Ontario Bass Fishing

Smallmouth Bass Biology

Smallmouth Bass

IN 1802, the French ichthyologist, Lacepede, examined a fish, which was sent to Paris from an unknown source in America, and named it Microplerus dolomieu. A few of the posterior rays of the dorsal fin were broken off, presenting the appearance of a separate small fin. Lacepede, supposing this to be a permanent and distinctive feature, used the name, Microplerus, which means small fin. The specific name, dolomieu, was used as a compliment to Lacepede’s friend, M. Dolomieu, a well-known French mineralogist after whom the mineral dolomite was named.
The name bass was first used for members of that family, and for members of the present family because of their resemblance to the original bass family. In the smallmouth bass, the maxillary, or upper jaw bone extends to a point between the middle of the pupil and the back of the eye but, in the largemouth bass, the rnaxitlary extends well beyond the back of the eye. Another good way of separating these fish is based on the number of scales in the lateral line. The smallmouth has 68 to 81 scales in the lateral line and the largemouth has 58 to 69. In the small mouth, the markings are in the form of dark, bronze-coloured vertical bands, but in the largemouth there is a dark, horizontal stripe along the side. The spinous rays of the dorsal fin are considerably less arched in the smallmouth although, in both species, the dorsal fins are deeply notched, but not divided. The colour of the smallrnouth varies with the environment and may be bronze, green, or brownish’ green. In the young, the tail fin has a yellowish base, a black centre and a white tip.

Distribution
Original distribution of the small- mouth bass included the Great Lakes watershed, the St. Lawrence River and southward in the upper Mississippi, Ohio and Tennessee Rivers. The Erie canal, opened about 1825, provided access to the Hudson Valley. Natural dispersal in Ontario was probably effected through utilization of glacial outlets connecting the Great Lakes with the Mississippi Valley; generally, this dispersal included Southern Ontario, extending northward to the area just north of Lake Nipissing and south of Lake Nipigon.

It would appear that the dispersal of the smallmouth bass developed by utilization of the Chicago and Fort Wayne glacial outlets which connected the Great Lakes with the Mississippi Valley. In 1901 and for several years later, the Ontario Department of Game and Fisheries planted con- siderable numbers of adult bass in lakes. In 1903, four hundred were shipped to Long Lake in the vicinity of the Lake of the Woods. The lake was closed to fishing for five years. Later, the dam at the foot of the lake was destroyed by fire and this enabled the bass easy access to Lake of the Woods.

Habitat
Lakes and rivers that are clear enough and rocky enough to be suitable for trout, but in which the water temperature is too high for trout, are generally suitable for smallmouth bass. Waters that are excessively warm, 80’F. and over, or those which remain cool, below 60’F., are not well suited to bass.

Habits
(a) Movements: Henderson and Foster showed that transplanted bass moved considerably, but a definite migratory pattern was not established. Some fish moved over 40 miles andim.any returned to the place of initial capture. Latta analyzed tag returns from nets and from anglers, and little movement of bass either to or away from the point of release was indicated. Tagged bass showed the same pattern, in this respect, as fin-clipped bass. Studies at the South Bay Research Station, Manitoulin Island, indicated that bass ranged very little during July and August, and that larger bass ranged farther than smaller ones (Fraser).

(b) Spawning and Hatching: Reproduction of smailmouth bass is limited by the availability of gravel beds, and is not established successfully in slow-moving streams having a muddy bottom. Nest building takes place in water up to ten feet in depth. When a sustained water temperature of approximately 59’F. is reached, the male bass prepares the nest by fanning the bottom vigorously with his tail and by rooting out coarse materials in the nest with his nose. Silt and sand are displaced and carried away with the current. The finished product is saucer-shaped, two to three feet in diameter, consisting of clean, polished stones in the centre with wide crevices between them. The preparation of the nest may take a few hours to several days. If the water temperature continues to rise slightly from 60’F., the smallmouth bass is ready for spawning. The male coaxes the female into the nest, and eggs are laid and fertilized by the male in lots of 20 to 50 at a time, until all have been deposited. The eggs settle to the bottom of the nest and adhere to the clean stones. The eggs are tiny; it takes 10 or 12 placed side by side to measure an inch. A female bass, ten inches long, may produce 2,000 eggs; one 18 inches long may produce 10,000 eggs. After spawning, the female leaves the nest and the male remains on guard. He is a most devoted parent, driving away intruders and fanning the eggs with a gentle movement of the fins to prevent silt from settling and to provide a supply of oxygen by creating a current over the eggs. The incubation period is three or four days at 70’F. and 10 to 12 days at 55’F. Tester investigated the spawning habits of the smallmouth bass in Georgian Bay and Lake Nipissing and found that, at a temperature varying from 54’F. to 73.5’F., with an average of 62.0″F., bass fry rose from their nests 12 days after hatching. Bass-embryos, at a stage just before hatching, were killed by the temperature of the water rising as high as 73.5’F. It has also been found that, if a cold snap occurs after the eggs are laid, the male deserts the nest and the eggs become fungused. In the Lake Ontario-St. Lawrence River area, there is considerable variation in the spawning time. In tributary streams and in some warmer bays of the St. Lawrence River, spawning may take place in late May and early June, while in the colder waters of Lake Ontario, spawning occurs in June and July. Stone, Pasko and Roecker explained that, in these areas, bass populations are not homogeneous but are composed of a number of local populations. After hatching, the fry soon use up the food stored in the yolk sac. At this stage, they are about an inch long and jet black in colour. They leave the nest and travel in schools under the protection of the male until they are several weeks old. After the male ceases to guard, the fry scatter in all directions. Temperature is a major factor in the successful reproduction of bass in May and June. According to Fry and Watt the strength of the year class is correlated directly with the accumulated temperature experience of the fish in their first summer. This is particularly important in Ontario where the bass are approaching the northern limit of their range.

(c) Food and Growth: When the yolk sac is absorbed, bass fry rise from the nest and are ready to take food through the mouth; this consists of minute crustaceans. They feed avidly on these until they are large enough to feed upon aquatic insects, large crustaceans, and fry of other species of fish that spawned later. Mayflies are eaten during their emergence in early summer. Crayfish is a preferred food of older smallmouth bass and constitutes about two-thirds of the diet. Next to crayfish in importance are fish (perch, darters, sculpins, minnows, suckers, sunfish and rock bass). Generally speaking, small bass feed on plankton, insects and small fish, and adults on crayfish and fish. Bass feed most actively when the temperature of the water is 65’F. to 70’F. They will be in the shallows at this temperature in the spring and will move progressively to deeper water in search of a preferred temperature. In winter, bass seeks the warmest water, at the bottom of the lake; at this period, they are mostly inactive.