Climate-Driven Risks for Aquaculture Farms

The waters of the Gulf of Maine are some of the most rapidly changing ocean environments in the world. Because of climate change, this economically important ecosystem is facing multiple concurrent impacts that threaten the region’s natural resources and the industries that depend on them. The waters of the Gulf of Maine are warming at a rate nearly three times faster than the global average. Warmer water brings with it an environment that may open the door for invasive species and increased predation, as well as creating more favorable growing conditions for algae and bacteria. Rising air temperatures also increase the capacity of the atmosphere to hold water in the form of rain, increasing the chance for larger, more powerful rainfall events. Rainfall events, in turn, can change coastal water chemistry, at least temporarily, and contribute to an environment of stress for marine creatures. The changes in the atmosphere can also lead to more energetic storm systems, resulting in damage to coastal infrastructure. All of these factors increase the operational risk aquaculture farms face in order to supply a fast-growing demand for shellfish.

In recent years, aquaculture farms in the northeast have already experienced impacts to their operations. As ocean temperatures warm, conditions can become more favorable for the growth of Vibrio bacteria in shellfish. In response to this increased risk, the state has strengthened regulations related to time and temperature controls for shellfish producers, transporters, and retailers. Warmer waters and increased rainfall have both contributed to the increased prevalence in shellfish harvesting closures, which can negatively impact farmers if they occur at critical moments during the grow–out cycle.

For farmers relying on wild spat, a decrease in wild spawning caused by environmental changes has contributed to reduced farm yields during some years. Ocean acidification, while unlikely to significantly impact adult shellfish by itself, can cause increased juvenile mortality, especially when combined with other environmental stressors. All of these conditions combined add to an environment of stress under which aquaculture farms must operate.

This project seeks to review the most impactful climatic stressors to the Gulf of Maine aquaculture industry and identify potential solutions and mitigation strategies for adapting farm operations.