the case of southern hemisphere humpback whales in Vava'u…flukes are not the optimal method for ID-ing individuals.

Here's my line of thinking:

1. Whales don't always fluke. In fact, they fluke on a very small minority of dives. I'd peg it at less than 10% of the time (being extremely generous).

2. Even when they fluke, the whales don't always show the ventral surface of their flukes. In other words, they don't always lift their hind-ends sufficiently high out of the water, and they aren't always facing the right way so you can see the ventral surface of their flukes.

3. It's not that easy to get a fluke shot even if a whale flukes and you're on the correct side. Complications such as boat motion, distance to subject, difficulty in using long lenses, getting correct exposures, having the sun on the wrong side (i.e., backlighting), having bits of the boat and people's heads get in the way, etc. often screw up photo opportunities.

4. Flukes may be unique, but many look alike. It sometimes takes a lot of squinting to tell the difference, if you can actually tell the difference. There are a lot of all-white flukes that show up here, for instance.

5. Flukes tell you zip about sex, size, shape, health, behaviour or social interaction.

These are the primary reasons I rely mostly on a combination of full body shots and dorsal fin images to ID whales:

1. Whales show their dorsal fins 99.999999999% of the time, so there's a much greater chance of getting dorsal fin images than fluke shots. Dorsals are not necessarily as unique as flukes, but they often have sufficiently unique markings and/ or shapes to facilitate ID. This is especially true in the case of mother/ calf pairs, where I can work with a pair of dorsal fins. The chances of having two separate mother/ calf pairs with two nearly identical dorsal fins in one season in Vava'u is remote, especially when other body markings are taken into consideration.

2. When it's possible to get in-water, full-body photographs, it's almost too easy to ID southern hemisphere humpback whales. They often have unique markings all over their bodies. The patterns created by the white areas on their bodies are much easier to see/ recognise than fluke markings.

3. For mother/ calf pairs, I can often more readily ID a mother than the calf. But if I can ID the mother, I can ID the calf (at least within a single season). I'm making the assumption that mothers don't switch babies mid-season, but I think that's a safe bet. Calfs often don't have readily recognisable markings, or what markings they do have might be subtle, or even change within a single season.

4. By getting into the water, I see behaviour, social interaction, injuries if any, and even…dare I say?…personality. All of these observations are useful in recognising whales when we see them again. Yes…whales often have consistent personalities (for lack of a better term). Sometimes, personalities make it really easy to ID a specific whale, and I only need the physical markers for confirmation (Ikumi being case in point).

None of this means I ignore flukes. It just means that flukes are not the end-all and be-all for ID-ing whales, at least not here for my purpose.

There seems to be a general belief that flukes and only flukes can and should be used for ID. I understand the need for standardisation in order to compare across regions, but as is often the case with human endeavour, it seems that in this instance, we are collectively placing artificial limits on our own efforts, and then wondering why we're not getting very far.

By limiting ourselves to just flukes, we haven't, for instance, been able to ID mother/ calf pairs beyond a shadow of doubt easily to date. In contrast, It's a piece of cake for me to make IDs when I can work with in-water full-body images.

So here are a couple of real-life examples from this season to underscore my point.

Case Study 1: Lele
On 22 August, I photographed this dorsal fin of a calf I marked as Unknown 08:

Dorsal fin of calf marked as Unknown 08. Note the white scars.

And I also photographed this dorsal fin of the calf's mother:

Dorsal fin of mother Unknown 08

On 25 August, I photographed and ID-ed Lele (8th ID-ed calf of the season) in the water:

Lele, photographed on 25 August. Note the white scars.

Lele, 8th ID-ed calf of the season, with mother

The photos aren't works of art, but they're good enough to see that the calf from the photos on 22 August and 25 August have the same dorsal fin shape and two white scars posterior to the dorsal fin.

Here's the mom's dorsal fin at high magnification:

Dorsal fin of Lele's mother

Again, no prize-winner here, but it's clear that the dorsal shape is the same as in the photo of the dorsal fin of the mother of Unknown 08.

These photos (and more images of course), coupled with my memory and note from 22 August: "Mom has unusually shaped dorsal fin, with white on trailing edge. The ends of her pectoral fins are quite white." confirmed the ID for me. Lele and Unknown 08 are one in the same.

Finally, on 1 September, Takaji took a series of photographs during an encounter with a mother and calf, one of which was this:

Lele and mom again. Note the white tip of the pectoral fin.

You can see that the white area on the tip of the mother's pectoral fin is the same in this image as it is in the in-water photo I took on 25 August.

So there you have it. 22 August, Unknown 08. 25 August, Lele and mom. Later that night, I realised Lele and Unknown 08 are the same. 1 September, second encounter with Lele.

All three IDs made without any fluke photos. In fact, we were unable to get any fluke images in all three encounters...so had we relied solely on fluke images, we'd have nothing.

Case Study 2: Blacktail
Let's take a look at another example.

Here's a shot of the backs of Unknown 12 and mom, taken on 31 August:

Unknown 12 on 31 August. Note bump on mom's dorsal fin.

Note the bump on the dorsal fin, as well as the small white scar visible just above the surface of the water on the mother's back.

And here's a photo taken on 3 September from a similar angle:

Blacktail's mom on 3 September. Note bump on dorsal fin and white scar on back.

See the bump and white scar?

These photos (and more images), coupled with Takaji's original comments on the Unknown 12 sighting on 31 August: "Mother's fluke is almost entirely black on ventral side. Baby is largely black. Mom seems to be mostly black as well. Mom's dorsal has a small bump on the right side. Found far east, near the foul grounds. Saw the calf once underwater, but unable to take underwater photos." allowed us to match these two sightings.

We named this calf Blacktail (14th ID-ed calf of the season), because the underside of its mom's fluke is mostly black:

Blacktail's mom's fluke

In this instance, the adult whale's fluke was a valuable reference for the ID.

In summary, if we step outside the framework of "flukes and flukes only" thinking, we can learn a lot more about humpback whales than we can by sticking with convention.