Jens C. Hegg

Jens C. Hegg
University of Idaho | UID · Department of Fish and Wildlife Resources

Ph.D. - Water Resources Science & Management

About

32
Publications
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182
Citations

Publications

Publications (32)
Article
Effective species management often requires understanding patterns of movement and habitat use. A common approach in identifying where individuals reside relies upon chemical tracers from the environment that are incorporated into an individual's tissues. For fish, isotopes in their otoliths, specifically the portion of their otolith formed during...
Article
Full-text available
Niche partitioning occurs among coexisting populations to reduce the effects of competitive exclusion among species of similar niche. The aim of the present study is to verify the trophic niche partitioning and feeding behavior between two mustelids, the Giant otter and the Neotropical otter, through the dry and rainy season hydrologic of the Lower...
Article
Full-text available
Ecological patterns are often fundamentally chronological. However, generalization of data is necessarily accompanied by a loss of detail or resolution. Temporal data in particular contain information not only in data values but in the temporal structure, which is lost when these values are aggregated to provide point estimates. Dynamic time warpin...
Article
• The ecology of endangered and rare species can be difficult to study owing to their low abundances and legal limits on scientist’s ability to catch, sample, and track them. This is particularly true of sawfish (family Pristidae), whose numbers have declined precipitously, placing all five species on the IUCN Red List of Threatened Species worldwi...
Preprint
Full-text available
Ecological patterns are often fundamentally chronological. However, generalization of data is necessarily accompanied by a loss of detail or resolution. Temporal data in particular contains information not only in data values but in the temporal structure, which is lost when these values are aggregated to provide point estimates. Dynamic Time Warpi...
Preprint
Full-text available
Chronological data from hard structures has been instrumental in reconstructing information about the past across numerous disciplines. Isotopic and trace elemental chronologies from the depositional layers of speleothems, corals, bivalve shells, fish otoliths and other structures are routinely used to reconstruct climate, growth, temperature, geol...
Preprint
Full-text available
The ecology of endangered and rare species can be difficult to study due to their low abundances and legal limits on scientist’s ability to catch, sample, and track them. This is particularly true of sawfish (family Pristidae) whose numbers have declined precipitously, placing all five species on the IUCN Red List of Threatened Species worldwide. B...
Article
Full-text available
Connecting maternal migratory behavior with the behavior and ecology of their progeny can reveal important details in the ecology of a population. One method for linking maternal migration to early juvenile life history is through maternal chemistry recorded in otoliths. Despite the wide use of maternal signatures to infer anadromy, the duration an...
Preprint
Full-text available
Connecting maternal migratory behavior with the behavior and ecology of their progeny can reveal important details in the ecology of a population. One method for linking maternal migration to early juvenile life-history is through maternal chemistry recorded in otoliths. Despite the wide use of maternal signatures to infer anadromy, the duration an...
Article
Full-text available
The migration of Pacific salmon is an important part of functioning freshwater ecosystems, but as populations have decreased and ecological conditions have changed, so have migration patterns. Understanding how the environment, and human impacts, change salmon migration behavior requires observing migration at small temporal and spatial scales acro...
Data
Clip3_PitchPitch transition used as positive control question in perceptual survey.
Data
Clip2_PanStereo panning sound transition used as positive control question in perceptual survey.
Data
Clip7_IntermittentRandom, granular, intermittent sound used as negative control question in perceptual survey.
Data
Q11_2Fish_VisualsSonification of two fish with accompanying visualization as seen by survey participants. The same audio was used for questions without visualizations.
Data
Clip5_CrecendoLoudness transition used as positive control question in perceptual survey.
Data
Clip6_StaticRandom static used as negative control question in perceptual survey.
Data
Q12_3Fish_VisualsSonification of three fish with accompanying visualization as seen by survey participants. The same audio was used for questions without visualizations.
Data
Clip1_Full_SonificationAudio recording of full sonification using data from 45 individual fish.
Data
Clip4_TimbreTimbre transition used as positive control question in perceptual survey.
Data
Q10_1Fish_VisualsSonification of a single fish with accompanying visualization as seen by survey participants. The same audio was used for questions without visualizations.
Thesis
Full-text available
Ph.D. Dissertation, University of Idaho Water Resources Program. This dissertations contains five chapters. The first details movement in Amazonian catfish using otolith microchemistry (published in PLOS One). The second examines factors affecting the maternal isotopic and elemental signature in salmon otoliths (Published in Can. J. Fish. & Aq. Sci...
Research
Full-text available
Spatialisation, pitch assignment, and timbral variation are three methods that can improve the perception of complex data in both an artistic and analytical context. This multi-modal approach to sonification has been applied to fish movement data obtained from otolith isotopic analysis with the dual goals of providing an aural representation for an...
Article
Full-text available
Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world’s largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some o...
Research
Full-text available
Hegg JC, Giarrizzo T, Kennedy BP (2015) Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management. bioRxiv (in-review, PloS One) pre-print: 1–37. DOI: http://dx.doi.org/10.1101/018671.
Preprint
Full-text available
Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world's largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some o...
Article
Full-text available
Recent advances in using naturally occurring isotopes to reconstruct movement patterns have revolutionized the study of migration and spatial patterns across taxa. Isoscape approaches utilize isotopic variation in the underlying geology to quantify migration pathways. Spatial patterns in the geology can be used to predict isotopic variation, such a...
Article
Full-text available
Human disturbances to ecosystems have created challenges to populations worldwide, forcing them to respond phenotypically in ways that increase their fitness under current conditions. One approach to examining population responses to disturbance in species with complex life histories is to study species that exhibit spatial patterns in their phenot...
Article
Geochemical fingerprinting methods using isotopic or trace elemental signatures have enabled more detailed understanding of migratory behavior across animal taxa. These methods are limited by geographic variation in geochemical signatures and by the resolution of baseline sampling within study systems. In particular, isotopes of strontium have been...
Thesis
Full-text available
Masters Thesis, University of Idaho. This thesis contains two chapters. The first uses otolith microchemistry to determine the origin and downstream movement of Snake River fall Chinook salmon using strontium isotope chemistry in their otoliths (later published in Oecologia). The second chapter details a regression method for predicting strontium...
Conference Paper
Background/Question/Methods The emergence and maintenance of life history strategies in salmon populations is the combined result of variation in individual migratory behaviors and fluctuating environmental conditions. It is therefore of fundamental interest to understand how different migratory strategies confer fitness advantages to individuals w...

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Projects

Projects (4)
Project
Migration timing has changed, with a larger proportion of juvenile fish exhibiting a late "yearling" outmigration strategy in a population that historically was made up of early "sub-yearling" outmigrants. Research indicates that this shift is an example of recent life-history evolution. Using otolith chemistry, growth and other ecological tools we are investigating how heterogenous environmental conditions and anthropogenic change drive spatial and temporal variation in the success of this life history within the basin.