Sound Production and Reproductive Behavior of Yellowfin Grouper, Mycteroperca venenosa (Serranidae) at a Spawning Aggregation
Reproductive behaviors and sound production of the Yellowfin grouper (Mycteroperca venenosa) are described from in-situ observations by divers as well as synchronous underwater audio-video recordings at a spawning aggregation off Mona Island, Puerto Rico. The highest abundances of M. venenosa estimated from underwater visual surveys were detected in March and April, five to nine days after the full moon (DAFM). Four distinct color phases were observed for M. venenosa; two of these were unique to the spawning aggregation and one, the white-headed phase, was exhibited during interactions with other conspecifics corresponding to courtship displays. Variations in color phases during fish interactions and group formation coupled with sounds preceded spawning, which occurred near sunset. Low-frequency (<150 Hz) sounds produced by M. venenosa were variable yet they were classified into two types, pulsed and tonal. Both types of sounds were associated with reproductive behaviors although not linked to spawning rushes. These sounds were most frequent between 1800 and 2100 h, peaked the eighth DAFM, and ceased between 11–13 DAFM. Temporal patterns in sound production suggest that peak reproduction occurred in April followed by a smaller aggregation in May of 2010. The association of passive acoustics with reproductive behaviors for M. venenosa provides a tool to help identify spawning aggregation sites and monitor spawning stock abundance to evaluate the effectiveness of management and conservation efforts for this Near Threatened grouper.
Location of Mona and Monito Islands in the Mona Passage west of Puerto Rico.
Mean (SE) density (individuals/100 m2) of E. guttatus, M. tigris, and M. venenosa by month, for years 2006–2010.
Size frequency distribution of M. venenosa based on diver's visual estimates of fork length (cm) during underwater surveys.
(A) Sexual dimorphism in the dark color phase M. venenosa; the female (smaller size) exhibits red coloration and the male (larger size) yellow markings on maxilla. (B) Monochrome photo extracted from the stationary video camera of a white-headed phase M. venenosa.
Oscillograms and spectrograms of sounds produced by M. venenosa. (A) Pulse train call, (B) tonal call, and (C) sequential combination of the two types of calls (FFT size = 256, no overlap).
Number of calls of M. venenosa per 20 s interval (boxes are Standard Errors and whiskers are 95% Confidence Interval), averaged per hourly interval throughout the day (from recordings between 5–11 April 2010; 7–13 DAFM).
Number of calls of M. venenosa per 20 s interval (boxes are Standard Errors and whiskers are 95% Confidence Interval), from 1900 to 2000 h, on days after the full moon (DAFM) during April and May 2010.
Contributor Notes
Associate Editor: J. F. Schaefer.