This project will examine the relationships between larval fish behavior, growth, and mortality, as related to population success. It concentrates on variability in behavior of larval cohorts during the spawning season due to variation in parental contributions and the possible trade-off between growth rate and behavior at the cohort level. It also seeks to identify critical survival skills from among a set of suspected survival skills and how critical survival skills change with habitat. Specific objectives are to: (1) determine how survival skills and growth rates of cohorts produced by individual adults vary during the season and among adults, (2) identify critical survival skills, (3) compare critical survival skills for presettlement and postsettlement larvae, and (4) confirm the importance of critical survival skills in reducing predation mortality. These objectives will be met through laboratory experiments on reared and wild-caught larvae that will measure 11 suspected survival skills. Characteristics-of-survivors analyses on wild-caught larvae will reveal the critical survival skills in each habitat, which will be confirmed by field-based experiments.
Intellectual Merits. Variation in recruitment levels is one of the most important, yet poorly understood problems in population dynamics of marine organisms, including many economically important fishes. This study will examine: (1) a source of variation in recruitment that has received little or no formal investigation and (2) the linkages between larval fish behavior and recruitment and the changes in these linkages in different habitats. The research will contribute to the ongoing effort to understand and predict variations in animal abundance and the mechanisms of mortality, by providing a better understanding of the link between behavior and mortality, including the mechanisms of individual survival as well as variability in mortality among cohorts. All of this is essential for management plans for commercially harvested species and those in need of protection from human impacts.
Broader Impacts. The results will have application beyond natural populations. Fishery management plans for exploited fish populations often include enhancement of natural populations through stocking of hatchery-produced fish. This study could allow hatchery managers to allocate effort and funds more efficiently so as to maximize the effectiveness of stocking protocols. It could also provide direction to future research efforts to improve the efficacy of stocking as a management tool. This project will provide professional training to one postdoctoral associate and two graduate students in the form of laboratory and field research experiences, data analysis, and report preparation. These participants will also attend scientific meetings to disseminate projects results, to learn from other researchers, and to expand their network of professional contacts. Undergraduate student volunteers will be incorporated as well, giving them their initial research experience. All participants will interact daily with an interdisciplinary group of researchers representing biogeochemistry, ecosystem dynamics, and fish physiology and ecology. The project represents a new professional linkage between Texas Parks and Wildlife Department (TPWD), a resource management agency, and the research and education missions of the university. The collaborator is an Hispanic American who received his PhD very recently. He will provide critical assistance at no cost to the project and, in return, will be exposed to a new array of experimental protocols and analyses. Results of the project will be disseminated to the scientific community through publications in primary journals, conference presentations, and newsletter articles, and to the public through the institution's public lecture series, which typically draws 150-200 people weekly, and a public display in the visitor center, which will reach thousands of people each year. Collaboration with TPWD will ensure that the relevant results are evaluated by the stakeholders.
