Bits & Pieces: Does C&R Work for Bass and Erie Pike Habitat

Research Insights: Does Catch and Release of Bass Work?

Live release of captured bass was actively promoted beginning in the late 1970s and well ensconced among bass anglers by the mid-1980s. Marketed by several slogans—for example “Let a Lunker Live” and “Don’t Kill Your Catch”—catch and release (C&R) seems to be the term that endured. Live release of captured fish has always been practiced by anglers, sometimes willingly, sometimes as mandated by length and creel harvest restrictions. Ray Scott and B.A.S.S. are given the credit for bringing the C&R concept to the bass world in 1972.

What’s surprising, considering the historically consumptive culture of anglers (bass anglers included) is how quickly and thoroughly bass anglers embraced the concept. By the mid-1980s, virtually all bass tournaments were live-release formats and most bass anglers were releasing all fish caught. Maybe it was such a quick sell because of the rapid increase of tournaments and the exploding interest in big bass.

Catch-and-release is intuitive: releasing bass keeps the number of catchable adult bass in the population high and allows them to grow to larger size. Achieving these endpoints requires high survival and no change in catchability of released fish. While fishery researchers work on the survival and catchability questions, a recently published study on Mille Lacs Lake smallmouth bass has found C&R can benefit angler catch.*

Minnesota DNR and Dartmouth College researchers developed a new method to estimate the “recycling rate” of fish in C&R fisheries using estimates of catch and abundance. They defined recycling rate as the observed catch of a species divided by the number of individuals caught at least once. They applied their estimation method to Mille Lacs Lake, which had gained a reputation as a world-class trophy smallmouth destination.

A mark-recapture study that included 2,084 marked fish resulted in a population estimate of 67,000 smallmouth bass longer than 12 inches in Mille Lacs in 2017. In that same year, the total catch of smallmouth bass as determined by a creel survey was 125,000. Using these values, the recycling rate was estimated at 2.53; the total number of smallmouth bass boated in 2017 was 2.53 times greater than the number that would have been expected if all fish were harvested the first time they were caught. Despite a three-fish bag with a 17- to 21-inch protected slot, anglers voluntarily released over 99 percent of their smallmouth bass. Clearly, C&R can improve the total catch of smallmouth bass in at least this one lake.

-Dr. Hal Schramm

*Jones, T. S., M. J. Jones, M. Treml, and T. Heinrich. 2022. Estimating recycling of fish in catch-and-release fisheries. Fisheries 47: 529-536.

Habitat Issues for Lake Erie’s Pike

For decades, Lake Erie’s headliners have been walleyes and smallmouth bass, more recently joined by steelhead, largemouths, and lake trout. But in their midst exists a small population of pike that are biologically tied to the shallow marshy habitats where they spawn.

Dr. Nate Stott has recently completed his graduate studies at Bowling Green University in Ohio, where he studied pike populations in five wetlands, implanting acoustic tags in 53 adults. He examined several aspects of their biology that linked them to these marshy areas: annual movements, particularly timing of movements into spawning marshes; return to specific spawning sites; correlations between year-class strength and water level; and habitat descriptions of these wetlands.* They’re also visited by common carp for spawning in spring, which can damage wetlands by increasing turbidity and limiting shallow vegetation. So another objective was to compare migration timing of the two species, with an eye toward finding a way to allow pike to access marshes, while excluding carp.

Stott’s study was linked into acoustic receivers that are part of the multijurisdictional Great Lakes Telemetry Observation System (GLATOS), which employs a full grid throughout Lake Erie. “Pike entered spawning areas just after ice-out, while carp filtered in over the following month or so, so there’s potential to block some carp migration without impacting pike,” Stott reports. “We found that over 90 percent of pike returned to the wetland where we’d captured and tagged them, the rest straying to others marshes in our study area. They generally remained in shallow bays, occasionally  moving into the lake itself.”

Though it’s the smallest of the Great Lakes, Lake Erie’s basin shape and windswept geography cause major seiches. These dramatic shifts in water level occur when strong prevailing winds pile up water on one side of the lake, raising its level and making the other end shallower. When wind subsides, the water rebounds to the other side, jostling back and forth until it comes closer to equilibrium. Southwest winds push water out of Ohio’s marshes and pile it on the Canadian side and it washes back many hours later.

“Year-class strength of pike was positively correlated with spring water levels,” Stott says. “Flooded vegetation in these Ohio marshes is prime spawning habitat and when water levels rise, pike move in. But when seiches occur in spring, egg-hatching and survival is poor. If you’re there when one occurs, you see why—water is sucked out of the shallowest areas, leaving the eggs, which adhere to vegetation after females release them, out of water. It takes 10 days to two weeks for eggs to hatch. Once they absorb their egg sacs, fry begin to feed on plankton and tiny insects. They remain shallow until they’re a couple inches long, so there’s a long window when they’re vulnerable to dewatering.”

If this natural threat wasn’t enough, invasive plant species have invaded one of the marshes he studied. “Prime areas have been taken over by giant reed grass, an exotic species of reed from Asia that’s aggressive and pushes native grasses out,” Stott says. “It reaches 10 to 12 feet in height, with a feathery flowering top. Its biomass tends to fill in marsh areas over time, damaging habitat for fish. Flowering rush is another exotic invader–this one from Europe–and we’ve found it in marshes as well.”

Fortunately for the future of Lake Erie’s pike, the Ohio Department of Natural Resources has embarked on an ambitious program called H2Ohio that’s dedicated to creating, enhancing, and restoring state wetlands, including several ongoing projects near Erie’s shores, including the large Sandusky Bay wetland complex.

-Steve Quinn

*Stott, N., and J. Miner. 2022. Environmental cues of spawning migration into a confined wetland by northern pike and common carp: identifying fine-scale patterns. N. Am. J. Fish. Mgmt. 42:239-249.

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