WILLIAMSBURG — The morning sun beat down as volunteers waded through 66-degree water in Grand Traverse Bay, dragging along a net device to catch a sample of the near-shore fish at Maple Bay Natural Area.
“As you’re pulling this you want to make sure you keep that lead line along the bottom,” said Stephen Hensler, executive director of nonprofit Cerulean Center in Traverse City.
The handful of helpers gathered at the preserve’s beach as part of an effort to take an inventory of Grand Traverse Bay’s fishery. That means native species, non-natives and even invasive species.
Hensler said the goal is to be proactive about halting creatures that shouldn’t be here. Early detection can make all the difference, he said.
Zebra and quagga mussels, round gobies and sea lampreys are well-known invasive species in the Great Lakes, but there are others on the verge of introduction and additional threats persist, Hensler said.
Saturday’s event involved the volunteer group pulling a seine net for 50 feet through the water and hauling their catch in to shore.
“Did we get anything?” Hensler asked.
They didn’t. Well, other than some stones and pebbles.
“That’s surprising. Very surprising. OK, so we write down zero catch on the form,” Hensler said. “It’s still data. It’s still a data point.”
He said a similar project at the same place at the same preserve in 2017 brought in hundreds of fish from the near-shore waters. That’s why the empty net came as a shock, he said.
So they tried again, but the same thing happened on the second drag. And the third. And the fourth.
“Do you think the warmer temperature has anything to do with it,” asked volunteer Gary Stauffer of Elk Rapids, recognizing the day’s unusual 86-degree forecast in late September.
“I don’t know. The one big difference from 2017 is the water levels. It’s way up this year,” Hensler said.
The group opted to try one more time before the volunteer event ended. The fifth seine net drag brought in about 10 small hatchlings — and only just.
“Are they small enough to get through the net,” asked Jon Throop, volunteer and events program manager with Grand Traverse Regional Land Conservancy.
Throop stood on the beach, clipboard in hand to record all findings of the day.
“Oh, yeah. They are coming through,” said Erin Paxson of Elk Rapids, a volunteer wearing waders who helped bring in the net and pointed into the water at small, escaping fish.
The participants gathered the 10 tiny fish into a cooler filled with water out of the bay, measured their lengths and tried to identify the species.
“Based on how big they are, they are about a month old,” Hensler said. “I’m surprised to see them this small this late in the year.”
Though unexpected, the day’s result coincides with what volunteers found at another fish sampling event this summer.
“We saw the same thing in Greilickville. They were very small,” said volunteer Pete Albers of Traverse City.
Earlier this year the Cerulean Center received a $140,000 grant from Rotary Charities of Traverse City to launch this program dubbed the Great Lakes Naturalist Initiative.
The mission is to mobilize area residents to participate in efforts to fight non-native species and prevent their establishment in this corner of northern Lake Michigan.
The program is a partnership among the conservancy, Cerulean Center and Suttons Bay-based nonprofit Inland Seas Education Association.
The last fish sampling event for the season will be Oct. 5, at the mouth of Mitchell Creek near Traverse City State Park’s beach.