Ontario Bass Fishing

Largemouth Bass Biology

Largemouth Bass

IN 1802, Lacpede, the French ichthyologist, was the first to describe the largemouth bass, from a drawin and description sent to him by M. Bosc of South Carolina. M. Bosc named the specimen “trout- perch” and, owing to this Lacpede gave it the specific name, “salmoides” which means “salmon-like” or “trout-like”. In 1772, pressed skins of the largemouth bass were sent to Linnaeus by Dr. Garden of Charleston, South Carolina, under the name, freshwater trout, but Linnaeus failed to describe or name it. The largemouth bass is still called trout in some southern states. It is similar in appearance to the smallmouth but it is more robust and has a broader and more powerful tail. The colour varies with the environment but it is mostly bronze-green, fading to white below, or dark green over the back, greenish- silvery on the sides, fading to white below. In clear water, colour and markings are much more vivid than in mud-bottomed lakes. Both adults and young have a broad, dark band of irregular patches on the sides; this band is much less distinct in old fish.
In contrast with the smailmouth bass, there are the following dis- tinguishing characters: the upper jaw extends behind the eye when the mouth is closed; the dorsal fin is deeply notched, almost com- pletely divided; there are 9 to 10 spines ahead of 12 to 13 soft rays in the dorsal fin; the spines in the anal fin usually number three, followed by 10 to 12 soft rays; and the scales in the lateral line number 58 to 69.

Distribution
The largemouth bass ranges from southern Ontario and southwestern Quebec through the Great Lakes system and Mississippi Valley to northeastern Mexico and Florida, and north along the coastal plain to Virginia. Utilization of the Erie Canal and other introductions have modified this range. In Ontario, the original range was similar to that of the smallmouth bass with local differences owing to habitat preferences. This fine game fish occurs throughout the range of the small- mouthandmaskinonge,forexarnple, the Kawartha and Rideau Lakes areas.

Habitat
The largemouth bass is adaptable to a large variety of habitats, from those suitable for smallmouth to sloughs and sluggish waters. It is typical of shallow, mud-bottomed lakes and slow-moving streams which contain an abundance of aquatic vegetation. It grows to a large size in ponds and, with reference to living in stagnant pools or under low-oxygen concentration, Whitmore et all showed that largemouth bass markedly avoided concentrations of oxygen near 1.5 mg. per litre but showed little or no avoidance of higher concentrations except that an avoidance reaction was evident near 4.5 mg/I.

Habits
(a) Movements: Largemouth bass move less extensively in mainstream reservoirs than in storage reservoirs, probably because there is less fluctuation of water levels in the former. Hulse and Miller showed that from the point of tagging to the point of recapture they averaged 2.7 miles. The average time at large was 68.2 days, ranging from 23 to 77.9 days. There was no significant difference in the average upstream and downstream travel. In the Norris reservoir, largemouth travelled an average of four miles, and small- mouth, 1.2 miles. Displaced largemouth bass return to the site of their original capture with varying degrees of success. The speed and accuracy of return of displaced fish could be affected by the sex and age of the fish, the season of the year, the number of available territories and the presence or absence of landmarks in the lake. According to Hasler and Wisby displaced largemouth did not return to their capture area with the same precision as the green sunfish. They had maintained their position in the lake from one summer to another, notwithstanding the intervening winter.

(b) Spawning: In early May or when the temperature of the water is about 60’F., the male builds the nest, a circular depression, six inches deep and two to four feet wide, in more or less sheltered areas on sand, gravel, clay or mud bottom, or on the roots of vegetation, in water up to three feet in depth. The spawning act is similar to that already described for the smallmouth bass. Eggs are extruded by the female and milt by the male simultaneously, thus effecting fertilization of the eggs. A female largemouth bass may lay 2,000 to 25,000 eggs. After fertilization of the eggs, the female leaves the nest, and the male remains on guard, driving away intruders and constantly fanning the nest with his fins. Hatching time depends upon the temperature of the water but it averages five to ten days. The male largemouth accompanies the school of fry until the fry reach a length of one inch or more. Largemouth and smallmouth bass are sensitive to environmental conditions at spawning time. A sudden lowering of temperature may interfere with egg laying; the male may desert the nest, and the deposited eggs may be destroyed by enemies or they may become fungused. Sudden temperature changes may cause the female to become egg-bound and to die as a result. Parasitism is also known to interfere with the proper functioning of the ovaries.

(c) Food and Growth: The food of young largemouth bass undergoes definite changes as one stage of growth to another takes place. Turner and Kraatz found that, up to 30 mm., the food consisted mostly of entomostracans and minute midge larvae; from 30 to 50 mm., amphipods (freshwater shrimps), larger insect larvae and fish in small quantities. At this stage, entomostracans were negligible and midge larvae were rapidly diminishing in numbers. From 50 to 80 mm., the food consisted, principally of larger insect larvae, crayfish and fish. The food series may therefore be summarized as follows: (1) entomostracans; (2) insects (larvae, pupae and adults); and (3) crayfish and fish. Adult largemouth bass take worms, mussels, frogs, crayfish and fish, including their own kind. They are partial to frogs and minnows in the absence of crayfish. Fingerling largemouth bass are more cannibalistic than smallmouth. Largemouth grow faster and take food earlier than smallmouth. Analysis of the stomach contents of 211 largemouth bass, taken during spring and summer of 1955, from Crab Orchard Lake, Williamson County, Illinois, showed that, in 107 stomachs containing food, 85 contained gizzard shad. Items of less frequent occurrence in the diet were crayfish, algae and miscel- laneous fishes. The rate of growth of this population of largemouth bass was found to be above the average (Schneidermeyer). Aquarium tests have shown that bass will readily swallow forage fishes whose maximum depth of body is equal to the mouth width of the bass. In Ontario, it is not unusual for largemouth bass to reach a length of three to five inches by the first winter; seven to ten inches, the beginning of the third year; and 12 inches or more at the end of the third year. Largemouth bass feed most actively in the morning and evening at temperatures ranging from 65’F to 73’F. They are inclined to feed near the surface at twilight and in deeper water during the day. The majority feed close to shore and in the vicinity of weed beds. They grow to a greater size than the smallmouth; six pound fish are not unusual. In the southern part of their range, they grow considerably larger.