that lack filaments (adhesive chorionic fibrils) and they often deposit those eggs inside empty mussel shells. The two subspecies are also distinguished based on slight morphological and genomic differences. Most mummichogs become sexually mature when two years old, around in length. Normal lifespan is four years. Parasites Mummichogs are hosts to a parasitic fluke, Homalometron pallidum, which has a complex lifecycle involving the aquatic snail, Ecrobia truncata. Other parasite species reported in mummichogs include 10 protozoans, eight trematodes, one nematode, two acanthocephalans, and two crustaceans. A study in New Jersey found that mummichogs heavily infested with the digenean gill parasite Ascocotyle phagicola, spent more time near the surface and exhibited conspicuous behaviors such as jerking, an example of a parasite affecting the behavior of its host in a way beneficial to the parasite, as conspicuous behaviors near the surface make the fish more likely to be noticed by predatory wading birds, the next host in the parasite's life cycle. Interest to humans Mummichogs readily eat mosquito larvae and attempts have been made to use them as biocontrol agents of mosquito populations. Fishing Mummichogs are sold as bait in sport fisheries for marine species such as summer flounder and bluefish, or even sometimes for freshwater species. They are the most popular baitfish species in the Northeast of America and traditionally when used as bait they were lip hooked and then dressed with a piece of squid. Scientific utility Mummichogs are considered an important environmental model organism because of their ability to tolerate various extremes of chemical (pollution, etc.) and physical (temperature, salinity, oxygen, etc.) conditions. They are relatively abundant in nature and can be easily captured, transported and reared in laboratory facilities. They are commonly used in scientific studies of stress biology, thermal physiology and toxicology, and have also been studied in the contexts of evolutionary biology, developmental biology, endocrinology, cancer biology, and chronobiology (study of circadian rhythms). With the successful sequencing and assembly of the full killifish genome, they serve as a premier scientific model for studying biochemical and physiological responses to varying environmental conditions. Their remarkable ability to tolerate various extremes of temperature and salinity has made them popular subjects in scientific studies of toxicology. For decades the killifish has been a useful laboratory model for toxicological studies that include exposures to single chemicals, chemical mixtures, and complex contaminated media. It is sometimes the only fish species found in