The importance of egg size for the diversity of salmonids

• Main Author: Leblanc, Camille A.
• Other Authors: Noakes, David L. G., Mason, Robert, Gitelman, Alix, Schreck, Carl, Snorrason, Sigurđur S., Fisheries and Wildlife, Oregon State University. Graduate School
• Format: Doctoral or Postdoctoral Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Steelhead (Fish) > Physiology; Hatchery fishes > Development; Steelhead (Fish) > Growth; Steelhead (Fish) > Development; Arctic char > Growth; Hatchery fishes > Physiology; Arctic char > Eggs > Size; Steelhead (Fish) > Eggs > Size; Hatchery fishes > Eggs > Size; Arctic char > Physiology; Arctic char > Development; Hatchery fishes > Growth; Arctic charr; Salvelinus alpinus
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/n009w5593

Understanding the origin and nature of intra specific biodiversity enables us to better conserve and manage animal populations. Biological diversity is seen at different scales and for different traits such as behavior, morphology, physiology, and life history. Behavior is especially important since behavioral changes are believed to precede changes in morphology or physiology among fishes. Salmonids display great diversity in terms of behavior, life histories and morphology within and among populations. Thus, differentiation among populations and morphs has been related to the evolution of new species. Various genetic, environmental and ecological factors have been shown to be important for segregation of morphs, including competition for food or other resources, phenotypic plasticity and sexual selection. Recently, it has been suggested that the importance of epigenetic and maternal effects for intra specific diversity have been underestimated. I studied the short- and long-term effects of egg size on development, behavior, body growth and physiology in Arctic charr Salvelinus alpinus and steelhead trout Oncorhynchus mykiss. I also examined how domestication can affect egg size. Egg size was smaller in domesticated fish populations after accounting for female body size and age. Egg size was negatively correlated with embryonic development before hatching, i.e. embryos in small eggs developed more rapidly. At emergence, egg size was positively correlated with length and weight of first feeding progeny. Juveniles coming from larger eggs tended to feed more at the surface whereas juveniles coming from smaller eggs fed more on the bottom. These relationships and effects of egg size on embryos and first feeding fish were observed in both species in laboratory conditions. In Arctic charr there was a higher energy content per egg in larger eggs in both aquaculture and wild populations, and the total energy content per egg varied among populations. Behavior of Arctic charr at first feeding was affected by egg size, ...