Shades of Black and White

I've attended the last three bi-annual American Cetacean Society Conferences, and at each event, someone gives a talk about diversity in orca and that we can expect to see sub-species, if not "new" species anytime soon, due to strong genetic differences.

Well, of course "anytime soon" in the scientific community may not be in my lifetime! But it certainly is interesting to see that the more we look at killer whales, the less we find we know.

It's certainly in my lifetime (since the 1970's), however, that we've learned of three distinct ecotypes:

Residents - salmon specialists in the Pacific Northwest
Transients - mammal specialists
Offshores - the least understood, but thought to feed on fish and specialize in sharks

The residents found off Washington and Vancouver Island are the most studied in the world, but turns out that they might also be somewhat unique. Ingrid Visser's work in New Zealand suggests that the whales there appear to be neither resident or transient, in the way that we've come to know the ecotypes of the U.S. west coast. More secrets to be uncovered there for sure!

It's now known there are three different variations of orca in Antarctica, each with different specializations of prey type and habitat preference and a fourth found in the sub Antarctic which appears to be different again. These whales even look different from the northern hemisphere cousins. Different size eye patch, and even a different (but subtly so) body shape.

Closer to home in the North East Atlantic, it's been established that there are two types of killer whales, both focusing on different prey types. It surely has to be the amazing adaptability to prey types and ecosystems that makes the killer whale the most successful marine mammal on the planet.

It's fascinating to watch this research unfold and learn more about the true diversity among the seemingly similar black and white mammals. I hope also, that it can lead to more protections, as each group can be recognized as distinct, as the southern resident population was, resulting in a listing under the ESA in 2005.

Contaminated Oceans (and Orca)

Killer whales in the North East Pacific are the most contaminated marine mammals in the world, so says Peter Ross, scientist for the Department of Fisheries and Oceans, Canada (DFO).

I don't know what concerned me most when I heard Peter speak recently. His testimony, or the fact that his position is to phased out. Who will speak on behalf of the orca on this crucial matter when he cannot?

Here are some of the horrific facts from Peter's presentation:

• There are 88,000 chemicals on the Canadian market.
• By way of small-scale spills, Puget Sound experiences the equivalent of 4 Exxon Valdez spills per year
• DDT in the form of DDE still persists in the marine environment
• PCBs are the bigger threat to killer whales, due to the way they mimic hormones. In a necropsy they were associated with 11 different hormone receptors, including estrogen and thyroid.
• Salmon - the food of choice of the southern residents, bring persistent organic pollutants (POP) from the open ocean

There were some good indicators also, however, in that levels are dropping for concentrations of PCBs, DDT and PBDE (flame retardant - thanks to the ban in 2004).

PCB levels in harbor seals are down ten fold, which is good news for the transients who venture into Puget Sound for a meal, where harbor seals are storing the highest known levels of PCB.

Killer whales, proposed Peter, are sentinels of global pollution. A giant black and white canary in the coal mine (he didn't say that, I did!) 

Chemical regulations are based on the impact on short living species, and not long-lived, like ourselves and orca. One wonders why the low bar when a third of the world relies on the ocean as the sole source of protein.