Known as marine bycatch, this problem is an ongoing challenge to the fishing industry, regulatory agencies, and conservationists. One recent proposal would compensate for bycatch by reducing other impacts on affected species, but a new analysis suggests that this strategy could end up doing more harm than good.
A paper published last year in Frontiers in Ecology and the Environment made the case for "compensatory mitigation" of fisheries bycatch, using seabird deaths caused by a longline fishery as an example. The authors suggested that eradicating rats from an island with seabird nesting colonies could have more benefits for a population of shearwaters than efforts to reduce bycatch in the longline fishery.
A number of seabird experts, however, were skeptical of the paper's findings. Given its potential influence on fishery policies, they decided the proposal warranted a careful evaluation.
"There are so many complexities involved in fisheries bycatch, we felt compelled to thoroughly examine the strengths and weaknesses of this approach and establish the criteria that would have to be met for it to work," said Myra Finkelstein, a postdoctoral fellow in ecology and evolutionary biology at the University of California, Santa Cruz.
Finkelstein is the lead author of a paper published June 18 in the journal PLoS ONE that evaluates the potential effectiveness of compensatory mitigation for marine bycatch. She worked with a dozen coauthors whose areas of expertise include seabird conservation and ecology, marine bycatch, and mathematical modeling of wildlife populations. The researchers concluded that compensatory mitigation could only rarely succeed in reducing or offsetting the effects of marine bycatch.
"It's very difficult to make this work," Finkelstein said. "Most of the species threatened by bycatch evolved to live long and reproduce slowly. When bycatch kills adults, these populations just aren't capable of making up for it through increased reproduction. It really is about the bycatch."
Another major stumbling block is that bycatch typically involves a large variety of nontarget species, whereas compensatory mitigation actions are likely to affect only one or a few of those species.
"Marine bycatch is not a single-species problem," Finkelstein said. "So many nontarget species are caught in a given fishery that mitigating the effects on one species could lead to a bigger impact on other species."
The researchers also found flaws in the case study of flesh-footed shearwaters used to support the compensatory mitigation strategy in the original paper. But the bulk of the new paper is devoted to a set of five criteria for evaluating any proposals to implement such strategies. The researchers found that compensatory mitigation for marine bycatch is likely to be successful only in a limited number of situations. In many cases, they said, it has the potential to accelerate declines of marine species currently threatened by fisheries bycatch.
"These are complicated situations. We have to be very cautious, especially with critically endangered species, before we adopt a policy that allows continued mortality from bycatch," Finkelstein said.
The coauthors of the paper include Victoria Bakker, William Satterthwaite, and Robert Henry of UCSC; Daniel Doak of the University of Wyoming; Ben Sullivan and John Croxall of the BirdLife International Global Seabird Programme; Rebecca Lewison of San Diego State University; Peter McIntyre of the University of Michigan, Ann Arbor; Shaye Wolf of the Center for Biological Diversity; David Priddel of the Australian Department of Environment and Climate Change; Jennifer Arnold of Pennsylvania State University; and Paul Sievert of the University of Massachusetts, Amherst.
Tim Stephens | EurekAlert!
Despite government claims, orangutan populations have not increased. Call for better monitoring
06.11.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Increasing frequency of ocean storms could alter kelp forest ecosystems
30.10.2018 | University of Virginia
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences