title: Growth and annual survival estimates to examine the ecology of larval lamprey and the implications of ageing error in fitting models.
abstract: This study used existing western brook lamprey Lampetra richardsoni age information to fit three different growth models (i.e. von Bertalanffy, Gompertz and logistic) with and without error in age estimates. Among these growth models, there was greater support for the logistic and Gompertz models than the von Bertalanffy model, regardless of ageing error assumptions. The von Bertalanffy model, however, appeared to fit the data well enough to permit survival estimates; using length-based estimators, annual survival varied between 0·64 (95% credibility interval: 0·44-0·79) and 0·81 (0·79-0·83) depending on ageing and growth process error structure. These estimates are applicable to conservation and management of L. richardsoni and other western lampreys (e.g. Pacific lamprey Entosphenus tridentatus) and can potentially be used in the development of life-cycle models for these species. These results also suggest that estimators derived from von Bertalanffy growth models should be interpreted with caution if there is high uncertainty in age estimates.
authors.affiliation: Department of Fisheries and Wildlife, Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University, U. S. Geological Survey, 104 Nash Hall, Corvallis, OR, 97331-3803, U.S.A.
authors.forename: L D
authors.initials: LD
authors.lastname: Schultz
authors.affiliation: Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall Corvallis, OR, 97331-3803, U.S.A.
authors.forename: B E
authors.initials: BE
authors.lastname: Chasco
authors.affiliation: Department of Fisheries and Wildlife, Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University, U. S. Geological Survey, 104 Nash Hall, Corvallis, OR, 97331-3803, U.S.A.
authors.forename: S L
authors.initials: SL
authors.lastname: Whitlock
authors.affiliation: Oregon Department of Fish and Wildlife, Corvallis Research Laboratory, 28655 Hwy 34, Corvallis, OR, 97330, U.S.A.
authors.forename: M H
authors.initials: MH
authors.lastname: Meeuwig
authors.affiliation: U.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, OR, 97331-3803, U.S.A.
authors.forename: C B
authors.initials: CB
authors.lastname: Schreck
mesh_terms: D000375:Aging; D063147:Animal Distribution; D000818:Animals; D007798:Lampreys / Q000502:physiology*; D007814:Larva / Q000502:physiology; D008018:Life Cycle Stages; D008954:Models, Biological; D016019:Survival Analysis
keywords: Entosphenus tridentatus; brook lamprey; larval fish; mortality estimates; population dynamics