Genetic effective size in hatchery-raised spotted sea trout, Cynoscion nebulosus, released for stock enhancement in Texas bays and estuaries

2010-2013 - $165,702

John R. Gold
Department of Wildlife and Fisheries Sciences
Texas A&M University

Robert R. Vega
CCA/CPL Marine Development Center
Texas Parks and Wildlife Department

Abstract

Recreational fishing for the estuarine-dependent sciaenids Cynoscion nebulosus (spotted seatrout) andSciaenops ocellatus (red drum) is a vital resource to economies of coastal communities in Texas, accounting in 2006 for roughly $530 million in expenditures by over a million “spenders.” Because of recent declines in abundance, the Texas Parks and Wildlife Department (TPWD) has initiated a program of stock enhancement of spotted seatrout, similar to the successful program for red drum initiated more than 20 years ago. A two-year project, utilizing molecular markers developed through current Texas Sea Grant funding, to address critical hatchery and hatchery-release aspects of the stock-enhancement program for spotted seatrout carried out by TPWD is proposed. Specific major accomplishments will include: (i) determination of the sex and productivity of individual brood fish at the two TPWD hatcheries; and (ii) assessment of the potential for a Ryman-Laikre effect (reduction in effective size and fitness of a “wild” population stemming from small effective size of a hatchery-release population) on the seatrout fishery in Texas waters. Data from the project also will be used to determine if levels of genetic variation and allele/genotype distributions of hatchery broodfish differ from those of seatrout resident in the four Texas bays or estuaries where seatrout from TPWD hatcheries are released, and to identify the proportion of hatchery-released fish among samples of 100 fish from each bay or estuary. The TPWD is a full partner in the proposed research and will contribute significant matching funds to attain project objectives. A number of outreach activities also is proposed and will include personnel from Texas A&M University, TPWD, Sea Grant, and the Coastal Conservation Association-Texas. Targets of outreach activities include the 90,000 annual visitors to TPWD hatcheries, two chapters of the Texas Master Naturalists association, and tour groups (primarily primary- and secondary-schools) at Sea Center Texas. Results of the project will benefit multiple users and stakeholders, including fishers, coastal communities economically impacted by recreational fishing, TPWD, and other states in the Gulf Coast region planning to implement stock-enhancement of spotted seatrout. Results of the study also will be disseminated to the scientific community through publication in peer-reviewed journals.