The Biogeography of the Dolphinfish :: Coryphaena Hippurus Animals Essays

The Biogeography of the Dolphinfish Description of Species Dolphinfish are compressed, elongated fish with a large mouth and many fine teeth. They have a long dorsal fin that stretches from their nape to a forked tail. The anal fin is also long, extending from mid-body to their forked tail. Males have a bony crest on the head that is not present in females. These colorful fish exhibit hues of gold on the sides, iridescent blues and greens on the sides and backs, and white and yellow underneath. The average size of the mature dolphinfish is between 1.5 - 3 ft. and weighs 15 - 30 lbs. Males are generally heavier than females regardless of length (Palko et al. 1982). The largest fish ever recorded was an 87 lb. fish caught off the coast of Costa Rica. Studies of sex ratios are inconclusive in regards to the distribution of males and females worldwide (Palko et al. 1982). Habitat Coryphaena hippurus is a pelagic fish that inhabits tropical and sub-tropical oceans worldwide. This cosmopolitan saltwater fish prefers water above 70 degrees F. (McClane 1974), and therefore, temperature determines the range for this species. The dolphinfish inhabits open waters near the edges of the continental shelves in tropical and sub-tropical environments (Palko et al. 1982). Vertical distribution in the ocean ranges from the surface to approximately 90 feet underwater (Palko et al. 1982). They are commonly found loitering near objects floating in water that may harbor prey species. These objects can be as substantial as large clumps of Sargassum weed, and insignificant as small streams of sea foam. Not much is known about the migration patterns of this fish, but it has been hypothesized that they follow seasonal fluctuations in water temperature in search of more productive food sources (Palko et al. 1982). Natural History Dolphinfish are migratory fish that travel in schools known as pods. The size of these schools is usually determined by size or sex. Young female dolphinfish tend to congregate near Sargassum patties while the young males usually seek the company of older males and females in the open ocean (Palko et al. 1982). Additionally, larger fish travel in smaller pods. Research concerning migration has provided little information about what determines the movements of dolphinfish.