Bringing the Urban Environment Into the Classroom: Learning From an Estuarine Mesocosm
Appendix C: Fundulus heteroclitus Fact Sheet (to be handed out to students)
Note: For the purposes of uninterrupted reading by students, references are not placed in the body of the fact sheet. References may be found in Literature Cited.
The Banded Killifish (Mummichog)
General Info and Habitat
The mummichog, Fundulus heteroclitus, is an estuarine species that can tolerate a wide range of temperatures and salinities. It often coexists with another Fundulus species, Fundulus diaphanus, and is often found in schools of large numbers. Growing up to 5 inches, when found in salt pools, they may be the largest predators; but in tidal creeks and open bays of estuaries, they are preyed upon by many larger fish.
What They Eat
The mummichog is an omnivore that consumes a wide range of organisms. It will eat eelgrass fragments, insect larvae, smaller fish, fish eggs, diatoms, mollusks, crustaceans, and worms in the sediment.
What Eats Them
The mummichog is an important food source for larger fish and wading birds.
Range
The mummichog is found from the Atlantic coast of Florida north through the Gulf of St. Lawrence in Canada.
Life Cycle
The mummichog spawns between April and August. Spawning occurs at high tides with the new and full moons, usually at night. Clutches of eggs, which may number up to 300, are deposited in mussel shells, on the underside of eelgrass leaves, or in other hidden places where they are protected from drying even after the high tide recedes. The eggs hatch after the tides reach them again.
The Urban Connection
This small fish is particularly well adapted to survive in urban environments. PCB's (poly-chlorinated biphenyls) are a type of contaminant that can prevent many organisms from surviving and reproducing. Heritable altered gene expression in populations of fish from polluted areas is thought to aide these fish in their survival in heavily polluted estuaries. Because of this genetic change, these fish have been found in heavily polluted harbors such as New Bedford, MA and Newark Bay, NJ.
The mummichog has also been used in a wide range of scientific studies, because it is a vertebrate that is capable of being held in large populations for experimental studies in laboratories. It has been an experimental animal used to study evolution, toxicology, and endocrinology.
But this fish's value to people extends beyond the laboratory. The mummichog is an important food source for larger fish and is important in maintaining their populations. Many fishermen use the mummichog as bait while fishing. And mummichogs are also important for mosquito control. They have even been introduced into ponds and ditches because they eat the mosquito larvae. One mummichog may eat as many as 2,000 larvae a day! This is important not only to prevent urban dwellers (like us) from itching annoying mosquito bites, but may even help prevent the spread of dangerous diseases spread by the mosquitoes, such as eastern equine encephalitis and West Nile virus.
Look It Up!
If you didn't understand something you read above, look it up! A "Google" search is a good place to start (www.google.com). Another good place to start is at the American Killifish Association (www.aka.org). It lists a number of "links" that you can use to navigate.