Category: New Research

Jellyfish in the Mediterranean

Jellyfish (Cotylorhiza tuberculata) with juvenile fish near Hvar Island, Croatia. (Photo © Tihomir Makovec)

A new journal article from the Sea Around Us Project reviews knowledge of jellyfish in the Mediterranean Sea, including how the abundance of a number of native and invasive species has changed over time, and what could be causing the changes. In addition, the authors offer advice on how to manage jellyfish blooms – a challenge given the high levels of uncertainty and variability.

Lucas Brotz, a PhD student supervised by Dr Daniel Pauly, is the lead author on the paper, which is published in Acta Adriatica.

You can access the paper here.

Brotz L and Pauly D (2012) Jellyfish populations in the Mediterranean Sea. Acta Adriatica 53(2): 211-230.

New database of marine aquaculture launched

The new Global Mariculture Database (GMD), released by the Sea Around Us Project, offers detailed information on the where and what of mariculture around the world since 1950. By mapping the production of marine aquaculture at smaller scales than the usual national scale and by digging deeper into the species being farmed, the GMD provides room for new insights into marine aquaculture.  And all of this information is now available online for anyone to browse on the Sea Around Us Project website!

The GMD confirms reports by the Food and Agriculture Organization of the UN (FAO) that the amount of seafood produced by marine aquaculture has tripled since 1950 – a massive increase. During this time, there has also been a shift in the type of seafood produced globally, with a larger percentage of predatory species, such as salmon and tuna, farmed around the world today compared to 1950. In the past, the relative production of species lower on the food chain, like mussels and oysters, was higher. This phenomenon has been described as “farming up the food web” a term derived from the concept of fishing down marine food webs.

In keeping with the Sea Around Us Project’s goal of improving public access to global fisheries and aquaculture information, this Global Mariculture Database (GMD) is freely available online at www.seaaroundus.org.

To find out more about the GMD and how it was created, you can read the paper recently published in the journal Marine Policy:

Campbell B and Pauly D (2012) Mariculture: a global analysis of production trends since 1950. Marine Policy 39: 94-100.

Grading ocean health: 60/100

The Ocean Health Index is the first global quantitative assessment of ocean health (Map credit: Halpern, et al, Nature)

The health of the world’s oceans received a score of 60 out of 100 from a team of international scientists, including researchers with the Sea Around Us Project. Kristin Kleisner, Dirk Zeller, Rashid Sumailaand Daniel Pauly were part of the team that undertook the first global quantitative assessment of ocean health and created the Ocean Health Index by evaluating ecological, social, economic and political conditions for every coastal nation in the world.

The Sea Around Us Project in particular was responsible for measuring the amount of seafood that is sustainably generated by fisheries and marine aquaculture for human consumption, which contributed to calculating the score for ocean health.

The article, published in Nature, is available here and the press release is here.

Law That Regulates Shark Fishery Is Too Liberal

Shark fins are worth more than other parts of the shark and are often removed from the body, which gets thrown back into the sea. To curtail this wasteful practice, many countries allow the fins to be landed detached from shark bodies, as long as their weight does not exceed five per cent of the total shark catch. New University of British Columbia research shows that this kind of legislation is too liberal.

A study published this week in the journal Fish Biology analyzes the fin to body weight ratios for 50 different shark species.  The authors find the average fin to body mass is three per cent  – considerably lower than the five per cent ratio currently legislated by the EU and other countries.

“The five percent ratio provides an opportunity to harvest extra fins from more sharks without retaining 100 per cent of the corresponding shark carcasses,” says Sea Around Us Project researcher Leah Biery, lead author of the study. “It does not prevent waste or overfishing, as the law intended.”

Currently, the EU and eight other countries use at least a five per cent shark fin to body weight ratio for landed catch. Only 59 countries in the world have any legislation related to sharks.

“Sharks are sensitive to overfishing and it’s embarrassing how little we have done to protect them,” says Daniel Pauly, principal investigator of UBC’s Sea Around UsProject and co-author of the study. “We would like to see more science in the management and protection of sharks in the coming years.”

Researchers estimate about 26 to 73 million sharks are killed each year to feed the growing demand for shark fin.  Sharks are sensitive to overfishing because they often grow slowly, mature later, and have very few offspring.

Canada MP Fin Donnelly introduced a bill last December that would ban the import of shark fin into Canada, but it has not been voted on. The Canadian municipalities of Brantford, Mississauga, Oakville, Pickering, London and Toronto have all banned the sale and possession of shark fin.

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.