Unit Leader - Vermont Cooperative Fish and Wildlife Research Unit
Mark Henderson recently started as the Unit Leader for the USGS Vermont Cooperative Fish and Wildlife Research Unit at the University of Vermont. Prior to joining the Vermont Cooperative Research Unit, he was the acting unit leader at the California Cooperative Research Unit for six years.<br><br>Mark's overarching research interests are how the physical, and biological, environment influences fish population dynamics (e.g., movements, growth, and mortality) on different spatial and temporal scales. He is a quantitative ecologist that uses various modeling approaches to answer applied research questions related to fisheries management. Research in his lab group primarily focuses on the interactions between fishes and their environment, and how our changing climate will affect species distributions, habitat availability, and population dynamics. <br><br>Prior to coming to Vermont, the majority of the research in Mark's lab focused on using population dynamics and species distribution models to understand the causes of salmonid mortality. Many of the salmonid populations in California are ESA listed as threatened or endangered, thus identifying the causes of mortality and what management and restoration actions may aid in population recovery is critical. In Vermont, Mark will apply similar quantitative methods to understand the population dynamics and management of Lake Champlain and inland fishes in Vermont.
Professional Experience
Unit Leader, Vermont Cooperative Fish and Wildlife Research Unit, 2022-
Assistant Unit Leader, California Cooperative Fish and Wildlife Research Unit, 2016-2022
Education and Certifications
PhD, College of William and Mary, 2007
MS, University of Washington, 2002
BS, SUNY Geneseo, 1996
Science and Products
Vulnerability to climate change of managed stocks in the California Current large marine ecosystem
Introduction: Understanding how abundance, productivity and distribution of individual species may respond to climate change is a critical first step towards anticipating alterations in marine ecosystem structure and function, as well as developing strategies to adapt to the full range of potential changes.Methods: This study applies the NOAA (National Oceanic and Atmospheric Administration) Fishe
Reduced recruitment of Chinook salmon in a leveed bar-built estuary
Estuaries are commonly touted as nurseries for salmonids, providing numerous advantages for smolts prior to ocean entry. In bar-built estuaries, sandbars form at the mouth of rivers during periods of low stream flow, closing access to the ocean and preventing outmigration. We evaluated how summer residency in a leveed bar-built estuary affects the growth, survival, and recruitment of a Chinook sal
Deep-sea coral and sponge taxa increase demersal fish diversity and the probability of fish presence
Fishes are known to use deep-sea coral and sponge (DSCS) species as habitat, but it is uncertain whether this relationship is facultative (circumstantial and not restricted to a particular function) or obligate (necessary to sustain fish populations). To explore whether DSCS provide essential habitats for demersal fishes, we analyzed 10 years of submersible survey video transect data, documenting
Fish predation on a landscape scale
Predator–prey dynamics can have landscape-level impacts on ecosystems, and yet, spatial patterns and environmental predictors of predator–prey dynamics are often investigated at discrete locations, limiting our understanding of the broader impacts. At these broader scales, landscapes often contain multiple complex and heterogeneous habitats, requiring a spatially representative sampling design. Th
Good practices for species distribution modeling of deep-sea corals and sponges for resource management: Data collection, analysis, validation, and communication
Resource managers in the United States and worldwide are tasked with identifying and mitigating trade-offs between human activities in the deep sea (e.g., fishing, energy development, and mining) and their impacts on habitat-forming invertebrates, including deep-sea corals and sponges (DSCS). Related management decisions require information about where DSCS occur and in what densities. Species dis
Outmigration survival of wild Chinook salmon smolts through the Sacramento River during historic drought and high water conditions
Populations of wild spring-run Chinook salmon in California’s Central Valley, once numbering in the millions, have dramatically declined to record low numbers. Dam construction, habitat degradation, and altered flow regimes have all contributed to depress populations, which currently persist in only a few tributaries to the Sacramento River. Mill Creek (Tehama County) continues to support these th
Predation strategies of larval clownfish capturing evasive copepod prey
Fish larvae depend on finding and capturing enough prey for rapid growth during the planktonic phase. The diet of many fish larvae is dominated by copepods, small crustaceans that are highly sensitive to hydrodynamic disturbances and possess strong escape responses. We examined how fish larvae with immature jaws, musculature and fins capture such evasive prey. The kinematics of feeding attempts by
Changes in adult Chinook salmon (Oncorhynchus tshawytscha) survival within the lower Columbia River amid increasing pinniped abundance
Significant effort towards conservation has contributed to the recovery of historically depleted pinniped populations world-wide. However, in several locations where pinnipeds have increased, they have been blamed for preventing the recovery of commercially valuable fish species through predation. Prompted by increasing pinniped abundance within the Columbia River (CR) USA, over a six year period
Spatial variability in ocean-mediated growth potential is linked to Chinook salmon survival
Early ocean survival of Chinook salmon, Oncorhynchus tshawytscha, varies greatly inter-annually and may be the period during which later spawning abundance and fishery recruitment are set. Therefore, identifying environmental drivers related to early survival may inform better models for management and sustainability of salmon in a variable environment. With this in mind, our main objectives were
Estimating spatial–temporal differences in Chinook salmon outmigration survival with habitat- and predation-related covariates
Low survival rates of Chinook salmon (Oncorhynchus tshawytscha) smolts in California’s Central Valley have been attributed to multiple biological and physical factors, but it is not clear which factors have the largest impact. We used 5 years of acoustic telemetry data for 1709 late-fall Chinook salmon smolts to evaluate the effect of habitat- and predation-related covariates on outmigration survi
Environmental conditions and prey-switching by a seabird predator impact juvenile salmon survival
Due to spatio-temporal variability of lower trophic-level productivity along the California Current Ecosystem (CCE), predators must be capable of switching prey or foraging areas in response to changes in environmental conditions and available forage. The Gulf of the Farallones in central California represents a biodiversity hotspot and contains the largest common murre (Uria aalge) colonies along
Science and Products
- Publications
Vulnerability to climate change of managed stocks in the California Current large marine ecosystem
Introduction: Understanding how abundance, productivity and distribution of individual species may respond to climate change is a critical first step towards anticipating alterations in marine ecosystem structure and function, as well as developing strategies to adapt to the full range of potential changes.Methods: This study applies the NOAA (National Oceanic and Atmospheric Administration) FisheReduced recruitment of Chinook salmon in a leveed bar-built estuary
Estuaries are commonly touted as nurseries for salmonids, providing numerous advantages for smolts prior to ocean entry. In bar-built estuaries, sandbars form at the mouth of rivers during periods of low stream flow, closing access to the ocean and preventing outmigration. We evaluated how summer residency in a leveed bar-built estuary affects the growth, survival, and recruitment of a Chinook salDeep-sea coral and sponge taxa increase demersal fish diversity and the probability of fish presence
Fishes are known to use deep-sea coral and sponge (DSCS) species as habitat, but it is uncertain whether this relationship is facultative (circumstantial and not restricted to a particular function) or obligate (necessary to sustain fish populations). To explore whether DSCS provide essential habitats for demersal fishes, we analyzed 10 years of submersible survey video transect data, documentingFish predation on a landscape scale
Predator–prey dynamics can have landscape-level impacts on ecosystems, and yet, spatial patterns and environmental predictors of predator–prey dynamics are often investigated at discrete locations, limiting our understanding of the broader impacts. At these broader scales, landscapes often contain multiple complex and heterogeneous habitats, requiring a spatially representative sampling design. ThGood practices for species distribution modeling of deep-sea corals and sponges for resource management: Data collection, analysis, validation, and communication
Resource managers in the United States and worldwide are tasked with identifying and mitigating trade-offs between human activities in the deep sea (e.g., fishing, energy development, and mining) and their impacts on habitat-forming invertebrates, including deep-sea corals and sponges (DSCS). Related management decisions require information about where DSCS occur and in what densities. Species disOutmigration survival of wild Chinook salmon smolts through the Sacramento River during historic drought and high water conditions
Populations of wild spring-run Chinook salmon in California’s Central Valley, once numbering in the millions, have dramatically declined to record low numbers. Dam construction, habitat degradation, and altered flow regimes have all contributed to depress populations, which currently persist in only a few tributaries to the Sacramento River. Mill Creek (Tehama County) continues to support these thPredation strategies of larval clownfish capturing evasive copepod prey
Fish larvae depend on finding and capturing enough prey for rapid growth during the planktonic phase. The diet of many fish larvae is dominated by copepods, small crustaceans that are highly sensitive to hydrodynamic disturbances and possess strong escape responses. We examined how fish larvae with immature jaws, musculature and fins capture such evasive prey. The kinematics of feeding attempts byChanges in adult Chinook salmon (Oncorhynchus tshawytscha) survival within the lower Columbia River amid increasing pinniped abundance
Significant effort towards conservation has contributed to the recovery of historically depleted pinniped populations world-wide. However, in several locations where pinnipeds have increased, they have been blamed for preventing the recovery of commercially valuable fish species through predation. Prompted by increasing pinniped abundance within the Columbia River (CR) USA, over a six year periodSpatial variability in ocean-mediated growth potential is linked to Chinook salmon survival
Early ocean survival of Chinook salmon, Oncorhynchus tshawytscha, varies greatly inter-annually and may be the period during which later spawning abundance and fishery recruitment are set. Therefore, identifying environmental drivers related to early survival may inform better models for management and sustainability of salmon in a variable environment. With this in mind, our main objectives wereEstimating spatial–temporal differences in Chinook salmon outmigration survival with habitat- and predation-related covariates
Low survival rates of Chinook salmon (Oncorhynchus tshawytscha) smolts in California’s Central Valley have been attributed to multiple biological and physical factors, but it is not clear which factors have the largest impact. We used 5 years of acoustic telemetry data for 1709 late-fall Chinook salmon smolts to evaluate the effect of habitat- and predation-related covariates on outmigration surviEnvironmental conditions and prey-switching by a seabird predator impact juvenile salmon survival
Due to spatio-temporal variability of lower trophic-level productivity along the California Current Ecosystem (CCE), predators must be capable of switching prey or foraging areas in response to changes in environmental conditions and available forage. The Gulf of the Farallones in central California represents a biodiversity hotspot and contains the largest common murre (Uria aalge) colonies along - News