Environmental drivers of the abundance and distribution of forage fishes on the Northeast US shelf, with a particular emphasis on northern sand lance

Justin Suca, Ph.D., 2021
Joel Llopiz, Advisor
Small pelagic fishes, also termed forage fishes, represent a critical link between secondary production and myriad top predators in marine ecosystems, including the Northeast US shelf. In this dissertation, I analyze the drivers of forage fish distribution throughout the Northeast US shelf and the drivers of the abundance of the ecologically important northern sand lance. Chapter 2 examines the basic ecology of northern sand lance and uses these insights to identify mechanistic drivers of their abundance. I then explore different scenarios of these drivers to project sand lance abundance through the end of the 21st century. Chapter 3 analyzes the environmental drivers of the distribution of the six dominant, offshore forage fish species on the Northeast US shelf to elucidate the role of environmental covariates in shelf occupancy by these taxa. Chapter 4 assesses the source-sink dynamics of three sand lance hotspots through Lagrangian particle tracking models simulating larval sand lance transport. The relationship between the connectivity of these hotspots and environmental conditions is also explored. Collectively, this dissertation improves our understanding of the dynamics driving variability in the Northeast US shelf forage fish complex, particularly for northern sand lance.