Eulachon Assessment Survey

Ashlee Prevost, Staff Biologist

The Lower Fraser Fisheries Alliance annually conducts the only in-season Eulachon Assessment Survey (EAS) to estimate the abundance of the returning Fraser Eulachon population.

This year we also developed a new program by implementing our ARIS Explorer 1800 (ARIS) in addition to our basal EAS. The ARIS is a hydroacoustic sonar device that collects real time footage of fish in the river. The LFFA acquired the ARIS Explorer 1800 last year and will be using it to conduct our new ARIS EAS surveys as well as develop a new method to assess the abundance of returning fish.

In terms of the basal EAS, to date (April 11th, 2021) we have set the net 17 times and caught over 500 fish. These surveys will continue until the end of April. The ARIS EAS will start on April 15th, 2021, before the peak of the run and be conducted in conjunction with our EAS sets. This pilot ARIS program will be extremely informative as we will be able to view and count other species of fish present at the index site (Sturgeon and Salmonid Species) as well as produce a comparable estimate between both the basal EAS and new ARIS EAS methods.

The LFFA also conducts Eulachon Exploratory Surveys during the month of February. These early surveys were initiated in 2020 as a pilot and continued this year. Overall, in 2021, we surveyed four index sites from New Westminster to the George Massey Tunnel and set the net 6 times at each site on a given survey day. Throughout the four survey days, we have collected a total of 72 fish, a portion of which will be sent to DFO for genetic analysis. Other fish caught will be retained by the LFFA for histological analysis.

The information and findings collected throughout this program will be prepared in a manuscript for publication. We look forward to continuing with our basal EAS and commencing our ARIS EAS surveys.

Stay tuned for the results of all Eulachon related work.

Pictured left: 2021 Eulachon survey work conducted by LFFA biologists