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The Hitch in the Oxbow – By Jim Steele

 Credit: Rick Macedo

As I sat listening to a presentation about the plight of the Clear Lake hitch, I daydreamed a little about how the County looked many years ago when the small fish ruled the lake. This species of minnow grew to a foot in length and was found in low-lying areas throughout much of California before newcomers plowed the land and changed the course of streams. Today, only small populations of the three subspecies remain near the mid-coastal plains of Monterey and the Clear Lake basin.

Back before the time of agriculture and flood control districts, streams meandered across the low-gradient valleys, coastal plains, and the shores of Clear Lake. Fish species like the hitch, roach, and sucker occupied these slow-moving, mostly shallow streams and lakes and were the food for indigenous tribes on their shores. Their life history and habitats dictate their survival.

Like the salmonids that escaped the ocean to protect their young and spawn in the freshwater of rivers that linked to the ocean, these inland fish also swam up streams in the spring during the rains to spawn and escape lake predators. While the salmonids would bury their eggs in gravel to keep fast-moving waters from washing them away, the hitch used slower-moving streams, which allowed for females to broadcast their eggs and be fertilized by males as they sunk to the bottom.

The demersal eggs lodged in the spaces of the gravel, swelled to be held in place and hatched in a shorter time than the salmonid buried eggs. The young, very small hitch fry matured while hiding between tules and foraged in the quiet meandering of the streams that slowly flowed across meadows, swamps, and sloughs lining the lake’s low gradient shorelines.

Floods would often overflow the banks of these streams, sometimes causing the channel to shift, leaving the old turns, called oxbows, and forming new ones. The flood would even carry the fish into the abandoned oxbow pools and back swamps of Tule Lake, Clover Creek and Middle Creek marsh to feed, grow and be protected until the next rains came to free them to Clear Lake. Here, they grew to adult size and swam in schools, waiting for the next spring storms so the cycle could begin again. What happens to the slow-moving waters also happens to the fish populations.

Settlers plowed the land up to and against the streams throughout California and Lake County, filling in the old oxbows and low-lying pooled water to maximize crop space for a growing population seeking gold and riches. They also stayed and grew wealthy with agricultural crops for the growing nation. Little thought was given to the fish populations as they slowly disappeared.

A flood-conscious population wanted water off the land quickly, and flood control districts straightened streams to speed the water’s progress, and levees were built to contain the volume. Gravel mining in streams began for highway building and flow-concentrating highway culverts were built to cross the streams. The increased energy of the flow would move smaller sediment and gravels along the way and as sediment disappeared into the lake, the channels became deeper. The deeper channels allowed for the groundwater to drain down a few more feet, causing the faster-moving streams to stop flowing earlier after the rains.

In a dry year, water disappeared too quickly for hatching demersal eggs and for supporting small hatchlings that needed quiet backwater. Fortunately for the hitch, spawning in the lakes is an option, but only at the expense of predation by voracious lake species, many of which are introduced and patrol the shoreline looking for a meal.

With the slow water of the land gone, the groundwater lower and the channel water faster, the wonder of what happened to the fish is left to those investigators measuring dwindling fish numbers. They also measure the depth of water wells that might affect the channels, and they rescue adult fish that, during high water, flood into fields near the stream.

It’s ironic that recent high water overflowing the nearby quiet backwater of the Tule Lake area introduced fish back into Clear Lake to migrate up streams while providing an important clue to the past. Perhaps investigating fish life history requirements, landform changes, and introduced species is where modern-day fish sleuths could begin. New thinking is emerging that will help build a better future for the hitch of Clear Lake. Where the oxbow goes, so do the hitch.

Jim Steele’s background includes being a retired freshwater ecologist, consultant, and past president of the Cal-Neva American Fisheries Society. He managed and investigated fish restoration and protection projects in marine, freshwater streams and lakes of California for over four decades.

Curated by The Bloom Staff

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