Sailfish are large oceanic predatory fish that attack their prey with their long, sharp bills. When hunting, individuals increase their success rate by specialising in one attacking side, as a team led by researcher Dr. Ralf Kurvers from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) has now been able to show. The crucial factor: Sailfish always hunt in groups containing roughly the same number of individuals that attack from the right as those that attack from the left. In this way, their prey is unable to predict from which side the attack will occur.
Predators and their prey evolve together: it is vital for predators to develop effective hunting strategies, whereas the prey species is intent on evading its attackers. An international team of researchers involving IGB has investigated the predator-prey relationship between sailfish (Istiophorus platypterus) and sardines (Sardinella aurita).
“When attacking, most sailfish specialise in attacks from either the left or the right, enabling them to attack more effectively,” reported Dr. Ralf Kurvers, lead author of the study whose results have now been published in the journal Current Biology.
The researcher and his team discovered that specialisation in attacking from the left or right – referred to technically as laterality – has its advantages in hunting. In fact, the more strongly an individual was lateralized, the more successful it was in capturing prey: the fish can attack very quickly with their preferred side.
This is an advantage because sardines are considerably more agile than their hunters. However, sailfish are only successful predators because they hunt in groups: a single sailfish that always attack from either the left or the right will have difficulty catching its prey, because the prey can then easily predict the side of attack.
The researchers were able to show that the key advantage of hunting in a group is that the prey species is unable to predict whether the sailfish are specialised in attacking from the left or from the right – making the predators more unpredictable to their prey. “The larger the group, the more balanced the left/right relationship is, and the more successful the sailfish will be in hunting sardines,” reported Dr. Kurvers.
In their study, the researchers analysed a total of 365 attacks by 73 sailfish, which occurred in 11 groups with up to 14 individuals per group, in the open ocean off the coast of Mexico. In a morphological analysis, the researchers also examined signs of wear in the microteeth on the long bill used by the predatory fish to attack their prey. This analysis confirmed that most fish prefer to attack from the left or from the right.
The fact that sailfish hunt in groups enables them – in evolutionary terms – to develop a very distinct specialisation. "Our study has enabled us to prove an important advantage that sailfish have when hunting in a group which, until now, was unknown,” explained Dr. Ralf Kurvers.
Incidentally, with around half of the sailfish preferring to attack from the right and the other half specialising in attacks from the left, laterality in sailfish differs from handedness in humans: some 90 per cent of the world’s population are right-handed, with only ten per cent preferring to use the left hand. “Using the same hand is useful when it comes to cooperative activities, which is why a predominant use of one hand has developed in the course of human evolution. The fact that left-handers still exist is explained by the advantages of this alternative laterality which, however, no longer plays an important role in today’s society – namely unpredictability in battle. Around half of top fencers, for example, are still left-handed, and the other half right-handed,” explained Dr. Kurvers.
Kurvers RHJM, Krause S, Viblanc PE, Herbert-Read JE, Zaslansky P, Domenici P, Marras S, Steffensen JF, Wilson ADM, Couillaud P & Krause J (in press). The Evolution of Lateralization in Group Hunting Sailfish. Current Biology.
Dr. Ralf Kurvers
Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) and the Max Planck Institute for Human Development
+49 30 82406 472
Work at IGB combines basic research with preventive research as a basis for the sustainable management of freshwaters. In the process, IGB explores the structure and function of aquatic ecosystems under near-natural conditions and under the effect of multiple stressors. Its key research activities include the long-term development of lakes, rivers and wetlands under rapidly changing global, regional and local environmental conditions, the development of coupled ecological and socio-economic models, the renaturation of ecosystems, and the biodiversity of aquatic habitats. Work is conducted in close cooperation with universities and research institutions from the Berlin/Brandenburg region as well as worldwide. IGB is a member of the Forschungsverbund Berlin e.V, an association of eight research institutes of natural sciences, life sciences and environmental sciences in Berlin. The institutes are members of the Leibniz Association.
http://www.sciencedirect.com/science/article/pii/S0960982216315251 Paper on sailfish in Current Biology
Johannes Graupner | idw - Informationsdienst Wissenschaft
Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology
Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences