Category: New Research

Fish Farms from Space: The Ground Truth from Google Earth

The Great Wall of China is not the only thing you can see from space. Fish farming cages are clearly visible through Google Earth’s satellite images and University of British Columbia researchers have used them to estimate the amount of fish being cultivated in the Mediterranean.

The study, published yesterday in the online journal PLoS ONE, is the first to estimate seafood production using satellite imagery.

“Our colleagues have repeatedly shown that accurate reporting of wild-caught fish has been a problem, and we wondered whether there might be similar issues for fish farming,” says lead author Pablo Trujillo, an Oceans Science Advisor for Greenpeace International, who conducted the study while a research assistant at the UBC Fisheries Centre.

“We chose the Mediterranean because it had excellent satellite coverage and because it was of personal interest,” says Chiara Piroddi, co-author and an ecosystem modeler at the UBC Fisheries Centre. “We hand counted 20,976 finfish cages and 248 tuna cages, which you can differentiate due to their extremely large size – each tuna cage measured at more than 40 metres across.”

Almost half the cages were located off the coast of Greece and nearly one-third off of Turkey – and both countries appear to underreport their farmed fish production. The researchers note that not all areas had full satellite coverage – for instance, images were missing for large portions of the coasts of France and Israel, for reasons the authors do not fully understand.

Combining cage counts with available information on cage volume, fish density, harvest rates, and seasonal capacity, the research team estimated ocean finfish production for 16 Mediterranean countries at 225,736 tonnes (excluding tuna). The estimate corresponded with government reports for the region, suggesting that, while there are discrepancies at the level of individual countries, overall, the Mediterranean countries are giving accurate counts.

“The results are reassuring, and the methods are inspiring,” says co-author Jennifer Jacquet, a post-doctoral researcher with UBC’s Sea Around Us Project. “This shows the promise of Google Earth for collecting and verifying data, which means a few trained scientists can use a freely available program to fact-check governments and other large institutions.”

Trujillo adds that Google Earth, with its high-resolution images and consistent time series, can be a powerful tool for scientists and non-governmental organizations to monitor activities related to ocean zoning and capture fisheries.

See some coverage of the work at The Scientist.

New Study Published in MEPS about Marine Predator Declines

Iconic marine predators such as sharks, tunas, swordfish, and marlins are becoming increasingly rare under current fishing trends, according to a new study published in the journal Marine Ecological progress Series. In half of the North Atlantic and North Pacific waters under national jurisdiction, fishing has led to a 90-per-cent decrease in top predators since the 1950s, and the impacts are now headed south of the Equator. The study was lead authored by former Sea Around Us Project M.Sc student Laura Tremblay-Boyer. The study is available here and the press release is here.

Analysis of FAO Report on Fisheries Statistics

Global fisheries statistics must be viewed with a critical eye. Fisheries landings data are collated by FAO and contributed by all member countries, which have varying resources and motives. In a new paper recently published in Marine Policy, Daniel Pauly and Rainier Froese take a close look at FAO’s State of the Worlds Fisheries and Aquaculture’ (SOFIA) report from 2010 and discuss the FAO’s history, as well as the implications, imperfections, and possible improvements to be made to fisheries data.

Pauly and Froese are both complimentary and critical. They point out the misleading use of the word ‘stability’ in the report as it refers to global catch data from 2005-2008, and point out that even if that global catches are indeed stable, fishing effort is rapidly expanding. They note the FAO’s acceptance of scientific data that showed China does not know how much its fisheries catch, and the large degrees of uncertainty around global trends this problem creates. Pauly and Froese point approvingly to SOFIA’s position on assemblage overfishing and their statement: ‘ We do not disagree that a general decline in mean trophic level of marine landings is likely to have occurred in many regions.’ Finally, Pauly and Froese call for cooperation between institutions, e.g., U.N. technical organization and civil society, as represented by universities and non-government organizations, to improve SOFIA reports and potentially the management of fisheries globally.

To read the full article click here.

Citation: Pauly, D. & Froese, R. 2012. Comments on FAO’s State of Fisheries and Aquaculture, or ‘SOFIA 2010’ Marine Policy 36: 746-752.

Climate Change to Further Degrade Fisheries Resources

A new study out this week shows how the effect of climate change can further impact the economic viability of current fisheries practices.

“Fisheries are already providing fewer fish and making less money than they could if we curbed overfishing,” says Rashid Sumaila, principal investigator of the Fisheries Economics Research Unit at UBC, member of the Sea Around Us Project, and lead author of the study. “We could be earning interest, but instead we’re fishing away the capital. Climate change is likely to cause more losses unless we choose to act.”

Partly supported by the Pew Charitable Trusts, National Geographic, the World Bank and U.S. National Oceanic and Atmospheric Administration, the study is a broad view of the impact of climate change on fisheries and their profitability. It was published online this week in the journal Nature Climate Change.

Over the last century the ocean has become warmer and more acidic. Other human-led factors, such as pollution and overfishing, have also been hard on marine species. With ocean warming, many species will move further towards the poles and into deeper water.

While fisheries in a few regions, such as the far north, may benefit from climate change, many other regions, particularly those in the tropics, can expect losses in revenues. Regional examples can help inform what could happen globally. For example, the reduction in landings of pelagic fisheries in Peru as a result of changes in sea surface temperature during the 1997-1998 El Niño event caused more than US$26 million of revenue loss.

“Changes in temperature and ocean chemistry directly affect the physiology, growth, reproduction and distribution of these organisms,” says William Cheung, associated faculty of the Sea Around Us Project. “Fish in warmer waters will probably have a smaller body size, be smaller at first maturity, with higher mortality rates and be caught in different areas. These are important factors when we think of how climate change will impact fisheries.”

“This study provides an early glimpse of how climate change might impact the economics of fishing,” says Sam Herrick, a NOAA scientist and co-author. “We must continue to study how climate change, combined with other factors, will affect marine ecosystems and the productivity of fishery resources.”

Biologically, maintaining more abundant populations can help increase fish’s capacity to adapt to environmental change. Curbing overfishing is crucial to making marine systems more robust and ready for changes that are already underway.

“This study highlights the potential negative impacts of climate change on the profitability of fisheries,” said Vicky Lam, UBC graduate student and co-author. “The next generation of scientists must put more effort on exploring ways to minimize the impacts of climate change.”

Fish stocks will also be more robust to climate change if the combined stresses from overfishing, habitat degradation, pollution runoff, land-use transformation, competing aquatic resource uses and other anthropogenic factors are minimized

“We have to remember that the effect of climate change on the marine environment will occur alongside the impacts on land,” says Daniel Pauly, principal investigator of the Sea Around Us Project and co-author. “It will not be easy to divert resources from one sector to help another sector. This is why a strong governance system is needed – to temper the losses on the sectors that are worst hit.”

“Governments must be anticipatory, rather than reactive,” says Sumaila. “We all need to think more of the future while we act now.”

For more information, see this summary provided by Pew.

Deep-Sea Fish in Deep Trouble

A team of scientists from around the world, including several members of the Sea Around Us Project, is recommending that most of the deep sea be closed to fishing. In an extensive review paper published in the journal Marine Policy, a team of ecologists, fisheries biologists, economists, and mathematicians make the case that high seas fisheries should be shut down.

Fish from the deep sea, like the Orange roughy shown here (photo credit: Claire Nouvian), make up less than 1% of seafood in the market. But fisheries, especially trawl fisheries, cause a lot of damage to the species themselves as well as the seafloor and animals that live on it, like deep-sea coral, the authors of the paper argue. In addition, high seas trawlers receive an estimated $162 million each year in government handouts, which amounts to 25% the value of the fleet’s catch, according to Rashid Sumaila, an author on the paper and a fisheries economist at UBC.

The study comes just before the United Nations deliberates on deep-sea fisheries on the high seas. In 2006, a proposed UN resolution to ban bottom trawling in the high seas failed due to opposition led by Iceland and Russia.

Read the full press release here, the full study here, and some media coverage in The Washington Post.

Reference: Elliott A. Norse, Sandra Brooke, William W.L. Cheung, Malcolm R. Clark, Ivar Ekeland, Rainer Froese, Kristina M. Gjerde, Richard L. Haedrich, Selina S. Heppell, Telmo Morato, Lance E. Morgan, Daniel Pauly, Rashid Sumaila, Reg Watson. Sustainability of deep-sea fisheries. Marine Policy, 2012; 36 (2): 307.