Full Description

"Drumming behavior and increased sonic muscle mass have both been associated with reproductive activity in weakfish (Connaughton and Taylor, 1994, 1995), but the actual role of male drumming in weakfish reproductive be- havior is unknown."

"The rate of drumming activity was calculated for one trial with a single male and one trial with multiple males. Drumming rate was calculated as the number of drumming bursts min—1. A typical drumming burst consisted of a brief, uninterrupted series of 6-10 pulses of sound."

"Drumming males remained relatively stationary just above the gravel at the bottom of the tank and did not rise from the bottom while drumming. Drumming activity was nearly con- tinuous once initiated, with no more than a few minutes passing between drumming bouts (Ta- ble 1, Fig. 1). Drumming ceased when the male left the bottom in pursuit of a female, and no drumming was heard during pursuit or gamete release. Following gamete release, the male of- ten returned directly to the bottom and began drumming again."

"Drumming activity was initiated immediately following the first spawning event of the evening in all four trials (Table 1). However, in trial 3, there was a period of irregular drumming bursts (bursts with less than the typical number of pulses) prior to the first spawning event. In trials where only one male was present, drumming duration ranged from 65-86 min, whereas it ranged from 116-186 min in trials with multiple males. In the trials with multiple males, it was impossible to determine which male was drumming and whether more than one male drummed during the course of the evening. However, at no time were two males heard to drum simultaneously or to alternate calls. No agonistic or territorial behavior was noted among males. The drumming rates of both single and multiple males were quite variable but largely unchanging over the course of an evening."

"In the present experiment, no change in male weakfish behavior was observed in the presence of a gravid female, short of the cessation of drumming and initiation of spawning. Similarly, no gross changes in drumming rate were associated with the spawning events in trials 3 or 4. No agonistic behavior was observed among weakfish males."

"Male drumming may aid in the attraction of gravid female weakfish, especially considering the relatively stationary posture the male assumes when drumming."

"Male drumming may also provide females with information about the drumming male. The frequency and sound pressure level of a given drumming burst varies with the length of the drumming individual (unpubl. data). These call characteristics may allow for some selection among drumming males, if females are able to process these data. Finally, drumming behavior may be involved in maintaining spawning aggregations."

"This suggests that the increase in drumming activity during the early evening in the field is more likely due to an increase in the number of calling males as the fish aggregate rather than to an increase in the rate of calling of individual males. This supports the field data indicating a daily formation of spawning aggregations but does not reveal whether male drumming activity results in, or is the result of, weakfish aggregation. Our observations suggest that male drumming is not involved in direct male-male interactions. No male-male agonistic behavior was noted during these experiments, nor was facilitation of drumming behavior noted in response to the calls of other males. However, weakfish drumming was associated with spawning behavior in the laboratory, though it was not directly involved in final courtship or gamete release."

Observation Environment Quotes

"Male and female weakfish were collected in May 1993 from the south-west portion of the Delaware Bay, near Lewes,Delaware. Captive fish were separated by sex and maintained at ambient photoperiod and 21-23 Cin two 4500-liter seawater tanks until needed for an experiment."

Behaviour Description Quotes

"Drumming males remained relatively stationary just above the gravel at the bottom of the tank and did not rise from the bottom while drumming. Drumming activity was nearly con- tinuous once initiated, with no more than a few minutes passing between drumming bouts (Ta- ble 1, Fig. 1). Drumming ceased when the male left the bottom in pursuit of a female, and no drumming was heard during pursuit or gamete release. Following gamete release, the male of- ten returned directly to the bottom and began drumming again."

"Male drumming may aid in the attraction of gravid female weakfish, especially considering the relatively stationary posture the male assumes when drumming. 'Finally, drumming behavior may be involved in maintaining spawning aggregations. "

"However, weakfish drumming was associated with spawning behavior in the laboratory, though it was not directly involved in final courtship or gamete release."

Sound Name Quotes

"Drumming behavior and increased sonic muscle mass have both been associated with reproductive activity in weakfish (Connaughton and Taylor, 1994, 1995), but the actual role of male drumming in weakfish reproductive be- havior is unknown. "

"The rate of drumming activity was calculated for one trial with a single male and one trial with multiple males. Drumming rate was calculated as the number of drumming bursts min—1. A typical drumming burst consisted of a brief, uninterrupted series of 6-10 pulses of sound."