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Charlevoix, MI, United States

Blukacz E.A.,Canadian Department of Fisheries and Oceans | Koops M.A.,Canadian Department of Fisheries and Oceans | Sutton T.M.,Purdue University | Sutton T.M.,University of Alaska Fairbanks | And 9 more authors.
Journal of Great Lakes Research | Year: 2010

Sexual-selection theory predicts males will increase investment in ejaculates if there is an increase in the level of sperm competition. Production of ejaculates is energetically costly, so males in better condition should be able to produce ejaculates of higher quality than individuals in poorer condition. We examined how ejaculate investment (i.e., relative testes mass) and sperm quality (i.e., sperm swimming speed) in lake whitefish (Coregonus clupeaformis) were related to residual soma mass, fork length, and fish age using data collected from Lake Michigan and Bay of Quinte (Lake Ontario). Populations from both lakes had positive relationships between relative testes mass and residual soma mass. Fork length was the most important predictor of sperm swimming speed with larger males from both lakes tending to have faster swimming sperm than smaller fish. Testis asymmetry, which is a commonly observed phenomenon in other animals but which has only recently been reported in fishes, was found to occur in the majority of examined lake whitefish with the left testes typically larger than the right. © 2010.


Andvik R.T.,University of Wisconsin - Stevens Point | Sloss B.L.,University of Wisconsin - Stevens Point | VanDeHey J.A.,University of Wisconsin - Stevens Point | Claramunt R.M.,Charlevoix Research Station | Isermann D.A.,University of Wisconsin - Stevens Point
Journal of Great Lakes Research | Year: 2016

Lake whitefish (Coregonus clupeaformis) support the primary commercial fishery in Lake Michigan. Discrete genetic stocks of lake whitefish have been identified and tagging data suggest stocks are mixed throughout much of the year. Our objectives were to determine if (1) differential stock harvest occurs in the commercial catch, (2) spatial differences in genetic composition of harvested fish were present, and (3) seasonal differences were present in the harvest by commercial fisheries that operate in management zones WI-2 and WFM-01 (Green Bay, Lake Michigan). Mixed stock analysis was conducted on 17 commercial harvest samples (n = 78-145/sample) collected from various ports lake-wide during 2009-2010. Results showed significant mixing with variability in stock composition across most samples. Samples consisted of two to four genetic stocks each accounting for ≥. 10% the catch. In 10 of 17 samples, the stock contributing the largest proportion made up <. 60% of the harvest. In general, seasonal and annual differences existed in the proportional stock contribution at a single capture location. Samples from Wisconsin's primary commercial fishing management zone (WI-2) were composed predominately of fish from the Big Bay de Noc (Michigan) stock as opposed to the geographically proximate, North-Moonlight Bay (Wisconsin) stock. These findings have implications for management and allocation of fish to various quotas. Specifically, geographic location of harvest, the current means of allocating harvest quotas, is not the best predictor of genetic stock harvest. © 2016.


Kolb T.L.,Charlevoix Research Station | Agnes Blukacz-Richards E.,Canadian Department of Fisheries and Oceans | Muir A.M.,Great Lakes Fish Commission | Muir A.M.,Michigan State University | And 6 more authors.
Fisheries | Year: 2013

Proper data management (applying coordinated standards and structures to data collection, maintenance, retrieval, and documentation) is essential for complex projects to ensure data accuracy and accessibility. In this article, we used a recent project evaluating changes in Lake Whitefish (Coregonus clupeaformis) growth, condition, and recruitment in the Great Lakes as a case study to illustrate how thoughtful data management approaches can enhance and improve research. Data management best practices described include dedicating personnel to data curation, setting data standards, building a relational database, managing data updates, checking for and trapping errors, extracting data, documenting data sets, and coordinating with project collaborators. The data management actions taken ultimately resulted in a rich body of scientific publication and a robust database available for future studies. Investing in data management allowed this project to serve as a model for taking the first steps toward a common goal of sharing, documenting, and preserving data that are collected and reported during the scientific research process.


Claramunt R.M.,Charlevoix Research Station | Muir A.M.,Purdue University | Muir A.M.,Golder Associates | Johnson J.,Charlevoix Research Station | And 2 more authors.
Journal of Great Lakes Research | Year: 2010

We compared diets of juvenile lake whitefish among six sites in Lake Michigan and one in Lake Superior during 2005 and 2006 to assess spatial and temporal patterns in food habits and evaluate if ontogenetic diet shifts occur that may influence growth and survival. A total of 262 and 496 juveniles were captured in 2005 and 2006, the majority of which were captured during June and July. Sites in southern Lake Michigan tended to have larger juveniles, and the smallest juveniles were observed at Naubinway, northern Lake Michigan, and Whitefish Point, Lake Superior. The mean number of prey items per stomach differed among sampling sites and years. Copepods were the most prevalent prey item, and were present in greater than 70% of juvenile stomachs from most sites. However, the percent by number of copepods decreased during July as chironomids and other benthic macroinvertebrates increased in number. There was a significant positive relationship between percent of benthic prey items and mean length of juvenile lake whitefish. A substantial increase in the percent of benthic prey consumed after 40 mm (total length) was observed and likely resulted from juvenile lake whitefish crossing a size threshold for benthic feeding relating to morphological changes (i.e., transition of mouth opening from terminal to sub-terminal) in addition to a potential increase in the availability of emergent macroinvertebrates. Timing of the transition to benthic feeding is likely regulated by the number of prey per juvenile and the overlap with peak emergence of important benthic aquatic invertebrates such as chironomids. A better understanding of these factors will increase our understanding of juvenile lake whitefish growth and survival, which are necessary for improving year-class strength predictions. © 2010.

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