Progress 10/01/06 to 09/30/11

Outputs
OUTPUTS: Our participation in this project included an investigation of the extant genetic diversity associated with diverse life history forms in brook trout. The outputs of this project have included a master's thesis, a master's student (Anna Varian) who is now employed at Michigan Tech University, and pending manuscripts. The outputs of this project will inform natural resource managers in the Great Lakes basin about the degree to which phenotypes characteristic of these life histories are genetic in nature, an important consideration for conservation. In addition to written dissemination of our results, several talks have been given at regional scientific meetings. PARTICIPANTS: Anna Varian was a master's student working on the project, and has completed her degree. This project provided for her professional development as she completed her research, and disseminated her results in both oral and written presentations. Partner organizations included the Iron River National Fish Hatchery and the Marquette Fish Hatchery. Several undergraduates also participated in the project both in data analysis and in fish husbandry. TARGET AUDIENCES: Target audiences for our work included the scientific community, as well as natural resource conservation and management agencies who seek to further understand the nature of phenotypic diversity in natural and hatchery populations of brook trout. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Our work has shown that there is significant genetic variation for morphology in brook trout strains that have historically been used for stocking in Lake Superior. The degree to which these types of traits were heritable within and among strains exhibiting different life history strategies was previously unknown. These results will impact future studies on the relative contribution of genetics and environment in promoting alternative life histories, while informing resource managers on the nature of phenotypic variation that they strive to conserve in natural populations.

Publications

• Varian, A. 2008. HERITABILITY OF DEVELOPMENT RATE AND BODY MORPHOLOGY IN COASTER AND NON-COASTER STRAINS OF BROOK TROUT. M.S. Thesis, Purdue University.

Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Outputs during this reporting period include the finishing of a Master's student who worked on a heritability analysis of development rate and morphology and several strains of brook trout from hatcheries in the Lake Superior basin. Anna Varian successfully defended her thesis in July 2008 and has at least one publication submitted for publication. Meanwhile we have recruited an additional student to work on similar questions of the genetic basis of alternative life history types of brook trout. PARTICIPANTS: Anna Varian, M.S. student, completed her M.S. thesis and presented her work at the MidWest Fish and Wildlife meeting in Madison, WI (Dec 2007). Garrett McKinney is a new PhD student on the project, and he started in August 2008. collaborators include the USFWS, Iron River National Fish Hatchery and the MI DNR Marquette State Fish Hatchery. TARGET AUDIENCES: Fish Biologists PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
In the past year, we found that morphology of brook trout from non-migratory and migratory populations was heritable both within and among stocks. This finding is significant in answering the question as to whether morphotypic diversity is a product of underlying genetic diversity or purely controlled by environmental processes. This information will be useful as we further strive to understand the genetic and environmental determinants of life history variability in migratory and non-migratory brook trout.

Publications

• Varian, A.M. 2008. Heritability of development rate and body morphology in coaster and non-coaster strains of brook trout. Purdue University M.S. thesis. 91 pp.

Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: The activities in the last year include commencing a new project on which a M.S. student is working, and use of data collected for teaching and eventually research publication. We have collected gametes from several brook trout strains and began a heritability study approximately one year ago. We continue to evaluate the phenotypic and genetic variance in traits from these crosses, and expect to get gametes for additional crosses soon. These data have been collected by a current Master's student advised by K. Nichols, and have also been used for the teaching of a quantitative genetics class at the graduate level. An additional M.S. student was just accepted and is working in the laboratory as a continuation of this project. PARTICIPANTS: Krista Nichols is the PI on the project, who is directing graduate students Anna Varian and Garrett McKinney and undergraduate Andrew Hornbeck. Additional agencies that have contributed to our study include the Marquette State Fish Hatchery, the Iron River Federal Hatchery, and the Keewenaw Bay Indian tribe for contribution of gametes for our genetic crosses. This project is specifically training graduate and undergraduate students in their respective degrees. TARGET AUDIENCES: Freshwater fish biologists PROJECT MODIFICATIONS: The major changes in this project includes the departure of Trent Sutton from Purdue University, as he took a faculty position at University of Alaska, Fairbanks. This project is now solely focused on genetic diversity of aquatic organisms from the Great Lakes basin, including brook trout.

Impacts
We have begun to identify whether or not genetic factors contribute to variability in embryonic development rate and juvenile morphology in brook trout, and continue to collect data on existing crosses made at the Aquaculture Research Lab at Purdue. These results will be important in the consideration of genetic diversity of stock used for rehabilitation and conservation in Lake Superior.

Publications

• No publications reported this period

Progress 10/01/05 to 09/30/06

Outputs
In 2004, a new research project was initiated on lake whitefish, an ecologically and commercially important species in the Great Lakes. We are evaluating the impacts of trophic food web change on lake whitefish recruitment by examining reproductive potential, survival, and growth through the first year of life. To date, we have successfully completed collections of spawning adults from October through December 2004 and 2005 in Lakes Michigan, Superior, and Erie, which has allowed for the evaluation of body condition, age structure, growth history, proximate composition, fatty-acid content, and gamete quality. Sampling at these sites during spring and summer 2005 and 2006 allowed for the collection of early life stages of this species. For all collections completed in 2004 and 2005, samples have been processed; completion of sample processing for 2006 collections is currently in progress. Eggs from lake whitefish will be collected and fertilized during fall 2006 to allow for the evaluation of diet quality on growth, mortality, and energetic condition in a series of laboratory experiments. This research will allow for a better understanding of the early life history dynamics of lake whitefish within the context of ongoing food-web changes in Lake Michigan and will be a necessary component for the successful management of this species. Evaluation of the population biology and recruitment dynamics of lake sturgeon in the Great Lakes are currently ongoing using both laboratory and field approaches. The first project, a laboratory study, is examining the impacts of sea lamprey predation on lake sturgeon growth and mortality. To date, experimental trials have demonstrated that sea lampreys can kill subadult lake sturgeon and have negative effects on growth. For the second project, the first of two field seasons has been completed to identify and measure the sources of egg, larval, and age-0 juvenile lake sturgeon mortality under natural conditions in the lower Peshtigo River, a tributary of Green Bay, and quantitatively assess the mechanisms responsible for these losses. Egg losses following lake sturgeon spawning were high (99.6%), with suckers and crayfishes identified as the primary predators. Survival from the larval to the age-0 juvenile life stage was also low (2%); however, no fish predators were captured that had consumed larval or juvenile lake sturgeon. These two research projects will increase our understanding of the mechanisms directing population and recruitment dynamics of lake sturgeon and help to identify mortality sources that may negatively impact ongoing and future recovery efforts for this species. Our research on age-0 juvenile coaster brook trout had been delayed until the completion of the Baker Aquaculture Research Laboratory which was destroyed by a fire in November 2004. Now that the facility has been reconstructed and is operational, this research has been initiated. Fish will be secured later this fall and winter, with laboratory experiments commencing during spring and summer 2007.

Impacts
By gaining a better understanding of the influence of environmental conditions on the population biology of Great Lakes fishes, critical information will be provided for the development of management and rehabilitation strategies. For lake whitefish in the Great Lakes, understanding the factors that influence growth, reproductive potential, and survival will allow for the prediction of year-class strength and recruitment dynamics of these two commercially important fishes. This information will become more important as the trophic food web in the Great Lakes continues to change as new exotic species become established and as global climate change continues to occur. Identification and quantification of mortality sources influencing lake sturgeon will provide critical information needed to aid recovery efforts throughout the Great Lakes basin. These evaluations will augment current modeling efforts to assess lake sturgeon population viability in the Great Lakes for this severely imperiled species. Understanding the early life history biology of coaster brook trout will also facilitate ongoing rehabilitation efforts in the upper Great Lakes. Preserving the integrity of this brook trout life history variant has been identified as critical to maintaining the biotic integrity of the upper Great Lakes region. Accomplishing these goals are important not only from a fisheries management perspective, but also in terms of the ecological, sociocultural, political, and economical framework associated with these important fishes throughout the Great Lakes basin.

Publications

• Benson, A. C., T. M. Sutton, R. F. Elliott, and T. G. Meronek. 2005. Movement patterns and habitat preferences of age-0 juvenile lake sturgeon in the lower Peshtigo River, Wisconsin. Transactions of the American Fisheries Society 134:1400-1409.
• Benson, A. C., T. M. Sutton, R. F. Elliott, and T. G. Meronek. 2005. Evaluation of sampling techniques for age-0 juvenile lake sturgeon in the lower Peshtigo River, Wisconsin, and nearshore waters of Green Bay. North American Journal of Fisheries Management 25:1378-1385.
• Benson, A. C., T. M. Sutton, R. F. Elliott, and T. G. Meronek. 2006. Biological attributes of age-0 lake sturgeon in the lower Peshtigo River, Wisconsin. Journal of Applied Ichthyology 22:103-108.

Progress 10/01/04 to 09/30/05

Outputs
New research has been initiated on lake whitefish, an ecologically and commercially important species in the Great Lakes. Growth of lake whitefish in Lake Michigan has slowed due to loss of important prey resources over the past decade, and fish are now smaller and in poorer condition. For this research, we will evaluate the impacts of these changes on lake whitefish recruitment by examining reproductive potential and survival and growth of this species through the first year of life using a combined field and laboratory focus. To date, we have successfully completed collections of spawning adults from October through December 2004 in Lake Michigan, which has allowed for the evaluation of body condition, age structure, growth history, proximate composition, fatty-acid content, and gamete quality. Sampling at these sites during May and June 2005 allowed for the collection of early life stages of this species. For all collections completed in 2004 and 2005, samples are being processed. Identical sampling ventures at the same locations in Lake Michigan will take place during fall 2005 and spring 2006. In addition, eggs from lake whitefish will be collected and fertilized during fall to allow for the evaluation of diet quality on growth, mortality, and energetic condition in the laboratory. This research will allow for a better understanding of the early life history dynamics of lake whitefish within the context of ongoing food-web changes in Lake Michigan and will be a necessary component for the for successful management of this species. Two new studies have been initiated to evaluate the population biology and recruitment dynamics of lake sturgeon in the Great Lakes. The first project will employ a laboratory approach to evaluate the impacts of sea lamprey predation on lake sturgeon growth and mortality. The use of the no observable effect (i.e., no mortality) lampricide treatment protocol to protect lake sturgeon populations might also increase production of sea lampreys and, consequently, parasitism on lake sturgeon. However, no studies have examined the influence of sea lamprey parasitism on lake sturgeon. Because previous model simulations indicate that sea lamprey attacks on adult lake sturgeon adversely affect long-term population viability, an understanding is needed of the relations among wounding rate, wound type, and host survival to ensure that sea lamprey control strategies optimize lake sturgeon rehabilitation in the Great Lakes. For the second project, we will identify and measure the sources of egg, larval, and juvenile lake sturgeon mortality under natural conditions in the Peshtigo River, a tributary of Green Bay, and quantitatively assess the mechanisms responsible for these losses. These research projects will increase our understanding of the mechanisms directing population and recruitment dynamics of lake sturgeon and help to identify mortality sources that may negatively impact ongoing and future recovery efforts for this species. Our research on juvenile coaster brook trout has been delayed until the completion of the Baker Aquaculture Research Laboratory which was destroyed by a fire in November 2004.

Impacts
By gaining a better understanding of the influence of environmental conditions on the population biology of early life stages of Great Lakes fishes, critical information will be provided for the development of proper management and rehabilitation strategies. For lake herring and lake whitefish in the Great Lakes, understanding the factors that influence growth, reproductive potential, and survival will allow for the prediction of year-class strength and recruitment dynamics of this species. Identification and quantification of mortality sources influencing all life stages of lake sturgeon will provide critical information needed to aid recovery efforts throughout the Great Lakes basin. Accomplishing these goals are important not only from a fisheries management perspective, but also in terms of socioculturally and economically for these important fishes within the Great Lakes basin.

Publications

• Sutton, T. M., E. T. Volkman, K. L. Pangle, D. A. Rajchel, and J. P. Duehr. 2004. Effects of absorbable suture strand diameter on retention of external radio transmitters by juvenile lake sturgeon. North American Journal of Fisheries Management 24:1394-1398.
• Benson, A. C. 2004. Characterization of early life history stages of lake sturgeon in the Peshtigo River and nearshore waters of Green Bay, Wisconsin. Masters thesis. Purdue University, West Lafayette, Indiana.
• Pangle, K. L., T. M. Sutton, R. E. Kinnunen, and M. H. Hoff. 2005. Effects of body size, condition, and lipid content on the survival of juvenile lake herring during rapid cooling events. Journal of Great Lakes Research 31:360-366.
• Pangle, K. L., and T. M. Sutton. 2005. Temporal changes in the relationship between body condition and proximate composition of juvenile Coregonus artedi. Journal of Fish Biology 66:1-13.

Progress 10/01/03 to 09/29/04

Outputs
For the initial research prospectus, three native fishes in the Laurentian Great Lakes (lake herring, lake sturgeon, and coaster brook trout) were selected for assessments of early life-stage biology. Although the project on winter mortality and recruitment of juvenile lake herring was completed in summer 2003, a comparable line of research has been initiated on an ecologically similar species of commercial importance in Lake Michigan, the lake whitefish. Growth of lake whitefish in Lake Michigan has slowed over the past decade, and fish are now smaller and in poorer condition. For this research, we will evaluate the impacts of these changes on lake whitefish recruitment by examining reproductive potential and the survival and growth of this species through the first year of life. This research will allow for a better understanding of the reproductive and early life history dynamics of lake whitefish within the context of ongoing food-web changes in Lake Michigan and will be a necessary component for improving fishery yield forecasts and establishing appropriate harvest-limit strategies for successful management of this species. Research on early life stages of lake sturgeon in the Peshtigo River, Wisconsin, was completed during summer 2004. Larval lake sturgeon were captured in drift nets from May to June 2002 and 2003, and age-0 juveniles were captured from June through October 2002 and 2003. Larval movement downstream occurred 14 d after adult spawning. The larval drift period was one to three weeks long, resulting in two peaks of drifting larvae. Age-0 juveniles grew rapidly, were in good condition, and preferred areas with low velocities, shallow depths, and sand substrates dominated by dipteran larvae. Daily movements of these fish showed that they were nocturnally active, while long-term movements were related to declining water temperatures in the fall. These study results will allow for the identification of critical habitats for early life stages of lake sturgeon that should be protected in Great Lakes tributaries supporting spawning populations of this species. For our research on juvenile coaster brook trout, we examined the hatchery-performance attributes of three strains (Lake Nipigon [Nipigon], Siskiwit Bay [Siskiwit], and Tobin Harbor [Tobin]) during a 12-wk laboratory experiment. Despite similar initial sizes, the final mean length and weight of Nipigon fish was significantly greater than those of the Siskiwit and Tobin strains. There were no differences in mean specific growth rates in length and weight or mean daily growth rate in length among the strains. However, there was a difference in mean daily absolute growth rate in weight, with Nipigon and Siskiwit strains displaying a greater rate of growth than Tobin Harbor fish. We recommend that these strains should be reared similarly in hatchery environments and that strain selection for rehabilitation stocking purposes should consider hatchery residence time and natural genetic variation of the source population of broodstock fish.

Impacts
By gaining a better understanding of the influence of environmental conditions on the population biology of early life stages of Great Lakes fishes, critical information will be provided for the development of proper management and rehabilitation strategies. For lake herring in Lake Superior, understanding the relationship between body size, energy stores, and feeding level relative to winter temperature regimes will allow for the prediction of year-class strength and recruitment dynamics of this species. Identification of the habitat requirements and movement patterns of larval and juvenile lake sturgeon in Lake Michigan tributaries will provide critical information needed for recovery efforts throughout the Great Lakes basin. Better rehabilitation strategies will also be developed for the management of coaster brook trout stocks in the upper Great Lakes by evaluating the life history and population biology of early life stages.

Publications

• Pangle, K. L., T. M. Sutton, R. E. Kinnunen, and M. H. Hoff. 2004. Overwinter survival of age-0 lake herring in relation to body size, physiological condition, energy stores, and food ration. Transactions of the American Fisheries Society 133:1224-1234.
• Volkman, E. T., K. L. Pangle, D. A. Rajchel, T. M. Sutton, and D. R. Bast. 2004. Comparison of hatchery-performance attributes among three strains of age-0 coaster brook trout. North American Journal of Aquaculture 66:278-284.

Progress 10/01/02 to 09/30/03

Outputs
For this research, three native fishes in the Laurentian Great Lakes (lake herring Coregonus artedi, lake sturgeon Acipenser fulvescens, and coaster brook trout Salvelinus fontinalis) were selected for assessments of early life-stage biology. Lake herring are a species of interest because population levels in Lake Superior have not rebounded to historical levels following declines that occurred in the mid-1900s. As a result, this species is not listed as threatened or endangered in some areas of the Great Lakes. Using a laboratory study, we conducted an overwinter mortality study using this species to evaluate the role of body size, energy stores, and lipid levels over a 225-day period. Mortality of large lake herring was significantly less than those of small fish, with starved fish in each treatment suffering greater mortality than fed fish. Lipid content declined over the experiment for all fish, with index values significantly greater for large and small fed fish than large and small starved individuals. These results suggest that depletion of energy stores contributes to greater winter mortality of small lake herring and may partially explain the variability in recruitment observed in Lake Superior. For lake sturgeon in the Peshtigo River, a tributary of Green Bay in Lake Michigan, a total of 206 juveniles were captured over the spring and summer months in 2003 and eight of these individuals were outfitted with radio transmitters to track movement patterns and habitat use. In general, fish have exhibited very limited movement throughout the river to date, choosing to occupy areas similar to their initial capture location (i.e., shallow, sandy areas with slow flow and no aquatic vegetation). Using the habitat and prey data obtained from samples collected from the entire river at predefined intervals in 2003, we have developed a detailed map of the river that documents the relationship between benthic prey assemblage, density, and diversity, substrate type, flow rate, and water depth relative to juvenile lake sturgeon distribution. This information will be combined with the 2002 field data to assess and identify the selective preference for habitat types and areas of the river for the future protection of critical nursery grounds. We have recently completed a hatchery evaluation to compare the performance attributes of three strains of coaster brook trout in a hatchery setting. Specifically, we compared the influence of strain type and density on the growth, condition, lipid storage, and behavior of juvenile life stages of this species. The results of this study will provide information to hatchery personnel for the development of more scientific rearing protocols which should enhance rehabilitation stocking efforts of these strains in coastal waters of Lake Superior.

Impacts
By gaining a better understanding of the influence of environmental conditions on the population biology of early life stages of Great Lakes fishes, critical information will be provided for the development of proper management and rehabilitation strategies. For lake herring in Lake Superior, understanding the relationship between body size, energy stores, and feeding level relative to winter temperature regimes will allow for the prediction of year-class strength and recruitment dynamics of this species. Identification of the habitat requirements and movement patterns of larval and juvenile lake sturgeon in Lake Michigan tributaries will provide critical information needed for recovery efforts throughout the Great Lakes basin. Better rehabilitation strategies will also be developed for the management of coaster brook trout stocks in the upper Great Lakes by evaluating the life history and population biology of early life stages.

Publications

• Pangle, K. L., T. M. Sutton, and P. B. Brown. 2003. Evaluation of practical and natural diets for juvenile lake herring. North American Journal of Aquaculture 65:91-98.
• Sutton, T. M., and A. C. Benson. 2003. Influence of external radio transmitter shape and size on tag retention and growth of juvenile lake sturgeon. Transactions of the American Fisheries Society 132:1257-1263.

Progress 10/01/01 to 09/30/02

Outputs
For this proposed research, three native fishes in the Laurentian Great Lakes (lake herring Coregonus artedi, lake sturgeon Acipenser fulvescens, and coaster brook trout Salvelinus fontinalis) were selected for assessments of early life stage biology. Lake herring are a species of interest because population levels in Lake Superior have not rebounded to historical levels. Using a laboratory study, we have developed a protocol for the rearing of this species in a culture environment that could prove useful should state, provincial, and federal fisheries management agencies choose to initiate rehabilitation stocking efforts. Currently, our overwinter mortality study using lake herring has only been in progress for 60 days (the study will last 225 days). As a result, it is too soon to determine what impacts that winter temperatures, feeding levels, body size, and energy stores will have on survival of juvenile fish. However, initial study results have been as expected as the smallest fish in the starvation treatment have not survived. For the lake sturgeon study in the Peshtigo River, a tributary of Green Bay in Lake Michigan, a total of 13 juveniles were captured over the summer and four of these individuals were outfitted with radio transmitters to track movement patterns and habitat use. Until water temperatures declined below 10 degrees Celsius, juvenile lake sturgeon remained in the river where they foraged for food in areas with soft substrates. In most cases, these fish exhibited very limited movement, choosing to occupy similar areas on a daily basis. After river water temperatures declined below 10 degrees Celsius, fish moved out of the river and into Green Bay where water temperatures were warmer. Habitat and prey samples were collected from the entire river at predefined intervals. These data will be incorporated with data collected from known areas that held lake sturgeon and assessments will be conducted this winter to determine selective preference for habitat types and areas of the river that appear to be critical nursery grounds. To date, no field studies have been conducted on juvenile coaster brook trout. However, we have conducted one hatchery evaluation to compare performance attributes of this strain relative to other known strains of brook trout. This spring, we will be conducting a similar evaluation with all three strains of coaster brook trout so that we can provide information to hatchery personnel for the development of more scientific rearing protocols which should enhance rehabilitation stocking efforts. In addition, we will be evaluating different rearing techniques for hatchery personnel which should prove useful for improving growth and survival of reared fish post-stocking.

Impacts
Understanding the relationship between body size, energy stores, and feeding levels of juvenile lake herring relative to winter temperature regimes, biologists will better understand the recruitment dynamics of this species in Lake Superior. For lake sturgeon in Lake Michigan tributaries, identification of the habitat requirements and movement patterns of larvae and juveniles will provide critical information needed for rehabilitation throughout the Great Lakes basin. Better rehabilitation strategies will also be developed for the management of coaster brook trout stocks in the upper Great Lakes by evaluating the life history, population biology, and community dynamics of early life stages in tributary streams. By gaining a better understanding of the influence of environmental conditions on the population biology of early life stages of these Great Lakes fishes, critical information will be provided for the development of proper management and rehabilitation strategies needed to maintain the sustainability of these fisheries.

Publications

• Sutton, T.M., K.L. Pangle, and R.W. Greil. 2002. Hatchery performance attributes of Nipigon, Assinica, and Iron River strains of age-0 brook trout. North American Journal of Aquaculture 64:188-194.