The Cod Fish of Alaska
In the Arctic waters of Alaska, the Arctic cod (Boreogadus saida) is a pivotal species, serving as essential prey for seabirds, fish, and marine mammals, many of which hold significance for Inuit communities. The Arctic is undergoing dramatic environmental changes due to climate change, potentially impacting the distribution, spawning time, and habitats of fishes like the Arctic cod. Understanding these shifts is crucial for ecosystem sustainability and informed fisheries management. In this study, the recording included Arctic cod’s vocalizations, specifically grunts consisting of 6 to 12 pulses, with an average duration of 289±13 ms. The frequency of these calls ranges between 59 and 234 Hz, with an average peak frequency of 107 Hz. The Burrunan dolphin (Tursiops australis) is a genetically distinct species with an isolated population of approximately 300 individuals in Port Phillip Bay. Listed as critically endangered under the Victorian Flora and Fauna Guarantee Act, this species faces numerous challenges, including anthropogenic noise, toxicants, and vessel impacts. Traditional visual observation methods have restricted the study of their behaviours, but the Marine Mammal Foundation (MMF) is leveraging acoustic technologies to conduct passive acoustic monitoring (PAM). Between 2018 and 2022, MMF collected 7,080 hours of recordings from 10 sites, generating over 2,000 annotations within 83 annotated hours. These efforts aim to reveal how dolphins use their environment on a 24-hour basis, their acoustic repertoire, and the impacts of human activity on their population.