September 26, 2023 — Climate change has radically altered the life cycle of ocean quahog (Arctica islandica), one of the longest-lived species in the ocean. According to a new pair of studies funded by the Science Center for Marine Fisheries (SCEMFIS), the species is growing much faster and maturing much earlier as global temperatures have risen over the past 200 years, one of the clearest examples yet of how climate change is affecting marine life.
Because of the ocean quahog’s extreme longevity, they provide a unique record of climate change over the centuries. The oldest ocean quahogs are over 200 years old, and can provide us with insights into the ocean climate before widespread industrialization. The new papers, published in the journals Continental Shelf Research and Estuarine, Coastal, and Shelf Science, examine ocean quahog growth rates, and their changes over time, by examining the age and length data of a large, diverse sample set of ocean quahogs, and finds a clear pattern of biological change over time in response to climate conditions.
In 1800, the average ocean quahog reached full maturity between 18 and 26 years, and reached a commercially harvestable size (according to the standards of the modern fishery, developed in the 20th century) in anywhere from 63 to 119 years. By 2000, ocean quahogs were reaching maturity as early as 8 years, and had reached harvestable size between 26 and 29 years, over three times faster than 200 years ago.