Environmental and lunar cues are predictive of the timing of river entry and spawning‐site arrival in lake sturgeon Acipenser fulvescens

Abstract

The associations were quantified between daily and interannual variation in the timing of a closed population of lake sturgeon Acipenser fulvescens migration and arrival at spawning sites with stream environmental and lunar covariates. Spawning data were gathered from 1262 fish in Black Lake, Michigan 2001 to 2008 and by video monitoring 2000 to 2002. Sex‐specific variation in responses to external cues was also tested. Results showed that a greater number of individuals initiated migration from lake to riverine habitats at dawn and dusk relative to other times of the day. Current and lagged effects of water temperature and river discharge, and periods in the lunar cycle were important variables in models quantifying movements into the river and timing of adult arrival at spawning sites. Different suites of covariates were predictive of A. fulverscens responses during different periods of the spawning season. The timing of initiation of migration and spawning, and the importance of covariates to the timing of these events, did not differ between sexes. Stream flow and temperature covaried with other variables including day length and the lunar cycle. Anthropogenic disruption of relationships among variables may mean that environmental cues may no longer reliably convey information for Acipenseriformes and other migratory fishes.

Review of a species in peril: what we do not know about lake sturgeon may kill them

“…In a similar study examining site fidelity, Forsythe et al (2012) found that individual spawning behavior was highly repeatable with respect to date and breeding site regardless of gender, size, or age, and it was less dependent, though still significantly linked, to water temperature, river discharge, and lunar phase. Repeatability in spawning time and location suggest that subpopulation differentiation may develop within populations, even within small and spatially contiguous areas.…”

“…The above paragraphs demonstrate the diversity in depth (e.g., Chiotti et al 2008 versus Manny andKennedy 2002), velocity (Manny and Kennedy 2002), temperature (LaHaye et al 1992), and substrate type (LaHaye et al 1992). This coupled with the potential for subpopulations that may rely on differing cues (Forsythe et al 2012) creates a complex picture for a manager that must locate and protect sturgeon habitat based solely on the literature. This is an excellent example of how lake sturgeon knowledge from one area may not be applicable or useful in another.…”

Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes?

“…use information on river discharge as well as current velocity and acceleration to make decisions about path choice [13, 44–46]. While comparable studies with sturgeon have not been conducted, the reported relationship between river discharge and the timing of Lake Sturgeon spawning runs in the Black River system (Michigan, USA) [47] suggests that Lake Sturgeon are capable of detecting variation in hydraulic variables. Many fish species also use olfaction to home to natal habitats in rivers [48], but the use of chemosensory cues for route selection in the lower Detroit and St. Clair Rivers seems unlikely given that over 95% of the water flowing through Detroit-St. Clair river system emanates from a single source (Lake Huron).…”

Effects of acoustic tag implantation on lake sturgeon Acipenser fulvescens: lack of evidence for changes in behavior

“…Difficulty with the determination of sex in the field limited our ability to detect whether being male or female affected behavior after tag implantation, and thus, may have introduced some bias into our analyses. The seriousness of this potential bias is difficult to assess given that sex-based differences in lake sturgeon activity, movements, and migration timing have been observed in some systems [28,29] but not in others [30,31]. Reproductive status also should be considered as an explanatory variable in future tagging effects studies on lake sturgeon given that activity may be greatest during the post-spawn phase [29,30,32].…”