Saving Seafood

Preliminary Results of e-DNA Study Shows Promise for Improving Understanding of Nearshore Habitats for Fish and Crabs in Alaska

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. ”

Read the full release here

Pink salmon could prosper in warmer Arctic rivers and streams, study says

September 9, 2020 — A new study has found that global warming could produce higher numbers of pink salmon in the Arctic by making rivers and streams more hospitable for spawning.

The analysis was published by U.S. and Canadian scientists in the journal Deep Sea Research Part II, Alaska’s Energy Desk reported Monday.

The findings bolster reports by Alaska subsistence fishermen that pink salmon numbers have increased as the Arctic warms at more than double the rate of the rest of the globe.

“Maybe in the past, they’d see a few adult pink salmon here and there every few years. Now they’re seeing them every year,” said Ed Farley, a federal fisheries scientist at the Auke Bay Laboratories in Juneau.

Read the full story at the Anchorage Daily News

Research on environmental DNA in salmon monitoring could have economic benefits

January 22, 2019 — Each year wild salmon return to the streams in which they were born to spawn and die. Salmon fishery managers must ensure that adequate numbers of fish return each year to spawn and produce offspring for future harvest. It is expensive and labor intensive to count returning salmon, especially in remote streams.

Researchers at the University of Alaska Southeast, Auke Bay Laboratories, Oregon State University, the UK and China have found that  DNA collected in water samples from Auke Creek can be used to infer the number of salmon passing upstream to spawn. Two of the authors on the published paper who contributed to the research are former UAS Biology students now in graduate school, Josh Russell and Donovan Bell. Russell is currently enrolled in the UAF College of Fisheries and Ocean Sciences program, and Bell is in the biology graduate program at the University of Montana.

This form of DNA, termed “environmental DNA” or “eDNA”, can be collected from water samples. Water samples are then filtered and probed using molecular genetic techniques to quantify the amount of DNA belonging to each salmon species, providing insights into the number of salmon upstream.

Read the full story at PHYS.org