Fisheries Stock Enhancement

New technology and products developed in the course of this program are made available to public and private organizations to facilitate research and to assist with commercial aquaculture development.

BACKGROUND
Many marine fish and bivalves may produce several hundred thousand offspring from a single mating. However, because natural mortality in the early life-history stages is very high, few offspring survive to juvenile stages in natural systems. By spawning and then rearing animals in hatcheries to a size or age beyond which these high rates of mortality occur, we can overcome this problem. Many of Florida's economically important marine species, such as red drum, snook, queen conch, and bay scallops, have declined in abundance relative to historic levels.

Hatchery production is frequently suggested as one remedy for this decline. The release of hatchery-reared animals may be particularly effective in restoring a population in areas where the abundance of naturally occurring animals has declined below a level at which recovery is likely or where natural populations have been affected by environmental or man-made perturbations such as freezes or chemical spills. The ultimate success of stock enhancement as a fisheries management tool is closely tied to an in-depth understanding of complementary fishery management strategies, population genetics, ecosystem dynamics, habitat structure and carrying capacity, disease management, economics (cost/benefit ratio), and an accurate assessment of enhancement efforts.

CURRENT RESEARCH
This program conducts applied research and develops technology to breed and rear finfish such as red drum and snook and mollusks such as bay scallops and queen conch. The Fisheries Stock Enhancement Program is a partnership between the Florida Fish and Wildlife Conservation Commission (FWC) and Mote Marine Laboratory (MML). MML scientists provide expertise and assistance in the areas of release experimental design and assessment of the impact of the releases. The finfish research includes spawning adults captured in the wild, incubating the developing eggs and larvae, and rearing the offspring to juvenile sizes in ponds and tanks. This research is currently conducted at the FWC Stock Enhancement Research Facility (SERF) at Port Manatee in Manatee County and at Mote Aquaculture, a division of MML, located on City Island in Sarasota. Also in progress is specific research relating to aspects of reproduction, cultivating phytoplankton and zooplankton for animal food, health management, marking and tagging, culture-system design, hatchery effluent management, and assessing the impact of stocking hatchery-reared fish into the wild.

Most of the hatchery-reared animals are stocked into estuaries or along the coast. Larger fish are marked prior to release with some sort of tag so that anglers and scientists can identify them if they are captured. Red drum are also identified using DNA fingerprinting techniques. Stocked hatchery-reared fish that are captured by Fish and Wildlife Research Institute (FWRI) and MML staff members, FWRI contractors, and anglers are used to determine survival rates, growth rates, diet, health, migration, and contribution to the fishery. By comparing cultured and wild fish with respect to these factors, the success of the stock enhancement effort can be assessed.

In mollusk studies conducted at SERF and at the FWC Keys Marine Laboratory at Long Key in Monroe County, wild adult bay scallops are spawned in the laboratory and egg masses are collected from naturally occurring queen conch aggregations. The eggs and larvae obtained are reared in tanks and ponds. Hatchery-reared scallops, identified by DNA fingerprinting, are placed in cages in selected natural waters to form spawning aggregates. The success of the spawning aggregates will be measured by the capture and identification (DNA fingerprinting techniques) of their offspring. Hatchery-reared queen conchs are marked with aluminum tags before release, which allows the animals to be tracked via underwater metal detectors. Technologies developed in the course of our research, as well as some of the animals produced, are made available to public and private entities for aquaculture research and for commercial food production.

GEOGRAPHIC COVERAGE
Releases of hatchery-reared red drum have occurred in Tampa and Sarasota bays and in Collier County on the west coast and in Volusia County, Indian River Lagoon and Biscayne Bay on the east coast. Beginning in 2000 red drum releases were concentrated in Tampa Bay. Snook have been released in Tampa and Sarasota bays and the Caloosahatchee River, all on the West Coast. Bay scallops were transplanted to field enclosures (cages) in lower Tampa Bay and between the Crystal River and the Homosassa River. Queen conch research occurs in the middle Florida Keys; queen conch transplants occur throughout the Florida Keys.

FUNDING SOURCES
Funding sources include Florida's Recreational Saltwater Fishing License (MRCTF), General Revenue (GR), U.S. Department of Interior Sports Fish Restoration Program, U.S Fish and Wildlife Service, and Nature Conservancy (GDTF).

PROGRAM PRODUCTS
Finfish eggs, larvae, and fingerlings; queen conch; stock enhancement and aquaculture technology; research publications and technical reports.