Every year, thousands of travellers from around from the world sign up for whale-watching tours in the hope of seeing the gentle giants of the ocean. Earth is home to numerous whale species, from the dwarf sperm whale, that measures around nine feet in length, to the blue whale, which spans over 95 feet. Catching sight of any of them—or better still, a pod of whales—is an unforgettable experience, likely to linger in the mind. Especially when the guide gets around to telling you about how crucial they are to the health of the marine ecosystem. And it all begins with their poop.
But before we get there, let’s take a minute to consider trophic cascades. This concept was first described in the 1900s by American writer and environmentalist Aldo Leopold. Aldo worked closely with wildlife from a relatively young age, and wrote extensively about bears, mountain lions, and wolves, and the role they played in the ecosystem. When wolf numbers declined due to building and development, he noticed that it had a cascading effect on the habitat: Without the predators, the deer population increased, which in turn impacted the green cover of the forest, as a lot more plants were being eaten. Eventually, Aldo explained, this would impact other species, trees, even rivers in the region. Many decades later, and long after Aldo passed away, grey wolves were reintroduced into Yellowstone National Park, USA, making conservation history. Officials who helped with the process noted the importance of the American writer’s work and writings.
Whales are to the ocean, what the wolves are to Yellowstone National Park. More specifically, it’s their poop that matters. Due to their size, whales consume vast amounts of food on a daily basis, and therefore produce vast quantities of excreta every day. This poop and pee is a rich source of phosphorus and nitrogen—super food for algae and phytoplankton. “Like well-steeped green tea,” says conservation biologist, Joe Roman in this podcast. More importantly, it is the primary food source for krill, which is eaten by fish and seabirds. When whale numbers drop, plankton reduces, which means less krill, and therefore less food for a number of other species, both in the sea and on land.
Unfortunately, whale numbers have been reducing, due to a number of reasons. Chief among them is hunting, with sperm whales poached for their oil, and blue whales for their meat and blubber. Whales also die from entanglement in fishing lines, and due to chemical and noise pollution, and environmental degradation. This is where we come in: If and when you do sign up for one of those whale-watching tours, ensure that it is being run by a reputable organisation that is involved in the conservation of marine life; follow the instructions of your guide; and treat the animal and its species with respect they deserve. It will undoubtedly yield a more meaningful experience.