Twait shad are silvery, sometimes with a bronzy tinge, and there are a distinctive row of six to ten large dark spot just behind the gill cover though these may fade when the fish is dead. The adult length is typically . The twait shad is found in most of Europe and all countries bordering the Mediterranean Sea. "Alosa fallax" has a similar lifecycle to "A. alosa" (allis shad). They are known to live in sympatry. Some studies have suggested "A. fallax" and "A. alosa" species can hybridize. They are anadromous species, like many other species in the genus "Alosa". However, some
Rachel Carson National Wildlife Refuge have extensive vernal pool habitat that would benefit several Species of Concern. Coastal marshes, bays, tidal creeks, and rivers support diverse shellfish and finfish populations. Sunfish ("Lepomis" species), creek chub ("Semotilus atromaculatus"), cunner ("Tautogolabrus adspersus"), golden shiner ("Notemigonus crysoleucas"), common mummichog ("Fundulus heteroclitus"), American eel ("Anguilla rostrata"), and white sucker ("Catostomus commersoni") abound. Brook trout ("Salvelinus fontinalis") and brown trout ("Salmo trutta") are stocked in rivers and estuaries each year. The Ogunquit River sustains alewife ("Alosa pseudoharengus"), blueback herring ("Alosa aestivalis"), pollock ("Pollachius virens"), bluefish ("Pomatomus saltatrix"), longhorn sculpin ("Myoxocephalus octodecimspinosus"), and winter flounder ("Pleuronectes americanus"). The Webhannet River has