Archive for February, 2019

Feb 26 2019

Environmental Impact Displacement in Fisheries & Food

A recent policy perspective paper in Conservation Letters, Lewison et al. 2019 (open access), summarized several examples of environmental impact ‘displacement,’ an important policy concept with implications for fisheries and food.

Examples of environmental impact displacement

Environmental impact displacement is when a conservation policy designed to reduce impact in one area, displaces it to another area, sometimes making the overall problem worse. Researchers cite sea turtle bycatch in swordfish fisheries as an example of displacement in fisheries: U.S. Pacific swordfish fishing was curtailed to protect sea turtles caught as bycatch. However, lower U.S. catch increased foreign swordfish demand which ended up killing more sea turtles as foreign swordfish fisheries had higher rates of bycatch.

ProPublica and the New York Times recently published a long exposé about how a U.S. policy meant to reduce carbon emissions (by increasing biofuel use) raised demand for palm oil in Southeast Asia, which actually increased emissions and jumpstarted the palm oil/biodiversity crisis (this example is also cited in Lewison et al.).

The viral Ocean Cleanup Project is another example of environmental displacement; the crowdfunded campaign was trying to remove marine debris from the great Pacific garbage patch by sweeping a giant net-like object across the ocean. However, if it had worked as intended (it broke), it would have killed many more organisms than the trash it was trying to remove from the ocean.

Environmental displacement in fisheries & food

The concept of environmental impact displacement is important to consider in fisheries management and marine conservation. The swordfish case above is a good example of displacement in individual fisheries, but there are other areas of fishery management that should consider environmental impact displacement. For example, no-take marine protected areas often increase fishing pressure outside the area being protected, nullifying the protection. In some cases, displacing fishing pressure benefits the ecosystem, but often it does not.

Zooming out in scale raises larger systemic questions about food: Consider fisheries and marine conservation as part of a broader, global system of food and ecological preservation. A legitimate argument can be made that fulfilling fishery potential and consuming more seafood is good for the planet—it provides low-carbon, low-impact protein.

As the developing world continues to acquire wealth, global demand for animal-protein will continue to rise. The more seafood that is eaten in place of cow, the better, since bovine farming is the largest driver of rainforest and biodiversity loss on the planet. Not only is seafood the lowest-impact animal protein, several kinds of seafood (e.g. farmed bivalves and wild-caught pelagics) are among the lowest impact foods of any kind.

Solutions to environmental displacement

Lewison et al. 2019 outline ways to reduce environmental impact displacement that can be applied to fisheries management and global food systems. The first step, researchers state, is explicitly considering displacement in policy design, scoping, and evaluation. Fishery managers should evaluate and understand the biological, economic, and social outcomes of proposed policies to avoid issues like accidentally increasing turtle bycatch across the world or raising fishing pressure in an area surrounding an MPA.

Other ways to avoid displacement include:

  • Think large-scale to consider all economic/biological/social relationships
  • Enact both demand-side and supply-side policies
  • International trade agreements and cooperation as a holistic approach to global conservation

Conservation groups should consider the global food system and environmental impact displacement in their advocacy; policy makers and natural resource managers should consider environmental impact displacement in their decision-making processes. Conservation will be more effective with a larger, broad approach—particularly with fisheries and food. Lewison et al. 2019 is open access and available here.


Original post: https://sustainablefisheries-uw.org/environmental-impact-displacement/

Feb 25 2019

Methane bubbling up from ocean floor provides a surprising food source for crabs, Oregon State University research shows

Oregon State University researchers have documented tanner crabs feeding at a methane seep site off British Columbia. Tanner crabs are also known as ‘snow crabs’ and sold as food. It is the first time a commercially harvested species has been known to feed at methane sites.The methane shouldn’t cause any health concerns and, in fact, it may provide an alternative energy source for seafloor-dwelling marine species. [Oregon State University]

 

Climate change will result in less ocean-borne food falling into the deep sea, scientists say. But that likely won’t be a problem for tanner crabs, according to a recent discovery by Oregon State University researchers.

The long-legged orange crabs — one of three species that crabbers harvest and sell as snow crabs — vigorously feed at methane seeps, where the gas bubbles up from the ocean floor.

“The thinking used to be that the marine food web relied almost solely on phytoplankton dropping down through the water column and fertilizing the depths,” OSU Marine Ecologist Andrew Thurber said in a statement. “Now we know that this viewpoint isn’t complete and there may be many more facets to it.”

Thurber co-authored a study that the journal Frontiers in Marine Science just published. The study details how scientists found tanner crabs in eating frenzies around a methane seep in the floor of the Pacific Ocean off British Columbia. It is one the first times that a commercially harvested seafood has been found to rely on methane seeps.

Methane seeps appear to be serving up food to seafloor-dwelling species, such as tanner crabs. This would be a hedge against climate change because nearly all models predict less food will drop into the deep sea in coming years.

“Tanner crabs likely are not the only species to get energy from methane seeps, which really haven’t been studied all that much,” Thurber said. “We used to think there were, maybe, five of them off the Pacific Northwest coast and now research is showing that there are at least 1,500 seep sites — and probably a lot more. … They are all over the world, so the idea that they may provide an energy source is quite intriguing.”

Researchers first noticed tanner crabs bunching up around methane seeps in 2012 off the British Columbia coast. The crabs sifted through sediment at the bubbling seeps. Mats of bacteria form around the seeps and the crabs munch on those.

Underwater video shows methane building up below tanner crabs hanging out at seeps and eventually flipping them. The entertaining video drew researchers to wonder why the crabs were gathered around the seeps in the first place.

OSU teamed up with scientists from the University of Victoria in Canada. The National Science Foundation in the U.S. provided support for the study.

Off the Oregon Coast, Pacific sole and black cod have been seen near methane seeps. Like the crabs, the fish are harvested.

But seafood lovers need not worry about what their food is eating. Researchers say methane seeps create nontoxic environments.

Sarah Seabook, the lead author of the study and a Ph.D. candidate at OSU, said scientists examined the guts and tissues of tanner crabs to confirm they were feeding around methane seeps.

″… We can apply these new techniques to other species and find out if the use of methane seeps as a food source is more widespread than just tanner crabs,” she said in a statement.


Original post: https://www.registerguard.com/news/20190225/methane-bubbling-up-from-ocean-floor-provides-surprising-food-source-for-crabs-oregon-state-university-research-shows