A Whale of an Effect on Ocean Life: The Ecological and Economic Value of Cetaceans

What if an animal could entertain and educate millions of people annually, enhance productivity (thereby increasing the number of fish in the sea), mitigate climate change, feed billions of marine animals, generate billions of dollars in revenue globally, and even help get tough stains out of your clothes? Does such an animal exist?

Whales—animals that humans nearly exterminated—can do all that and more. The unsubstantiated claims that whales compete with humans for fish or that they must be killed to ensure global food security are nonsense. Instead, a growing body of scientific evidence demonstrates that saving whales could help save the planet and, in turn, humankind.

Photo by Daniel Benhaim
Photo by Daniel Benhaim

Approaching Extinction
The era of large scale commercial whaling lasted nearly 400 years, from the early 17th century to 1986. During that period, whalers mercilessly pursued their prey, exploiting and depleting one species after the next. While the exact death toll amassed over these four centuries is not known, scientists have estimated that during the 20th century alone, over 3 million whales were killed, mainly for their valuable oil.

By the time a global moratorium on commercial whaling, approved by the International Whaling Commission (IWC), went into effect in 1986, scientists estimated that whale numbers had plummeted from 66 to 90 percent of their pre-whaling abundance, with some populations, like blue whales in the Southern Hemisphere, declining by 99 percent. While the moratorium remains intact today—saving countless whales—commercial and “scientific” whaling continue, with Iceland, Norway, and Japan killing more than 43,000 whales since 1986.

A previously ignored consequence of the slaughter was that it prevented whales from fulfilling their evolutionary role in the ecosystem. In every ecosystem, every native species has a role in the ecology of their habitat, from the smallest microorganisms to the most dominant predator. In a properly functioning ecosystem, they collaborate in a symbiotic dance that maximizes productivity and abundance within nature’s parameters.

Enhancing Productivity
Far from just providing huge amounts of meat, blubber, and oil for human consumption, whales provide important ecosystem services that have gone overlooked in debates about commercial whaling and whale conservation.

Whale fecal plumes contain valuable nutrients like iron, nitrogen, and phosphorus. They stimulate production of microscopic marine algae, or phytoplankton, which form the base of many marine food chains. Phytoplankton, via photosynthesis, convert chlorophyll, sunlight, and a variety of nutrients including carbon dioxide into energy, while expelling oxygen. Phytoplankton feed zooplankton, tiny animals that live in surface waters, and both are critical food sources for many marine species such as krill and other marine invertebrates, fish, and even marine mammals, including whales.

In a study of blue whales in Antarctica, scientists determined that iron concentration in blue whale feces is 10 million times that of Antarctic seawater. As iron is a limiting micronutrient in the Southern Ocean, its availability triggers phytoplankton blooms. Another study determined that blue whales in the Southern Ocean, via fecal plumes, increase primary production available to support fisheries by 240,000 (metric) tonnes of organic carbon (which all animals in the oceans need to survive) per year. If blue whales recover to pre-industrial whaling levels, this benefit will increase to 11 million tonnes of carbon per year—increasing, not decreasing, fishery yields. While this is only a small fraction of the overall primary production in the Southern Ocean, at the local scale where such fertilization benefits are realized, the impacts may be significant.

Indeed, scientists have determined that the slaughter of baleen whales in the Southern Ocean caused a long-term decline in primary production, which, in turn, caused the krill population to plummet to as low as 20 percent of pre-industrial whaling levels. Today, although whale stocks in the Southern Ocean are recovering—some more quickly than others—krill numbers have not recovered to pre-industrial whaling levels and are now threatened by direct harvest and climate change.

In the Gulf of Maine, scientists found that marine mammals enhance primary production in feeding areas by supplying nitrogen to surface waters through release of fecal plumes and urine. They determined that whales and seals may replenish 23,000 tonnes of nitrogen per year in the Gulf of Maine surface waters, more than the input of nitrogen from all of the rivers feeding the gulf combined.

In another study, endangered right whales in the Bay of Fundy in Canada were found to enhance primary productivity through the release of nitrogen and phosphorus in their fecal plumes. In Hawaii, the feeding behavior of 80 sperm whales transferred 100 tonnes of nitrogen from deep waters to surface waters, enhancing primary production by 600 tonnes of organic carbon per year. Due to the decimation of sperm whales by commercial whaling, however, Hawaiian waters have lost 2,000 tonnes of new nitrogen each year, decreasing primary production in the region by 1,000 tonnes of organic carbon annually.

The deep diving and surfacing behavior of sperm whales and some baleen whales transports nutrients in their fecal plumes from deeper water to the surface and, for gray and humpback whales, by carrying sediment from the sea floor and redistributing it in the water column, to the benefit of sea birds and other marine species. As noted by Drs. Joe Roman and James McCarthy, “Cetaceans feeding deep in the water column effectively create an upward pump, enhancing nutrient availability for primary production in locations where whales gather to feed.” This vertical transport of nutrients is referred to as the “whale pump” and was first postulated in 1983. Scientists have determined that biomixing by marine vertebrates, including whales, contributes one-third of total ocean mixing, comparable to the effect of tides or winds.

Whales also transport nutrients in their fecal plumes, urine, sloughed skin, and placental materials horizontally, a phenomenon referred to as the “whale conveyor belt,” as they migrate between nutrient-rich feeding areas and nutrient-limited breeding/birthing areas. Blue whales in the Southern Ocean, for example, transport approximately 88 tonnes of nitrogen per year from their feeding to their calving grounds. Before commercial whaling, blue whales would have transported 24,000 tonnes of nitrogen via the conveyor belt.

Sequestering Carbon
Phytoplankton use carbon dioxide during photosynthesis. Thus, enhancing phytoplankton productivity via the release of nutrients in whale feces increases the removal of carbon dioxide from the atmosphere. In the Southern Ocean, approximately 12,000 sperm whales deposit an estimated 36 tonnes of iron into surface waters each year, enhancing primary production in phytoplankton. While the carbon contained in some phytoplankton will continue to be recycled by marine animals feeding and defecating in surface waters, 20 to 40 percent of such carbon will settle to the sea floor as phytoplankton die and sink, effectively locking up the carbon for centuries to millennia. Globally, more than 200,000 tonnes of carbon may be sequestered—and its negative effects on climate removed—each year.

Sperm whales, by enhancing primary productivity, effectively remove 240,000 tonnes more carbon from the atmosphere than they add during respiration. Since sperm whale population numbers in the Southern Ocean have not recovered to pre-industrial whaling levels, an extra 2 million tonnes of carbon that could have been removed by a full complement of sperm whales remains in the atmosphere each year. Since Southern Ocean sperm whales represent only 3 percent of all sperm whales globally, the species may significantly contribute to iron fertilization and carbon drawdown.

When whales die, their massive bodies contain a large amount of carbon. As their carcasses sink to the ocean floor—often referred to as “whale fall,” this carbon is effectively stored in the ocean for centuries. Scientists have estimated that the combined global populations of nine great whale species (blue, fin, gray, humpback, bowhead, sei, Bryde’s, minke, and right whales) sequester nearly 29,000 tonnes of carbon per year via whale falls. Due to the significant loss of whales to commercial whaling, current populations of large baleen whales store 9.1 million tonnes less carbon than if their numbers were at pre-exploitation levels. If these whale stocks were rebuilt, they would remove 160,000 tonnes of carbon each year through whale falls, which is roughly equivalent to 110,000 hectares of forest (or an area the size of Rocky Mountain National Park).

Nourishing the Depths
In addition to storing carbon, whale carcasses feed an array of marine and terrestrial species. When whales strand on land, bears, other mammals, scavenging birds, and marine and terrestrial invertebrates benefit from the massive windfall of food and nutrients and, in turn, expand the nutrient flow from the sea to land.

Whale falls, according to the scientific literature, create habitat islands, benefiting scavengers like sharks and hagfish, crustaceans, gastropods, bivalves, clams, shrimp, anemones, bacteria, and a litany of other marine organisms, including some species heretofore unknown. Indeed, scientists have identified 129 new species collected from whale remains, including over 100 considered to be whale-fall specialists, and predict that hundreds of other whale-fall specialist species remain to be discovered.

The frequency of whale falls declined substantially due to industrial whaling and may have caused a substantial number of anthropogenic species extinctions in the deep sea. Whether such species would have had any value to humans will never be known—although, in an interesting twist, enzymes of psychrotrophic bacteria (bacteria adapted to extremely cold environments) found at whale falls have garnered commercial interest from the laundry detergent, pharmaceutical, and food processing industries. One biotechnology company has determined that clones of bacteria found on whale carcasses may be effective in removing stains from laundry during cold-water washing, potentially providing significant energy savings, increased profits, and cleaner clothes.

Creating Value
Whales have an enormous economic value as the popular subject of marine tourism. Globally, whale watching generated over 2 billion dollars in revenue in 2012 and supported some 13,000 jobs while providing millions of people an opportunity to observe and learn about whales and other marine species in the wild. Such revenue is well in excess of the value of whale meat, blubber, or other products sold commercially, demonstrating the obvious fact that a live whale is worth far more than a dead one.

The ecosystem services provided by whales, including increasing primary production, directly and indirectly sequestering carbon, and providing nutrients and habitat to myriad marine species, also have an economic value. Such values have been calculated for other species, including bats and pollinators. While economists have calculated the value of whale watching, no comprehensive assessment has been done of the direct and indirect value of whales and the economic and ecosystem services they provide.

Going Forward
The direct and indirect value of whales warrants attention. At its 2016 meeting, the IWC adopted a resolution that recognizes the contributions of cetaceans to ecosystem functioning and encourages IWC member governments to factor these contributions into decision-making. It further envisions a central role for the IWC Scientific Committee in (1) reviewing the ecological, economic, and other contributions of cetaceans to ecosystem functioning, (2) identifying gaps, and (3) creating a plan for future research needs. It also promotes collaboration with other multilateral environmental agreements to study the issue.

The subject has since been discussed at a conference about whales in Tonga. It was also the subject of an AWI-cohosted workshop in late July, at the Society for Conservation Biology’s International Congress for Conservation Biology in Cartegena, Colombia, that considered how to integrate this emerging issue into global environmental policy—for the good of the whales and the health of the planet. For example, although saving whales will not fully mitigate the impacts of climate change, it should be part of a comprehensive, global strategy to reduce greenhouse gas emissions.

Whales may not swim with capes but, based on the evidence of their immense ecological and economic value, perhaps they should be considered superheroes saving the planet. They should no longer be considered as a source of consumables. Instead, they should be fully protected from commercial and “scientific” whaling, bycatch in fishing gear, and other threats to their survival, so that they can fulfill their role in helping to sustain the planet and humankind.

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