Lionfish on a reef
Lionfish (Pterois volitans) hunting smaller fish on a coral reef. The lionfish is a predator, often hunting in groups. It uses its widespread fins to force prey, mostly smaller fish, into a crevice in coral or rocks, before sucking it into its mouth with a huge gulp. The spines in the fins contain a potent toxin, which deter predators and can deliver a very painful sting. The lionfish inhabits reefs in the tropical Indo-Pacific region, and in recent years has been sighted in the Caribbean, probably due to escapees from aquaria. It can reach about 38 centimetres in length. Photographed in the Egyptian Red Sea.
© GEORGETTE DOUWMA/SCIENCE PHOTO LIBRARY
Sea cucumber (Thelenota sp.) spawning. Microscopic sex cells (gametes) are being released to allow fertilisation (the fusing of a male and a female sex cell). The resulting larvae may grow into adult sea cucumbers. This marine invertebrate is a member of a group of animals (echinoderms) that includes starfish. A sea cucumber lives on the sea floor, crawling on its projecting tube feet, but mostly remaining motionless and gathering its food from the water. It feeds on microscopic sea life (plankton) and also extracts nutrients from the surrounding mud. Sea cucumbers range in length from 2 centimetres to 2 metres. They are found worldwide. Photographed in the Red Sea.
© PETER SCOONES/SCIENCE PHOTO LIBRARY
Dugong, remora and golden trevallies
Dugong (Dugong dugong) with a remora (Echeneis naucrates) attached at its rear and juvenile golden trevallies (Gnathanodon speciosus) swimming in front. The dugong is a herbivorous marine mammal found in shallow, tropical waters throughout the Indo-Pacific region. It can grow to three metres in length and 400 kilograms in weight. Remoras have a symbiotic relationship with large sea animals. They use a sucking disk on the top of their heads to attach to their host. They clean the host's skin of parasites and the host's presence protects the remoras from predators. The golden trevallies swim in front of harmless sea animals to be pushed along by the animal's propulsion. Photographed in the Red Sea, Egypt.
© Alexis Rosenfeld/Science Photo Library