Impact of Motorboat Noise on Vocalizations of Nesting Plainfin Midshipman Fish

As noise pollution in coastal environments continues to grow, it is imperative to understand how it may be negatively impacting marine life. The study in this chapter tested whether noise from a real motorboat would alter the vocalizations of nesting plainfin midshipman fish (Porichthys notatus), a soniferous toadfish that breeds in the intertidal zone and uses its vocalizations for courtship and defense. The results show evidence that wild plainfin midshipman guarder males may decrease their agonistic vocalizations in periods where they are exposed to large amounts of boat noise. There was an overall decrease in agonistic vocalizations on the nights when boat noise trials were run compared to control nights. While there was not a statistical difference in the number of agonistic vocalizations exhibited in sequential 10-minute periods with and without boat noise in the same night, there was a trend of fewer vocalizations during boat noise periods. This study helps elucidate how boat noise affects midshipman vocalizations in their natural habitat at the level of the individual, which has never been tested in plainfin midshipman fish and has scarcely been studied in other species.