Determination of the Spawning Season of Bigmouth Sleeper in Puerto Rico by Examination of Gonad Maturation and Reproductive Hormone Cycles

Abstract

Bigmouth sleepers, Gobiomorus dormitor, are diadromous fish that have potential for hatchery production as both food and sport fish and for conservation purposes. Understanding of bigmouth sleeper maturation and seasonal hormone cycling are necessary in order to realize hatchery production. Therefore, seasonal trends in gonadosomatic index (GSI) and plasma vitellogenin, estradiol, progesterone and total testosterone concentrations were examined in wild and captive populations in Puerto Rico during the presumed spawning season. The spawning season for wild river populations of bigmouth sleepers was protracted over several months, but peaks in male testosterone (6.5 ng/mL) and female vitellogenin (11.3 ng/mL), estradiol (3.3 ng/mL), and GSI (9.5-12.0%) demonstrated that the bigmouth sleeper spawning season occurred primarily in July and August in southwestern Puerto Rico. Captive female broodstock held in shallow hatchery ponds demonstrated accelerated maturation, presumably due to warmer water temperatures in the ponds. Therefore, induced and natural spawning attempts using captive female bigmouth sleeper broodstock should be conducted from June through July. However, advanced gonadal maturation and increased testosterone production in captive males was minimal. Hence, induced spawning for captive rearing purposes should use wild broodstock captured during the peak of the natural spawning season in July and August.

Movement of Bigmouth Sleeper, Gobiomorus dormitor, in the Río Cañas, Puerto Rico, revealed by radio telemetry, and a discussion of the species’ amphidromous characterization

“…Amphidromous species would presumably move downstream during the spawning season to facilitate rapid conveyance of eggs and larvae to the sea. We observed a downstream movement, but not until September, after the spawning season for Puerto Rico Bigmouth Sleeper identified by Harris et al (2012). However, the spawning season might be longer than originally determined by Harris et al (2012).…”

“…We observed a downstream movement, but not until September, after the spawning season for Puerto Rico Bigmouth Sleeper identified by Harris et al (2012). However, the spawning season might be longer than originally determined by Harris et al (2012). Perhaps movements downstream were brief and episodic, and thus not observed during our 1-2 d tracking periods occurring weekly during the spawning season.…”

Effects of Temperature and Salinity on Early Ontogeny of Bigmouth Sleeper Larvae

“…The Bigmouth Sleeper can survive and grow in impounded waters and upstream river reaches wherever juveniles can colonize (Harris et al. ), and in rare cases the species can complete its lifecycle in landlocked lakes or reservoirs (Darnell ; McKaye et al. ; Bedarf et al.…”

“…This species is amphidromous and normally requires unimpeded access between freshwater and marine environments to complete its lifecycle (Gilmore 1992;Holmquist et al 1998;Hernández-Saavedra et al 2004). The Bigmouth Sleeper can survive and grow in impounded waters and upstream river reaches wherever juveniles can colonize (Harris et al 2012), and in rare cases the species can complete its lifecycle in landlocked lakes or reservoirs (Darnell 1962;McKaye et al 1979;Bedarf et al 2001;Bacheler et al 2004). In general, however, this species is eliminated from impounded systems above dam structures.…”