February 25, 2021 — The following was released by NOAA Fisheries:
Many marine fish and crab species spend their critical early development stages of life in shallow, coastal waters. Scientists at the Alaska Fisheries Science Center’s Auke Bay Laboratories conducted a pilot study using environmental DNA (eDNA) techniques in 2020. They identified more than 40 species in nine sites around Juneau, Alaska.
Every marine organism sheds small amounts of tissue and waste into the water. This material potentially contains eDNA from the source organism. Genetic analysis of the eDNA can help us to identify species and detect the diversity of species. It can also possibly determine the abundance of each species that have been present in the water sample even days after the organism has left the area. Environmental DNA can complement traditional surveys that are able to identify the age or size of a species.
The major objective of this study was to demonstrate that eDNA metabarcoding represents a feasible and cost-effective alternative to traditional sampling for collecting species diversity data and identifying Essential Fish Habitat (EFH). While eDNA has been used to assess biodiversity in many environments, it is important to verify the technique and compare it to data collected from traditional surveys to ensure that results are robust. This is especially important in dynamic environments such as those found in Alaska, where variables such as large tidal swings and severe weather can influence eDNA transport and detection.
“There are so many ways eDNA research can help us do our jobs better,” said Wes Larson, program manager, Genetics Laboratory. “We are able to detect a fish after it has left an area. It is also a less invasive means for sampling habitats that enables us to detect cryptic fish. Cryptic fish are fish that may not typically be sampled in traditional survey gear or may be a rare or low-density organism that surveys miss. Additionally, eDNA can help us detect important pelagic fish like cod and pollock that may be offshore and could avoid smaller nets. ”