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Jefferson (Jesse) Humbert

Curriculum vitae


Marine Ecology

UC Davis, SDSU



Projects


Current projects include designing and deploying in-situ octopus habitats to evaluate how shelter availability and habitat structure influence occupancy, movement, behavior, and local ecological interactions. These habitat systems also provide standardized locations for monitoring octopuses through time and examining how individuals respond to environmental variability and changes in prey availability.
In captive settings, we conduct controlled predator–prey experiments to investigate prey detection, selection, handling behavior, capture success, and decision-making under different environmental conditions. These experiments allow us to test how factors such as prey identity, prey abundance, habitat complexity, and previous experience influence octopus foraging strategies.
We also use genetic and molecular methods to analyze stomach contents and other dietary samples. DNA-based identification can reveal prey species that are difficult to identify visually because they have been partially digested or lack diagnostic hard parts. These studies help characterize octopus diets, quantify individual variation in prey use, and evaluate how foraging choices change across habitats, seasons, and populations.
Underwater camera systems are used to observe octopuses in their natural environments with minimal disturbance. Continuous and remotely operated video monitoring allows us to document activity patterns, den use, prey encounters, predator interactions, movement, and other behaviors that may be difficult to observe directly. Together, these complementary approaches improve our understanding of octopuses as adaptable predators and their broader ecological roles within coastal marine communities. This research also provides information that can support the conservation and management of the habitats and food webs on which octopuses depend.


The Open-source Camera Trap for Organism Presence and Underwater Surveillance (OCTOPUS)


OCTOPUS is an open-source, motion-activated underwater camera system that can operate for about 72 hours at depths up to 800 feet. It has been used to document cryptic species, including Octopus rubescens, and their ecological interactions.




Octopus Behavior and movements


Motion-activated cameras tracked tagged Octopus rubescens in bottle dens, revealing daytime activity, frequent conspecific interactions, and differences in fish and crab visits between occupied and unoccupied dens.




Octopus Diet study


This study uses DNA metabarcoding of octopus stomach contents to identify prey and compare diets across habitats, revealing how habitat, prey availability, and octopus traits influence foraging and trophic interactions.




Octopus foraging decisions


This study examines how octopuses forage across different habitats by tracking prey choice, handling behavior, and habitat use to understand how environmental structure influences feeding strategies and predator–prey interactions.

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