A green sturgeon tag is a real find, for a kid on the beach and for NOAA scientists.
Ethan Mora and Liam Zarri, researchers from NOAA's Southwest Fisheries Science Center in Santa Cruz, woke up early on a recent October morning to gather critical scientific data on green sturgeon. But they weren't off to some remote research station; they were going to an elementary school in Napa to reward one of the students with $20 for finding a lost satellite tag.
Deja Walker, a third-grade student at Napa Valley Boys and Girls Club, was strolling with her grandparents on Stinson Beach near San Francisco in early October when she noticed some boys throwing around what looked like a toy. When the kids tossed it aside, she investigated and found the nearly foot-long tube offered a reward for its return to NOAA.
What Deja didn't know was that she had found one of several satellite tags used by NOAA researchers to understand the impact of commercial halibut fishing on green sturgeon, one of nature's most prehistoric fish.
Green sturgeon are bottom feeders, scavenging on invertebrates and small fish. They can grow to about eight feet in length and live for about 70 years. Although they spawn in fresh water, the adults may travel up and down the West coast from Mexico to Alaska.
Sturgeon have meandered throughout our oceans and rivers since dinosaurs roamed the Earth. But despite their long history, one population of green sturgeon in California may be edging closer towards extinction. The southern population, or those green sturgeon that spawn in the Sacramento River basin, were listed as threatened under the Endangered Species Act (ESA) in 2006 because of the loss of historical spawning habitat.
NOAA researchers then began looking into impacts or threats to the listed population. Green sturgeon are incidentally caught as bycatch in the same nets as California halibut but released back into the ocean when the fish are brought on deck. The scientists wanted to determine the survival rate of those green sturgeon returned to the ocean.
"What we don't really know is how many green sturgeon survive that interaction once they're released back into the wild," said Phaedra Doukakis lead researcher for this project from NOAA Fisheries West Coast Region. "From the NOAA Observer data, it looks like immediate survival is quite high and we wanted to confirm that and look at longer term survival."
To study this issue, Doukakis and Susan Wang, also from NOAA Fisheries' West Coast Region in Long Beach, wrote a grant to NOAA Fisheries National Cooperative Research Program. Part of the grant provided funding for a workshop in 2013 in Santa Cruz to bring researchers and fishermen together.
"It was really cool," said Mora. "We had researchers, fishermen and observers in one room and we met for a couple of days. The fishermen and observers gave us great feedback and the group collaborated to determine what tagging technologies would work best."
The group determined the best method for estimating the survival of green sturgeon was with a pop-off satellite tag, or a tag that "popped" off after a specific length of time. If a green sturgeon was caught, fishermen attached the tag to the dorsal fin and released it back into the ocean. In about three weeks the tag floats to the surface and uploads information to a passing satellite overhead. But the physical tag contains even more information than what was usually transmitted to the satellite, which is why NOAA offered the reward for its return.
So far 27 tags have been attached to green sturgeon and several of the tags have already been returned. Researchers are excited by the data received so far and are hoping more tags will be recovered soon.
When Deja's grandparents called to notify researchers of finding the tag, Ethan and Liam were more than happy to drive to Napa and recover the tag, thank Deja and offer a short class on green sturgeon to her classmates.
"The presentation was not only interesting and informative but completely inspiring to our students," said Amanda Frances Fisher, Sr. Program Director for the Napa Valley Boys & Girls Club. "For the next few weeks students here at Salvador Elementary will be talking about and researching what kind of scientist they want to become; that is not a discussion the students would have engaged in otherwise which is very exciting."