About This Project

Plankton are critically important to the health and production of global fisheries and are sensitive to forcing by large-scale climate signals. To better understand how the current El Niño event is affecting spring plankton communities, we are using a ship of opportunity and a novel plankton imaging and net system to sample the cross-shelf, fine-scale distribution of larval fish and plankton along the US West Coast. Data will be compared to distributions measured during future non-El Niño years.

Ask the Scientists

What is the context of this research?

Almost all animals in the ocean start their lives as zooplankton, including fish, crabs, shrimp, and oysters. For fish, mortality is high and variable during this early life stage as larvae must avoid predators and locate patchily distributed prey in sufficient abundance and quality to survive and grow. These interactions between larval fish, their prey, and predators operate at fine spatial scales (≈10 cm) and are often mediated by biophysical conditions; which are, in turn, affected by variability in larger scale climate forces. Determining how the frequency and intensity of these fine-scale predator-prey interactions change in response to an El Niño event will help us understand how energy transfer from plankton to fish in coastal food webs will vary under different climate scenarios.

What is the significance of this project?

California Current fish larvae and their prey are often affected by environmental changes driven by El Niño. El Niño events can alter the intensity, timing, and duration of upwelling periods of cold, nutrient-rich waters that support productive coastal food webs. These changes can alter food web energy flows when cold-water, lipid-rich (i.e. fatty) copepods, an important prey item for fish, are replaced by warm-water, lipid-poor species (i.e. low-fat).

Previous work has focused on either 10-100 km shifts (McClatchie et al. 2008) or temporal variation (Peterson et al. 2002) in fish and plankton. Using our system, we will for the first time simultaneously sample at fine resolution, sufficient volumes of water to quantify larval fish, their prey, and predators both along and across the shelf.

What are the goals of the project?

The goal of this project is to quantify variation in plankton assemblages, individual predator-prey distributions, and broad, cross-shelf distributions of larval fish, their prey, and their predators at fine spatial scales (cm to km) in the Northern California Current.