Edinburgh Napier University

  Underwater soundscapes have grown considerably louder over the previous century due to increases in anthropogenic noise, with increasing evidence that manmade sound can negatively impact aquatic fauna. Despite their vital ecological roles, and increasing commercial importance, the effects of sound on aquatic invertebrates are understudied in comparison to marine mammals and fish, despite their ability to perceive sound. Even fewer studies have considered the responses of early life aquatic invertebrates to underwater sound, despite their often greater vulnerability to environmental stressors compared to adults.

Through a series of controlled laboratory experiments, five model species (Norway lobster Nephrops norvegicus (L.), European lobster Homarus gammarus (L.), the European flat oyster Ostrea edulis (L.), the veined squid Loligo forbesii (Steenstrup, 1857) and the water flea Daphnia magna (Straus, 1820)) were exposed to playbacks of anthropogenic noise. Two key knowledge gaps were addressed in this thesis: whether, and how 1) continuous noise (the most common anthropogenic noise source in the field) affects the early life stages of aquatic invertebrates and 2) noise impacts on aquatic invertebrates carry over from one life stage to the next e.g. from larva to juvenile or from mother to offspring.

The early life stages of four out of the five model species studied were negatively impacted by noise, demonstrating that noise susceptibility is shared across a functionally and taxonomically diverse range of early life aquatic invertebrates. The experiments also revealed that impacts can carry over from larva to juvenile (N. norvegicus) and from mother to offspring (D. magna). The scientific evidence generated here will inform future research, legislative decision makers and managers of the importance of considering early life invertebrates as receptors of anthropogenic noise impacts, allowing them to generate more adequate mitigation strategies to uphold their commitments to limiting the impacts of noise on the marine environment.