HATTIESBURG, MS / ACCESSWIRE / 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 20^th 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.

The dramatic shift in growth and maturity rates correspond directly with long-term rising temperatures at the sample sites, which were taken from two areas off the coast of New Jersey, one area on Georges Bank off the coast of New England, and one area off the coast of Long Island. These results indicate that ocean quahogs are very sensitive to changes in temperature, and are currently more productive than in previous decades.

'This is a clear demonstration of the dramatic change in ocean climate over the last 200 years, and how one species has adapted with it over time,' said Jillian Sower, of the Gulf Coast Research Laboratory at the University of Southern Mississippi, and a lead author of one of the studies. 'Studying ocean quahogs gives us the history of both this species and the ocean around it, and these studies are a significant addition to that historical record.'

A unique aspect of these studies is the unusually large sample size of ocean quahogs available to the authors. Over the past several years, SCEMFIS-funded research on ocean quahogs has allowed researchers to collect and age hundreds of ocean quahogs from several regions across the species' range. This provides a broad, representative sample of the ocean quahog population across ages and regions, and leads to a high confidence in the findings of the studies.

'We are in a unique position to draw from one of the most extensive samples of ocean quahog available anywhere,' said Kathleen Hemeon, of the Gulf Coast Research Laboratory, and a lead author of another one of the studies. 'We have an unusually clear picture of ocean quahogs both over time and across regions, and can be confident that the results of these studies reflect an accurate picture of the ocean quahogs over the last 200 years.'

About SCEMFIS
SCEMFIS utilizes academic and fisheries resources to address urgent scientific problems limiting sustainable fisheries. SCEMFIS develops methods, analytical and survey tools, datasets, and analytical approaches to improve sustainability of fisheries and reduce uncertainty in biomass estimates. SCEMFIS university partners, University of Southern Mississippi (lead institution), and Virginia Institute of Marine Science, College of William and Mary, are the academic sites. Collaborating scientists who provide specific expertise in finfish, shellfish, and marine mammal research, come from a wide range of academic institutions including Old Dominion University, Rutgers University, University of Massachusetts-Dartmouth, University of Maryland, and University of Rhode Island.

The need for the diverse services that SCEMFIS can provide to industry continues to grow, which has prompted a steady increase in the number of fishing industry partners. These services include immediate access to science expertise for stock assessment issues, rapid response to research priorities, and representation on stock assessment working groups. Targeted research leads to improvements in data collection, survey design, analytical tools, assessment models, and other needs to reduce uncertainty in stock status and improve reference point goals.

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SOURCE: Science Center for Marine Fisheries