Whales are aquatic mammals and are descendants of land-living mammals that returned to the sea some ten million years ago, and have since adapted well to their marine environment. As mammals, they still have to come to the surface to breathe air; done through their blowholes. Only by living in water with its dense buoyancy, could the largest of today’s whales have reached their current sizes, with the blue whale being the largest mammal that has ever lived; reaching lengths of 24-27m and weights of 130-150 metric tonnes. Whales belong to the order Cetacea and are further split into two suborders; Mysticeti (the baleen whales) and Odontoceti (the toothed whales).
Baleen whales have horny teeth which are made from the same material as human nails (keratin), and these filter water out when they feed on crustaceans and small fish. The toothed whales eat fish and squid (giant squid is eaten by the sperm whale) and other marine mammals. Whales either travel alone or in small groups called ‘pods’, depending on the species and the sex; usually females form groups with their young and males typically live solitary lives. Most species of whale can be found at the polar regions of the globe. Regions nearer to the poles have a higher primary productivity and therefore have the highest number of fish and squid available. However, when whales breed they travel to warmer waters due to the polar summer (where primary productivity is at its highest), not being long enough to sustain mother and calf.
Humans have been hunting whales for centuries and highly exploiting them in certain regions, even to the brink of extinction. Using small sailing boats and harpoons, they were either tailed onshore, or killed and processed at sea. As new technology developed and boats improved, the same basic methods were still used, however, this meant that new larger species could also be hunted; such as the sperm whale. The sperm whale was hunted for oil found in the spermaceti organ located in the whale’s head; which takes up about a third of its entire body. As demand for whale meat and oil grew, whaling became very popular and more people took to whaling in other regions of the world, causing populations to decline rapidly. Whale hunts often involve long and intense suffering to whales. When harpooned, whales rarely die instantly and they can often be in the throes of death for many hours. Their K selected life strategy means they are particularly vulnerable to any dramatic loss in numbers, as it can take up to 25 years to reach sexual maturity and even after that they have low fecundity and are very slow growing.
As technology increased and demand for the resources remained, catches far exceeded the sustainable limit for whale stocks and numbers dramatically declined to the brink of extinction for many species by the 1950′s. This led to a global ban against commercial whaling that came into effect in 1986 by the International Whaling Commission (IWC). However, whaling still continues in some countries today. Whaling is not the only threat these animals face from man, with the continued industrialisation of the human world; there is an ever greater demand on the oceans. Toxic waste, agricultural runoff and coastal development, all have an impact on the marine environment and by extension; to all marine life. The creation of shipping pathways can also cause risk of collisions for whales, often leaving them with fatal injuries. Furthermore, overfishing of food sources can cause whales to travel further than their usual range in search for food. In some cases, this can lead to them being stranded on beaches, or trapped in river systems. Smaller whales can also be the victims of by-catch from commercial fisheries using long lines and purse seines.
The importance of whales and why we should care
In the co-evolution of predator and prey, whales can be seen as partly responsible for shaping the behaviour and morphology of their prey. Whales therefore, are very important to ocean ecosystems. Within the ocean ecosystem, whales are responsible for consuming large numbers of krill and fish and as a result, they play an important role in influencing community structures (the marine food chain). Not only do they influence through their predatory behaviour, they also support communities as a food source. For example, when a whale dies, it rapidly sinks to the bottom of the ocean and becomes a huge food source for numerous other marine species.
There is also evidence of commensal relationships with other species (one species benefits and the other is neutral), such as sea birds. When some whales feed, they drive their prey to the surface making it easier for seabirds to catch fish. Studying marine ecosystems and the effects upon it, is a very complex process. It still isn’t exactly known what effect removing whales would have on the wider ocean ecosystem, and this is an area that requires further study. However, we do know that the removal of any apex (top) predator will not be beneficial to the marine environment, as all apex predators play a crucial role in maintaining the health of ecosystems by controlling populations beneath them in the food chain.
The solution: what we can do
A lot of whales die needlessly by getting entangled in fishing lines and netting which could be reduced significantly through the development of whale friendly fishing equipment. One example of this is with lobster fishing; whales can easily become entangled in the floating lines, so experiments and tests are ongoing for alternatives, such as a sinking or weighted rope.
There are several organisations dedicated to defending whales and it is hoped that by working with governments and fishing industries, that it might be possible to reduce shipping speeds within critical whale habitats. Public help given to these organisations will aid them in their conservation efforts. Some organisations campaigning on behalf of whales include; Sea Shepherd, Greenpeace, World Wildlife Fund (WWF) and the Whale and Dolphin Conservation Society (WDCS). We need to gain a better understanding of the roles whales play in the wider marine ecosystem, to assist with their conservation. Furthermore, we need to carry out more research, particularly in relation to noise pollution; in determining the long-term effects.
The International Whaling Commission 1986 moratorium, went a long way in helping whale populations recover, but it is not without its problems and a lot more could be done. The moratorium does not cover all endangered Cetaceans and in particular, several smaller species have been neglected. Furthermore, the ban is not binding and countries are able to object and opt out of its restrictions, for example; Norway and Iceland. The ban also only covers commercial whaling and therefore whales caught for ‘scientific purposes’, are within quotas. Japan has been whaling for these purposes since 1986, but many accuse them of using this as an excuse. Once the whales are caught for scientific purposes and data is collected, the carcass can be used for anything; even sold as meat.
To prevent whaling from continuing, the wider public needs to be made further aware of the issues surrounding the practice, including some the welfare issues. In addition, fishing communities that still kill whales, could be shown new ways of making money without killing them. Financial incentives need to be greater for protecting them, than they are for exploiting them; especially in poorer economic regions. Whale watching has become a great way of doing this, if it is done responsibly. More and more people are enthusiastic about experiencing these animals in the wild and are thereby encouraged to help save them in their natural environment. If more people can be shown that whale watching is economically viable and in turn the industry expands to a responsible and maintainable level, not only will the conservation of these animals become a larger priority, but their use in captivity will become less necessary.