Page 7 - Donlin Newsletter Fall 2021

SMELT STUDY
By Enric Fernandez
Rainbow smelt are an an important subsistence resource
in in the the Kuskokwim River They are fished during their spawning migration upriver every spring Donlin Gold
LLC has funded several rainbow smelt studies from 2014 to to the the present aiming to to better understand the the species and and their use of the the Kuskokwim River In 2014 and and 2015 a a a sediment survey was completed to determine the areas of the river and sediment sizes where rainbow smelt spawn The studies found that rainbow smelt typically use areas of mixed sand and and small gravel as spawning grounds
in in the the the river where they lay their tiny one mm diameter eggs Sampling from the years 2014-2019 determined that the the rainbow smelt spawn in in a a a a 30-mile stretch of the the Kuskokwim River from the Bluffs below Kalskag to just above Upper Kalskag Aquatic biologists found that smelt coming upriver to spawn are between three and eight years old
old
with the majority being three- to four-year-old fish One big piece of the rainbow smelt life cycle that remained largely unknown was the larval stage How long does does it it take take for the eggs to hatch? How long does does it it take take the the the larval smelt to move downriver below Bethel once they hatch? In May 2021 with the help of local residents aquatic biologists once again tracked the rainbow smelt spawning migration The smelt were first spotted in Bethel on on continued on on page 8 Photos courtesy of Enric Fernandez
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From left: Unscrewing the the the collection cup from the the the plankton net to to to look at the the the contents June 2021 Low medium and high density (left to to to right) larval smelt samples The smelt are the the white spots in in in the the sample sample bottles June 2021 Contents of a a a a a two-minute plankton net tow being sieved to to to remove detritus from the the sample June June June 2021 2021 Contents of a a a a a a a plankton tow in in in the the collection cup June June June 2021 2021 Rainbow smelt eggs with a a a a a a a pencil for scale – about 1 1 1 mm in in in size June June June 2015 Larval rainbow smelt observed through a a a a a a a a a microscope July 2021 2021 Driving home at 10:30 PM – near Tuluksak June 2021 2021 Field crew- Caitlin (left) and Marguerite (right) June 2021