Blue Pike Workshop Minutes July, 1997............ A lot of questions answered

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    BLUE PIKE WORKSHOP MINUTES     
U.S. FISH AND WILDLIFE SERVICE
LOWER GREAT LAKES FISHERY RESOURCES OFFICE
AMHERST NY

List of attendees at the end of this report

 1. Why revisit the blue pike issue?

Dieter listed several reasons to this question. There has been continued interest and questions by the fishing public about blue colored suspects caught in other lakes, especially in northern Ontario. A new tool, DNA analysis, that may be able to better differentiate blue pike from walleye. A guild approach analysis by our office found that blue pike fit into the offshore, coldwater community. A search of suspects should focus on lakes with coldwater habitat. He showed a graph of the historic commercial catch of blue pike indicating their economic importance.

2. Issues in identification

DNA Analysis

Dr. Stepien reviewed research on the mitochondrial DNA (mtDNA) analysis of walleye and a few blue pike suspects from Lake Erie and Canadian lakes. The blue pike suspect samples were not significantly different than the Lake Erie yellow walleye. However, she cautioned that mtDNA follows only the maternal line. The mtDNA of one sample provided through Dieter's office from a source in Canada did fit within that found in Lake Erie's walleye but it also had a few differences. She has not completed the analysis of mucus from blue pike scale samples. She will be using nuclear DNA analysis as a second method of testing genetic differences of populations and species. This process provides more complete data. She is also currently looking for museum specimens not fixed in forinalin. Some recent research on extracting DNA from specimens fixed in formalin, has been reported in the literature but she has not been able to get complete DNA from formalin preserved samples. The preferred material/tissue for new/fresh samples is liver or a piece of muscle tissue from fresh blue pike suspects for DNA analysis. The samples should be wrapped in foil and frozen. If the sample cannot be sent frozen, it can be preserved in 95% ethanol and shipped to her lab. Information on location fish was caught, and morphological characteristics such as length and weight should be sent with the sample.

Dr. Burnham‑Curtis has scale samples of blue pike and walleye, including samples collected by John Parsons from the 1920's through the 1950's. She has found DNA, but there is contamination from chemicals in the paper used in the envelopes to hold the scales. She is working on separating the chemical contaminants and DNA fragments.

Larry Halyk mentioned a researcher at the University of Guelph, Dr. Moira Ferguson and a graduate student who will be analyzing scale sa:mples collected by OMNR in the central basin during the 1950's.

Dieter mentioned another researcher, Dr. Neil Billington, who analyzed three suspects sent by our office. He also found no difference in the mtDNA of the blue pike suspects and walleye.

Discussion continued on the need for funding to continue these efforts. There was a promise of support for any grant proposals. Other suggested sources of funding are non‑profit groups and sport fishing clubs.
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Mo1phometric Analysis

Betsy Trometer passed out a table listing physical and habitat differences between the sauger, walleye and blue pike based on a literature search. If there are any suggestions or changes, please forward them to Betsy.

Dr. Ed Crossman, Royal Ontario Museum, Toronto, has been reviewing their blue pike and walleye collection and measuring morphological characteristics and has been unable to separate the two subspecies. It is unclear whether he was looking at the traditional characteristics such as eye size, or was looking for other differing characteristics. He has also compared blue pike suspects with the museum collection, and has not found any to be blue pike.

Bob Daniels, New York State Museum, Albany, also has a reference collection that he has compared blue pike suspects with and found none of the suspects to be blue pike.

Carsten Jorgensen gave a short presentation on the history of the blue walleye in Lake Nipissing. Historically there may have only been blue pike in the lake, but has since been replaced by numerous stockings of walleye. The average depth of the lake is approximately 14', but there are places in the French River near the mouth as deep as 300’, which could have been the summer refuge for blue pike. In the 1970's, blue walleye were examined morphologically and only one was identified as a blue pike.
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3. How could blue pike be located (if they survived)?

Search of historic agency transfers

Our office has received several documents that indicate there were transfers of Lake Erie blue pike to lakes in Tennessee and Minnesota. Ontario Ministry of Natural Resources has an electronic database of fish transfers that go back to the 1970's. Earlier records are in files. There is a code for blue pike that indicates it may have been transferred. Larry Halyk will search this data for transfers.

Search for inland lakes with "blue pike" habitat

An effort is needed to identify bodies of water that provide the correct habitats needed to support blue pike and to identify the historic and current population of Stizostedion (walleye). Larry Halyk will also try to review the morphology of Ontario lakes and identify those that have coldwater habitat.

Field guide for screening suspects

Our office will be working on producing a field guide to help the fishing pubic screen suspects based on morphologic and habitat characteristics. Those that they identify as potential blue pike can be saved for more rigorous screening and DNA analysis.
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4. Potential hindrance to restoration if stock were found

There are concerns that the present environmental conditions and fish community may be a hindrance to efforts to restoration. Of particular interest is the impact of rainbow smelt if they are a major part of the diet of blue pike. Smelt were becoming very abundant at the same time the Lake Erie blue pike population crashed. Smelt have high levels of the enzyme thyaminase, which causes thiamine deficiency in some of the fish species that feed on them. Thiamine deficiency has been linked to reproductive failure in lake trout, coho and Atlantic salmon. Dr. Ketola has been heading a project examining the impacts of thiaminase on Lake Erie walleye. Walleye in Lake Erie feed heavily on smelt. Preliminary research indicates the levels of thiamine in walleye eggs collected in the eastern basin of Lake Erie are significantly lower than in walleye eggs collected from Oneida Lake. Next he will be measuring thiamine levels in walleye eggs collected from several sites around Lake Erie. He will also be comparing egg viability.

5. What next?

·         Primary concern is to find funding to continue DNA research.
·         Search databases for blue pike transfers
·        Search databases for lakes that provide "blue pike" habitats.
·         Prepare a “field guide” and get this information out to the fishing public so that they can use for field screening to provide samples of potential blue pike for DNA analysis.
·         Continue efforts to restore native forage fish diversity and to limit negative impacts caused by exocitc forage fish such as smelt.
·         Keep public informed as to progress in the search for blue pike.
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For more information:

Lower Great Lakes Fishery Resources Office
U.S. Fish and Wildlife Service
405 N. French road, Suite 120A
Amherst NY 14228-2008

Email: xxxxxxxxx

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