Thursday, January 1, 2015

New baby orca J-50 spouts rainbows across Puget Sound! OR Acronymous B.I.G.[G.]

In Seattle, orca births are celebrated on the front page of the paper! Go ahead, make your jokes about what yokels we must be, we know better.

Yay baby J-50!

You gotta be kidding me! Photo by Ken Balcom of Center for Whale Research
J-50 is Slick's (J-16) sixth calf, but two of her calves haven't survived, including the calf I announced a few years ago, J-48

It's difficult not to get excited about an absurdly cute baby apex-predator, but it's been a rocky month for this pod. They just lost one of the best hopes for the growth of the pod. J-32, AKA Rhapsody, washed up dead on the shore near Courtenay, in British Columbia. A necropsy indicated she was underfed, and had an aborted, nearly full-term, fetus in her uterus. The thought is that she was unable to expel the fetus which ultimately resulted in an infection that killed her. Of the [now] 78 whales in the Southern Resident Killer Whale (SRKW) population, only about a dozen are reproductively viable(1) - you don't need to understand population viability analyses to understand why that doesn't sound good.

J-50 is a hopeful sign, maybe the nice round number will be good luck, but this whale faces an uphill climb. Something like 35-45% of SRKWs die within the first year of life. The three pods that comprise this population J, K, and L, are culturally (in terms of diet and dialect) and genetically distinct from other groups of orcas worldwide, even those they live right next to. J pod is known as the "urban orcas", and spend more time than the other pods closer to dense human populations. These whales have astonishingly high levels of toxins, such as PCBs, in their blubber, concentrations which can be as much as twice the level at which seals are known to experience immunotoxic effects. Orcas accumulate PCBs and other toxins from the food they eat over the course of their lives (Figure 1). PCBs are fat-soluble and get passed on to calves in their mom's fatty milk, so females end up with lower PCBs than males (Figures 1 & 2), but first-born calves get the highest dose. 

Figure 1. Yay, boring graphs! Bear with me here: The concentration of PCBs increases in male killer whale blubber as they age. But females start offloading PCBs on calves when they reach sexual maturity. Then whey they stop reproducing they start accumulating again. Reproduced from Ross et al. Mar. Poll. Bull. 2000
Figure 2. Transient killer whales eat marine mammals, higher up the food chain than the salmon that make up most of the residents' diet. That means they get an even higher dose of PCBs. Reproduced from Ross et al. Mar. Poll. Bull. 2000

The resident whales' diet protects them from PCBs relative to transient killer whales (which find seals and sea lions very tasty - biomagnification if you want to sound snooty at your next cocktail party). Ironically, the fish-based resident diet is also a reason they are imperiled. Super classy predators that they are, they really would rather eat Chinook salmon than anything else. Humans are good at copying nature and pretending we invented it, so we decided we also like Chinook...and electricity. We built a lot of dams and et a lot of salmon, so....good luck, orcas!

As a result, in spite of the fact there are at least 50,000 Orcinus orca in the world(2), the SRKW were listed under the Endangered Species Act 10 years ago. There was an awful hubbub about this(3), because globally, the species is no where near in danger. So why should we have to stop eating salmon!? SRKW are listed as a DPS (discrete population segment(4)), meaning they are culturally and genetically distinct enough to be considered a separate population, worthy of their own conservation plan. In spite of added protection, the population of SRKW is now the lowest it's been in 30 years. The 10 year milestone prompted NOAA to put together a report on status of the recovery efforts, and acknowledge that there is clearly ongoing need to improve conservation management efforts.

One major change that conservationists want to make is to dramatically expand the area that is considered "critical habitat" for SRKW, since it has been discovered that, like geese and wealthy retirees, SRKW (at least K and L pods) are snowbirds, and travel as far south as Point Reyes to find food during the winter (Figure 3).

Figure 3. By tracking two whales (K25/Scoter and L88/Wave Walker), researchers found out that K and L pods also get tired of Seattle winter weather. They spend nearly all of their time between January and June time foraging along the outer coast, almost to SF...hipsters. Map by Curt Bradley, Center for Biological Diversity
Given the hell this could raise with fisheries management along the 700 miles of additional coastline being considered, it's pretty unsurprising that this proposal is meeting some resistance. I will undoubtedly be keeping my eyes on this  one.

References and Miscellany
(1) - Female orcas, like elephants and some primates, often live well beyond their reproductive years. How does survival after menopause get selected for? Here's a possibility, and here's a more accessible explanation.
(2) - No one really can come up with a good number for the global population of orcas. Here is one of the better reviews of the data available. 
(3) - The Orca Conservation Network has a great timeline of news coverage of the ESA listing status of SRKW here including efforts to repatriate Lolita, who was captured from L pod in 1970.
(4) - You want more acronyms? I can go all day long!

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