page_title: Dusky dolphin
section_title: Foraging and predation
hierarchical_section_title: Dusky dolphin / Ecology and behaviour / Foraging and predation
caption_attribution_description: Español: Delfines oscuros
context_page_description: The dusky dolphin is a dolphin found in coastal waters in the Southern Hemisphere. Its specific epithet is Latin for "dark" or "dim". It is very closely genetically related to the Pacific white-sided dolphin, but current scientific consensus holds they are distinct species. The dolphin's range is patchy, with major populations around South America, southwestern Africa, New Zealand, and various oceanic islands, with some sightings around southern Australia and Tasmania. The dusky dolphin prefers cool currents and inshore waters, but can also be found offshore. It feeds on a variety of fish and squid species and has flexible hunting tactics. The dusky dolphin is known for its remarkable acrobatics, having a number of aerial behaviours. The status of the dolphin is unknown, but it has been commonly caught in gill nets.
context_section_description: Dusky dolphins prey on a variety of fish and squid species. Common fish species eaten include anchovies, lantern fish, pilchards, sculpins, hakes, horse mackerel, hoki and red cod. They are generally coordinated hunters. Their very flexible foraging strategies can change depending on the environment. In certain parts of New Zealand, where deep oceanic waters meet the shore, dusky dolphins forage in deep scattering layers at night. They arrive at the hunting site individually, but form groups when in the layer. The dolphins use their echolocation to detect and isolate an individual prey. Groups of foraging dolphins tend to increase when the layer is near the surface and decrease when it descends.
  When hunting in shallower waters in New Zealand and Argentina, dusky dolphins tend to forage during the day. The dolphins chase schools of fish or squid and herd them into stationary balls. They may control the school with light reflected from their white bellies. Dolphins herd prey against the surface, but also horizontally against the shore, a point of land, or the hull of a boat. During these times, dusky dolphins are believed to increase prey availability for other predators, including other dolphins, seabirds, sharks, and pinnipeds. In Argentina, dusky dolphins may use bird aggregations to locate and herd prey. Conversely, pinnipeds and sharks take advantage of the dolphin hunts. Dusky dolphins are themselves preyed on by killer whales and large sharks. Dolphins avoid killer whales by swimming into shallower water. Dusky dolphins are also susceptible to parasitism by certain nematode, cestode, and trematode species, mostly the genera Nasitrema and Anisakis, and Phyllobothrium delphini, Braunina cordiformis, and Pholeter gasterophilus.
caption: Dusky dolphins
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