2005 Lake Sturgeon Research

Great Lakes Fishery Trust Funds Black Lake Sturgeon Research Collaborative

By James Crossman and Patrick Forsythe, Michigan State University

Sturgeon Research Strategies

There is clearly a need for research directed at determining the most effective culture and stocking techniques that will satisfy the desire for lake sturgeon rehabilitation and recovery and at the same time protect the remnant populations existing around the Great Lakes. We lack fundamental information on critical aspects of this species' early life history that will dictate management prescriptions designed to restore lake sturgeon populations.

Though the importance of maintaining genetic diversity is universally recognized in conservation planning, the emphasis placed on specific variables to offer in management recommendations varies.

This research is directed toward obtaining critical experimental data upon which detailed management prescriptions and guiding principles can be made. We will use field, hatchery, and molecular techniques in the context of our ongoing studies of lake sturgeon in the Black Lake system. This multi-disciplinary approach will build upon previous and ongoing sponsored research based on the established research program, infrastructure, and background data on the Black Lake population. This combines expertise from principal investigators from Michigan State University and their respective students and staff, the Michigan DNR and Sturgeon For Tomorrow collaborators in areas of fisheries management including hatchery management, population ecology, and population genetics.

We will determine the effects of different gamete-takes, rearing environments and stocking strategies on juvenile lake sturgeon growth, survival, movements, and levels of genetic diversity.

Specific objectives include:

  • the effects of different gamete-take and juvenile collection strategies
  • comparisons of the relative growth and survival rates
  • sources of mortality of juvenile sturgeon
  • quantification of habitat use and in-stream retention time of juvenile sturgeon at ages 4, 8 and 12 weeks at release
  • quantification of survival of juveniles through the first winter and comparison of over-winter survivorship between fish reared in a hatchery and stream-reared conditions

Three collection strategies will be used to collect individuals, including:

  • taking gametes by directly handling and spawning males and females to perform artificial crosses
  • collecting fertilized eggs from the water column directly below the spawning areas
  • collecting juveniles immediately following hatch down-stream of spawning areas

The two different rearing treatments will compare traditional hatchery culture practices using the Wolf Lake State Fish Hatchery with rearing in a streamside culture facility.

We will raise the larvae in two different environments to quantify differences in growth, survival, and movements following release. Differences in stream retention time between stream-reared and hatchery-reared juveniles of each size class will provide evidence of how rearing conditions (stream vs hatchery) and size at stocking contribute to the variance in probability of survival, and in movements within an out-migration from the stream.

This experiment is designed to provide quantitative information on effectiveness of each of three gamete/juvenile collection methods relative to management goals of maximizing the survival, growth, stream retention time, and genetic diversity of offspring.

It is important to note that larvae sampled using each of the three different collection treatment groups will be assessed during release at three different size/age classes. This experimental design allows simultaneous quantification of different factors. Juveniles will be stocked into the Upper Black River 4, 8, and 12 weeks following hatch (approximately mid-July, mid-August, and mid-September, respectively).

First, we will determine whether mortality rates are size-dependent. Secondly, we will quantify habitat selection and determine the stream retention time of each age class. Third, we will determine whether mortality has an effect on the genetic diversity of surviving progeny. Fourth, knowledge of the pedigree of juveniles will allow for quantification of differences in juvenile growth and survival during development and after stocking has occurred.

To visually identify individuals from the different collection and rearing treatments and ages at release, we will use a combination of fin clips, visible florescent elastomer (VFE) tagging, and coded wire tags.

Sampling will be conducted to assess the survival, growth, movement, and habitat use of stocked fish. We will confine our research to waters within the Cheboygan River watershed. Juveniles will be released at the Kleber Dam located on the Upper Black River. Juvenile assessment will occur downstream from the spawning sites 4, 8, and 12 weeks post hatch. We will also use stream shocking to collect predators and determine sources of predation.

Results from this project will provide much needed guidance for managers involved in lake sturgeon restoration efforts and can be used to improve the effectiveness of lake sturgeon culture and stocking efforts.

Great Lakes Fishery Trust

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