Butterfish (Peprilus triacanthus)
Alternate common names: Shiner, Butters, Dollarfish.
Color: Grayish blue on back with silvery sides and belly; numerous irregular dark spots
Size: 6 to 9 inches long; weighs less than 1/2 pound.
Habitat: Sheltered bays and estuaries, sandy bottoms; prefer areas of high salinity.
Seasonal appearance: Late April to August.
The butterfish is a small, round fish distinguishable by its thin, deep body and lack of pelvic or ventral fins. It resembles a flounder swimming on its edge. The butterfish has a soft-rayed dorsal fin running along the length of its back and an anal fin almost as long. Its tail is deeply forked, and the pectoral fins are long and pointed. The butterfish has a small mouth with a single row of weak teeth and a concealed upper lip. Its snout is heavy and rounded, and the large eyes are rimmed with fatty tissue. Butterfish scales are quite small and will easily slough off when touched.
Life History and Behavior
Butterfish found in Rhode Island are part of a larger population of butterfish that migrate along the Atlantic coastline from southern New England to Cape Hatteras. They migrate out of the estuaries to deeper waters in late fall as water temperatures cool.
The butterfish reaches sexual maturity after its first year, but rarely lives past the age of three. Juvenile fish stay close to the shore during their first year of its life, preferring areas of high salinity to fresher estuarine waters. When in estuarine waters, butterfish swim near the surface, particularly over sandy-bottom habitats.
Butterfish travel in large schools, preying on small pelagic fish, shrimp, squid, and some-times jellyfish and comb jellies. Juvenile butterfish are often seen taking shelter among the tentacles of sea nettles and other jellyfish, apparently immune to the toxins in the stinging tentacles.
Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.