Delta Smelt (Hypomesus transpacificus) Exhibit Wide Variation in Spawning Behavior: An Investigation of Substrate Type, Diel Timing, and Participants

Abstract Studies of cultured populations can be invaluable to the conservation imperiled species for which little is known and whose very low abundance in wild preclude studies with robust sample sizes. For example, endangered delta smelt ( Hypomesus transpacificus ), measures developed mitigate population decline are hindered by a lack knowledge regarding spawning behavior. However, availability allows important questions about addressed experimentally. We examined effect substrate type on behavior egg fertilization success H. under laboratory conditions. also diel frequency sex number participants. found that spawns resulting did not differ between sand, gravel, control (acrylic) substrates. demonstrated was predominantly nocturnal, though rare diurnal were observed. Of five mature males ripe females available within given trial, included up seven participants, but most frequently occurred single female one or two males. Our results highlight wide behavioral variation exhibited during spawning, particularly terms use, timing, These findings provide detailed experimentally data date thereby ongoing efforts much-needed information.