Drones help study jellyfish

The Canadian Press
Gemma Karstens-Smith

VANCOUVER–Technology is allowing researchers in British Columbia to study blooms of jellyfish and their impact on the ocean in a whole new way.
University of B.C. oceanography Prof. Brian Hunt and undergraduate student Jessica Schaub have been using drones to get a better picture of the size and composition of clusters of moon jellyfish off B.C.’s central coast.
Images from cameras soaring high above the ocean provide a bird’s-eye view that can’t be replicated on the water, Hunt said.
“One of the challengers we had with using boats is that, because you’re so low to the water, you don’t really get a good impression of the horizontal spatial expanse of a jellyfish bloom,” he explained.
Photos taken by the team’s drone show vast swaths of the gelatinous creatures speckling the ocean, creating cloud-like formations in the water.
Combining data from the drone with information gathered from nets and underwater cameras, Hunt and Schaub were able quantify the masses–determining the weight of the blooms can vary from 60-120 tonnes.
The number is “enormous” and exceeded the team’s expectations, Hunt admitted.
He said it’s unclear if the population is growing because this is the first time scientists have been able to fully study these jellyfish.
Globally, there has been a trend towards an increase in such blooms and there is anecdotal evidence of the same thing happening on the west coast, Hunt noted.
Accurate measurements could help determine what impact the jellyfish are having on the rest of the ocean.
“With a good estimate of the biomass, we can make better estimates of what type of effect they might be having in the ecosystem through competition and predation,” Hunt reasoned.
Jellyfish feast on a variety of ocean fare, including plankton and juvenile fish. Their appetites make them competitors for–and predators of–several coastal fish species, including herring and salmon, Hunt added.
As such, he said it’s important to be able to assess the number of jellyfish.
“This can have a really major impact on population,” Hunt stressed.
“There can be really high predation mortality on these larval stages of coastal fish species.”