There is a and always has been a relationship between humans and the world we live in. Every action has a reaction, every cause an effect and in recent years the effects of the problems we are causing have become clearer and clearer. It begins quite obviously with thousands of years of human expansion, as we expanded our territory and grew in size, we did so by taking natural habitats and turning them into towns or farms etc. Since most of human civilisation thrives by the water, using boats to trade and fish, more and more coastal territory was claimed as well.
Whilst nature is quite resilient, re-growing what has been taken, it can only grow so much in a year. In fact, world overshoot day, the day of the year by which we have used all the resources that the planet can produce in a year was reached on July 29th this year. Meaning that after that we are digging into reserves the planet will not have time to regenerate. All this brings us to current events, namely the ongoing Holocene extinction, the sixth mass extinction.
With all this happening, a reduction in biodiversity becomes a large problem. Biodiversity is the variety of life in an ecosystem. Basically, the amount of different species. This is so important because with a larger variety of species the food web becomes bigger, more complex, and therefore more resilient. For example, if in a field with a high biodiversity many rabbits get hunted, the foxes may still eat mice or fowl or other animals. But with a low biodiversity, there may be little alternative prey and the foxes may die, then a few years later rabbit populations shoot up, and all the plants get eaten. So, you see an ecosystem with a high biodiversity is much more stable. And therefore, it will also be able to provide a constant stream of resources for local human populations.
This brings us, finally to cetaceans. Dolphins and whales, in general, are on the top of the food chain. Where a blue whale eats krill and plankton, making it a very short food chain. An orca for example is the absolute apex predator atop a long food chain. Quite simplified: Phytoplankton grows using sunlight > who get eaten by zoo plankton > who get eaten by krill> who get eaten by small fish > who get eaten by bigger fish > who get eaten by seals > who get eaten by orcas.
Of course, the true food-web is much more complex, but for our example this will do. The orca food chain, since it is so long, has many stabilising factors, yet if the orca population in this example were to fail, it’s controlling role would disappear and seal populations would increase greatly, in turn reducing the availability of larger fish species, but making smaller fish species abundant. This unbalancing the system. It is especially noticeable in the short food chain of baleen whales. Whale hunting would reduce their population greatly, which in turn would cause a drastic increase in krill population. This could lead to a catastrophic decline in the plankton populations that the whole ecosystem depends on.
The top down control function that whales fulfil are vital if we intend to keep our oceans healthy and full of life, with the great increase of fishing, by catch problems, plastic pollution, metal pollution, temperature change, coastal habitat loss, and many more problems, the seas need every species to stay full of life. We need the whales, it may sound contradictory, but we need cetaceans to eat so there is more food for us. And with the human population growth, especially by the coast. It is important now more than ever that we listen to scientists and preserve what we have, so that future generations may enjoy the bounty of the sea as we have.
By Scott Dorssers