Why do bass school?
There are two thoughts of belief on if bass actually school or if it should technically be call an aggregation.
The first thought of belief is that bass do school. Bass group together as fry and the thought is that they retain this schooling trait throughout their lives – continuing to school for a portion of the year before dispersing prior to the mating season.
The second train of thought is that bass are not schooling animals but ambush predators and may only come together on occasions where they benefit by doing so. Therefore new terminology is needed, hence the term aggregation. There has been an analogy that bass, like feral dogs, may join into a loose pack for the purposes of hunting larger game (i.e. large groups of bait fish) but that generally, unlike wolves, are not true pack animals.
Some believe that bass can be split into these two categories and that you can find them both on the same body of water. For example, you could catch a fish off a dock that is much darker in color and seemingly more solitary as no other fish are able to be pulled from the dock. You could then travel to another dock or simply revisit the same dock at another time and catch several fish in row. These fish would fit more into the school category and are likely passing by the dock or have recently moved in to feed.
Bass school into large groups for a variety of reasons. One common belief about schooling fish is that bass of similar size school together or that the larger fish are typically underneath or deeper than most of the smaller fish in the group.
The pictures above are underwater photographs of huge largemouth bass schooling in the Barton Creek section of Lady Bird Lake (Town Lake) of Austin, Texas. This area of the lake is feed by a creek that is substantially cooler than the rest of the lake. The bass like to congregate here during the summer months.