Few people will argue that California is experiencing one of the coldest springs in recent memory and the effect on the fish and wildlife could be profound. The bass should have completed their spawning cycle by now but that hasn”t yet happened. In fact, many of the bass still haven”t moved into their spawning areas. One day they move onto the spawning beds and then a blast of cold weather hits and they move off. This could go down as one of the latest spawning periods for bass in years.
The same goes for birds and other wildlife. Wet and cold springs normally result in a high mortality of the young. The young birds get wet and die of exposure. Even deer offspring have a hard time surviving when the weather is such as we are experiencing this year.
The length of the day and water temperature are what determines the spawning cycle in largemouth bass. During the spring months when the water temperature reaches 60 degrees, the male bass selects a location and fans an area about the size of a dinner plate with his tail. When the water warms up to 62 degrees or more the females start to stage near the spawning beds. The actual spawning occurs when the water temperature reaches about 65 degrees. The height of the spawn occurs when it is between 68-70 degrees.
Water temperature determines how long the eggs take to hatch. When it is less than 65 degrees it can take as long as 12 days for the eggs to hatch. However, if the water temperature rises to 70 degrees the eggs hatch in two or three days. This is important because the longer the eggs take to hatch the more vulnerable they are to predation. Bluegill and other fish constantly try to devour the eggs.
If the water temperature never warms up to 65 degrees most of the females will still spawn although the success of the spawn is diminished. This often occurs in northern states.
So far this year there have been very few days when the water temperature has even reached 63 degrees at Clear Lake. Most of the time it has been hovering between 58-60 degrees.
During cold springs, such as we are experiencing this year, the survival rate for the young is much lower than in warm months. Even under optimum conditions less than 1 percent of all the bass spawned survive. A typical nest sees approximately 2,000 eggs actually hatch but fewer than 20 fingerlings will survive to 10 inches.
Young bass feed on their yolk sack for the first week of their life. Within two weeks they start to feed on insect larva and other small aquatic creatures. Normally by October the young bass should be two or three inches in length and feeding heavily on small minnows or even other young bass. Like most predator fish they are cannibalistic and think nothing of gulping down a brother or a sister. In fact, stomach analyses of adult bass have shown that up to 10 percent of the contents is comprised of young-of-the-year bass.
The later in the year that bass spawn also has an effect on the overall population. If they spawn too late the young bass go into the winter with little body fat and they will have a lower survival rate.
It”s not only the bass that delay spawning when the water is cold. Channel catfish require a water temperature between 70 and 85 degrees to spawn. The optimum for spawning success is 75 degrees. Catfish are well into their spawning cycle by the end of May at Clear Lake in normal years. However, this year that could be delayed until well into July. Other game fish such as bluegill and crappie also require warm water to spawn and so far that hasn”t happened.
As for other wildlife, I have seen very few fawns this year. That means the does are delaying dropping their fawns because of the cold and wet weather. Baby turkeys also have been rare. When a young turkey gets wet it has little chance of surviving. The same applies to just about all species of song birds. As a biologist once told me, “when a wild bird or other animal gets sick it can”t go to a doctor; it either recovers on its own or dies.”
