Striped Bass

Adult striped bass, Morone saxatilis

Occurrence and Description

Striped bass, Morone saxatilis, are widely distributed along the Atlantic coast of North America from the St. Lawrence River in Canada to the St. Johns River in Florida. A separate population naturally exists along the northern coast of the Gulf of Mexico from the Suwannee River in Florida west to Lake Pontchartrain in Louisiana. Striped bass have also been successfully introduced to the Pacific coast, and many lake and reservoir systems throughout the United States.

Striped bass are designated a freshwater game fish in Mississippi, with a minimum length limit of 15" and a daily creel limit of six fish per person for 2013. The current Mississippi state record striped bass is held by Tony C. Graves with a 37.82 pound pound fish caught on the Bouie River in 1993.

Jennifer Green with a 3.0-kg. (6.6-lb.) striped bass that was acoustically-tagged and released in the Tchoutacabouffa River, Misssissippi.
Jennifer Green with a 3.0-kg. (6.6-lb.) striped bass that was acoustically-tagged and released in the Tchoutacabouffa River, Misssissippi.

Striped bass have an elongated and moderately compressed body. Dorsal coloration ranges from green to steel blue or almost black.  Their sides are silver with seven or eight dark continuous horizontal stripes, one of which always follows the lateral line. Additional distinguishing features are two sharp spines on the posterior edge of the operculum (back edge of the gill cover) and two distinct parallel tooth patches on the tongue.

Source: Native and Introduced Ranges of Striped Bass.
Source: Native and Introduced Ranges of Striped Bass.

 

Striped bass in Gulf drainages are considered a separate strain from populations along the Atlantic coast. Charcteristics such as the number of lateral line scales and fin rays are used to distinguish Atlantic and Gulf striped bass populations.

Striped bass are usually considered an anadromous cool water species, meaning that they migrate from saltwater to freshwater to spawn.  However, Gulf-strain striped bass are primarily riverine and typically do not make extensive coastal migrations, which are characteristic of striped bass populations along the Atlantic coast. Seaward movements of striped bass in their southern range may be limited because coastal water temperatures of the Gulf region are much warmer than the upstream portions of large rivers. Although it has been hypothesized that Gulf-strain striped bass are more tolerant of higher temperatures than Atlantic striped bass, Gulf-strain striped bass tend to avoid temperatures higher than 25°C (77° F). Thus, striped bass within the southern extent of their range would be more likely to find suitable temperatures within large rivers rather than in the coastal and estaurine waters of the Gulf.

Life Cycle & Reproduction

Male striped bass are sexually mature by age two at a total length of about 174 mm (6.8 inches). Most females are sexually mature by age four at a total length of about 432 mm (17 inches).

Peak spawning activity occurs at night in freshwater during the spring from February to May, when water temperatures are between 13°-22°C (55.4°-71.6°F). Striped bass migrate a sufficient distance upstream to assure that the eggs and larvae hatch and develop by the time they reach nursery areas near the mouth of the river. Females broadcast spawn, releasing thousands of eggs into the water column which typically hatch in two to three days after fertilization as they drift downstream. The larvae must reach a nursery habitat where there is sufficient prey within seven days after hatching to ensure survival and recruitment into the juvenile population.

Young juveniles tend to occupy shallow habitats with slow to moderate current and sand or fine gravel substrate, where food availability and water temperatures promote rapid growth.  Juveniles feed on larval clupeids (shad, menhaden, herring, and anchovies), mysid shrimp, insect larvae, and polychaetes (segmented aquatic worms). As juveniles increase in size and age, they become more piscivorous (fish-eating).

Adult striped bass are opportunistic feeders, consuming a variety of fishes (primarily clupeids) and crustaceans. Adult striped bass seasonally use an array of estuarine and riverine habitats dependent upon feeding, spawning, and thermal refuge needs. Within the Gulf rivers, cool water refuges typically identified as well oxygenated, deeper areas associated with springs or groundwater input, are critical habitats that alleviate thermal stress during the summer months and ensure striped bass survival.

Historical Declines

Historically, native stocks of Gulf-strain striped bass inhabited freshwater streams and estuaries of all major tributaries along the Gulf coast. However, beginning in the 1950s, populations severely declined so that by the 1970s, striped bass were considered to be extirpated from all Gulf drainages except for a remnant population in the Apalachicola Drainage in Florida. Speculation suggests that the decline is a result of chemical contamination, increased runoff, and extensive habitat alterations to coastal river systems, such as the construction of dams and dredging.

In an effort to reestablish and maintain self-sustaining populations of Gulf-strain striped bass along their native southern range, northern GoM drainages have been stocked with hatchery striped bass since 1969. For the past four decades, the striped bass stock enhancement program in southern Mississippi has released more than 13 million fingerlings in the Pearl River, Jourdan River, Wolf River, Biloxi River, Tchoutacabouffa River, Fort Bayou, and Pascagoula River. The restocking program has been successful in establishing recreational put-and-take fisheries throughout most of the stocked tributaries. However, despite this enduring stocking effort, the past 25 years of recreational recapture reports coupled with no evidence of natural reproduction suggest the Gulf-strain striped bass population has yet to be self-sustaining. 

To establish a self-sustaining population of hatchery reared striped bass, the introduced habitat must meet the minimum requirements necessary to support reproduction, growth, development, and provisions for each life stage. Unfortunately, adequate estuarine and riverine habitat can be seasonally limited along the northern GoM. The availability of suitable water temperatures and dissolved oxygen (DO) concentrations during the summer months (June - September) can become greatly reduced. Consequently, this may severely limit the availability of suitable refuge habitat to striped bass and thus further reduce survival rates. Therefore, if stocking programs want to increase post-stocking survival of hatchery reared Gulf-strain striped bass within the coastal river systems, availability of suitable habitat will have to be investigated based on seasonal variability, along with the post-stocking dispersal patterns of striped bass. An effective method to accomplish this is by the use of acoustic telemetry. Acoustic telemetry is an important technique that enables researchers to gain knowledge about the behavior and movement patterns of aquatic species for long durations and across vast distances.

Biological Research on Striped Bass at GCRL

Since November 2012, research has been focused on site fidelity, diel activity (regular daily cycles), and seasonal habitat selection of acoustically-tagged Gulf-strain striped bass in relation to dynamic abiotic (physical rather than biological) environmental characteristics of the Biloxi River. Using telemetry methods, acoustically-tagged juvenile hatchery-produced Gulf-strain striped bass are passively and manually tracked in the Biloxi River.

The acoustic transmitter is surgically implanted in the body cavity of the fish.
The acoustic transmitter is surgically implanted in the body cavity of the fish.
Image of a Vemco V-7 acoustic transmitter.
Image of a Vemco V-7 acoustic transmitter.

 

An array of 14 receivers strategically positioned in the Biloxi River continually record the presence of acoustically-tagged fish within a radius of one km (0.6 mi.) from a receiver. Manual tracking events are conducted monthly to pinpoint locations of individual fish. Once an exact location of the fish is determined, physiochemical variables (water temperature, salinity, specific conductivity, DO, and pH) and depth are recorded to determine if subhabitats occupied by juvenile hatchery reared Gulf-stain striped bass are unique compared to the overall abiotic environmental condition of the river. Identifying the physiochemical characteristics of striped bass locations and the seasonal variability of selected subhabitat will also provide hatcheries with much needed insight regarding potential critical habitat that may maximize survival of juvenile hatchery Gulf-strain striped bass in Mississippi’s coastal systems.

Map of the Biloxi River striped bass acoustic receiver array.
Map of the Biloxi River striped bass acoustic receiver array.

 

Our findings so far suggest that poststocked juvenile Gulf-strain striped bass are mobile upon initial release into a natural system and actively seek deeper (≥ 4 m or 13 ft), more saline (8.3-12.4 psu on average), and warmer temperature (16.3-19.4 °C or 61.3-66.9° F) sub-habitats relative to November mean river conditions. These deep habitats may facilitate acclimation to these natural environments due to the buffering effect of higher salinities reducing physiological stress of the fish.

Map of striped bass locations during manual tracking events at 1 day, 4 days, and 15 days after being released in the Biloxi River, Missipppi, on November 6, 2012. The map on the right is an enlarged view of the upper part of the monitored area.
Map of striped bass locations during manual tracking events at 1 day, 4 days, and 15 days after being released in the Biloxi River, Missipppi, on November 6, 2012. The map on the right is an enlarged view of the upper part of the monitored area.

 

Continued research on Gulf-strain striped bass will enhance our understanding of their behavior and habitat requirements for the northern Gulf of Mexico, which may facilitate increased survival, potential for natural reproduction, and reduce the need for hatchery efforts. 

Paul Mickle with a 2.04-kg (4.5-lb.)striped bass that was acoustically-tagged and released in the Biloxi River, Mississippi.
Paul Mickle with a 2.04-kg (4.5-lb.)striped bass that was acoustically-tagged and released in the Biloxi River, Mississippi.

Report Your Striped Bass Catches

Anglers who catch striped bass are requested to report their catch to the GCRL Striped Bass Program. Tagged fish are particularly interesting, but reports of untagged fish are also very helpful. Striped bass caught can also be reported to Jennifer Green at the Gulf Coast Research Laboratory at (228) 818-8820 or Jennifer.L.Green@usm.edu. Anglers reporting striped bass catches will receive a Striped Bass Program t-shirt or baseball cap.

Our Partners and Supporters

We thank the Mississippi Department of Marine Resources and the Lyman Fish Hatchery, the Sportfish Restoration Program, the U.S. Fish and Wildlife Service, and the Coastal Impact Assessment Program.


Resources and References