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Hickory shad (''Alosa mediocris'') is an member of the herring family Clupeidae, ranging along the East Coast of the United States from Florida to the Gulf of Maine. It is an anadromous fish species, meaning that it spawns in freshwater portions of rivers but spends most of its life at sea. It is subject to fishing, both historic and current, but it is often confused with or simply grouped together with catch statistics for American shad (''Alosa sapidissima''). ==Distribution, habitat, and life history== Hickory shad ranges from northern Florida to the Gulf of Maine. The largest populations occur in Chesapeake Bay and coastal North Carolina (Munroe 2002). It is a schooling anadromous species that inhabits marine waters, probably never far from land. Adults enter estuaries and freshwater tributaries from the St. John's River, Florida, to the Patuxent River, Maryland,to spawn during the spring. Their oceanic movements are poorly documented (Hardy 1978; Cooper 1983; Rulifson 1994). Spawning occurs from December to June, earliest in Florida and later with increasing latitude (Hardy 1978; Harris et al. 2007). The slightly adhesive and demersal eggs, approximately 1 mm in diameter, appear to be dispersed at random over gravel bars in moderate current. After water hardening, the eggs become semi-buoyant and develop as they drift along the bottom (Mansueti 1962; Hardy 1978; Cooper 1983). Fecundity ranges from 43,000 – 475,000 eggs per female, and, although the developmental stages of eggs, larvae, and juveniles have been described, little is known concerning the distribution, ecology, and growth rates of these early life stages (Mansueti 1962; Hardy 1978). Hickory shad live to seven years (Harris et al. 2007). Both sexes mature at 2–4 years and can repeat spawn. Females are larger than males; in Florida, the average female is 37 cm fork length and the average male is 34 cm fork length (Harris et al. 2007). Hickory shad are piscivorous, feeding primarily on small fishes, although crustaceans and squid contribute to their diet (Cooper 1983; Munroe 2002). One study showed that their diet on the spawning grounds was almost exclusively fish (97% by weight; Harris et al. 2007). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hickory shad」の詳細全文を読む スポンサード リンク
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