Zooplankton ecology of the Fraser River estuary

Zooplankton are critical components of the pelagic food web. This presentation will discuss zooplankton ecology in the Fraser River Estuary, drawing on the preliminary results of a monitoring study, which ran from August 2013 to May 2016, as well as specific investigations into the life history and behaviour of one of the dominant species, the copepod Eurytemora affinis. Data analysis is ongoing, but, for most of the year, estuarine zooplankton appear limited by the estuary’s short residence time. Due to the advective nature of their environment, estuarine zooplankton have evolved mechanisms to retain populations within the estuary. Our results suggest that E. affinis employs tidal vertical migration and the production of benthic resting eggs, but that these mechanisms may be insufficient to maintain populations in the fast-flowing channel areas of the estuary. The predicted changes to the Fraser’s annual hydrograph will further reduce the estuary’s residence time during the spring but will increase it in the summer. Paired with higher temperature, this may open a novel niche in the estuary with could be exploited by non-indigenous species. One such species, considered invasive in the U.S., has been found to date. The results of this study can help inform policy, management, and restoration efforts by lending insight into the ecology of this estuary and how its zooplankton community will respond to changes in climate.