**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**

 

 

 

Identification of a genetically diverse and compatible source of bloater (Coregonus hoyi)

for reintroduction in Lake Ontario

 

Turgeon, J., and M.J. Favé ¹

 

¹ Département de biologie

Université Laval

Quebec City, Quebec, Canada G1K 7P4

Tel: 418-656-3135

Fax: 418-656-2043

Email: julie.turgeon@bio.ulaval.ca

 

 

Abstract:

 

The originally diverse ciscoe fish fauna of the Laurentian Great Lakes has suffered many extinctions and local extirpations. Bloaters (Coregonus hoyi) are presumed extirpated from Lake Ontario and the reintroduction of this deepwater fish is under consideration. Our first goal was identify a genetically diverse and similar source of bloaters suitable for reintroduction via an analysis of genetic diversity and population structure of C. hoyi using 10 microsatellite loci. Despite well-documented demographic declines, we found no genetic evidence of bottlenecks in 12 bloater samples from the four potential donor lakes (Huron, Michigan, Superior and Nipigon). Patterns of genetic differentiation also suggested that the few deepwater ciscoes recently caught in Lake Ontario are part of a small undetected population most similar to bloaters of Lake Huron and Lake Michigan. On the basis of genetic criteria, and given the high genetic diversity, the absence of significant bottlenecks and the similarity to Lake Ontario ciscos, we conclude that bloaters from any location within Lake Huron or Lake Michigan would be judicious sources of breeders for reintroducing C. hoyi in Lake Ontario. Albeit with a diversified source of genitors, captive breeding and reintroduction procedures can rapidly generate inbreeding among offspring. Therefore, simulations based on bloaters’ life history and demographic parameters were used to investigate the inbreeding dynamics of a reintroduced population of bloaters. As expected, a high number of breeders, a balanced sex ratio, a high proportion of effective crosses all contributed to lower F values. But moderately high (>= 20) numbers of breeders combined with all but the most biased sex ratios produced mean F values near minimal even with proportions of effective crosses as low as 40%. Simulations of the long-term inbreeding dynamics indicated that the annual number of introduced offspring is a decisive factor in establishing long-term F values in the supplemented population. Low supplementation levels quickly generated an almost completely inbred population whereas high levels produced stable F values close to that of the introduced offspring. With alternating supplementation regimes, F eventually reached levels close to that corresponding to the largest supplementation.