Whales: Recovering, But Not Recovered

Trigger-happy pro-whaling countries are itching to get whales back in their cross hairs, claiming some species have recovered enough to warrant lifting the global hunting ban.  But, "recovered enough" compared to what? The answer to that question has big implications for how we manage whales — and the rest of marine life.

The International Whaling Commission has said that a species is recovered when it reaches 54% of its pre-hunting level. Pacific minke whales and Atlantic humpbacks are nearing this threshold — if you accept the historic levels set by the IWC. Many scientists and historians emphatically don't.

IWC calculations are based on current population estimates and how many whales were caught since about mid 19th century, the dawn of the exploding harpoon. But this data is inaccurate and woefully incomplete.

It's inaccurate because, like other successful businessmen — like, say, Jeffrey Skilling — 20th-century whalers doctored their books. And it's incomplete because only a small number of whales that were harpooned were actually hauled in — many swam off but likely died later from injuries — and only some of those landed on board were recorded. A researcher recently uncovered 10,000 harpooned southern right whales from the 19th century that never made it into the catch records. Not to mention all the whales hunted before the 1850s, when the IWC's data starts.

Historical data, based on unconventional sources such as explorers' journals, tax records, and older log books, reveals that we hunted whales (and many other marine species) much earlier, to a greater extent, and with bigger consequences, than previously thought.  For instance, Dutch whalers drove local extinctions of Arctic Bowhead whales in the 17th and 18th centuries.

But, for those of you wary of pirate tales and salty yarns, there's also evidence embedded in the DNA of living whales.  It works like this: the more genetic diversity in a population, the bigger the original population size had to be to produce all that variation. Researchers have measured this diversity in modern whales (humpback, fin, minke, Pacific grey, and most recently, southern right whales) and calculated that historic populations were often orders of magnitude higher than IWC estimates.

For example, genetic data indicates that there used to be about 78,500 grey whales in the pacific. Most IWC estimates range from 15,000-20,000.

Such evidence helps stifle ridiculous claims by pro-whaling countries, like Japan, who argue that declines in fish are due to unnaturally high numbers of whales.

But it also means that species such as minke and humpback whales are nowhere near as close to the 54 percent threshold as the IWC maintains — and what's up with that 54 percent, anyway? With climate change altering the entire ocean ecosystem — starting with tiny krill, which many whales eat — not to mention our continued overfishing, how can we know for sure that 54 percent is enough?

So yes, some whales are recovering. But they are far from recovered.  And without the continued global ban on whale hunting, even this brief flirtation with population increase may become a thing of the past.

Photo credit: lostajy