Homebodies…Studies show bass don’t move much

Running a line of crab nets is still just as relaxing, fun and productive as it was when you were a kid.

Like any other non-migratory critter, each largemouth bass has a home range, loosely defined as the area that the animal uses regularly in its quest for survival and reproduction each year. Lots of anglers assume that largemouth bass rove widely in their pursuit of food and oxygenated water.

While indeed, evidence exists that young school-size bass do move extensive distances, particularly in open reservoirs, most of the time bass just don’t go that far. As hard as it is for fishermen to admit, a lot of times when they can’t buy a bite, the fish haven’t left the area.

The angler just isn’t good enough to coax these moody fish into feeding, or conditions such as oxygen are so poor that the fish are just hunkered down in a survival mode, with no interest whatsoever in what is for supper. Cold-blooded fish need to feed far less often then the warm-blooded anglers chasing them.

Oxygen levels, the biggest stressor (besides fishermen catching them), seem to cause the most movement. A study done in the Kissimmee River in Florida involved surgically implanting radio transmitters in 2- to 6-pound bass and then releasing them where they were originally caught. The biologists located them twice each week to follow their movements.

Oxygen levels did not affect bass behavior as long as it stayed about 2 parts per million (ppm). During the summer, some were located at levels of 1 to 2 ppm, but almost none were found below 1 ppm. (For comparative purposes, 10 to 11 ppm is considered the maximum that southern waters can hold, and that occurs only in flowing waters at low temperatures. Cold water can dissolve much more oxygen than warm water.)

During the fall of the study, some bass moved as much as 825 yards per day. But when dissolved oxygen levels increased to above stressful levels, the bass quickly returned to their home ranges. That bass are homebodies was shown by the fact that most of them didn’t move 100 yards all year when they had enough oxygen.

Most studies on largemouth bass in purely fresh waters show home ranges of 0.02 to 19.34 acres. The largest average home range found for bass was in a Florida lake and was 51.9 acres. But this lake was not in stable condition, having been disturbed by having all its plants removed by grass carp.

Home ranges do not seem to be influenced at all by the size of the water body, but some research indicates that bass do have larger home ranges in waters that lack enough food.

The generality of small home ranges may not, however, apply to marsh bass, those found in marshes influenced by tides and salinity. Research done 10 years ago in the very upper reaches of the Chespeake Bay in Maryland showed largemouth bass there had huge home ranges, averaging an amazing 949 acres.

The large area studied (30,146 acres) had an average daily tide range of nearly 2 feet and salinities of 1 to 2.5 parts per thousand. (Full strength seawater, by comparison, is 35 ppt.) Bass were implanted with tiny radio transmitters on both sides of the bay, and then tracked one to three times a week.

The smallest home range was 25 acres and the largest was 6,029 acres. The two sides of the bay had major habitat and home range differences. The west side had substantial water currents and heavy growths of submerged water plants. Home ranges there ranged from 32 to 6,029 acres, with an average size of 608 acres.

Things on the east side were not as simple. Here, there was very little current and almost no vegetation, but it had many pilings, boat houses and fallen timber. Eighteen of the 22 tagged fish on the east side had home ranges of 25 to 1,001 acres.

But the other four fish had huge home ranges and, in fact, showed migratory behavior. Their home ranges were 3,618 to 6,029 acres, with an average of 5,288 acres. They crossed the bay from the eastern shore to the western shore for two consecutive years. After two to three months there, they crossed back to the eastern shore.

The movement was during spawning season, in spite of the fact that biologists considered the eastern shore to hold good spawning habitat and other bass spawned successfully there.

Bass also show some daily and seasonal movements as well. While they are small, they can leave an angler looking where they are not. Biologists in North Carolina radio-tracked 11 bass from mid-fall through the spring spawn. From November through February, the bass shifted positions during the middle of the day. On average, they were 28 yards offshore in the morning, 44 yards during the afternoon and 11 yards during the evening. By March, as the spawning season neared, this daily movement stopped and the fish stayed near shore all day.

Some seasonal shifts also occurred. Four of the 11 fish moved to slightly deeper waters during the colder months of the winter. In the spring, when the weather warmed, these fish moved back to the initial range. This shift in range was 440 to 1,650 yards. Home ranges for 10 of the 11 fish were small, averaging 1.3 acres. The 11th fish in the bunch was the odd fish. It showed continuous movement throughout the study, traveling an average 940 yards per day.

Without a doubt, what moves bass the most are bass boat live wells. In an Oklahoma study, biologists tagged hundreds of bass released after tournaments in a 6,120-acre lake.

Two hundred thirty-two recaptures were made during the two-year study. The first year, 84 percent were recaptured on shorelines connected to the release site. Only 16 percent were recaptured from areas they had to reach by crossing open water.

Although two bass were recaptured over 7 miles from the release site within two weeks after release, the average distance moved was three-tenths of a mile the first year and 1.9 miles by the second year. For the whole study, 55 percent of the bass were caught within 1 mile of their release.

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About Jerald Horst 959 Articles
Jerald Horst is a retired Louisiana State University professor of fisheries. He is an active writer, book author and outdoorsman.

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