Cool Striped Bass
Summertime—an idyllic period of oven-like temperatures when many people enjoy vacations to the beach or mountains. Fish also seek to escape extreme temperatures by staying in water of a more preferred temperature. Fisheries biologists have learned that, during the summer, striped bass will sacrifice other needs in order to satisfy their need for cool water.
In the 1960s and early 1970s, many states jumped on the bandwagon promoting the stocking of striped bass. Well known for its tremendous fighting qualities and tackle busting ability, the striped bass, is a fantastic sport fish. Although striped bass are classified as an anadromous species (live in a marine environment, but migrate into fresh water to spawn), stripers can live in totally fresh water without migrating to marine waters.
This fish seems ideal! Striped bass grow to gigantic size; Alabama’s state record stands at 55 pounds. Striped bass can feed on large gizzard shad, which few other predators can utilize efficiently. Additionally, competition with other sport fish, such as the largemouth bass, is limited as research indicates stripers feed almost exclusively on shad and live primarily in open waters. Unfortunately, studies in several southern states indicate that stripers, particularly those larger than ten pounds, may suffer from thermal stress, which may cause lethargic behavior, poor feeding habits, weight loss, bacterial and fungal infections, and even death to the fish.
On occasion, large striped bass have died in reservoirs throughout the Southeast, including Lake Martin in Alabama. Landlocked striped bass were found to be very sensitive to temperature variations within stocked waters and will sacrifice food requirements to remain in areas with cool water. These cool water areas are usually produced from the waters of flooded springs or are found in cooler layers of water deep within the reservoir. Striped bass prefer temperatures around 68 degrees Fahrenheit. If oxygenated water in this temperature range is unavailable during the summer months; the reservoir may not be suitable for a striped bass fishery.
Since 1979, biologists in the Fisheries Section of the Alabama Division of Wildlife and Freshwater Fisheries have been investigating this phenomenon at several reservoirs statewide with the use of ultrasonic and radiotelemetry tagging of stripers. Data gathered in these studies indicate that striped bass begin concentrating in thermal refuges along the Alabama and Coosa River systems as early as late May when water temperatures climb into the high 70s and low 80s. During the remaining months of summer, as ambient water temperatures continue to climb higher, even into the 90s, stripers may literally stack on top of each other in an attempt to get into the coolest water possible.
Biologists have collected as many as 43 saltwater striped bass in an area no larger than an average size bedroom. Many fish, particularly the larger ones, were in poor condition with slack bellies and parasitic or bacterial infections being the rule rather than the exception. In cool water areas with low oxygen level, fish may show no interest in feeding. Areas with the right temperatures and oxygen levels can present excellent angling opportunities.
Although a few dead stripers have been observed floating or on nearby shorelines, Alabama has been fortunate to escape the massive die-offs of big stripers such as those which have been reported in Tennessee, South Carolina and Louisiana. Research showing striped bass require cool thermal refuges has led fisheries managers in Alabama to stock hybrid striped bass in many of our reservoirs which have little or no cool water available during the summer months.
The hybrid striped bass is a cross between the female striped bass and the male white bass. Although hybrids do not grow quite as large as stripers, they tolerate warmer water and are high angling quality. Reservoirs that are relatively shallow and fertile with little or no cool water available appear to be more suited to the hybrids. Other reservoirs, such as Smith Lake and Lake Martin, which usually have abundant cool and well-oxygenated waters during the summer, are suitable for striper growth and survival. The striped bass fishery in these lakes can provide world class angling throughout the summer.