How scallop restoration can help Long Island communities
Commercial scallop fishing has been an integral part of Long Islanders’ identity for generations and has supported the local economy for decades. Until the 1980s, commercial fishing contributed more than $10 million to the local economy, but over recent years, because of brown tides, increasing water temperatures, and dissolved oxygen in the ocean, the harvests have decreased 95% resulting in a $60 million loss to the regional economy. Since 2005, the Cornell Cooperative Extension (CCE) has been leading the effort to restore Long Island’s Peconic Bay scallop populations with new research and hatchery programs. The Moore Charitable Foundation, focused on restoring coastal habitats and ensuring clean water, is proud to support this important work. Keep reading for part two of our series with Chris Pickerell, the Marine Program Director of CCE of Suffolk County, and his team. Click here for part one, on efforts to cultivate ribbed mussels as filters of water pollution around Long Island.
MCF: What are the issues you are trying to address with bay scallops?
CCE: On Long Island, the Peconic Bay scallop populations have supported an economically important and ecologically sustainable fishery for the island’s fishing community for many generations. However, since 2019, adult Peconic Bay scallop populations have suffered declines of up to 99% prior to commercial harvest, resulting in financial losses of up to $1 million annually. The causes of the mass die-offs of adult bay scallops is now largely understood to be caused by climate change and a newly discovered parasite. With this understanding, CCE scientists have initiated various field projects to address these problems head-on. The results of this work will help inform future management strategies that promote resiliency in Peconic Bay scallop populations to support the fishery and the local community.
MCF: What is special about this species?
CCE: Bay scallops are unique, for they have a lifespan of only 18–24 months. During their roughly two-year lifespan, bay scallops typically have their largest spawning event in the late spring/early summer of their second year followed by smaller, less common spawns in the late summer/early fall. By the time the commercial fishery opens in November, the adult bay scallops harvested already have contributed to the next generation and likely will not survive the winter, resulting in the fishery being very sustainable and having little impact on the future bay scallop populations. Another unique aspect of bay scallops is that they are very sensitive, or finnicky, to environmental stressors, such as elevated water temperatures and low dissolved oxygen. Typically, bay scallops can recover from these stressors. However, the greatest increases in water temperature and decreases in dissolved oxygen begin occurring when adult bay scallops spawn in the late spring/early summer. To prepare for spawning, adult bay scallops allocate energy away from survival and toward reproduction, naturally weakening their ability to mitigate the effects of environmental stressors. Additionally, early summer is also when parasite intensity rapidly increases, likely driving a significant portion of adult bay scallops in the Peconic to early mortality, dramatically decreasing commercial landings in the fall. High mortality of adult bay scallop populations in the summer months is also likely resulting in the loss of robust fall spawns, which could negatively impact the resiliency of Peconic Bay scallop populations.
MCF: Your research has yielded successful results so far. What have you discovered, and what do you hope to discover or achieve in your project’s next phase?
CCE: Hatcheries typically spawn bay scallops in the months of May and June, when the largest bay scallop spawns naturally occur in wild populations. The reason for timing hatchery spawns with wild spawns is because it is easy to condition the scallops, for they are naturally preparing to spawn, reducing the amount of effort by hatchery staff to induce spawning. Fall spawns are less common in wild populations, and not all adult bay scallops will have a fall spawn. This makes conditioning bay scallops for fall spawns more difficult and labor intensive, resulting in most hatcheries avoiding fall spawns. However, CCE’s hatchery was successful in conducting two fall spawns in 2022. With most of the adult bay scallops in wild Peconic populations dying before fall spawns can occur, hatchery-conducted fall spawns may be important for restoration purposes. Results from field studies conducted in 2023 indicate that bay scallops from a fall spawn have significantly higher survival compared to spring-spawned scallops when faced with stressors associated with climate change and disease. Furthermore, fall-spawned scallops had significantly lower parasite intensity compared to spring-spawned scallops. These results indicate fall-spawned bay scallops, which are likely minimal in wild Peconic populations due to the mass die-offs of adult bay scallops in the summer, could help promote resiliency of Peconic Bay scallop populations and the fishery on Long Island. The next phase of this project will be to replicate the comparative field study conducted in 2023 over the course of another summer season in 2024. The reason for replicating the same study is because field studies are subjected to natural environmental parameters that can change year-to-year. Thus, having a multiyear study makes results more robust, which is essential when designing large-scale restoration strategies for fishery managers, such as CCE’s bay scallop restoration team.
MCF: If these projects are ultimately successful, what could your research help achieve or be used for? Can you explain the potential environmental impact of the work? Can you elaborate on the everyday impact on communities or fisheries?
CCE: If the increased survival and reduced parasite intensity in fall-spawned scallops compared to spring-spawned scallops observed in field studies in 2023 is again observed in the second year of the study, then the use of fall spawns in restoration strategies could help restore the Peconic Bay scallop fishery. CCE could implement fall spawns as part of the larger restoration program, bringing back fall spawns to wild populations and aid in promoting a more resilient Peconic Bay scallop population and fishery. With planted fall-spawned scallops likely surviving through the stressors associated with summer months (climate change and the parasite), then they could produce their own fall spawns, promoting population resiliency, while also surviving to harvest season, promoting resiliency of the fishery. Resiliency of the fishery would help promote the recovery of lost revenue seen since the collapse of the fishery, increasing revenue in local communities.
MCF: Why is it important to invest in these projects, and what would the restoration of these species mean to the big picture of healthy waters?
CCE: Since the collapse of the fishery in 2019, dockside value of the Peconic Bay scallop fishery has decreased by almost $1 million annually. This loss of revenue has significantly impacted local baymen and their communities. Investing in research that will help restore the fishery would have significant beneficial impacts on local Long Island communities that have relied on the Peconic Bay scallop fishery for decades.
Additionally, bay scallops are part of Peconic ecosystem as a whole, helping clean the water by filter feeding while also being a food source for predators above them in the food chain. Removal of bay scallops from the Peconic ecosystem would have negative impacts on food web dynamics and water quality, reducing the resiliency of the Peconic ecosystem, making it more vulnerable to future changes and stressors.
