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Quantitative and temporal relationships of egg production and sound production by black drum Pogonias cromis

Authors

  • J. V. Locascio,

    Corresponding author
    1. University of South Florida, College of Marine Science, 140 Seventh Avenue South, St Petersburg, FL 33701, U.S.A.
    2. Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, U.S.A.
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  • S. Burghart,

    1. University of South Florida, College of Marine Science, 140 Seventh Avenue South, St Petersburg, FL 33701, U.S.A.
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  • D. A. Mann

    1. University of South Florida, College of Marine Science, 140 Seventh Avenue South, St Petersburg, FL 33701, U.S.A.
    2. Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, U.S.A.
    Search for more papers by this author

Tel.: +1 727 424 8680; email: jlocasci@mail.usf.edu

Abstract

The timing and levels of black drum Pogonias cromis sound production and egg production were compared in an estuarine canal basin of Cape Coral in south-west Florida. Surface plankton samples were collected hourly from 1800 to 0400 on two consecutive nights while continuous acoustic recordings were made simultaneously at five locations in the canal basin. Five pairs of nights were sampled during a part of the spawning season from late January to early April 2006. Pogonias cromis sound production and egg production occurred on all evenings that samples were collected; however, both the timing and levels of sound production were negatively associated with those of egg production. Egg production estimates ranged from a low of 4·8 eggs m−3 in February to a high of 2889·2 eggs m−3in April. Conversely, maximum nightly sound pressure levels (SPL) ranged from a low of 89·5 dB in April to a high of 131·9 dB (re: 1 µPa) in February. The temporal centre of sound production was relatively stable among all nights sampled but spawning occurred earlier in the day as the season progressed and exhibited a strong, positive association with increased water temperature. The negative relationship between the levels of sound production and egg production was unexpected given the usefulness of sound production as a proxy for reproduction on a seasonal basis and may possibly be explained by differences in the spawning potential of the female population in the study area on nights sampled. Egg mortality rates increased throughout the season and were positively associated with densities of hydrozoans and ctenophores.

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