F. Joseph Margraf, Jr., Ph.D.
Joe Margraf is supervisor of the U.S. Geological Survey Cooperative Fish and Wildlife Research Units in the western US and is stationed in Pagosa Springs, CO. He has served in the Coop Unit Program since 1980 at the Ohio, West Virginia, Maryland, and Alaska Units where he was major advisor for nearly 50 graduate students and on the graduate committees of over 75 others.
He has authored or co-authored over 100 publications and technical reports and over 100 presentations for scientific meetings. He received his BS degree in Fisheries Science from Cornell University, and MS and Ph.D. degrees from Texas A&M University. Joe has been a member of the American Fisheries Society (AFS) since 1972 and life member since 1984. He is currently President-elect of AFS and will become President in August 2016. He has received both the AFS Distinguished Service and Meritorious Service awards, and was in the inaugural class of AFS Fellows. Joe is also a Fellow in the American Institute of Fishery Research Biologists and has served on its Board of Governors and Membership Committee.
Freshwater and anadromous fishes, Large lakes and rivers, Population and community ecology, Trophic interactions and bioenergetics, Fish & habitat interactions, Development of new management tools and paradigms
Quantitative Fisheries Science
Ecological Energetics of Fish
Science and Products
Bioelectrical impedance analysis: A new tool for assessing fish condition
Bioelectrical impedance analysis (BIA) is commonly used in human health and nutrition fields but has only recently been considered as a potential tool for assessing fish condition. Once BIA is calibrated, it estimates fat/moisture levels and energy content without the need to kill fish. Despite the promise held by BIA, published studies have been...Hartman, Kyle J.; Margraf, F. Joseph; Hafs, Andrew W.; Cox, M. Keith
Chronicling long-term predator responses to a shifting forage base in Chesapeake Bay: an energetics approach
The population of Striped Bass Morone saxatilis in Chesapeake Bay has increased significantly since the 1980s because of management efforts while the relative abundance of some key prey fish has declined since the 1970s. We examined the trophic interactions and prey consumption patterns of Striped Bass in Chesapeake Bay to determine how...Overton, Anthony S.; Griffin, Jennifer C.; Margraf, F. Joseph; May, Eric B.; Hartman, Kyle J.
Lipid and moisture content modeling of amphidromous Dolly Varden using bioelectrical impedance analysis
The physiological well-being or condition of fish is most commonly estimated from aspects of individual morphology. However, these metrics may be only weakly correlated with nutritional reserves stored as lipid, the primary form of accumulated energy in fish. We constructed and evaluated bioelectrical impedance analysis (BIA) models as an...Stolarski, J.T.; Margraf, F.J.; Carlson, J.G.; Sutton, T.M.
A remote-sensing, GIS-based approach to identify, characterize, and model spawning habitat for fall-run chum salmon in a sub-arctic, glacially fed river
At northern limits of a species’ distribution, fish habitat requirements are often linked to thermal preferences, and the presence of overwintering habitat. However, logistical challenges and hydrologic processes typical of glacial systems could compromize the identification of these habitats, particularly in large river environments. Our goal was...Wirth, Lisa; Rosenberger, Amanda; Prakash, Anupma; Gens, Rudiger; Margraf, F. Joseph; Hamazaki, Toshihide
Common relationships among proximate composition components in fishes
Relationships between the various body proximate components and dry matter content were examined for five species of fishes, representing anadromous, marine and freshwater species: chum salmon Oncorhynchus keta, Chinook salmon Oncorhynchus tshawytscha, brook trout Salvelinus fontinalis, bluefish Pomatomus saltatrix and striped bass Morone...Hartman, K.J.; Margraf, F.J.
Using a bioenergetic model to assess growth reduction from catch-and-release fishing and hooking injury in rainbow trout, Oncorhynchus mykiss
A bioenergetic model was used to predict the potential effects of feeding cessation caused by catch-and-release capture and a reduction in feeding efficiency from hooking injuries on rainbow trout, Oncorhynchus mykiss (Walbaum), growth in southwest Alaska, USA. Simulations indicated that a 1-day feeding cessation for a rainbow trout...Meka, Julie M.; Margraf, F.J.
Relationships among condition indices, feeding and growth of walleye in Lake Erie
Condition indices are often used as surrogates of fish health, growth, and feeding and to compare ecological well-being among fish populations. In an effort to identify easily measured indices, growth and food consumption were compared with gonadal-somatic index, liver-somatic index (LSI), fat-somatic index and relative weight (Wr) for ages 1-3...Hartman, K.J.; Margraf, F.J.
A sampler for capturing larval and juvenile Atlantic menhaden
Interest in capturing larval and juvenile Atlantic menhaden Brevoortia tyrannus for use in laboratory studies required the design and construction of a sampling device that would allow us to make collections of live fish from open-water areas. Our device for capturing 1-2.5-in larval-juvenile fish was constructed of a stainless steel frame that...Hedrick, J.D.; Hedrick, L.R.; Margraf, F.J.
The influence of diet, consumption and lipid use on recruitment of white bass
The abundance of white bass (Morone chrysops) in Lake Erie has declined in recent years, sparking interest in mechanisms influencing its recruitment. We evaluate two mechanisms affecting recruitment: diet and the potential for competition, and storage of lipid energy reserves and the relationship to overwinter survival. The fish in our study were...Eckmayer, W.J.; Margraf, F.J.
Searching for a life history approach to salmon escapement management
A number of Pacific salmon populations have already been lost and many others throughout the range are in various states of decline. Recent research has documented that Pacific salmon carcasses serve as a key delivery vector of marine-derived nutrients into the freshwater portions of their ecosystems. This nutrient supply plays a critical...Knudsen, E.E.; Symmes, E.W.; Margraf, F.J.
The diet of Chesapeake Bay striped bass in the late 1950s
The diet of Chesapeake Bay striped bass, (Morone saxatilis) Walbaum, based on unpublished stomach content data from 916 fish collected between 1955 and 1959 was described. The diet in the late 1950s, quantified using an index of relative importance (IRI), was dominated by Atlantic menhaden, Brevoortia tyrannus Latrobe. Atlantic menhaden (66%) and...Griffin, J.C.; Margraf, F.J.
US Atlantic coast striped bass: Issues with a recovered population
Striped bass, Morone saxatilis (Walbaum), is an anadromous species naturally occurring along the US Atlantic coast, which historically supported valuable commercial and recreational fisheries. In response to a near order-of-magnitude decline in landings, the Atlantic States Marine Fisheries Commission enacted a management plan in 1981 protecting...Hartman, K.J.; Margraf, F.J.