The research, which is published in today’s Nature, involved compiling the largest ever survey of both exploited fish and non-exploited fish off the California coast. The research team looked at how the abundance of both types of fish varied over a 50 year period, and found the first evidence that exploited species’ population levels vary far more than non exploited species’ in the same ecosystem.
Researchers concluded that this increased variability in exploited fish stocks was most likely to be caused by the effect fishing has on the age structure of a population. Heavily-fished populations are unlikely to contain any fish older than a few years old, and as such are wholly reliant on the successful growth of larvae into baby fish (recruits) to maintain population numbers year on year.
Professor John Beddington from Imperial College London’s Division of Biology, who worked on the study, explained: “Intensive fishing makes populations vulnerable because if they rely on recruits to replenish their numbers, there is always the danger that some kind of environmental factor will devastate the recruits in one season. This would leave the population close to collapse, with very few young fish coming into the group to replace those being caught.”
Professor Beddington adds that the increased variability has serious implications for the way in which fish stocks are managed: “Typically fish populations are managed by governments setting total allowable catch limits (TACs), but a fixed TAC which doesn’t take into account the variability of abundance over time, may mean that in some years it is completely incompatible with the population size. This means that fishing vessels could unwittingly overexploit the population, even though they are abiding by set limits.”
Researchers hope that their findings will mean future decisions about fishery management take into account the variations caused by fishing, to safeguard the future of key fish populations.
Danielle Reeves | alfa
Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Life Sciences
24.04.2017 | Earth Sciences
24.04.2017 | Machine Engineering