Striped killifish

Striped killifish
Male specimen at the New England Aquarium
Female specimen at the New England Aquarium
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cyprinodontiformes
Family:	Fundulidae
Genus:	Fundulus
Species:	F. majalis
Binomial name
Fundulus majalis (Walbaum, 1792)

The striped killifish (Fundulus majalis), also called the striped mummichog, is a North American species of saltwater killifish (occasionally also found in brackish water), dwelling in shallow coastal waters close to shore, and is found from New Hampshire to Florida.

It exhibits sexual dimorphism, with the males having vertical black stripes and the mature females having horizontal black stripes along the sides of their silver-colored bodies. Juvenile females have vertical stripes, however, and one or two vertical stripes remain at the end of the tail even on adult females. The striped killifish reaches lengths of 6 (or occasionally 7) inches.

Tidepool survival techniques

In Feb 1916, Popular Science Monthly had a news article on research being done by Professor S. O. Mast of the zoological department of Johns Hopkins.^[1] The professor was studying the Fundulus majolisis and noted their ability to survive the draining of ocean tide pools. These fish would swim and out of the tide pools on regular intervals, somehow knowing when to swim out before the tidewaters drained from the pools. If for some reason the outlet of the pool were to close off as the tide went out, the fish would quickly swim around the tide pool randomly looking for an alternate escape route.

If the fish cannot find an exit, they actually leave the water and flop over land to reach the ocean. Professor Mast saw scores and scores of these fish leave large tide pools and travel across sand bars up to 12 feet wide and six inches tall. The fish nearly always leave the pool on the side towards the ocean, and are able to travel straight towards the ocean rather than flopping around randomly. At the time it was not known how the fish are able to find the ocean so readily.

After about three minutes of becoming trapped in a rapidly disappearing tide pool, a dense aggregation of fish form on the side of the pool towards the ocean, and swim up and down the side of the pool. Then, in groups of about twelve, the fish leave the pool and head across land towards the sea.

References

• Striped mummichog, Gulf of Maine Research Institute.
• Phil Maier, Striped Killifish, South Carolina Dept. of Natural Resources
• Striped Killifish, fishbase.org