Chances are, you've heard a multitude of arguments against the killing of whales.
It's cruel. It has decimated whale populations. Whale meat is full of pollutants. Continued whaling will prompt preventive measures by 23rd century time travelers.
To which, we may now add another.
It wasn't long ago that researchers first confirmed that whales contributed to ocean ecology even after death, their carcasses landing on the seabed and forming the basis for unique communities known as "whale falls". Now, two whale scientists have found that, as well as seeding the seabed, whales also stimulate biological production at the ocean's surface, thanks to their nutrient-rich feces. Writing in the online journal PLoS One, Joe Roman of the University of Vermont and James McCarthy of Harvard University note that, because whale feces are expelled in the form of light plumes, they do not sink, but float (if at the surface) or disperse laterally or upwardly (if below).
As a consequence, whales increase primary productivity — that is, they create conditions that allow the growth of greater amounts of phytoplankton, the basis of the marine food web, which feed on the nutrients in cetacean fecal matter. That in turn leads to greater secondary productivity: the tiny animals called zooplankton that eat the tiny phytoplankton. And so on.
Roman and McCarthy found that, in this way, whales in the Gulf of Maine added 23,000 metric tons of nitrogen to the ocean each year – a greater nutrient input than all the rivers that feed into the gulf combined. And that's now, after whale populations worldwide have been decimated. The mere presence of many more whales in the past would almost have certainly have meant the ocean was a vastly more productive place than today, they argue.
And, in the same vein, Roman and McCarthy help puncture one of the tired refrains trotted out by whalers to justify their activities: That whales compete with fisheries and should therefore be "culled" to allow fish populations to grow:
Image: Peter Roopnarine, Joe Roman, James J. McCarthy. The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin. PLoS ONE, 2010; 5 (10): e13255 DOI: 10.1371/journal.pone.0013255