Fields of interest: Bioacoustics Reproductive physiology and behavior Muscle physiology Ichthyology Reproductive endocrinology Current research interests - Sound production in family Sciaenidae Overall research goal To describe the anatomy and physiology of the sonic muscles of sciaenid fishes, characterize the sounds produced by these muscles, and describe the behaviors in which sound production plays a role. Introduction Sciaenid fishes, or drum fishes, are considered important commercial and recreational species throughout the Mid-Atlantic region of the United States. Most of the members of this family are prolific sound producers and sound has been tied to courtship behaviors, and has even been used to locate spawning populations of some sciaenids. The more we know about the sonic behaviors of these fish, the more accurately we may be able to predict the location and timing of spawning activity. This, in turn, might be used to manage the stocks of these species more effectively by proscribing certain waters at certain times of the year from commercial fishing. Drum fishes produce sounds, variously described as knocks, purrs, or grunts, through the use of sonic muscles. These muscle lie along the inside of the body cavity, down the length of the swimbladder, a gas filled gland that functions to maintain neutral buoyancy in the fish, but which also amplifies the sounds produced by the sonic muscles.
Figure 1. An illustration showing the position of the sonic muscles (vertically striated structure) inside the body cavity of the weakfish. The tip of the swimbladder (in white) can just be seen behind the swim bladder. Past and current studies My past work on the weakfish, Cynoscion regalis, has included field studies of the seasonality of sound production and laboratory observations of the role of sound production in courtship behaviors. In addition, we have studied the seasonal tripling in mass of the sonic muscle in
response to increasing sex steroids, the mechanism of sound production, and the impact of fish size, water temperature and sonic muscle size on the sounds produced. Recently completed work has involved an anatomical study of the number and pathways of nerves supplying the sonic muscles in three related, but morphologically and ecologically distinct species, the weakfish, the Atlantic croaker Micropogonias undulatus, and the spot, Leiostomus xanthurus.
Figure 2. An illustration of the pathways of the spinal nerves supplying the sonic muscle (those in red) of the Atlantic croaker relative to the skeletal structures. Ongoing work in my lab centers on the Atlantic croaker. In this species, both the male and female bear sonic muscles, unlike the weakfish or spot in which only the male bears these muscles. The croaker also use their sonic muscles in at least two distinct behaviors; courtship and fright responses. In the lab, we have been using a hydrophone to record and compare the sounds produced during these two behaviors. We hope to describe the differences in these two calls, which have very different functions: one warns of danger and may scare away other croaker, while the other may act to draw a female closer to the male during courtship.
Figure 3. Waveforms of sounds produced by croaker during a fright response behavior (top panel) and during courtship (bottom panel). Note the difference in the repetition rate of the pulses within
each call, the courtship call is much slower. There are also differences in the frequencies of these two types of calls which cannot be seen in this figure. Student publications: Vance, T.L, Hewson, J.M., Modla, S. and M.A Connaughton. 2002. Variability in sonic muscle size and innervation among three sciaenids: spot, Atlantic croaker and weakfish. Copeia, in press. Copeia is the journal of the America Society of Ichthyologists and Herpetologists. Petrone, C.J. 2001. Copepod diversity and density at the mouth of the Delaware Bay. Bios 72(3): 92-99. Vance, T.A. 2000. Variability in stridulatory sound production in the channel catfish, Ictalurus punctatus. Bios 71: 79-84. Bios is an undergraduate research publication of Tri-Beta, the national biology honor society. Student research project titles and presentations at local or national conferences: 2002 J. Drummond. Sound Production in Atlantic Croaker: Fish Size, Sex, and Sonic Muscle Condition. Presented at: 2002 Washington College Summer Research Colloquium, July, 2002. 2001-2002 L. Marini. Do croaker sonic muscle fibers hypertrophy or atrophy during the spawning season? Senior thesis Presented at: Tri-Beta North East District 2 Convention, Washington College, April 2002 B. Neal. Whole-mount clearing and staining determination of croaker sonic muscle innervation patterns. Senior thesis Presented at: Tri-Beta North East District 2 Convention, Washington College, April 2002 S. Modla. Seasonal variability in the sonic muscles of the Atlantic croaker. Summer 2001 Presented at: Tri-Beta North East District 2 Convention, Washington College, April 2002 J. Hewson. An examination of sciaenid sonic muscle innervation. Summer 2000, BIO 495: Ind. Research SP 2001 Presented at: Tri-Beta North East District 2 Convention, The College of New Jersey, March 2001. Presented in part at: The 81st annual meeting of the American Society of Ichthyologists and Herpetologists, Penn State University, State College, PA, 2001. Title: A comparison of the sonic muscle innervation patterns of three Sciaenids: the spot, weakfish and Atlantic croaker. Co-authors: Vance, T.L., M.A. Connaughton. Published along with work by Vance and Modla in Copeia, see above.
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M. Lunn. Comparison of Atlantic croaker fright response and courtship sound production. Senior thesis Presented in part at: International Workshop on the Application of Passive Acoustics in Fisheries. Brooks Center, Massachusetts Institute of Technology, Dedham, MA, April 2002. Title: Characterization of sounds and their use in two sciaenid species: weakfish and Atlantic croaker. Co-authors, Connaughton, M.A., M.L. Fine, and M.H. Taylor. M. Lunn. Seasonal variability in Atlantic croaker sonic muscle mass. Summer 2000 Presented at: Tri-Beta North East District 2 Convention, The College of New Jersey, March 2001. C. Petrone. Species Diversity and Density of Copepods at the Mouth of the Delaware Bay, USA. Presented at: Fifth Annual Centennial Conference Student Research Colloquium, April 2000, Dickinson College. Published in Bios, see above. T.L. Pyhel. Androgen sensitivity in croaker sonic muscles. Senior thesis, Summer 1999 Presented at: Fifth Annual Centennial Conference Student Research Colloquium, April 2000, Dickinson College. T.L. Vance. A comparative study of sonic muscle innervation patterns of three sciaenids: spot, croaker and weakfish. Senior thesis. Presented at: Fifth Annual Centennial Conference Student Research Colloquium, April 15, 2000, Dickinson College. The 81st annual meeting of the American Society of Ichthyologists and Herpetologists, Penn State University, State College, PA, 2001. Title: A comparison of the sonic muscle innervation patterns of three Sciaenids: the spot, weakfish and Atlantic croaker. Co-authors: Hewson, J.M., M.A. Connaughton. Published along with work by Hewson and Modla in Copeia, see above. Vance, T.L. An anatomical study of the Weberian apparatus in the channel catfish, Ictalurus punctatus. Summer 1998 Presented at: Fourth Annual Centennial Conference Student Research Colloquium, April 1999, Washington College. Vance, T.L. Sound production via pectoral stridulation in the channel catfish, Ictalurus punctatus. Summer 1998 Presented at: Fourth Annual Centennial Conference Student Research Colloquium, April 1999, Washington College. Published in Copeia, see above.
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For a compete list of my publications and presentations at national and international meetings, please see my curriculum vitae.