Striped Bass, Morone saxatilis
- All stocking requests within the ACF system are now consistently met and requests for rivers outside the ACF system are typically fulfilled.
- Genetic markers are being used to identify the contribution of hatchery versus wild fish to the ACF population, so the use of Oxytetracycline (OTC) marks is no longer necessary.
- Standardized sampling is in place to aid in estimating year class strength, relative abundance, and recruitment into the fishery.
- Mean CPUE of broodfish greater than 0.7 – 1.0 adult fish per hour has been achieved.
- Protocols necessary to reduce stress during handling, holding, and distribution have been determined.
Striped bass. Credit: USFWS Image.
Striped bass have an elongate body which is moderately compressed. Dorsally their color ranges from light green to olive or steel blue, to brown or black. Laterally the fish are silver with 7-8 dark continuous stripes running longitudinally.
Gulf race striped bass are considered anadromous but for the most part are riverine in nature. When water temperatures start to rise (mid-February in Florida) mature males begin spawning runs up freshwater rivers and streams. The females follow and when they arrive at selected areas, usually spawn with several males. Semi-buoyant eggs are deposited directly into the water, as is the sperm. The eggs, if fertilized, hatch after 36-42 hours under normal conditions. This is the most crucial period for young stripers. The water current must be strong enough, and the river distance long enough to keep the eggs and young from settling to the river bottom, where silt would smother them. This period lasts several days and the correct amount of clean, flowing water is essential.
After the spring spawning run, the fish disperse downstream seeking cool water springs where they spend the hot summer months.
The Gulf race of striped bass was once common to rivers of the Gulf of Mexico, ranging from Lake Pontchatrain, Louisiana, to the Ochlockonee River, Florida. These fish were historically important in the bays and estuaries of the Gulf of Mexico, contributing to both commercial and recreational landings. By the 1960s, the native Gulf race striped bass population had declined significantly due to loss of habitat, including blocked access to historical spawning areas and summer thermal refuges and to water quality degradation. It is believed that the last populations of Gulf race striped bass survive in relatively low numbers in the Apalachicola-Chattahoochee-Flint (ACF) river system in Florida, Georgia, and Alabama.
One method to insure greater numbers of striped bass is to produce the fish in hatcheries. Millions of various sized fish are currently being stocked along the Gulf coast by the Fish and Wildlife Service and in cooperation with State fish and wildlife agencies. Hatchery raised fish are released in established areas that provide the young stripers with the best possible chance of survival. Some are tagged, enabling biologists to evaluate the success of the stocking programs.
Artificial propagation is conducted at three national fish hatcheries: Warm Springs NFH (Warm Springs, GA), Private John Allen NFH (Tupelo, MS) and Welaka NFH (Palatka, FL), and at several state hatcheries in Alabama, Florida, Georgia, and Mississippi. Yolk sac fish (fry), and Phase I fish (1" - 3") are shipped to various federal and state hatcheries to be raised and stocked according to the striped bass management plan.
Juveniles (1" - 2") utilize zooplankton and gradually switch to fish species preferring soft rayed fish such as shad. They are opportunists and tend to prey on schooling species as well as eels, needlefish and other spiny rayed fish.
Threats to Survival
The reasons for the decline of native striped bass along the northern Gulf coast are speculative. Environmental alterations in the form of water control structures and extensive channelization may have prevented successful reproduction. Dams not only prohibit migration upstream eliminating prime spawning habitat, but also reduce access to cool water springs which are crucial for large striped bass to survive the hot summer months. Industrial and agricultural pollution have also been implicated as probable causes of the drastic decline of striped bass.
As the need arose for conservation measures, agency directors and commissioners from Florida, Georgia, Alabama, and the U.S. Fish and Wildlife Service signed a Cooperative Agreement in 1987, to establish by mutual consensus the restoration of striped bass in the ACF river system. The goal of the agreement was “to restore a self-sustaining stock of striped bass to the maximum extent possible.” As per the Cooperative Agreement, the ACF Striped Bass Technical Committee, comprised of representatives from Georgia Department of Natural Resources (GDNR), Florida Fish and Wildlife Conservation Commission (FWC), Alabama Department of Conservation and Natural Resources (ACDNR), and U.S. Fish and Wildlife Service (FWS), coordinates Gulf striped bass restoration efforts for the ACF. This committee meets semi-annually to evaluate progress and program logistics; once at the Annual Morone Workshop in February and again in the fall.
To evaluate the efficacy and to update the previous 5-year plan, the ACF Technical Committee participated in a Structured Decision Making workshop facilitated by U.S. Geological Survey. Structured Decision Making (SDM) is a tool used to evaluate complex problems that often have multiple objectives and alternatives. The process may lead to more rational or transparent decisions. The SDM process involved identification of the problem, determination of fundamental and means objectives through creation of an objectives hierarchy, development of management alternatives, and adding weights to these alternatives to evaluate consequences of management actions. Key uncertainties were identified regarding effects of management actions, a model informed with long-term data, and expert knowledge was developed. Because recurrent decisions regarding genetic integrity, stocking strategies, and habitat restoration activities are made annually, the team recognizes the potential for adaptive management of this valuable trust resource.
In the past 25 years, much progress toward the ecology, restoration, and management of Gulf striped bass in the ACF was made. The following includes some of the more significant events:
Warm Springs NFH Involvement
WSNFH receives fry from several hatcheries to be raised in ponds on station, typically 100,000 to 250,000 fry per surface acre. Following 28 to 32 days of culture all ponds are harvested and distributed to sites within the ACF Basin. Over the past three years WSNFH has raised and distributed approximately 499,184 fry.
In addition to rearing fry, hatchery staff assists in studies that examine bone samples from striped bass marked with OTC to evaluate marking success to determine whether fry are hatchery produced fry or wild produced fry. With these results, management objectives can be adjusted to increase or decrease the need for hatchery produce fry.