Comparison of the Cortisol and Glucose Stress Response to Acute Confinement among White Bass, Morone chrysops , Striped Bass, Morone saxatilis , and Sunshine Bass, Morone chrysops X Morone saxatilis

Sunshine bass are hybrids produced by crossing female white bass, Morone chrysops with male striped bass, Morone saxatilis. Hybrids produced by crossing female striped bass with male white bass are referred to as palmetto bass (Kerby 1993). Hybrid striped bass are considered more desirable than either parental species for aquaculture because of their fast growth and the ability to withstand handling and other stressors associated with culture conditions. The growth rates between the two hybrids are similar (Harrell 1997). Hybrid striped bass are thought to tolerate handling better than striped bass (Stevens 1984). Sunshine bass have become the most widely used hybrid for aquaculture because of the ease of handling of female white bass when compared with female striped bass, which are very large and difficult to handle and they often do not survive the spawning procedure. Gravid female striped bass are most often collected from the wild as they often do not mature in aquaculture ponds particularly in the southern USA. The hybrid’s retention of fast growth and tolerance of culture conditions, such as handling, must be as a result of a contribution from each of the parental species; however, the relative contributions of the parental species are largely unknown. Many common aquaculture practices result in a stress response by the fish. The severity of the stress can be measured by the amount and longevity of an increase in plasma cortisol and glucose, which is induced by the stressor (Carmichael et al. 1984). The stress