Until recently, scientists provided fishery managers only such limited data as stock counts and catch estimates, said Charles Greene, Cornell professor of ocean sciences and lead author of the study published in the March issue (Vol. 22, No. 1) of the journal Oceanography.
But new advances in miniature sensors and fish-tracking tags, ocean observing systems and computer models are providing much more insight into environmental changes and how fish are responding behaviorally and biologically to such changes, thereby enabling better modeling to predict fish populations. As a result, researchers are making more informed recommendations for strategies to address falling fish populations.
Obtaining real-world data is essential, stressed Greene. "Many of the commercial fish populations in the world are pretty highly depressed. It's a bleak picture in terms of the status of many wild marine fish populations."
For example, the Atlantic bluefin tuna fishery, which can garner more than $15,000 per fish, is managed as two separate stocks, one in the eastern Atlantic basin, with a breeding ground in the Mediterranean, and another in the western basin, with a breeding ground in the Gulf of Mexico. Both stocks are not sustainably harvested, and the western population has declined by roughly 90 percent over the last 25 years, despite strict quotas.
A project known as Tag A Giant (TAG) uses an implanted tag in the tuna to record external pressure, internal and external temperature and ambient light, though the tuna must be recaptured to recover these data. TAG also uses a pop-up tag that is attached to the tuna but self releases, floats to the surface and transmits data on each tuna's external conditions via satellite. The tags help researchers estimate geo-locations and track each fish's daily movements.
According to the study, new TAG data have revealed that as tuna grow, they swim all over the Atlantic, and that the fish from the two stocks commingle. Past failure to account for this mixing of the two stocks has led to unsustainable management practices, especially for tuna originating in the Gulf of Mexico, Greene said. New strategies must account for mixing stocks, since fishing in the eastern basin has undermined the quotas and recovery plans for the western basin stock.
With regard to Pacific salmon, fishery managers have assumed that juveniles traveling from spawning grounds to the ocean face great mortality along heavily dammed rivers, like the Snake-Columbia river system, than in undammed rivers. Thus, they collected juveniles and transported them past the Snake-Columbia river system's eight dams before releasing them downstream. However, adult salmon numbers returning from the ocean did not increase.
The Pacific Ocean Shelf Tracking project, which tagged juvenile fish, showed that the smaller, less developed fish were dying in high numbers in the lower river and coastal ocean. This kind of knowledge will help managers test and adapt their strategies in wild-fish systems, which historically have been hard to monitor.
This work was supported by more than a dozen entities, including the Gordon and Betty Moore, Packard, Monterey Bay Aquarium and Sloan foundations, and the Bonneville Power Administration.
Blaine Friedlander | EurekAlert!
Further reports about: > Climate change > Gulf > Overfishing > Pacific Ocean > Snake-Columbia river system > computer model > computer models > environmental change > fish populations > fish's daily movements > fish-eye views > fish-tracking tags > miniature sensors > ocean observing systems > wild marine fish populations
Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy