Sentinel behaviour is found in the animal kingdom in species that live in communities such as marmots, meerkats, and birds. However, it has never been described for marine fish living in groups. Researchers at the Leibniz Centre for Tropical Marine Research (ZMT) have now found that coral reef fish also appear to show this behaviour. The study was published in the journal Environmental Biology of Fishes.
In the damselfish genus, there are species that live in close proximity to branching stone corals. They swarm around them and seek shelter between their branches as soon as danger threatens. The corals also benefit from their subtenants.
Damselfish of the genus Pomacentrus swarm around a branch coral, Indonesia
Photo: Robin Gauff, Leibniz Centre for Tropical Marine Research
Through their fanning behaviour, the damselfish ensure better water circulation as well as the supply and removal of oxygen. Hence, corals that live in a mutualistic relationship with damselfish can grow much faster.
Dr Sebastian Ferse, reef ecologist at the ZMT, and his team wanted to more closely investigate this symbiosis in lemon damselfish, shoal-forming reef fish of the species Pomacentrus moluccensis. They observed that the large, adult damselfish behave differently than the smaller, juvenile fish in case of danger.
In the area of the "Thousand Islands", which belongs to Indonesia, the researchers used underwater cameras in four different locations to film stone corals where reef fish were sheltering. In addition, they laid out pieces of dried squid as bait to attract predatory fish and also studied other factors that could threaten the damselfish.
The evaluation of the video material revealed that the fish perceived certain situations as particularly dangerous. The juvenile fish in particular disappeared deeper into the coral when the water was turbid and approaching predators such as snappers, groupers or angel fish could not be spotted immediately. While predators were close by, the adult fish positioned themselves relatively far away from the coral.
"With this behaviour, the larger lemon damselfish can better perceive their enemies. When a predator approaches, they pull back into the coral at lightning speed. As a result, they warn their inexperienced, smaller conspecifics," said Sebastian Ferse. The young fish sense the retreat of the big fish via their lateral line organ, with which they register water movements. The “sentinel fish” may also give alarm cues, as has already been proven with clownfish.
"Such selfless behaviour can only be explained by the fact that the members of a group are closely related," said Ferse. When reef fish spawn, the water flow drives the larvae away. However, the young damselfish have an amazing ability to find their way back to their original host coral. Thus, there may be close family ties between the inhabitants of a coral. Here molecular genetic investigations can provide information about the relationships.
Robin P.M.Gauff, Sonia Bejarano, Hawis H. Madduppa, Beginer Subhan, Elyne M.A. Dugény, Yuda A. Perdana, Sebastian C.A. Ferse: Influence of predation risk on the sheltering behaviour of the coral-dwelling damselfish, Pomacentrus moluccensis. Environmental Biology of Fishes (2018).
Dr. Sebastian Ferse
Leibniz Centre for Tropical Marine Research
Phone: +49 ()421 / 23800 - 28
About the Leibniz Centre for Tropical Marine Research
In research and education the Leibniz Centre for Tropical Marine Research (ZMT) in Bremen is dedicated to the better understanding of tropical coastal ecosystems. As an interdisciplinary Leibniz institute the ZMT conducts research on the structure and functioning of tropical coastal ecosystems and their reaction to natural changes and human interactions. It aims to provide a scientific basis for the protection and sustainable use of these ecosystems. The ZMT works in close cooperation with partners in the tropics, where it supports capacity building and the development of infrastructures in the area of sustainable coastal zone management. The ZMT is a member of the Leibniz Association.
Dr. Susanne Eickhoff | idw - Informationsdienst Wissenschaft
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy