The interns from last year had collected some brook trout (Salvelinus fontinalis) egg sacs for a study on brook trout fecundity (the ability to produce offspring). They didn’t finish, so we had the lovely task of processing the ones that were preserved in formaldehyde (yay!). A smelly, but not overall unpleasant task. We knocked it out in three days while listening to podcasts. It involved weighing the eggs, measuring their volumetric displacement, and counting them. So much counting, and also the least amount of counting we’ve done so far. Brook trout eggs are pleasant to handle, sturdier than I would have imagined, and closely resemble couscous.

I should mention that brook trout are an invasive species. They endanger our species of interest bull trout (Salvelinus confluentus) through competition and hybridization. We’re looking at their fecundity in order to see what sort of impact we make by removing them from the streams (which we will be doing by electrofishing starting next Monday!). It’s possible that us removing them reduces intraspecies competition, and count therefore improve their fecundity. We’d have to harvest them again to compare before and after. We’re also checking other studies to make inferences.

Until next time,

Brianne Nguyen
USFWS, Klamath Falls Fish and Wildlife Office