Banner
    Like Fishing And The Ocean Ecosystem? Thank Whales
    By News Staff | July 5th 2014 11:30 AM | 3 comments | Print | E-mail | Track Comments

    Whales are relatively rare and so they probably don't make much of a difference in the overall ocean. 

    A team of biologists disagrees. They reviewed several decades of research on whales from around the world and found that whales make a huge difference and have a powerful and positive influence on the function of oceans, global carbon storage, and the health of commercial fisheries. "The decline in great whale numbers, estimated to be at least 66% and perhaps as high as 90%, has likely altered the structure and function of the oceans," claims University of Vermont conservationist Joe Roman and colleagues in Frontiers in Ecology and the Environment, "but recovery is possible and in many cases is already underway."

    "The continued recovery of great whales may help to buffer marine ecosystems from destabilizing stresses," they write. This recovered role may be especially important as climate change threatens ocean ecosystems with rising temperatures and acidification. "

    Baleen and sperm whales, known collectively as the "great whales," include the largest animals to have ever lived on Earth. With huge metabolic demands—and large populations before humans started hunting them—great whales are the ocean's ecosystem engineers: they eat many fish and invertebrates, are themselves prey to other predators like killer whales, and distribute nutrients through the water. Even their carcasses, dropping to the seafloor, provide habitat for many species that only exist on these "whale falls." Commercial whaling dramatically reduced the biomass and abundance of great whales.


     


    Huge blue whales plunge to 500 feet or deeper and feed on tiny krill. Then they return to the surface—and poop. This 'whale pump' provides many nutrients, in the form of feces, to support plankton growth. It's one of many examples of how whales maintain the health of oceans described in a new scientific paper by the University of Vermont's Joe Roman and nine other whale biologists from around the globe. Credit: Frontiers in Ecology and the Environment

    As long-lived species, they enhance the predictability and stability of marine ecosystems," Roman said. "As humpbacks, gray whales, sperm whales and other cetaceans recover from centuries of overhunting, we are beginning to see that they also play an important role in the ocean," Roman said. "Among their many ecological roles, whales recycle nutrients and enhance primary productivity in areas where they feed."

    They do this by feeding at depth and releasing fecal plumes near the surface—which supports plankton growth—a remarkable process described as a "whale pump." Whales also move nutrients thousands of miles from productive feeding areas at high latitudes to calving areas at lower latitudes.

    Sometimes, commercial fishermen have seen whales as competition. But this new paper summarizes a strong body of evidence that indicates the opposite can be true: whale recovery "could lead to higher rates of productivity in locations where whales aggregate to feed and give birth," supporting more robust fisheries.

    As whales recover, there may be increased whale predation on aquaculture stocks and increased competition—real or perceived—with some commercial fisheries. But the new paper notes " a recent investigation of four coastal ecosystems has demonstrated the potential for large increases in whale abundance without major changes to existing food-web structures or substantial impacts on fishery production."

    In death, whale carcasses store a remarkable amount of carbon in the deep sea and provide habitat and food for an amazing assortment of creatures that only live on these carcasses. "Dozens, possibly hundreds, of species depend on these whale falls in the deep sea," Roman notes.

    "Our models show that the earliest human-caused extinctions in the sea may have been whale fall invertebrates, species that evolved and adapted to whale falls," Roman said, "These species would have disappeared before we had a chance to discover them."

    Until recently, ocean scientists have lacked the ability to study and observe directly the functional roles of whales in marine ecosystems. Now with radio tagging and other technologies they can better understand these roles. "The focus of much marine ecological research has been on smaller organisms, such as algae and planktonic animals. These small organisms are essential to life in the sea, but they are not the whole story," Roman said.

    New observations of whales will provide a more accurate understanding of historical population dynamics and "are likely to provide evidence of undervalued whale ecosystem services," note the ten scientists who co-authored this new paper, "this area of research will improve estimates of the benefits—some of which, no doubt, remain to be discovered—of an ocean repopulated by the great whales."



    Comments

    As whale poop declined, human poop substituted admirably. Seven billion humans provide sewage effluent, nitrogen and phosphate crop fertilizer runoff, plus plastic waste. Every bit of human waste goes into the sea and promotes the life of microorganisms in the food chain.

    A recent study of plastic in the pacific gyro had a surprising result. Only one tenth of the plastic expected was found. The rest was degraded by sunlight and abrasion down to the smallest molecules that become food for the ecosystem.

    It is true that humans have over fished some species and some locales. Notably California salmon, Chile anchovies, North Atlantic cod, the Grand Banks, some oyster beds, whales, bluefin tuna, etc. Corrective steps have been taken.

    Meanwhile some top level ocean predators have become so successful that they are pests. Seals, walrus, great white shark populations are expanding on the ocean food supply fed mainly by human waste.

    Gross misstatement of the facts. Yes, the plastic degrades, but remains a polymer down to the molecular level, enters the food chain, and kills. Your dismissal of this catastrophe would be laughable, were it not so nefarious. Who pays you?

    We can't afford to ignore this kind of stupid any longer.

    Thank you. You are correct ignoring and not calling out ignorant statements must stop. I noticed the OP ignored/failed to mention the MOST successful ocean predator/pest...humans. I loved the line about the plastic polymers becoming food! HAH.

    Semper Fidelis