All stocks of wild seafood species to collapse by 2048 says new study

All stocks of wild seafood species to collapse by 2048 says new study

mongabay.com

November 2, 2006

All stocks of currently fished wild seafood species are projected to collapse by 2048 according to a study published in the November 3 issue of the journal Science. The four-year analysis by an international group of ecologists and economists shows the marine biodiversity loss is reducing its resilience due to overfishing, pollution, and other stresses like climate change.

“Species have been disappearing from ocean ecosystems and this trend has recently been accelerating,” said lead author Boris Worm, an assistant professor of marine conservation biology at Dalhousie University, Halifax, Canada. “Now we begin to see some of the consequences. For example, if the long-term trend continues, all fish and seafood species are projected to collapse within my lifetime — by 2048.”

“Whether we looked at tide pools or studies over the entire world’s ocean, we saw the same picture emerging. In losing species we lose the productivity and stability of entire ecosystems. I was shocked and disturbed by how consistent these trends are – beyond anything we suspected,” added Worm.

Photo by B. Mathy.

The study, which analyzed dozens of controlled experiments and observational studies along with U.N. catch data and a variety of other records, found an “accelerating decline in coastal species over the last 1000 years, resulting in the loss of biological filter capacity, nursery habitats, and healthy fisheries,” said co-author Heike Lotze of Dalhousie University.

“Unless we fundamentally change the way we manage all the oceans species together, as working ecosystems, then this century is the last century of wild seafood,” says co-author Steve Palumbi of Stanford University.

An American Association for the Advancement of Science news release describing the research appears below.

American Association for the Advancement of Science: By 2048 all current fish, seafood species projected to collapse

Marine species loss is accelerating and threatening human well-being, according to a report published in the 3 November issue of the journal Science published by AAAS, the nonprofit science society.

“Species have been disappearing from ocean ecosystems and this trend has recently been accelerating,” said lead author Boris Worm. “Now we begin to see some of the consequences. For example, if the long-term trend continues, all fish and seafood species are projected to collapse within my lifetime — by 2048.” Worm is an assistant professor of marine conservation biology at Dalhousie University, Halifax, Canada.

Table courtesy of the Marine Resources Service, Fishery Resources Division, FAO Fisheries Department.

In the paper “Impact of Biodiversity Loss on Ocean Ecosystem Services,” an international team of ecologists and economists studied the role marine biodiversity plays in maintaining ecosystem services, which are those goods and functions that are essential for the growing human population.

“Worm and colleagues have provided the first comprehensive assessment of thestate of ecosystem services provided by the biodiversity of the world’s oceans to humanity,” said Science International Managing Editor Andrew Sugden. “The news is both bad and good.

“The strength of this paper lies in the breadth of the array of information the authors used for their analysis; they not only used new experimental data and recent data, they also delved into historical archives to assess the impact of humans on marine ecosystem overdecades and centuries,” Sugden said.

“At this point,” Worm said, “29 percent of fish and seafood species have collapsed — that is their catch has declined by 90 percent. It is a very clear trend, and it is accelerating. We don’t have to use models to understand this trend; it is based on all the available data.”

Researchers also determined that the problem is much greater than losing a key source of food. Damage to the oceans impact not only fisheries, but the ocean ecosystem’s overall productivity and stability. Specific services that have declined involve the maintenance of water quality by biological filtering, the provision of nursery habitats and the protection of shorelines by marine species. The loss of marine diversity also appeared to increase the risks of beach closures, harmful algal blooms (red tide, for example), oxygen depletion, fish kills and coastal flooding.

“The good news is that it is not too late to turn things around,” Worm said. The scientists studied 48 areas worldwide that have been protected to improve marine biodiversity. “We see that diversity of species recovered dramatically, and with it the ecosystem’s productivity and stability.”

Researchers studied a variety of information in four meta-analyses, progressing from local to regional and global scales.

Chart showing decline of Atlantic cod catch off the coast of Newfoundland
Graph based on data from the Marine Resources Service, Fishery Resources Division, FAO Fisheries Department.

First, they analyzed 32 marine experiments that manipulated species diversity on small, local scales, and monitored the effects. Second, researchers tracked the 1,000-year-long history of change in species diversity and associated services across 12 coastal regions around the world. These included Chesapeake, Delaware, Massachusetts, Galveston, San Francisco Bay and Pamlico Sound (all U.S.), The Bay of Fundy and Gulf of St. Lawrence (Canada), The Adriatic, Baltic and North Seas (Europe), as well as Moreton Bay (Australia). Sources included archives, fishery records, sediment cores and archeological data.

Then, the team compiled global fisheries catch data from 64 large marine ecosystems to test for the effects of large-scale species loss on fisheries-related services. They used the fisheries database compiled by the United Nations Food and Agriculture Organization and the Sea Around Us Project at the Fisheries Centre, University of British Columbia. Finally, the scientists investigated how recovery of biodiversity in 48 marine protected areas — reserves and fishery closures — affected the recovery of services.

The researchers were surprised to find very similar relationships between biodiversity change and ecosystem services at scales ranging from small square-meter plots to entire ocean basins, Worm said. “This suggests that small-scale experiments can be used to predict large-scale ocean change.

“Through this research, it became clear to me that we hardly appreciate living on a blue planet,” Worm said. “The oceans define our planet, and their fate may to a large extent determine our fate, now and in the future.”

Tables courtesy of the Marine Resources Service, Fishery Resources Division, FAO Fisheries Department.

Commercial fishing can cause fish population imbalance. New research has found that commercial fishing can cause significant fluctuations in marine fish populations. Writing in Nature, scientists from several institutions and agencies argue that fishing can amplify the highs and lows of natural population variability.

Up to 73 million sharks killed per year for their fins. Between 26 million and 73 million sharks are killed each year for their fins according to a new paper published in the October 2006 edition of Ecology Letters. The estimates are three times higher than those projected by the United Nations.

History of the Chilean Sea Bass market. Today The Wall Street Journal ran an account of how the Chilean Sea Bass was first brought to market in 1977. Since its introduction, the species — also known as the Patagonian toothfish — has gone from being shunned to being welcomed at the worst’s finest restaurants. But demand for the fish has taken its toll and the slow-growing species which takes 10-12 years to reach sexual maturity suffers from illegal over fishing in parts of its range. Some groups estimate that the illegal take may be up to five times the legal catch limit, leading some ecologists to predict the immanent collapse of the fishery.

Where are the fish? Ocean fisheries in trouble. Talks began in Canada this week aimed at addressing the deteriorating condition of the world’s marine fisheries, but in an atmosphere with little reason for optimism. Past efforts to manage fisheries or control overfishing have largely failed to slow the depletion of marine resources.

This article used information and quotes from a SeaWeb news release and includes a release from the American Association for the Advancement of Science.