Environmental and Conservation Factors
Estimates suggest that between 1925, when the first whaling ship was introduced, and 1975, more than 1.5 million whales were killed.1 A recent study based on coalescent models for mitochondrial DNA sequence variation suggested that pre-whaling populations may have been underestimated and could in fact be between 6 and 20 times higher than present-day population estimates.2 This implies that whalers killed many more millions of whales.
Clearly, whaling on this scale could not continue without risking the future of the whaling industry. Thus in 1986 a whaling Moratorium began to prevent over exploitation and ensure the sustainability of the whaling industry.
However, populations have been slow to recover, as whales mature and breed slowly. Today, many species of whale are still endangered or vulnerable. Some populations are limited to a few thousand, for example, the Blue Whale (estimated population 6,000-14,000) and the North Atlantic Right (estimated population 3,000-5,000).3 According to the World Conservation Union (IUCN) both the Bowhead Whale (Spitsbergen stock) and the Gray Whale (Northwest Pacific Stock) are critically endangered, meaning they are at an extremely high risk of extinction in the wild.4
Besides the whaling industry, whales face many other threats. These include sea pollution, noise pollution, entanglement in fishing nets, climate change, global over-fishing, collisions with ships and habitat loss. These factors can all impact whale populations.
GLOBAL CLIMATE CHANGE
Changing global climate patterns are having a serious impact on marine food webs. For example, increasing sea surface temperatures are impairing photosynthesis in phytoplankton and the stability of food webs and marine communities.5 As a consequence of global warming, sea levels may rise, which could affect the migration of marine species.
UNSUSTAINABLE FISHING PRACTICES
The United Nations Food and Agriculture Organisation (FAO) estimates that 71-78% of the world’s fish stocks are fully exploited, overexploited or depleted.6 Over-exploitation by humans is the major cause for the collapse of fish stocks.7 There is evidence to suggest that the vast volumes of fish taken from marine ecosystems by industrial fishing methods have a detrimental affect on whales and ecosystem dynamics in general.8
Another more direct impact is incidental capture in fishing equipment, killing unknown numbers of cetaceans.
TOXIC POLLUTION
Toxic chemicals, in particular persistent organic pollutants (POPs) pose a major threat to whales, as they concentrate in fatty tissue such as blubber.
The accumulation of toxic contaminants in the marine food chain may damage the immune system and reproductive ability, further restricting recovery potential.9
OCEAN NOISE
Noise pollution arises from a number of causes; shipping, seismic surveys, oil drilling, marine construction and sonar devices. Noise pollution can interfere with natural behaviour, for instance, by masking vocal communication, or averting whales from feeding or rearing habitats. Of physiological damage, is the use of active sonar deployed by the military. Scientists believe that there is a link between the use of sonar in naval exercises and whale strandings.10 The sonar prompts the whales to shoot to the surface, leading the whales to suffer tissue and organ damage caused by gas bubbles.
SHIP COLLISIONS
Ship collisions can cause injuries and fatalities, some of which may be a significant threat to local endangered populations. The North Atlantic Right whale is close to extinction. The number of these whales who fall victim to ship collisions and entanglement in fishing gear further endangers its vulnerable status.11
The severity of these threats have been recognised and acted upon by the International Whaling Commission (IWC), most recently by the establishment of a Conservation Committee. This Conservation Committee is tasked with collating information and recommending solutions on such issues as by catch and growing environmental threats, such as toxic contamination and the effects of sonar.
The IWC does offer some protection to whales through designating closed areas for whaling. Currently, there are two Ocean Sanctuaries, where whaling is prohibited; the Indian Ocean Sanctuary and the Southern Ocean Sanctuary. Yet Japan continues to routinely hunt in the Southern Ocean Sanctuary, affording the whales in this "protected zone" little sanctuary.12
Taking into account environmental threats and whaling history, conservationists argue that it is wise to adopt a precautionary approach to whaling. The Moratorium should not be overturned whilst so many uncertainties regarding numbers remain.
References
- Greenpeace (2004) www.greenpeace.org/international_en/campaigns/intro?campaign_id=4017
- Joe Roman and Stephen R. Palumbi (2003) Whales Before Whaling in the North Atlantic in SCIENCE Volume 301
- Source: Reuters, WWF, IWC cited in Guardian Education 30/9/03
- IUCN 2003 IUCN Red List of Threatened Species
- Hanley, K (1997) Polar exposure: Environmental threats to Arctic marine life and communities Swiss Coalition for the Protection of Whales and Global Survival Network (eds) Wädenswil/Washington; MacGarvin and Simmonds (1996) Whales and climate change in The Conservation of Whales and Dolphins Simmonds & Hutchinson (eds) John Wiley & Sons Ltd UK 321-353 cited in Running out of Fish…Who is responsible for the Plundering of the Oceans? (2002) Dr Sandra Altherr
- Greenpeace (2003) Greenpeace Briefing: Cetaceans and the Oceans Crisis
- Dr Sandra Altherr ECCEA, Third Millennium Foundation, Pro Wildlife e.V. (2002) Running out of Fish…Who is Responsible for the Plundering of the Ocean?
- Greenpeace (2003) Cetaceans and the Oceans Crisis
- WWF (2003) Whales, Whaling and the International Whaling Commission
- Jepson, P.D. et al (2003) Gas bubble lesions in stranded cetaceans Nature 425 575-576
- P Kareiva (2001) When one whale matters Nature Volume 404 pp 493-494 cited in Greenpeace (2003) Cetaceans and the Oceans Crisis
- Matthew Scully (2002) Riches of the Sea in Dominion St Martin’s Press
