The bass fishing at Clear Lake has slow down considerably the last few weeks and a number of fishermen are wondering why. Whereas just a year or two ago a fisherman could count on catching anywhere from 20 to even 40 bass per day, most are happy with 10 fish this year.
Actually, catching 10 bass at most lakes would be considered a very good day, especially when you take into consideration the size of the fish at Clear Lake. Clear Lake bass are heavier on average than their counterparts at any other lake in Northern California, with the possible exception of the Delta.
A possible contributing factor to the slower fishing at Clear Lake could be the threadfin shad explosion of two years ago. Threadfin shad feed on plankton, which juvenile bass also use as a food source the first few weeks of their life. Every fishery biologist will tell you that while shad are great for adult bass, they are bad for juvenile fish.
There was a time when the shad were so thick in the lake that you could literally walk on the small baitfish. I remember going across the lake and watching my fish finder show a solid line of baitfish only a few feet down from the surface, even in the middle of the lake.
The abundance of the shad also attracted thousands of grebes, seagulls and cormorants diving and feeding on the small fish.
Whereas adult bass and other fish can survive with less food, juvenile bass will starve within a few days if their food source disappears. It”s a known fact that when the shad were at their peak, the plankton count was way down in the lake. A lot of people aren”t aware that the county”s Vector Control Department regularly seines the lake for plankton and keeps track of the amount in the lake. Their records show that when the shad population peaked, the plankton counts dropped significantly. Have the lower plankton numbers impacted the juvenile bass population?
I recently asked several local fishing guides if they were catching many young bass smaller than 13 inches long. All said that 90 percent of the bass their clients caught were in the 2-pound-plus class and very few smaller bass were being caught. Normally a young bass will be very aggressive and attack a plastic worm, especially for fishermen using the drop-shot technique. Many of the guides say they use this style of fishing because it”s easier for their clients to catch fish.
The shad population crashed last year and now very few schools of shad are being seen. The die-off is probably because of the cold weather we had this winter. Threadfin shad are a fragile fish and any rapid change in water temperature can cause a massive die-off. This has happened at Clear Lake before. Obviously all the shad didn”t die and they will come back.
If a significant number of juvenile bass didn”t survive during the peak population of the shad, there could be a year or two when there was little recruitment of bass. That means we may have lost a year or two of fish replacement and this could explain why there are fewer bass between 10-14 inches long in the lake. The good news is that the fish spawned this year should have an excellent chance of survival because the plankton counts will be up because of the lack of shad.
Shad have been in Clear Lake only since about 1985. The fishery biologists believe fishermen who wanted to see bigger adult bass probably introduced the shad into Clear Lake. There is a good chance the shad originally came from nearby Lake Mendocino or Lake Berryessa, which have held shad for many years.
A lot of fishermen are wondering what the bass are eating now that the shad population is so low. Clear Lake has always had a healthy population of crayfish and bass love them. They are easy to catch and provide a good protein source. The lake also has young hitch, bluegill, baby carp, blackfish and several other species of minnows. But for a food source for an adult bass, few baitfish can match the shad.
Whereas the lack of smaller bass will have little impact on the tournament angler, who is only looking for five quality bass per day and doesn”t even want to catch the smaller fish, it could impact the recreational fisherman who wants numbers, not size. Actually there is little to worry about. Clear Lake has been down this road before and in a year or two the bass will be back in good numbers and so will the shad.
