very effectively. Range and habitat Halfbeaks inhabit warm seas, predominantly at the surface, in the Atlantic, Indian, and Pacific oceans. A small number are found in estuaries. Most species of marine halfbeaks are known from continental coastlines, but some extend into the western and central Pacific, and one species (Hyporhamphus ihi) is endemic to New Zealand. Hemiramphus is a worldwide marine genus. Ecology and behavior Feeding Marine halfbeaks are omnivores feeding on algae; marine plants such as seagrasses; plankton; invertebrates such as pteropods and crustaceans; and smaller fishes. For some subtropical species at least, juveniles are more predatory than adults. Some tropical species feed on animals during the day and plants at night, while other species alternate between carnivory in the summer and herbivory in the winter. They are in turn eaten by many ecologically and commercially important fish, such as billfish, mackerel, and sharks, and so are a key link between trophic levels. Behavior Marine halfbeaks are typically pelagic schooling forage fish. The southern sea garfish Hyporhamphus melanochir for example is found in sheltered bays, coastal seas, estuaries around southern Australia in waters down to a depth of . These fish school near the surface at night but swim closer to the sea floor during the day, particularly among beds of seagrasses. Genetic analysis of the different sub-populations of the eastern sea garfish Hyporhamphus melanochir in South Australian coastal waters reveals that there is a small but consistent migration of individuals among theme, sufficient to keep them genetically homogeneous. Some marine halfbeaks, including Euleptorhamphus velox and Euleptorhamphus viridis, are known for their ability to jump out of the water and glide over the surface for considerable distances, and have consequently sometimes been called flying halfbeaks. Reproduction Hemiramphidae species are all external fertilizers. They are usually egg-layers and often produce relatively small numbers of fairly large eggs for fish of their size, typically in shallow coastal waters, such as the seagrass meadows of Florida Bay. The eggs of Hemiramphus brasiliensis and H. balao are typically in diameter and have attaching filaments. They hatch when they grow to about in diameter. Hyporhamphus melanochir eggs are slightly larger, around in diameter, and are unusually large when they hatch, being up to in size. Relatively little is known about the ecology of juvenile marine halfbeaks, though estuarine habitats seem to be favored by at least some species. The southern sea garfish Hyporhamphus melanochir