The striped killifish (''Fundulus majalis''), also called the striped mummichog, is a North American species of fundulid killifish. It lives in salt and

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estu ...

waters in shallow coastal regions from

New Hampshire New Hampshire is a state in the New England region of the northeastern United States. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec to the nor ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, and in the northern

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

. It exhibits

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...

, 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. Striped killifish typically reach lengths of up to , occasionally .

Tidepool survival techniques

In Feb 1916, ''

Popular Science Monthly ''Popular Science'' (also known as ''PopSci'') is an American digital magazine carrying popular science content, which refers to articles for the general reader on science and technology subjects. ''Popular Science'' has won over 58 awards, incl ...

'' had a news article on research being done by Professor S. O. Mast of the zoological department of

Johns Hopkins University Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private research university in Baltimore, Maryland. Founded in 1876, Johns Hopkins is the oldest research university in the United States and in the western hemisphere. It consi ...

. The professor was studying the ''Fundulus majolisis'' and noted their ability to survive the draining of ocean tide pools. These fish would swim in 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 Endemic fish of the United States Fish of the Eastern United States Fish of the Gulf of Mexico Fauna of the Southeastern United States striped killifish {{Cyprinodontiformes-stub