Speckled Trout Aquaculture

Speckled Trout (also known as Speckled

Seatrout) Taxonomy: Cyoscion nebulosusAdults reach 19-25 inches in length and 1-4

pounds in weight Reside in virtually any inshore waters

DistributionGulf of Mexico and Southern Atlantic OceanLive in the top of the water columnEstuarine coasts are prime settlement areasOften found in shallow tidal creeks near flooded

salt marshesKnown to congregate heavily over oyster reefs

Economic Importance-Fishing

Speckled Trout are endorsed by the American Fishing Society

Caught both commercially and recreationally, although the majority caught is due to recreational fishing (premier sport fish)

According to NOAA, speckled trout are in the top 10 species for recreational fishing

It ranks second by weight among recreational saltwater anglers mainly in the southeastern United States.

In South Carolina, the species was officially declared a game fish on July 1, 1986. Game Fish status means that this species

caught in state waters cannot be bought or sold

recreational catch for spotted seatrout averaged 266,000 individuals per year over an 11-year period.

The population of spotted seatrout in state waters is declining, albeit slowly, due to increased fishing pressure.

NEED for Aquaculture: YES-stock enhancement*http://www.nerrs.noaa.gov/Doc/SiteProfile/

ACEBasin/html/sppgal/sgfish.htm

Need for ProgramAs human populations increase, greater pressure is

placed on marine fisheries resources through habitat destruction and demand for food and recreation.

Two-thirds of harvested marine species for which data exist are either at or below the levels required for sustainability.

Marine resource management agencies are seeking reliable procedures for enhancing populations of heavily fished species and for assessing the success and value of stocking programs.

*http://www.usm.edu/gcrl/research/seatrout_main.php

Example: Culture of Spotted Seatrout for a Pilot Stocking Program at GCRL

A partnership between GCRL and the Mississippi Department of Marine Resources, is testing the effectiveness of using hatchery-raised fish to enhance Mississippi's seatrout population.

The goal of the project is to develop the methods to acquire, maintain and spawn broodstock of spotted seatrout in order to facilitate production, rearing, tagging, releasing and assessing of juveniles in a stocking program.

Growth and Development

Embryo (<1mm) Day 1 (~2mm)

Milestones in the Growth and Development of Seatrout Cultured at GCRL

Day 10 (~5mm) Day 15 (~10mm)

Milestones in the Growth and Development of Seatrout Cultured at GCRL

Day 24 (~25mm) Day 70 (~10cm)

Production MethodsNewly collected

seatrout arrives at GCRL quarantine facility. Seatrout are initially treated to remove external parasites that may multiply and kill fish in closed systems.

The seatrout are held 30 days in this quarantine facility to ensure the removal of external parasites.

*Fluidized Bed FilterRAS system

Early in the project, researchers used catheters to determine sex and take samples from the females to monitor the development of eggs. The degree of egg development, or maturation, indicates how close the fish are to spawning.

Tanks holding broodstock under controlled temperature and photoperiod conditions that induce spawning.

Spotted seatrout broodstock in the maturation system.

Production Methods Summarized

Brood Stock Acquisition: hook and line, coolers for transport, stress-coat: O2. (never out of water)

Quarantine: primary tanks, freshwater dip, drug treatment, secondary tanks (feeding)Purpose: exclude diseases

Maturation: ~50 animals2 tanks for spawningFed shrimp, squid, cigar minnows three times a week

Typically extensive culture

Water ChemistryTemperature and photoperiod cycle to

mimic natural cycleSpawning water temperature: 24-29 COptimum temperature for adults: 15-27 CSpawning salinity peak: 30-35pptOxygen: cannot be below 5 ppm*http://www.sms.si.edu/irlspec/

cynosc_nebulo.html (smithsonian)

AdvantagesBeing an extensive species there isn’t as much

riskAbove carrying capacity

DisadvantagesSkilled laborUsually expensive

TechnologyEducational background etc.

SummaryCollection and quarantine system Husbandry procedures for brood stock

developmentLive food productionTag and Release System