Get Caught Up
Part 4: Whales and Dolphins: Threats and future
The great whales were most threatened during the period of commercial whaling, which ended for some species only as recently as 1986, but these animals and their smaller cetacean relatives, the dolphins and porpoises, are subject to a number of other environmental and anthropogenic threats. These include: deliberate hunting and capture, indirect catches and mortality caused by interactions with fishing and other vessels, chemical pollution, and climate change.
History of Whale Stocks and Whaling
Little is known about the state of whale populations prior to the whaling activities of the previous 500 years. The present depleted state of great whale populations is due largely to the era of commercial whaling, which dates back to the 16th century. The history of whaling reaches back several millennia and while the earliest practices remain relatively unknown, it was certainly not until the hunts took to the high seas and increased throughput and capacity to feed a burgeoning industry that populations began to suffer. Whaling was primarily driven by a demand for oil (derived from the blubber, or fat layer on these animals) which lit the street lamps of London and many other cities prior to the adoption of gas lighting. For an inefficient and dangerous practice that included pursuing whales in small, wooden, oar-powered boats and spearing them with hand-thrown harpoons, these early centuries of whale hunting made a remarkable dent in some populations, taking hundreds of thousands of individuals.
Expansion of commercial whaling beyond the North Atlantic, beginning in the 1700’s, included on-board carcass and oil processing, and improved, mechanical harpoons as well as bomb-lances, which explode once inside the body of the whale. The primary species targeted during these centuries were the sperm, bowhead, humpback, grey and right whales. In 1870, Sven Foyn invented the exploding harpoon which led to modern industrialised commercial whaling and a rapid expansion of whaling operations across the North Atlantic, the Pacific and in the Southern Ocean around the Antarctic. In the 1930’s, Japanese whaling industry researchers traveled to Norway to adopt the new technology that became highly efficient and extremely destructive of whale populations. The establishment of a wide network of onshore whaling stations in remote outposts, particularly in the southern latitudes, extended the commercial hunting to include blue, fin, minke, Bryde’s, and sei whales (Reeves and Smith 2003). Development of factory ships, which obviated the need for shore operations, allowed access to the Antarctic and cast the die for many species: it is estimated that more than a million whales were taken by the pelagic factory ships over the course of the twentieth century. In 1946, the dire situation of the world’s whale populations was of enough concern to warrant the formation of the International Whaling Commission (IWC) in an attempt to manage the world’s whale populations. An increasing number of species-specific restrictions on hunting were enacted during the twentieth century, generally too late to prevent depletion or commercial extinction of some species and populations
By 1982, the International Whaling Commission, buoyed by international public opinion and faced with the downward spiral of most species, placed a moratorium on the commercial hunting of whales which came into effect in 1986. The IWC regulations maintain provisions for aboriginal subsistence hunting as well as research activities. Almost all commercial whaling nations ceased their activities – the former Soviet Union mothballed its pelagic whaling fleets while Spain, Brazil, Peru, Chile, and South Korea ceased their commercial whale hunts. Only Japan, Norway and Iceland persisted in their hunts, with Iceland quitting catches in 1988 and some recent smaller whale hunts that have now ceased. Only Japan and Norway, two of the wealthiest nations in the world persist with commercial whale killing. Whaling today remains surprisingly crude, with whales often suffering long periods between harpoon strike and death, which is frequently by asphyxiation, as the whale cannot lift its head from the water to breathe.
There is still uncertainty about the current status of many cetacean populations in the post-whaling period, but some populations remain undoubtedly depressed. The most notable include the blue whale, northern right whale and bowhead whale whose populations and ranges have been impacted. With the recent extinction of the Yangtze River dolphin (last confirmed sighting in 2004) the threats to imperiled river dolphins have also been highlighted.
The deliberate catching or hunting of small cetaceans (all species except the great whales), which are not covered under the IWC’s ban on commercial killing of great whales, has an unknown impact on cetacean populations. Dolphins are regularly caught in order to put them on display in dolphinariums and other marine parks world-wide, often without pre-removal population assessments. In addition, several coastal communities, notably in the Faroe Islands and Japan and continue to hunt pilot whales, dolphins and porpoises species for subsistence or commercial trade purposes.
Fisheries and Boats
Fisheries, and the boats that constitute them, pose a grave threat to cetaceans on many levels. Gill nets, which are hung like curtains vertically in the ocean and can be miles in length, are intended for other species, but catch dolphins which get tangled in them and cannot surface for air. Long lines, laced with hooks and bait and strung out over many miles, and trawl nets, which sweep the sea floor and midwater reaches, also catch dolphins. Thought of as a nuisance, dead and dying dolphins are usually tossed over the side of the fishing vessel when the nets are brought in. Discarded and derelict fishing gear can also cause entanglement and drowning of cetaceans. There is ongoing experimentation with various technologies, including noise-making repellent devices and escape hatches, but these are far from foolproof and not universally employed. Strikes from boats and their propellers are a problem for all marine mammals, particularly calves, which need to surface more often than their mothers. Recent strike incidents on both coasts of the United States have resulted in mandatory speed limits for vessels in known whale pathways.
The sheer volume of fish and invertebrate biomass that the global fishing fleet extracts, both in target and non-target species, reduces the amount of prey available for odontocetes. Expansion of the krill fishery in the Antarctic, primarily to supply food for fish farms, threatens the prey base of the southern oceans’ baleen whales, including the vulnerable (IUCN Red List) humpback, the endangered (IUCN Red List) population of the blue whale, the fin, minke, sei, and southern right whales. Krill may be particularly vulnerable to climate-change induced changes in sea ice cover and changes in the algae community upon which they depend.
Finally, our knowledge of how increased boat noise and sonar activities (particularly for military explorations and tests) affect populations and individuals is incomplete, but it is known they cause significant disruption and impacts on both large and small cetaceans.
Marine Pollution
Pollutants enter the world’s oceans from direct discharge into terrestrial waterways or the oceans, atmospheric deposition, and accidental spills. Materials range from industrial and agricultural chemicals to sewage, refuse and petroleum products. The bioaccumulation of chemicals in cetaceans is a result of their position near the top of the marine food chain: they consume large volumes of animals which have in turn consumed other animals or plant materials that have taken up the contaminants. Persistent organic pollutants, which include many pesticides (DDT, for example) and chemicals with industrial applications (polychlorinated biphenyls-PCBs), are known to bioaccumulate in cetaceans, especially in fatty tissues. Mercury, a product of fossil fuel combustion, is also known to accumulate in cetaceans, particularly odontocetes, resulting in concentrations that are much higher than environmental levels. Mercury may increase liver abnormalities and suppress immune response in cetaceans; in humans, PCBs are known to cause neurological damages and disrupt the immune and endocrine systems, and are associated with reproductive failure. These pollutants are also passed through milk from mother to calf, which means that young cetaceans may be starting life with high pollutant loads, even if environmental levels fall.
A further danger results from human consumption of cetaceans containing significant pollutant burdens. Although the Government of Japan limits the amount of mercury that can be consumed by humans at 0.4 parts per million, the Environmental Investigation Agency has found dozens of products sold in Japan that range from several times that level up to 12 times higher. As the market demand for whale meat in Japan has fallen off, whale and dolphin meat is being provided to children for school lunches. Recently councilors in the town of Taiji, in southern Japan, publicly opposed feeding the polluted cetacean products to children as an unnecessary risk to their health.
The vast amount of human-produced garbage currently floating in the world’s oceans presents a threat to cetaceans: they may ingest it, or become tangled in it. Plastic items are often found in the stomachs of stranded or by-caught cetaceans that are autopsied. Petroleum spills may affect cetaceans by contaminating their prey and the air they breathe, or fouling their baleen.
Changes in the global climate, “very likely” induced primarily by the burning of fossil fuels (IPCC 2007), are expected to alter the extent, location and duration of sea ice, water chemistry, and even the global-scale circulation of the oceans (known as thermohaline circulation, it is the result of differences in salt concentrations and temperature across the latitudes). A former Australian commissioner to the IWC has said that “climate change is as dangerous as an exploding harpoon to the whales.” Cetaceans are expected to see changes in the availability of their prey sources and increased human activity which brings with it increases in pollution and ship traffic. Species which spend their entire lives in the polar regions, such as bowhead, belugas and narwhals may be especially at risk.
Freshwater cetaceans face a special set of challenges. Upstream abstraction of water as well as channelization, damming, and dredging of waterways changes the environmental conditions of rivers, with as-yet unknown consequences for populations. In addition, they contend with agricultural runoff, removal of their prey and increased boat traffic. The Yangtze River dolphin, or baiji was concluded to be extinct following extensive surveying in 2006. The Indus and Ganges River dolphins are listed as endangered (IUCN Red List).
The interactive effects of depressed populations, chemical pollution, boat and fishing gear endangerments and potential changes in the global climate combine to create intensifying threats and substantial degradation of the environment and habitats which whales and their relatives rely on for their survival. The precautionary principle, enshrined in the Rio Declaration on Environment and Development (1992) dictates erring on the side of caution when there are scientific unknowns. Given the uncertainties of the population status of many species as well as the cumulative environmental impacts listed above, a very conservative approach to the management of these creatures, including care of their environment and the regulation of hunting is warranted.
The future of some of the largest, and oldest, mammals on this planet hangs in the balance.
You can help!
If you live in any of the OECS states, please visit the website of Caribbean Whale Friends at www.caribbeanwhalefriends.org and learn about your government’s policies regarding whales. On the website there is also the opportunity to write to your government with your opinion.
Go whale watching! If you live near somewhere that offers whale watching, take a trip out to see these magnificent creatures in action. Check the website of Caribwhale, the association of Caribbean whale watching outfits or click here to find operators on your island!
History of Whale Stocks and Whaling
Little is known about the state of whale populations prior to the whaling activities of the previous 500 years. The present depleted state of great whale populations is due largely to the era of commercial whaling, which dates back to the 16th century. The history of whaling reaches back several millennia and while the earliest practices remain relatively unknown, it was certainly not until the hunts took to the high seas and increased throughput and capacity to feed a burgeoning industry that populations began to suffer. Whaling was primarily driven by a demand for oil (derived from the blubber, or fat layer on these animals) which lit the street lamps of London and many other cities prior to the adoption of gas lighting. For an inefficient and dangerous practice that included pursuing whales in small, wooden, oar-powered boats and spearing them with hand-thrown harpoons, these early centuries of whale hunting made a remarkable dent in some populations, taking hundreds of thousands of individuals.
Expansion of commercial whaling beyond the North Atlantic, beginning in the 1700’s, included on-board carcass and oil processing, and improved, mechanical harpoons as well as bomb-lances, which explode once inside the body of the whale. The primary species targeted during these centuries were the sperm, bowhead, humpback, grey and right whales. In 1870, Sven Foyn invented the exploding harpoon which led to modern industrialised commercial whaling and a rapid expansion of whaling operations across the North Atlantic, the Pacific and in the Southern Ocean around the Antarctic. In the 1930’s, Japanese whaling industry researchers traveled to Norway to adopt the new technology that became highly efficient and extremely destructive of whale populations. The establishment of a wide network of onshore whaling stations in remote outposts, particularly in the southern latitudes, extended the commercial hunting to include blue, fin, minke, Bryde’s, and sei whales (Reeves and Smith 2003). Development of factory ships, which obviated the need for shore operations, allowed access to the Antarctic and cast the die for many species: it is estimated that more than a million whales were taken by the pelagic factory ships over the course of the twentieth century. In 1946, the dire situation of the world’s whale populations was of enough concern to warrant the formation of the International Whaling Commission (IWC) in an attempt to manage the world’s whale populations. An increasing number of species-specific restrictions on hunting were enacted during the twentieth century, generally too late to prevent depletion or commercial extinction of some species and populations
By 1982, the International Whaling Commission, buoyed by international public opinion and faced with the downward spiral of most species, placed a moratorium on the commercial hunting of whales which came into effect in 1986. The IWC regulations maintain provisions for aboriginal subsistence hunting as well as research activities. Almost all commercial whaling nations ceased their activities – the former Soviet Union mothballed its pelagic whaling fleets while Spain, Brazil, Peru, Chile, and South Korea ceased their commercial whale hunts. Only Japan, Norway and Iceland persisted in their hunts, with Iceland quitting catches in 1988 and some recent smaller whale hunts that have now ceased. Only Japan and Norway, two of the wealthiest nations in the world persist with commercial whale killing. Whaling today remains surprisingly crude, with whales often suffering long periods between harpoon strike and death, which is frequently by asphyxiation, as the whale cannot lift its head from the water to breathe.
There is still uncertainty about the current status of many cetacean populations in the post-whaling period, but some populations remain undoubtedly depressed. The most notable include the blue whale, northern right whale and bowhead whale whose populations and ranges have been impacted. With the recent extinction of the Yangtze River dolphin (last confirmed sighting in 2004) the threats to imperiled river dolphins have also been highlighted.
The deliberate catching or hunting of small cetaceans (all species except the great whales), which are not covered under the IWC’s ban on commercial killing of great whales, has an unknown impact on cetacean populations. Dolphins are regularly caught in order to put them on display in dolphinariums and other marine parks world-wide, often without pre-removal population assessments. In addition, several coastal communities, notably in the Faroe Islands and Japan and continue to hunt pilot whales, dolphins and porpoises species for subsistence or commercial trade purposes.
Fisheries and Boats
Fisheries, and the boats that constitute them, pose a grave threat to cetaceans on many levels. Gill nets, which are hung like curtains vertically in the ocean and can be miles in length, are intended for other species, but catch dolphins which get tangled in them and cannot surface for air. Long lines, laced with hooks and bait and strung out over many miles, and trawl nets, which sweep the sea floor and midwater reaches, also catch dolphins. Thought of as a nuisance, dead and dying dolphins are usually tossed over the side of the fishing vessel when the nets are brought in. Discarded and derelict fishing gear can also cause entanglement and drowning of cetaceans. There is ongoing experimentation with various technologies, including noise-making repellent devices and escape hatches, but these are far from foolproof and not universally employed. Strikes from boats and their propellers are a problem for all marine mammals, particularly calves, which need to surface more often than their mothers. Recent strike incidents on both coasts of the United States have resulted in mandatory speed limits for vessels in known whale pathways.
The sheer volume of fish and invertebrate biomass that the global fishing fleet extracts, both in target and non-target species, reduces the amount of prey available for odontocetes. Expansion of the krill fishery in the Antarctic, primarily to supply food for fish farms, threatens the prey base of the southern oceans’ baleen whales, including the vulnerable (IUCN Red List) humpback, the endangered (IUCN Red List) population of the blue whale, the fin, minke, sei, and southern right whales. Krill may be particularly vulnerable to climate-change induced changes in sea ice cover and changes in the algae community upon which they depend.
Finally, our knowledge of how increased boat noise and sonar activities (particularly for military explorations and tests) affect populations and individuals is incomplete, but it is known they cause significant disruption and impacts on both large and small cetaceans.
Marine Pollution
Pollutants enter the world’s oceans from direct discharge into terrestrial waterways or the oceans, atmospheric deposition, and accidental spills. Materials range from industrial and agricultural chemicals to sewage, refuse and petroleum products. The bioaccumulation of chemicals in cetaceans is a result of their position near the top of the marine food chain: they consume large volumes of animals which have in turn consumed other animals or plant materials that have taken up the contaminants. Persistent organic pollutants, which include many pesticides (DDT, for example) and chemicals with industrial applications (polychlorinated biphenyls-PCBs), are known to bioaccumulate in cetaceans, especially in fatty tissues. Mercury, a product of fossil fuel combustion, is also known to accumulate in cetaceans, particularly odontocetes, resulting in concentrations that are much higher than environmental levels. Mercury may increase liver abnormalities and suppress immune response in cetaceans; in humans, PCBs are known to cause neurological damages and disrupt the immune and endocrine systems, and are associated with reproductive failure. These pollutants are also passed through milk from mother to calf, which means that young cetaceans may be starting life with high pollutant loads, even if environmental levels fall.
A further danger results from human consumption of cetaceans containing significant pollutant burdens. Although the Government of Japan limits the amount of mercury that can be consumed by humans at 0.4 parts per million, the Environmental Investigation Agency has found dozens of products sold in Japan that range from several times that level up to 12 times higher. As the market demand for whale meat in Japan has fallen off, whale and dolphin meat is being provided to children for school lunches. Recently councilors in the town of Taiji, in southern Japan, publicly opposed feeding the polluted cetacean products to children as an unnecessary risk to their health.
The vast amount of human-produced garbage currently floating in the world’s oceans presents a threat to cetaceans: they may ingest it, or become tangled in it. Plastic items are often found in the stomachs of stranded or by-caught cetaceans that are autopsied. Petroleum spills may affect cetaceans by contaminating their prey and the air they breathe, or fouling their baleen.
Changes in the global climate, “very likely” induced primarily by the burning of fossil fuels (IPCC 2007), are expected to alter the extent, location and duration of sea ice, water chemistry, and even the global-scale circulation of the oceans (known as thermohaline circulation, it is the result of differences in salt concentrations and temperature across the latitudes). A former Australian commissioner to the IWC has said that “climate change is as dangerous as an exploding harpoon to the whales.” Cetaceans are expected to see changes in the availability of their prey sources and increased human activity which brings with it increases in pollution and ship traffic. Species which spend their entire lives in the polar regions, such as bowhead, belugas and narwhals may be especially at risk.
Freshwater cetaceans face a special set of challenges. Upstream abstraction of water as well as channelization, damming, and dredging of waterways changes the environmental conditions of rivers, with as-yet unknown consequences for populations. In addition, they contend with agricultural runoff, removal of their prey and increased boat traffic. The Yangtze River dolphin, or baiji was concluded to be extinct following extensive surveying in 2006. The Indus and Ganges River dolphins are listed as endangered (IUCN Red List).
The interactive effects of depressed populations, chemical pollution, boat and fishing gear endangerments and potential changes in the global climate combine to create intensifying threats and substantial degradation of the environment and habitats which whales and their relatives rely on for their survival. The precautionary principle, enshrined in the Rio Declaration on Environment and Development (1992) dictates erring on the side of caution when there are scientific unknowns. Given the uncertainties of the population status of many species as well as the cumulative environmental impacts listed above, a very conservative approach to the management of these creatures, including care of their environment and the regulation of hunting is warranted.
The future of some of the largest, and oldest, mammals on this planet hangs in the balance.
You can help!
If you live in any of the OECS states, please visit the website of Caribbean Whale Friends at www.caribbeanwhalefriends.org and learn about your government’s policies regarding whales. On the website there is also the opportunity to write to your government with your opinion.
Go whale watching! If you live near somewhere that offers whale watching, take a trip out to see these magnificent creatures in action. Check the website of Caribwhale, the association of Caribbean whale watching outfits or click here to find operators on your island!
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