We conducted a PHABSIM study on Bingham Creek, Washington, by using validated habitat suitability criteria for the rearing of coho salmon Oncorhynchus kisutch. We compared the relationship between weighted usable area (WUA) and flow with a previously determined empirical relationship that showed increasing coho salmon smolt production with increasing summer low flow (). The relationship between juvenile coho salmon WUA and flow indicated that the greatest amount of habitat occurred at a flow that was lower than our low‐flow measurement, and the amount of habitat decreased with increasing flow. Thus, PHABSIM results were contrary to empirical measurement of coho salmon smolt production. Based on the relationship between summer flow and smolt production, production of smolts would decline if flow was reduced to the flow that maximizes WUA. The failure of PHABSIM to be consistent with empirical results may have be related to habitat suitability being influenced more by the numerous subdominant, schooling juvenile coho salmon and less by the dominant, territorial individuals, which have higher survival and prefer higher velocities.
We tested for an effect of temperature during embryonic and larval development on the sex ratio of offspring in two cyprinodontid fishes (Fundulus heteroclitus and Cyprinodon variegatus) having life histories in which temperature-dependent sex determination might be expected to occur. In both species, field collections showed that as young of the year recruited to the population, the sex ratio did not vary over time, nor did it deviate from 1:1. In laboratory experiments, there was no influence of incubation temperature on sex ratio in either species and sex ratios were near unity in all treatments. Although there was no evidence of temperature-dependent sex determination in the populations we studied, this result should be confirmed on other populations before it is generalized to the species level.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.