Systematics and evolution of migration in Clupeiformes (Herring, Sardines, Shad, Anchovies, and their allies)

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Migration is a widespread phenomenon among animals. One of the most spectacular types of migration, which occurs in fish such as salmon, eels, shad and sturgeon, involves movement between rivers and oceans to feed and reproduce. Many of these migratory fishes are important to their ecosystem and for recreational and commercial harvests. However, the evolution of migration and its consequences for species traits remains mysterious. The group of fishes that includes herrings, sardines, shads, and anchovies (Clupeiformes), is an excellent model for studying migration because it includes a large number of migratory species, many of which are of economic importance. Surprisingly, the evolutionary relationships and taxonomy of these fishes is poorly understood. The goal of this project is to use DNA sequence and anatomical data to generate a tree of life for Clupeiformes, and use this group as a model to understand the evolution of migration. The project will determine which traits are associated with migration, and how these traits evolve differently in migratory fishes compared to non-migratory fishes. The broader impacts of this project include training for a postdoc, two graduate students, high school teachers and first-generation undergraduates from underrepresented groups in STEM disciplines, including current and former military members and community college transfer students. In addition, this project will revise the taxonomy of Clupeiformes, including discovery and description of new species, provide taxonomic keys for their identification, and develop an open, online database of all migratory fishes. This project will generate a comprehensive phylogeny of Clupeiformes using genome-scale data and morphological characters to investigate the evolution of diadromy and its impact on lineage and phenotypic diversity. Using targeted exon capture, the project will sequence 1000 loci for phylogenetics and investigating the molecular evolution of diadromy. Morphological characters will be identified in understudied systems such as the gill arches, brain case, and soft tissue using dry skeletons, whole specimens, digital CT-scanned images and clear and stained specimens. The molecular basis for adaptation to a diadromous life history will be determined by testing for differences in rates and patterns of selection in osmoregulatory and vision genes. State-dependent diversification and sister comparison analyses will be used to test whether diadromy drives differences in rates of lineage diversification. Rates of morphological evolution will be estimated using maximum likelihood and Bayesian methods that incorporate missing taxa and uncertainty in parameter estimates and phylogeny. Using functional traits related to locomotion and feeding, the project also will determine whether migratory fishes reside on distinct macroevolutionary adaptive peaks associated with locomotion and feeding. Comparative methods will be used to determine the best-fit models of evolution for various traits associated with diadromy, and test to whether these traits are under strong selection. This project will reveal the macroevolutionary dynamics of diadromy across multiple biological scales and resolve the systematics and taxonomy of Clupeiformes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.