The banded killifish (Fundulus diaphanus) is a North American species of temperate freshwater killifish belonging to the genus Fundulus of the family Fundulidae. Its natural geographic range extends from Newfoundland to South Carolina, and west to Minnesota, including the Great Lakes drainages. This species is the only freshwater killifish found in the northeastern United States. While it is primarily a freshwater species, it can occasionally be found in brackish water.
The common name, "banded killifish", commonly refers to the distinct black and white vertical bandings found along their sides. The Latin genus name Fundulus is the diminutive of fundus, which means "bottom," and the specific name diaphanus means "transparent" in Greek.
Ov
OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
No
Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
B
starts withThe banded killifish has a narrow, elongate bluish-gray or olive-colored body with a darker dorsal surface and white or yellowish underparts extending to the anal fin. Spawning males develop yellow pectoral and pelvic fins, a bright blue patch on the anal fin, and brilliant blue iridescence on the lower portion of the body including the area around the anal fin. There are 12–20 vertical bands along the sides. In females the bands usually appear as thin and distinct black bands that often do not span the full width of the body. In males, the bands are silvery in color, are less distinct, and are closer together. The number of bands are useful in sexing an individual; male banded killifish have a greater (approximately >9) number of bands anterior to the dorsal fin. Fins rounded, base of first dorsal ray slightly ahead of or directly over first anal ray. Snout is blunt, with small superior mouth and projecting lower jaw. Lateral line is missing; 39–43 scales in the lateral series. There are 10 to 13 dorsal fin rays, 9 to 11 anal fin rays and 6 pelvic fin rays. Max length is 13 cm (5.1 in) total length (TL), average length is 6.3 cm (2.5 in) TL.
The eastern subspecies, F. d. diaphanus, can be differentiated from the western subspecies, F. d. menona, by the presence of a further anterior dorsal fin position, increased number of anterior bars in the males of the subspecies (9-15 compared to 5-0 for F. d. menona) with more intense bars along the side that stay intact along the anterior back, a higher number of scale rows (40–44 F. d. menona, 45–49 F. d. diaphanus), and a combined number of dorsal and anal fin rays totaling 24 to 26, compared to 23 to 24 for F. d. menona. Larger maximum sizes have been reported for F. d. diaphanus than F. d. menona.
The banded killifish is similar in habitat preference and appearance to the mummichog, Fundulus heteroclitus, and the two species have been known to interbreed where their habitat overlaps. The banded killifish, while euryhaline, is more commonly found in freshwater, whereas the mummichog primarily inhabits brackish and coastal waters. The two species can be visually identified by the difference in bands; the banded killifish has thin dark bars, while the mummichog has thin light bars. The species can also be differentiated by the thicker caudal peduncle in the mummichog and branchiostegal rays often numbering 6,6 for the banded killifish (5,5 in the mummichog). Banded killifish have larger and more numerous gill rakers compared to mummichogs (8–12 vs. 4–7, respectively).
The Waccamaw killifish, Fundulus waccamensis, is a closely related species to the banded killifish that is endemic to Lake Waccamaw, North Carolina, and its tributaries. the Waccamaw killifish differs by its slimmer profile; the ranges of the two species do not overlap.
The banded killifish is widely distributed throughout eastern North America, ranging from the Pee Dee River, South Carolina to Newfoundland; also found in southern Pennsylvania, northeastern Nebraska, and northern Illinois, and north to St. Lawrence-Great Lakes and Mississippi River basins from Manitoba to Quebec. The eastern subspecies is found on the Atlantic Slope, and the western subspecies in the rest of its range. Westward expansion by the eastern subspecies may be the result of introductions as bait or aquarium fish into novel waterbodies, climate change expanding favorable habitat, or a higher pollution tolerance compared to the western subspecies.
The population of banded killifish in Newfoundland was assigned a status of special concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) due to biogeographical isolation and limitation of potential for range expansion. In the United States, Ohio and Illinois list the western subspecies as endangered and threatened, respectively, due to range expansion of the eastern subspecies which has been documented to hybridize wherever the ranges of the subspecies overlap. As such, Ohio also classifies F. d. diaphanus as an injurious aquatic invasive species. Intergrades occur in the Saint Lawrence and Lake Erie drainages where the ranges of the two subspecies naturally come in contact.
The banded killifish has been introduced outside of its native range in the states of Idaho, Ohio, Oregon, Pennsylvania, South Dakota, Washington, and West Virginia. In Oregon and Washington, the western banded killifish is reported to be the introduced subspecies.
Adults range from 2 to 3 years in age. Banded killifish are schooling fish, usually traveling in groups of 3–6 individuals, while the juveniles travel in groups of 8–12. The fish are most often found in the shallow and quiet areas of clear lakes, ponds, rivers, and estuaries with sandy gravel or muddy bottoms and with abundant aquatic vegetation. The sand and gravel provides hatchlings and juveniles with places to hide when threatened by predatory fish such as the largemouth bass Micropterus salmoides, northern pike Esox lucius, bluegill Lepomis macrochirus, and trout. Because the banded killifish is small, it generally does not venture into deeper waters, where it would be vulnerable to predation as well as unable to swim in the fast currents. However, adult banded killifish have been observed to travel into deep bodies of water to feed. Banded killifish often congregate near aquatic vegetation, as it provides protection as well as breeding habitat.
Banded killifish are euryhaline, but they usually inhabit freshwater streams and lakes. The largest adult recorded, observed in Indian Bay, Canada, was 12.8 cm (5.0 in). People have used banded killifish as fish bait. Most people do not favor them as pets because they require a high level of maintenance and therefore do not survive well in an aquarium setting. They are important to aquatic ecosystems because they are a food source for larger fish such as largemouth bass, northern pike, and trout. They are also a food source for birds such as belted kingfisher (Megaceryle alcyon), common merganser (Mergus merganser), and herons.
In January 2005 the banded killifish was listed as a vulnerable species under the Newfoundland Labrador Endangered Species Act and the Canada Species at Risk Act (SARA) for the Newfoundland population. This species is facing habitat degradation due to industrial development, motorized watercraft activities, and removal of aquatic vegetation.
Banded killifish have been observed to feed at all levels of the water column. The adults feed on a variety of items such as insects, nymphs, mollusks, turbellarians, and other small crustaceans. Mosquito larvae are also a popular food source. In contrast, the smaller individuals are limited to fewer items such as chironomid larvae, cladocerans, copepods, and midge larvae. Both young and adult banded killifish have been observed to feed mostly in the afternoon.
Banded killifish are commonly observed to spawn in dense aquatic vegetation because they practice external fertilization where the female lays her eggs that are equipped with adhesive threads that adhere to plants. Spawning occurs from June to mid-August in shallow waters. During the spawning season, the males go through a color change phase. They develop a bright blue patch near the anal fin. In addition, the lower portion of the body changes to a bright blue color.
Spawning occurs at water temperatures of 21 to 23 °C (70 to 73 °F). The male chooses a site in the shallow part of the water and protects it from other males. When a female appears, the male will court the female and fight with the other prospecting males. The female will emit one egg while the male pursues her. Once together, the female emits 10 eggs that falls onto the bottom or gets attached to aquatic plants in the chosen spawn area. The male will continue to pursue the female until the female have laid 50 to 100 eggs.
A single female may lay several clutches of eggs during one summer. After the eggs have been fertilized, both the parents will leave and go their separate ways; the eggs do not receive parental care. Fry (6–7 mm or 0.24–0.28 in in length) emerge within 10 to 12 days depending on the temperature of the water. They reach maturity at approximately 1 year with an average length of 6 cm (2.4 in). Banded killifish can live for a little over 2 years. However, there have been some that have been observed to live up to 3 years.
