How do Larval Traits Influence Marine Dispersal and Population Dynamics?
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Larval Fish EcologyMarine fish larvae develop for days to months in the upper water column where, due to their tiny size, they were once expected to disperse widely with ocean currents. However, recent studies using genetic techniques have revealed that many larvae stay within 1 km of their home reef. Efforts to identify where larvae are distributed during early development have been hampered by the minute morphological characteristics that differentiate closely related species. To better understand the role of physical and biological processes in shaping patterns of larval dispersal, the Majoris Lab is using DNA barcoding and Metabarcoding techniques to resolve species level patterns of larval fish distribution and abundance around coral reefs.
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Larval Dispersal TraitsTo influence their dispersal, larvae need to have sensory organs and swimming abilities that allow them to orient their movement. To determine when these traits develop, the Majoris Lab works with lab-raised larvae to study the development of sensory systems, swimming abilities, and orientation behavior throughout the entire larval phase of marine fishes. In our current research, we are working to determine whether larvae exhibit suites of correlated morphological, behavioral, and genetic traits (i.e., behavioral syndromes) that may help to explain why some fish larvae remain close to home (i.e., philopatry), while others disperse over long distances.
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Parental Care and Embryo Hatching PlasticityPhenotypic plasticity is the ability of a genotype to express different phenotypes to match variation in environmental conditions. For many species, hatching represents perhaps the most vulnerable life-history transition, which makes expressing the optimal hatching phenotype a crucial determinant of survival. The Majoris Lab is working to understand what environmental cues parents and their embryos use to determine the optimal time to hatch, and how plasticity in hatching time influences an individual's development, behavior, and dispersal potential during the larval phase.
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Population DynamicsTo complete early development, reef fish larvae must find and settle in suitable benthic habitat. As with many things in nature, recently-settled juveniles are often non-randomly distributed, suggesting that pre- and post-settlement processes shape their distribution. Using a series of experimental and observational field studies, research in the Majoris Lab seeks to determine whether larvae express behavioral preferences for settling on habitats that will maximize their post-settlement survival. These settlement behaviors have important implications for the population dynamics and conservation of marine fishes.
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