Long-term acoustic recorders (black instrument in figure) can be used to estimate spawning timelines and rhythms by detecting fish calls associated with courtship. Design by Tim Devine, USCB Graphics ManagerMar Ecol Prog Ser 581: [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] 2017 2015). In the family Sciaenidae, sound-producing fishes include Atlantic croaker Micropogonias undulatus, silver perch Bairdiella chrysoura, black drum Pogonias cromis, spotted seatrout Cynoscion nebulosus, weakfish C. regalis, red drum Sciaenops ocellatus, spot Leiostomus xanthurus, and southern kingfish Menticirrhus americanus (Luczkovich et al. 1999, Sprague 2000, Ramcharitar et al. 2006, Gannon & Taylor 2007, Lowerre-Barbieri et al. 2008, Walters et al. 2009, Tellechea et al. 2011, Montie et al. 2015. Sound production in these fishes typically involves rapid movement of the sonic muscle surrounding the swim bladder. The resulting calls are species-specific due to anatomical differences in swim bladder and sonic muscle morphology as well as neural programming; therefore, call types can be used for species identification (Winn 1964, Ramcharitar et al. 2006.Sound production in fish species has been associated mainly with courtship behavior and reproduction (e.g. Saucier & Baltz 1993, Mann & Lobel 1995, Luczkovich et al. 2008, Walters et al. 2009, Mann et al. 2010, Montie et al. 2016, 2017. Studies have recorded underwater sounds during spawning seasons and have shown that patterns of peak calling coincide with patterns of reproductive senescence (i.e. gonadosomatic indices, sperm motility, and plasma androgen levels; Connaughton & Taylor 1995). Other wild studies have simultaneously collected acoustic recordings and plankton tows, and these data have shown that fish calling and spawning are tightly associated (Mok & Gilmore 1983, Saucier & Baltz 1993, Luczkovich et al. 1999, Aalbers & Drawbridge 2008, Lowerre-Barbieri et al. 2008. For example, the timing and amount of calling in wild weakfish were positively correlated with the timing and numbers of sciaenid eggs collected (Luczkovich et al. 1999). Similar findings have been observed in captive studies (Guest & Lasswell 1978, Connaughton & Taylor 1996, Lowerre-Barbieri et al. 2008, Montie et al. 2016, 2017. In weakfish held in laboratory tanks, courtship behavior, male calling, and spawning were correlated (Connaughton & Taylor 1996). In a quantitative study with captive red drum, findings revealed that spawning was more productive when the amount of calling increased; more eggs were collected when calls were longer in duration and contained more pulses (Montie et al. 2016). In a similar study with captive spotted seatrout, spawning was more likely to occur when male fish called more frequently; a positive relationship was found between sound pressure levels in tanks and the number of eggs collected (Montie et al. 2017). These findings indicate that acoustic metrics can accurately predict spawning potential for some soniferous fishes and that deployment of lon...

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.

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.