Various partners of the Michigan Arctic Grayling Initiative met in Traverse City on October 29 to discuss work from the past year. Folks in attendance heard about the following:
Troy Zorn, a fisheries research biologist with the Michigan Department of Natural Resources, provided a brief overview of the process that is being developed for prioritizing streams for Arctic Grayling reintroductions. Thus far, field techniques and methods for rating on-site habitat quality for each grayling life stage (egg, fry, juvenile, adult) have been developed, implementing them on survey sites sampled in the Manistee River watershed in 2017.
Remote Site Incubators
Little River Band of Ottawa Indians and Grand Valley State University conducted a study using rainbow trout (Oncorhynchus mykiss) eggs as surrogates for Arctic Grayling to evaluate remote site incubators (RSIs) in tributaries of the Manistee River. Dan Mays from LRBOI and Alan Mock from GVSU presented preliminary results that suggest differences in hatching success may not be biologically relevant between the two RSI designs tested, and that removing dead individuals from RSIs during incubation did not significantly increase hatching success. Information learned in the first year of this two-year, graduate study provides valuable insight into optimal RSI designs and implementation processes for future Arctic Grayling reintroduction efforts in Michigan.
Fish Production Core Group
Ed Eisch, the DNR’s Fish Production Manager, presented on the design work that continues on the ultraviolet filter installation for the Oden State Fish Hatchery isolation building. Design is nearly complete, but in order to receive eggs in late spring 2019, construction work needs to start soon, but insufficient funds have been received to put the project out for bids. If this project is not out for bids by mid to late November, it is unlikely the project will be done in time to receive eggs. However, leftover fish from Nicole Watson’s research at Michigan State University might allow us to “jumpstart” the program anyhow. Final determination still needs to be made as to where the brood will be reared after they clear isolation. Right now, Marquette State Fish Hatchery is the likely location, but a second location would be desirable for redundancy.
MAGI solicited stream nominations for potential re-introduction of Arctic Grayling in Michigan. Based on historic range of this species and community support, the partners will assess the Maple, Upper Jordan and Boardman rivers, along with continued assessments of the Upper Manistee River. Nominations will continue to be reviewed for future considerations.
Research on Juvenile Arctic Grayling
Nicole Watson, Ph.D. student at Michigan State University, provided an overview of the first year of research examining Arctic Grayling early life history imprinting, predation of Grayling fry by resident young trout, and competitive interactions between young Grayling and resident trout of the same year class. Preliminary results indicate that age-1 Brown Trout exhibit a high predation rate on Grayling fry and the influence of competition is very high between age-0 Grayling and Browns. While age-1 Brook Trout do prey upon Grayling fry, it is at a lower rate than Brown Trout. These preliminary results also indicate growth of age-0 Grayling may not be affected by the presence of Brook Trout of the same year class. The results of the imprinting study are currently pending. While these preliminary results provide insight to interactions between Grayling and young resident trout, additional replicates over the course of the next two years are critical to increasing our confidence and robustness of the data.
*NOTE: Fundraising efforts following the annual partners meeting were successful enough to prompt putting the UV project out for construction bids. A pre-bid meeting is scheduled for December 10, 2018.