Environmental Biology of Fishes

, Volume 15, Issue 1, pp 59-68

First online:

A novel sexual pattern in serranid fishes: simultaneous hermaphrodites and secondary males in Serranus fasciatus

  • Philip A. HastingsAffiliated withDepartment of Ecology & Evolutionary Biology, University of Arizona
  • , Christopher W. PetersenAffiliated withDepartment of Ecology & Evolutionary Biology, University of Arizona

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Gulf of California populations of Serranus fasciatus are composed of functional simultaneous hermaphrodites and males. This is the first serranid known to have this sexual pattern which is functionally intermediate between the typical serranid patterns of simultaneous and protogynous hermaphroditism. Males of S. fasciatus are derived from hermaphrodites by resorption of ovarian tissue and proliferation of the extant testicular band. Distinct sexual roles are evident in spawning events. Hermaphrodites gain female function by pair spawning with males (124 and 125 observed spawns) and rarely with other hermaphrodites (1 of 125). Hermaphrodites gain male function by sneak spawning (9 of 125) and rarely by pair spawning with other hermaphrodites. Males exclusively pair spawned with hermaphrodites. Despite its unusual sexual pattern, S. fasciatus appears allied with other Serranus species based on similarities in gonad morphology.


Gonad morphology Reproductive behavior Gulf of California