Shout out for the Sea, Part II: Phytoplankton and Fisheries
Shout out for the Sea, Part II: Phytoplankton and Fisheries
Meera Subramanian: Phytoplankton and Fisheries
Last time I wrote, we were out watching whales, the biggest creatures in the ocean. This time, let?s start small, with those phytoplankton that are the foundation of the marine food web, the organisms that make water so blue to our eyes. According to NASA?s Earth Observatory, phytoplankton serve as a ?biological carbon pump? that transfers about 10 gigatonnes of carbon from the atmosphere to the deep ocean each year. They bloom and retreat. They move and wander through the ocean. They provide sustenance for everything from teeny tiny fish to the great whales I saw off Cape Cod.
Warming ocean temperatures can adversely affect the growth of phytoplankton, which in turn may affect atmospheric carbon dioxide concentrations, since there are fewer carbon-suckers floating around out there. This process creates a feedback loop, similar to the one caused by cutting down trees, that then continues to warm waters. A recent report from the International Program on the State of the Ocean states that human activities have already managed to warm and acidify the world?s waters, as well as deplete the oxygen in large portions of them.
These conditions were present in the carbon-cycle disruptions that marked the five past eras of mass extinctions?many believe we are in the sixth?but this is the first time that humans are the root cause. The changes are happening faster and are more severe than initially suspected, and our window of time to act is shrinking. None of this is new information, though, unless one lives in the land of denial.
But humans don?t eat phytoplankton. Predominantly, it?s fish we take from the seas for our dinner plates. And around the globe, our appetite is growing. Within days of my whale-watching adventure, the International Union for Conservation of Nature (IUCN) announced that five out of the eight tuna species are at risk of extinction. Dr. Kent Carpenter, manager of IUCN?s marine biodiversity unit and an author of the study, was quoted in the Guardian:
All three bluefin tuna species are susceptible to collapse under continued excessive fishing pressure. The southern bluefin has already essentially crashed, with little hope of recovery. If no changes are made to current fishing practices, the western Atlantic bluefin stocks are at risk of collapse as they are showing little sign that the population is rebuilding following a significant reduction in the 1970s.
A new article published in the scientific journal Marine Policy is calling for a blanket ban on deep-sea fishing. The paper lambastes an industry that survives off subsidies and operates fisheries that ?more closely resemble mining operations that serially eliminate fishable populations and move on.? The problem with deep-sea fishing is the longevity and slow reproductive rate of the fish that inhabit deep waters. Orange roughy live up to 150 years; Chilean sea bass up to fifty years. And the methods of fishing haul in heaps of non-target species, from sea birds to sea turtles, sharks to corals.
Sometimes small, simple things can transform an industry. The New York Times? Cordelia Dean recently reported on advances being made within the industry to help reduce the collateral damage from fishing. Ideas like experimenting with noisemakers, tinkering with the shape and strength of hooks or the shape of net mesh, and making lines or nets more visible are all at stages of research or implementation. At a seabird conservation conference last year, I met Hans Jusseit, an inventor and retired fisherman, who has come up with the Smart Hook, which has a small shield to protect the baited hook, in hopes of decreasing the number of accidental deaths of birds that trail behind fishing boats searching for an easy meal. And each year, the World Wildlife Fund sponsors the International Smart Gear Competition, seeking out new ways to reduce unintended bycatch.
It is crucial that industry adopt these changes, because the great waters of the world are a difficult place to implement broad, uniform regulations. UN conventions help, along with the international work of other Geneva-based organizations and large-scale NGOs. But some smaller nonprofits organizations are advocating for a?sorry?sea change in attitude, arguing that the traditional approach to saving the oceans simply isn?t working. The World Ocean Observatory, for example, is redefining the world?s oceans as an ?integrated, global, social system? and has decided to toss out all the high overhead of most organizations and leap into new technology to develop classroom and museum curricula that are available free or at a low cost to educators anywhere. Also using the internet, which links us globally as much as the oceans these days, the Census on Marine Life has been bringing together scientists from around the globe for over a decade to inventory marine biodiversity. And there is a flip side to the fishing industry?s ability to go ever deeper in search of species to feed an ever-growing human population: the same technological advances could be used to make fisheries more sustainable, if there is commitment on the part of industry and governments to support change.
In spite of the frequent use of the word ?collapse? when it comes to talking about fish populations, there is evidence that sound management can have an effect, according to a study published in Science a couple of years ago. The authors advocated, as is the current trend on land as well, approaching conservation with entire ecosystems in mind.
Closer to home, there is the power of the consumer. Piscivores can check out the work of places like the Marine Stewardship Council and Friend of the Sea, and keep the Monterey Bay Aquarium Seafood Watch guide (and downloadable apps) handy. And here are Ten Solutions to Save the Oceans from Conservation Magazine.
