Whales play a vital role in the marine ecosystem where they help provide at least half of the oxygen you breathe, combat climate change, and sustain fish stocks. How do they do it? By providing nutrients to phytoplankton, microscopic forest of tiny plant-like organisms.
As the base of the marine food web, phytoplankton is a key component in sustaining fish stocks and as they take in C02, phytoplankton sequester hundreds of thousands of tons of carbon each year, helping to fight climate change.
Whales belong to the Cetacean family made entirely of aquatic mammals commonly known as whales, dolphins, and porpoises. Cetaceans are warm blooded, breathe air through lungs, give birth to live young that they produce milk to nurse and have traces of hair or fur —all features of mammals.
There are around 89 living species, divided into two parvorders:
Odontoceti (the toothed whales) consisting of around 70 species including the dolphin (includes killer whales), porpoise, beluga whale, narwhal, sperm whale, and beaked whale.
Mysticeti (the baleen whales which have a filter-feeder system) consisting of fifteen species including the blue whale, right whale, bowhead whale, rorqual, and gray whale.
The term whale can be used in reference to any cetacean, but in general is applied to those more than 3 meters (10 feet) long with exception of the dwarf sperm whale which is only 2.7 meters (8.5 feet).
North Atlantic Right Whale
North Pacific Right Whale
Threats to Whales
The oceans were teaming with whales a century ago, but human intervention has changed this.
Commercial whaling to satisfy the consumption of lamp oil, lubricants, cosmetics and food killed millions of whales. While regulatory means have reduced the impact, whaling continues in Iceland, Norway, Japan and the Faroe Islands.
Persistent organic pollutantssuch asoil slicks, chemical contaminants (PCBs-polychlorinated biphenyls, dichlorodiphenyl trichloroethane-DDT, polybrominated diphenyl ethers-PBDEs, mercury, dioxins and furans) and other man-made toxins are commonplace in the oceans. These pollutants have many adverse health effects on whales – affecting their reproduction, development, endocrine and nervous systems – ultimately increasing their susceptibility to cancer, pathogens and diseases.
Loss of food source and impact to habitats resulting from climate change and coastal developments have increased mortality rates and reduced populations. While many animals may not die specifically from ‘starvation’, low prey availability may result in ‘nutritional stress’ – and this can make them prone to illness, infection, and the affects of contaminants.
Noise from shipping, seismic exploration and military sonar contribute to underwater noise and may impact the ability of cetaceans (whales, dolphins, and porpoises) to conduct critical life processes such as communicating, foraging, finding mates, and navigating through their underwater environment.
Entanglementin commercial fishing and aquaculture gear can cause significant injuries to whales, affecting their ability to swim and feed. Whales can also be immobilized by fishing gear such as crab and prawn traps, causing them to suffocate and drown.
Vessel disturbance by large and small ships may interrupt natural behavior and alter activities that are crucial for survival such as foraging, feeding, socializing and breeding. For example, when vessels are nearby, whales reduce the time spent foraging in favor of traveling. The interruption of feeding may impact the energy intake of these animals, which if persistent over time, may have individual and population-level impacts. Humpback whales displayed avoidance behaviors such as diving, swimming away, reducing surface time and changing respiration rates in the presence of cruise ships. Vessel collisions causing serious injury or death pose a real risk to many species of whales worldwide.
Plastics may be ingested by whales mistakenly while feeding on prey, or may enter their digestive system from inside of prey that has previously fed on plastic. Once ingested, the plastic piles up in the whale's stomach and can then obstruct bowels, preventing whales from digesting food and leading them to starve to death. It can also give a whale a false sense of being full, leading the whale to eat less and get weaker. That leaves it vulnerable to predators and disease.