A PIT-tag system for tracking benthic invertebrates

A biotelemetry system based on Passive Integrated Transponder (PIT) tags will support research proposed in my concurrent application for an NSERC Discovery Grant: Species Invasions and the Ecology of Rocky Subtidal Communities. The research examines large-scale transitions in the structure of shallow seabed communities off Nova Scotia, which are driven by major changes in the abundance of a native herbivore (the sea urchin) and an introduced seaweed species. The primary research goals are to 1) investigate biological interactions and environmental factors that govern these ecosystem "phase shifts", 2) assess effects of native and invasive species on ecosystem structure and dynamics, and 3) develop predictive models to aid in conserving natural resources and native biodiversity. The PIT tag system will be used to track the movements of sea urchins and other bottom-dwelling invertebrates. This will allow us to monitor the rate of recovery of harvested urchin populations by measuring the rate of immigration into experimentally fished areas, and to identify potential sources of immigrants. Tagging also will enable us to track the survival, growth and reproduction of urchins, and the predatory fish and invertebrates and that associate with them, to explore the causes and consequences of animal feeding aggregations in this ecosystem.