M. LaCava | Gvl Website

Dr. Melanie LaCava - Postdoctoral Scholar

Research Interests

I use molecular techniques to study wildlife populations with the goal of informing conservation and management. I investigate evolutionary and ecological processes underlying the relationships between spatiotemporal patterns of genomic variation and behavior, demographics, landscape characteristics, disease, and more. I am particularly interested in population genetics and genetics for captive breeding and reintroduction programs.

B.S., Wildlife, Fish & Conservation Biology, UC Davis

Ph.D., Ecology, University of Wyoming

Delta Smelt Conservation

Estimation of effective population size in the wild Delta Smelt Population

The Delta smelt (Hypomesus transpacificus) is an endangered estuarine fish endemic to the Sacramento-San Joaquin Delta in California that has experienced population declines for decades. We are using genetic samples collected across 25 years to characterize the long-term trend in effective population size ( ). We also used a portion of this valuable dataset as a case study for a new method for calculating temporal . See a preprint presenting the new method called MaxTemp here: https://www.biorxiv.org/content/10.1101/2024.06.04.597400v1

Captive spawning strategies for Delta Smelt supplementation

The UC Davis Fish Conservation and Culture Lab (FCCL) maintains a refuge population of Delta smelt that is genetically managed by the UC Davis Genomic Variation Lab (GVL). Continued population declines has led managers to begin supplementing the wild population with hatchery fish, requiring increased production of fish while maintaining vital genetic diversity. We experimentally evaluated the genetic consequences of two spawning methods to inform management of supplementation production. See our publication: LaCava, M.E.F., I.M. Donohue, M.E. Badger, T.-C. Hung, L. Ellison, M.M. Rahman, K. Kelvas, A.J. Finger, E.W. Carson. 2023. Assessing captive spawning strategies for supplementation production of Delta Smelt (Hypomesus transpacificus). Transactions of the American Fisheries Society https://doi.org/10.1002/tafs.10450

Loss of plasticity in maturation timing after ten years of captive spawning in a delta smelt conservation hatchery

The endangered Delta smelt has been spawned in captivity at the UC Davis FCCL for more than a decade. Since its founding in 2008, the UC Davis GVL has genetically managed the spawning program to maintain similarity to the wild population by avoiding inbreeding, equalizing family sizes, and incorporating wild fish each year. Despite these efforts, previous research by the GVL found evidence of adaptation to captivity at the FCCL. We expanded on this work by exploring the hypothesis that captive spawning may favor fish that mature early in the spawning season. Using more than a decade of spawning data and a complete pedigree, we evaluated the temporal trend in age at maturity, assessed the fitness of early maturing fish relative to later maturing fish, and estimated the heritability of age at maturity. See our publication: LaCava, M.E.F.*, J.S. Griffiths*, L. Ellison, E.W. Carson, T.C. Hung, A.J. Finger. 2023. Loss of plasticity in maturation timing after ten years of captive spawning in a delta smelt conservation hatchery. Evolutionary Applications https://doi.org/10.1111/eva.13611. *these authors contributed equally to this work.

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