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Montie EW, Hoover M, Kehrer C, Yost J, Brenkert K, O'Donnell T, Denson MR.2016. Acoustic monitoring indicates a positive relationship between calling frequency and spawning in captive spotted seatrout (Cynoscion nebulosus)PeerJ PrePrints4:e1656v1https://doi.org/10.7287/peerj.preprints.1656v1
Background: Fish sound production is widespread throughout many families. Agonistic and courtship behaviors are the most common reasons for fish sound production. Yet, there is still some debate on how sound production and spawning are correlated in many soniferous fish species. In the present study, our aim was to determine if a quantitative relationship exists between calling and egg deposition in captive spotted seatrout (Cynoscion nebulosus). This type of data is essential if scientists and managers plan to use acoustic metrics to identify spawning aggregations over large spatial scales and monitor reproductive activity over annual and decadal timeframes.Methods: Wild caught spotted seatrout were held in three laboratory tanks equipped with long-term acoustic loggers (i.e., DSG-Oceans) to record underwater sound throughout an entire, simulated reproductive season. Acoustic monitoring occurred from April 13 to December 19, 2012 for Tank 1 and from April 13 to November 21, 2012 for Tanks 2 and 3. DSG-Oceans were scheduled to record sound for 2 min every 20 min. We enumerated the number of calls, calculated the received sound pressure level (SPL in dB re 1 µPa; between 50 and 2000 Hz) of each 2 min ‘wav file’, and counted the number of eggs every morning in each tank.Results: Spotted seatrout produced three distinct call types characterized as “drums”, “grunts”, and “staccatos”. Spotted seatrout calling increased as the light cycle shifted from 13.5 to 14.5 h of light, and the temperature increased to 27.7oC. Calling began to decrease once the temperature fell below 27.7 oC, and the light cycle shifted to 12 h of light. These captive settings are similar to the amount of daylight and water temperatures observed during the summer, which is the primary spawning period of spotted seatrout. Spotted seatrout exhibited daily patterns of calling. Sound production began once the lights turned off, and calling reached maximum activity approximately 3 h later. Spawning occurred only on evenings in which spotted seatrout were calling. Significantly more calling and higher mean SPLs occurred on evenings in which spawning occurred as compared to evenings in which spawning did not occur. Spawning was more productive when spotted seatrout produced more calls. For all tanks, more calling and higher SPLs were associated with more eggs released by females.Discussion: The fact that more calling and higher SPLs were associated with spawns that were more productive indicates that acoustic metrics can provide quantitative information on spotted seatrout spawning in the wild. These findings will help us to identify spawning aggregations over large spatial scales and monitor the effects of noise pollution, water quality, and climatic changes on reproductive activity using acoustic technology.
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Raw data of fish lengths and weights
Dataset 1. Raw data that contains the sex, length, and weights of all fish in tanks 1, 2, and 3.