Seasonal and daily cycles in sound production associated with spawning in the weakfish,Cynoscion regalis

Abstract

SynopsisHydrophone recordings were made to document the daily and seasonal cycles of weakfish, Cynoscion regalis (Sciaenidae), sound production in the Delaware Bay . Recordings were made at three stations perpendicular to the shore and rated qualitatively on a scale of 0-4 . `Drumming' (sonic muscles, males only) and `chattering' (pharyngeal stridulation, both sexes) were tallied separately . Weakfish were collected from the field throughout the spring and summer to monitor the reproductive status of the population . A clear seasonal trend was noted in both drumming and chattering activities . Drumming activity rose abruptly in mid-May to maximal levels, which were maintained through late June, then dropped off in July and ceased in August . Chattering activity began abruptly in late June, then rose through July and remained high in August . Seasonal drumming activity was more intense at the inshore station . On a daily scale, drumming activity was at its lowest level during the early to mid-morning, then increased to maximal levels in the early evening and remained high until the following morning . There was no daily trend in chattering activity . Daily drumming activity was also most intense at the inshore station . Male and female reproductive readiness, determined by gonadosomatic indices, sperm motility and plasma androgen levels, peaked within the period of maximal seasonal drumming activity .

Morphometric changes and sex steroid levels during the annual reproductive cycle of the Lusitanian toadfish, Halobatrachus didactylus

“…The higher levels of 11-KT, but not T, in H. didactylus type I males suggests also that 11-KT must be the androgen responsible for the increase in size of sonic muscle. Swimbladder muscle hypertrophy during the matting season has been identified in three sound-generating species, the haddock Melanogrammus aeglefinus (L.) (Templemen and Hodder, 1958), the midshipman Porichthys sp (Mommsen & Nickolichuck in Walsh et al, 1995) and the weakfish Cynoscion regalis (Bloch and Schneider) (Connaughton et al, 1997;Connaughton and Taylor, 1995b). In C. regalis T implants induced sonic muscle growth but 11-KT was not tested (Connaughton and Taylor, 1995a).…”

Acoustic signalling in female fish: factors influencing sound characteristics in croaking gouramis

“…Sexually dimorphic sonic mechanisms have been described in cods (family Gadidae) (Templeman and Hodder 1958), cusk-eels (Ophidiidae) (Kéver et al 2012), European hakes (Merluciidae) (Groison et al 2011), toadfishes (Batrachoididae) (Fine et al 1990), callichthyid catfishes (Callichthyidae) (Hadjiaghai and Ladich 2015), gouramis (Osphronemidae) (Kratochvil 1985) and croakers (Sciaenidae) (Hill et al 1987, Connaughton andTaylor 1995). In gadiforms, this sexual dimorphism is pronounced during the pre-spawning and spawning season due to hypertrophy of sonic muscles and higher vocal activity of males during the breeding season (Rowe and Hutchings 2004).…”

Identifying Sciaenid Critical Spawning Habitats by the Use of Passive Acoustics

“…Before scoring the DI for each segment of recorded tape, the analyst consulted with the authors to make certain of the identification of each sound and used spectral analysis to classify sounds when necessary (described below). This qualitative DI, based on a similar index developed for frogs (Heyer et al 1994;Bridges and Dorcas 2000) and weakfish (Connaughton and Taylor 1995), ranged from 0 to 3 and represented the frequency of occurrence with which a species was detected on a segment of a sonobuoy recording. For each 90-s audio sample on a sonobuoy recording, the analyst assigned a drumming value for a species of fish according to the following relative scale: (0) not heard; (1) drumming heard infrequently; (2) drumming heard frequently; and (3) continuous drumming indicative of aggregation chorusing.…”