Coastal Resilience in Sitka Sound: Monitoring Pinto Abalone and Kelp Forests in a Changing Climate
Sitka Sound Science Center
Kelp forests have long been known as ecological powerhouses that support high levels of biodiversity and fish production, which helps to support local economies. They also serve as critical habitat to species of conservation concern, such as pinto (or northern) abalone (Haliotis kamtschatkana), an important subsistence species recently under consideration for listing as endangered in Alaska. However, kelp beds themselves are also susceptible to the very weather events they protect coastal communities against, and recent research indicates they may also be negatively impacted by ocean acidification. The pinto abalone is currently being considered for listing under the US Endangered Species Act. There is a renewed interest in assessing the current status of pinto abalone populations in Alaska. Fortunately, several long-term data sets are available that can be used as a baseline to quantify temporal trends as well. Resampling abalone density and size frequency at these historical survey locations will provide much needed data to assist with the upcoming evaluation by the National Marine Fisheries Service. Through a collaborative project with the Sitka Sound Science Center, the Alaska Department of Fish and Game, University of Alaska Southeast, and the US Coast Guard Academy, cadet interns will map, assess, and monitor Sitka Sound kelp beds and evaluate changing environmental conditions (pH, temperature, currents). Concurrently, scientists will collect density and demographic data on pinto abalone in Sitka Sound. Kelp beds and pinto abalone are important species in the coastal ecosystem of Sitka Sound. Monitoring these populations and correlating trends with factors related to climate change will help inform management decisions and help the community respond to a changing environment. Further, this study will be a conduit for training and mentoring a new generation of scientists and managers through internship programs at the Sitka Sound Science Center.
For more information and project news, please see the 2015 news story “Sitka Sound abalone and kelp: Looking for answers” and a video “Kelp and Abalone: Sentinels for Climate Change” filmed and produced by Pioneer Studios Production Company for the Sitka Sound Science Center.
Kelp beds and pinto abalone are important species in the coastal ecosystem of Sitka Sound. Monitoring these populations and correlating trends with factors related to climate change will help inform management decisions and help the community respond to a changing environment.
Sitka Sound Science Center
Alaska Department of Fish and Game
University of California Santa Cruz
US Coast Guard Academy
What researchers learned
Researchers from the Sitka Sound Science Center (SSSC), the Alaska Department of Fish and Game, and the University of California Santa Cruz collaborated to develop a long-term monitoring plan for pinto abalone in Sitka Sound, Alaska. Permanent index sites were established and monitored throughout the summers of 2015 and 2016, providing the first comprehensive look at abalone populations in this region. Over 85% of abalone surveyed across all sites were smaller than the minimum legally harvestable size (89 mm) of abalone in personal use and subsistence fisheries. New pinto abalone recruits observed at all monitored aggregation sites indicated that successful reproduction was occurring despite varying densities of adult abalone. The refined methods and initial results from this monitoring effort have already informed a new suite of research programs for pinto abalone across Southeast Alaska. As another component of this project, The U.S. Coast Guard Academy (USCGA) and Sitka Sound Science Center initiated a long-term study to monitor the relationship between the spatial extent of giant kelp canopy cover and specific environmental variables in Sitka Sound. Leading this field effort were undergraduate students from the USCGA in New London, CT. Each June through July, two cadets traveled to Sitka for a 6 week science internship at SSSC, with room and board provided by the USCG Air Station Sitka. Students found that surface spatial extent of the kelp canopy at each site varied more considerably between high and low tides than from growth or loss over the 6-week field season. The students also found little difference in surface temperature between kelp and non-kelp sites, suggesting that kelp canopy cover has relatively little influence on surface environmental conditions over the small spatial scales considered in this study. Through direct participation in scientific research, these four cadet interns deepened their understanding of climate change and coastal resilience, while developing a lasting appreciation for the importance of healthy marine ecosystems.
Researchers develop and implement monitoring protocol for kelp and abalone
Relevance: Kelp beds form underwater forests that provide ecosystem benefits to Alaska’s coastal resources. Pinto abalone, which live in and feed on kelp beds, were once widespread and common in Sitka Sound, but populations declined in the 1960s and 1970s due to sea otter predation and commercial fishing. Commercial fishing was banned in 1996, and pinto abalone are being considered for the endangered species list. Researchers have little understanding of kelp and abalone populations in Sitka Sound, or how these two understudied species may respond to human activity and climate change.
Response: Alaska Sea Grant–funded scientists developed methods to monitor kelp and pinto abalone populations in Sitka Sound. In summer 2015 researchers used scuba diving techniques to count and measure abalone at eight sites. They created a protocol to monitor kelp bed size using GPS and GIS mapping, monitored kelp beds, and recorded water temperature, salinity, and pH.
Results: Researchers began establishing baseline data on kelp and pinto abalone and developed a monitoring protocol to track changes over time. Developing and implementing this program with undergraduate interns had the mutual benefit of producing high-quality baseline research while helping build the next generation of marine biologists interested in Alaska’s coasts. The methods and fieldwork protocols that are successful for this project could be used in other regions to learn about similar habitats. The Alaska Department of Fish and Game designed a regional abalone assessment based on this project, which will allow these results to be directly comparable to a larger study on abalone population characteristics.