Observation Environment Quotes

"Sound production by other sciaenid species commonly noted in the area (Bairdiella chrysoura and Micropogonias undulatus) was recorded in the laboratory and compared with laboratory and field recordings of weakfish sound production using a Kay DSP Sonagraph workstation (Model 5500) ."

Full Description

"Hydrophone 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."

"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."

"The data were analyzed qualitatively by scoring the number or intensity (if too many to score) of drumming or chattering bursts in a minute."

"Drumming and chattering sounds were more easily separated this way, due to the difference in frequency of the calls ; drumming 300- 500 Hz, chattering > 1000 Hz (Fish & Cummings 1972, unpublished data) ."

"Drumming activity at the inshore station began abruptly in mid-May and remained high until late June, after which activity dropped gradually back to zero . Levels at the midwater and offshore stations increased later in the season, but decreased at the same time as the inshore levels . Drumming activity remained at or near maximal levels at the inshore station during late May and June and was higher at this station than at either of the others throughout the season . Chattering activity, when pooled by date, appeared abruptly at all three recording stations in late June and remained high through July and August (Fig . 3) . In general, chattering activity appears to have been slightly higher further inshore ."

"During the spawning period (Fig . 4b), daily drumming activity reached a low at all three stations during the early to mid-morning, then increased at all three to peak between 23 :00 and 02 :00 h."

"The duration of high intensity sound production in a 24 h period decreased at greater distances from shore."

"There was little drumming activity during the pre-spawning and post-spawning periods (Fig . 4a, c) ."

"Maximal levels of all of these indicators of reproductive readiness fell within the period of maximal drumming activity, expressed as a trace of seasonal inshore drumming activity in Fig . 6a ."

"The rapid increase in drumming activity in early May is most likely due to both an increase in the number of drumming males present as well as an increase in the drumming activity of individual males ."

"Daily drumming activity in this study increased from morning through late evening, with maximal activity between 17:00 and 02 :00 h for all three stations ."

"Chattering activity, while also seasonal, did not coincide with the spawning period of the species, only begining as reproductive and drumming activities were decreasing . There was also no apparent daily cycle in chattering activity. Chattering may be influenced by temperature, as the surface temperatures did not reach above 22 C until mid-June, just prior to the first substantial recorded chattering activity. Chattering was observed with or without drumming individuals near by, in single specimens or in choruses . The function of this chattering behavior is, as yet, unknown ."

"Increased drumming activities at the midwater and offshore stations in late June and July suggest that spawning may be occurring in these deeper waters late in the spawning season. Though our reproductive data suggest that spawning might have been finished by this late in the season, our sampling sites were primarily inshore and it is possible that reproductively active fish might be found in deeper waters at this time ."

"Daily drumming activity during the spawning season peaked between 19:00-23 :00 h. Drumming at the midwater and offshore stations peaked later in the evening, between 23 :00 and 02 :00 h, by which time inshore activity had decreased to some extent ."

"Weakfish spawning in captivity were noted to continue drumming for between 0 .5 and 3 h following the final spawning event of the evening (unpublished) ."

"Daily drumming activity in weakfish was substantial prior to daily peak spawning activity (Taylor & Villoso 1994), supporting the hypothesis that drumming in weakfish may also play a role in the formation of daily spawning aggregations ."

Observation Environment Quotes

"Recordings of weakfish sound production were made using a hydrophone at three stations perpendicular to the shore near Lewes, DE in the southwestern portion of the Delaware Bay (Table 1) . One minute recordings were made at each of these stations at several times on a sampling day."

Behaviour Description Quotes

"Sound production has also been observed in Sciaenops ocellatus (Guest & Lasswell 1978), and Cynoscion regalis (unpublished) during spawning in captivity."

" Daily drumming activity in weakfish was substantial prior to daily peak spawning activity (Taylor & Villoso 1994), supporting the hypothesis that drumming in weakfish may also play a role in the formation of daily spawning aggregations ."

Sound Name Quotes

"Hydrophone 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."

" The data were analyzed qualitatively by scoring the number or intensity (if too many to score) of drumming or chattering bursts in a minute."

" Chattering was observed with or without drumming individuals near by, in single specimens or in choruses . The function of this chattering behavior is, as yet, unknown ."

Observation Environment Quotes

"Sound production by other sciaenid species commonly noted in the area (Bairdiella chrysoura and Micropogonias undulatus) was recorded in the laboratory and compared with laboratory and field recordings of weakfish sound production using a Kay DSP Sonagraph workstation (Model 5500) ."