Development and application of laser ablation-inductively coupled plasma-mass spectrometry to determine estuary entry size of juvenile salmonids and track habitat usage
PSSI Project Summary
Division: Ocean Sciences (OSD)
Section: Ecology and Biogeochemistry
Organization: DFO
Session(s): Follow The Fish
Presentation Date(s): December 04, 2025
Speakers: Nicole LaForge, Micah Quindazzi
Abstract:
Microchemistry of fish otoliths (calcium carbonate ear crystals) is a very useful tool for tracking habitat usage. IOS currently has the only instrumentation and expertise within DFO to carry out this type of analysis. During this project we developed a method for relating the size (fork lengths) of juvenile WCVI Chinook Salmon at estuary entry to their otolith radii, and using it to back-calculate the estuary fork lengths of returning adult spawners using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) for PSSI priority river systems including Sarita, Robertson/Stamp and Nitinat from 2015-2023. We found that, generally, there are two types of natural origin (NO) outmigrants: those that leave the river early at small fork lengths, and those that use the river for longer and thus leave later and at larger fork lengths. In the Sarita River, these life history types emerge as Early Small NO smolts that leave the river under 50 mm between February to April, and Late Large NO smolts that leave the river above 50 mm after April. These Late Large NO smolts can survive up to 20X better than the Early Small smolts, 40% better than the hatchery origin smolts and comprise a much larger proportion of the returning spawners than would be expected considering that they represent around 5% of the outmigrants in the Sarita River system. While Late Large NO smolts survived better, the Early Small NO smolts comprised over 80% of the oldest Chinook salmon in the system. Otolith microchemistry provides a cost-effective means of gleaning information on the life histories of salmonids that can enhance our understanding and inform population rebuilding strategies, and demonstrates that NO Chinook Salmon provide significant phenotypic diversity, which would not be possible to replicate with hatchery production alone and provide a buffer against population extinction events. We conclude that there are significant carry-over effects from freshwater to the marine environment affecting WCVI Chinook entry timing and size, which may also correlate to their health.
Bio:
Nicole LaForge is a scientist who studies the microchemistry of biological tissues such as fish otoliths at the Institute of Ocean Sciences (IOS) for the Department of Fisheries and Oceans (DFO) in Sidney, BC. She has an MSc from the University of Victoria in Developmental Biology and Embryology. Nicole has extensive experience in the preparation and analysis of samples by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and joined DFO in 2023 to develop the use of this powerful analytical technique in-house for the Pacific Salmon Strategy Initiative and beyond. The mass spectrometry laboratory at IOS has the only instrumentation capable of generating this type of high-resolution time-resolved biological data within DFO.
Micah Quindazzi is a PhD Candidate who uses microchemistry to study the migrations of Chinook and Coho salmon at IOS in Sidney, BC. Micah has comprehensive experience in the study of all topics related to the otoliths of salmonids. He has been involved in PSSI since 2021 to study the estuary entry size and marine migrations of WCVI Chinook salmon. He has worked with Nicole to develop techniques for the study of salmonid otoliths using LA-ICP-MS. He is also working on ECVI and Fraser River systems using similar techniques.
Collaborators:
LGL Ltd., Huu-ay-aht First Nation