Beluga whispers: Filtering beluga dietary patterns through eDNA and passive acoustics

FY 2024 | 3 – Inform | 24-10-05

Beluga whispers: Filtering beluga dietary patterns through eDNA and passive acoustics

Sonia V Kumar, University of Alaska-Fairbanks (UAF)
Contract Term: 5/01/24-4/30/25
Award: $30,000

This project is dedicated to advancing our understanding of endangered Cook Inlet
beluga whales' (CIB) acoustic presence and the dynamic shifts in fish community assemblages in
the Kenai and Kasilof rivers from May through October 2022. Our aim is to compare the patterns
of CIB river usage with target prey biodiversity within critical habitat designated by the National
Marine Fisheries Service. We strategically placed six passive acoustic monitoring (PAM) devices
– four in the Kenai River and two in the Kasilof River – to continuously track the acoustic
presence of CIBs. Concurrently, we conducted weekly water sample collections, harnessing
environmental DNA (eDNA) techniques to map the fluctuations in fish communities during the
ice-free season. Using metabarcoding and quantitative polymerase chain reactions (qPCR), we
will analyze these eDNA samples to unravel the complexities of fish community transitions.
A part of this study involves juxtaposing quantitative abundance estimates of sockeye and
chinook salmon, derived from quantitative polymerase chain reaction (qPCR) methods, with the
Alaska Department of Fish and Game's sonar counts in each river. This comparison will be
useful in evaluating the precision and viability of qPCR techniques in this ecological setting.
By merging the insights from eDNA analysis of weekly fish assemblages with the CIB
acoustic data, we are set to uncover important ecological interactions, particularly focusing on
the CIB's foraging patterns and habitat preferences. This research supports the Oil Spill Recovery
Institute’s mission to identify baseline characteristics of the Cook Inlet subarctic ecosystem, a
region significantly influenced by oil and gas activities. The outcomes of this study will
significantly augment environmental sensitivity maps, incorporating a temporal analysis of the
seasonal movements of an endangered marine mammal and the often overlooked, yet
ecologically important, diversity of marine fish species that also utilize that ecosystem. This
endeavor not only illuminates the ecological dynamics of Cook Inlet but also serves as a useful
tool for targeting important foraging areas in the occurrence of an oil spill.