The importance of whales to ecosystems at sea and on land is a growing area of research. There is an expanding body of evidence to suggest that high numbers of whales support other lifeforms throughout the ecosystem—including those the whales prey upon—and commercial fish stocks.
According to Joe Roman, a research professor at Rubenstein School of Environment and Natural Resources – University of Vermont, whales are useful because they redistribute large amounts of nutrients in the sea. He says that while extensive research has been carried out on what whales eat, as well as where and when they eat, much less is known about their other impacts on their ecosystem.
He says the fact that 50 years ago many whale species were on the brink of extinction due to whaling has given researchers a chance to study the changes as their numbers increase again. Whales redistribute nutrients in the sea in their feces, as well as shed skin and other smaller ways—as well as their corpses when they die. These nutrients feed krill and other small creatures, which in turn are eaten by larger fish and predators, which are in turn eaten by the whales again as part of the nutrient cycle.
Importantly, Joe Roman believes, the migration of the whales means necessary nutrients from rich temperate seas are transported with the whales to poorer tropical seas, where lifeforms readily consume them. Scientists have found 60 different species living on whale carcasses in the deep ocean—species which rely on the dead whales.
New research in the field goes some way to dispelling the argument that whaling is necessary to control whale populations to prevent dangerous decline in fish stocks targeted by both humans and whales.
Joe Roman was in Iceland for a conference at the University of Iceland this week, where he spoke about his research alongside Gísli Víkingsson, a whale specialist from the Marine Research Institute.
Gísli’s research has concluded that whale stocks are in very different states of recovery from over-hunting around the world in the Atlantic, Pacific and Southern Oceans. There is evidence, he believes, that stocks of some whales around Iceland, including the fin whale, have regained their historic size. Blue whales have not recovered, however, and neither have whale stocks around the Antarctic.
One suggested reason for the north-south difference is that the Antarctic ecosystem is simpler than the northern one and the sudden drop in whale numbers could have seen other species take their place; such as seals, penguins, minke whales and seabirds. These historically larger than normal populations could be preventing the whales recovering, it is theorized.
The theory that whales might be putting more back into the ecosystem than they take is revolutionary, Gísli told Vísir. The Marine Research Institute maintains that present Icelandic whaling activity is small enough to have no effect on whale stocks overall, both from a population size and nutrient redistribution perspective.