Greater Redhorse Ontogeny


Adult greater redhorse Moxostoma valenciennesi, were seined from the Grand River, Ontario, and artificially spawned in May 1997 and May 1998, Eggs hatched after 6-8 d at a mean temperature of 19 C. Eggs and larval development of 9-22 mm specimens are described. Ontogeny of larval greater redhorse was compared to that of other syntopic Moxostoma species from previously published studies, including river redhorse ( Mcarinatum), black redhorse (Mduquesnei), golden redhorse (Merythrurum), shorhead redhorse (Mmacrolepidotum), coper redhorse (Mhubbsi) and spotted sucker (Minytrema melanops). There was significant overlap between most meristic variables that were compared. However, the majority of greater redhorse ( up to 18-mm) have myomere counts (27-33 pre-anal myomeres, 9-10 postanal myomeres and 39-42 total myomeres) that are different from other sympatric redhorse species and spotted suckers and may allow identification of greater redhorse as small as 9-mm.