Speaker: Scott Heppell, Professor, Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University
Topic: Decadal change and the abundance of fishes and invertebrates in Yaquina Bay.
Natural environmental change, anthropogenic development, and inter-annual variability can affect the diversity and abundance of estuarine fish and invertebrates. Yaquina Bay has undergone substantial change in the last sixty-plus years, including widespread development, deep-draft dredging, shoreline hardening, and infill of former tide flats. In 1967, prior to much of the modern rearrangement of the estuary, the United States Environmental Protection Agency conducted a 21-month survey of Yaquina Bay to characterize the demersal fishes and epibenthic crustaceans that occupy the bay. From 2003 to 2005, we replicated that work to provide a comparative snapshot across a 35-year time interval. We found a 90+ percent decline in CPUE between surveys, as well as a decline in overall biodiversity. Furthermore, by the time of our sampling the estuary had shifted from a fish-dominated system to one dominated by epibenthic crustaceans. While we can’t establish causal relationships between these changes and human or natural events, we do document substantial changes in both the diversity and total abundance of animals in the Yaquina benthic community over three-plus decades. The Yaquina estuary continues to change, and twenty years on from our work, a repeat study is now due.
15 сен 2024
