Simulating Potential Impacts of Dredging on Local Fish Populations

We present a study of the potential impact of deepening the Corpus Christi Ship Channel through Aransas Pass; in particular, we study the effect on the transport of red drum fish larvae due to the change in channel depth. The study uses TACC’s Stampede2 in order to run a high resolution ocean circulation model called ADCIRC to model the seawater entering and exiting the pass for the current and proposed Ship Channel depths. ADCIRC’s parallelized structure along with Stampede2’s Intel Skylake nodes make it possible to model a domain large enough to model the effects of incoming winds and tides: the entire Gulf of Mexico and the North American Atlantic coast, while also providing enough resolution to account for changes in the Ship Channel depth: resolution of up to 10 m. The corresponding transport of larvae modeled as passive particles due to the sea water circulation is established by releasing particles in the nearshore region outside Aransas Pass and subsequently tracking their trajectories. We compare the difference in the number of larvae that successfully reach appropriate nursery grounds inside Aransas Pass for four distinctive initial larvae positions in the nearshore region. Our results indicate that the change in channel depth does not significantly alter the number of red drum larvae that reach suitable nursery grounds, overall, across all considered scenarios, we see a net increase of 0.5%