A Whale-Sized Impact on the Environment

Whale hunting began thousands of years ago, and many countries grew dependent on this practice for whale oil and baleen. The Japanese and Norwegians were among the first countries to hunt whales and this began 4,000 years ago. Interestingly, one of the earliest methods of whale hunting was for multiple small boats of fishermen to surround the whale, scare it towards the shore, then kill it once it reached the beach. Whale meat and blubber were eaten as sources of protein, baleen (the flexible plates found inside the mouth of whales in order for them to filter food from the ocean) was used to make baskets and tools, and their bones were also used to make tools. Whaling gained popularity in Europe during the 16th and 17th centuries in which whale oil was used for lamps and whale bone was used for fashion and more specifically for skirts and corsets. During the 17th century, the demand for whale products increased and therefore so did hunting. Whaling would continue to grow and eventually hit its peak during the 18th and 19th century. The development of the first steam-powered whaling ship in 1863 and gun-loaded harpoons in 1868 contributed to the industry's success. The industry eventually declined in the 19th century after the invention of kerosene. In 1971, the US banned whaling after declaring eight whales species endangered. Additionally, the International Whale Commission, or IWC, was founded in 1946 in order to prevent the overhunting of whales. Their efforts have been effective and certain whale species have recovered. However, illegal whale hunting exists to this day and Norway and Japan still hunt whales.

Some countries continue to practice whaling. Shown is a Japanese whaling ship in Antarctica. 

When whaling was most commonly practiced, the endangerment of whales caused a lasting impact on the Earth's ecosystem. The steep decrease in the whale population led to an unstable food chain and a change in the eating habits of many species. For example, the decline in the whale population caused a predator of whales, orcas, to begin preying on other marine animals such as sea otters. As a result, the otter population declined. Sea otters are a keystone species meaning their disappearance would drastically change the ecosystem. When the sea otter species is affected, the sea urchin population increases. This leads to kelp forests being destroyed by the increasing number of sea urchins. Many species depend on kelp for food and habitat, so the destruction of these kelp forests has had a devastating effect on marine life. In biology class, we learned about the Green World Hypothesis and how predators and even more importantly, keystone species, are able to regulate ecosystems. Keystone species come in all shapes and sizes. Similar to otters, Pisaster ochraceus starfish are a keystone species. Their removal largely impacts other species in their habitat and harms the biodiversity of intertidal ecosystems. The change in population of an apex predator results in what is known as a trophic cascade. Trophic cascades happen when a decrease in the population of a predatory species causes the deregulation of resources and cascades of indirect effects on other species. The Green World Hypothesis and trophic cascades demonstrate how ecosystems are regulated from the top down. The decrease in whales which led orcas to hunting sea otters, caused the structure of the ecosystem to be altered and added a fourth level to the trophic cascade of their ecosystem. Learning about trophic cascades and examining the effects whaling has had on them, shows the interconnectedness and fragility of the structure of ecosystems. Humans tampering with one species such as whales, affects all life on Earth. 

Sea urchins taking over a kelp forest off the California coast.

Like most organisms, whales play an important role in our environment and allow for many other species to survive. In particular, whales help the ocean's ecosystem by helping to maintain stable populations of other marine species. Whales most directly impact krill populations. Blue whales can eat up to 40 million krill a day! Whale poop also benefits the environment. Whale poop is filled with nutrients and is eaten by phytoplankton and allows them to grow. Phytoplankton is able to take in carbon dioxide from the atmosphere and turn it into cellular energy. It also releases oxygen that is then taken in by many different organisms. Once the phytoplankton have absorbed carbon, the carbon is then stored and is not able to return to the atmosphere even once the plankton dies. In sum, whale poop contributes to the growth of phytoplankton which allows for many species to grow and reproduce. In fact, it is estimated that 400,000 tons of carbon is extracted from the atmosphere by whales each year!

Sperm whale discharging waste.

Aside from supplying food to phytoplankton, whales also directly lower the atmosphere's carbon dioxide levels. Whales are extremely large mammals that are able to store tons of carbon in their bodies. When whales die, their bodies sink to the sea floor and all of the carbon previously stored in the whales remain in the deep sea for centuries. In fact when whales die, on average each whale sequesters 33 tons of carbon dioxide that has been accumulated over their lifetime. However, after centuries of whaling, whale populations have not recovered. Unfortunately, this means whales are not capturing and sequestering as much carbon as they could have been, had we left their species unharmed. Believe it or not, scientists calculated that before the increase of industrial whaling, whale populations(excluding sperm whales) could sink as many as 1.9 million tons of carbon to the bottom of the ocean each year. Furthermore, when whaling is being practiced, whale carcasses are prevented from reaching the bottom of the ocean and upon their removal and processing, the carbon is released back into the atmosphere. 

Two humpback whales.

Overall, helping toreverse the harmful effects of whaling and restoring whale populations would lead to an increase in both direct and indirect carbon sequestration. This would be key in combating climate change and decreasing the deadly amounts of carbon dioxide released into the atmosphere each year. Aiding the whale population is a risk free project that can help fight against climate change and improve the entire ecosystem and marine life. Incorporating the restoration of whale populations into the global fight against climate change is a necessary and very possible step for our planet.