Discovery Passage Plankton Monitoring Program

Initially funded by the BC Ministry of Environment, this five year pilot project relied on community level funding. Without the generous contributions of the following organizations, this important work would not have been possible.

2010 Contributors 2009 Contributors
  • Aboriginal Fisheries Society
  • Campbell River and District Fishing Guides Association
  • Campbell River Salmon Foundation
  • City of Campbell River
  • Marine Harvest Canada
  • Positive Aquaculture Awareness
  • Aboriginal Fisheries Society
  • Campbell River Salmon Foundation
  • Grieg Seafood BC
  • Mainstream Canada
  • Marine Harvest Canada
  • Pacific Salmon Foundation
  • Turner Design (donation of Trilogy Lab Fluorometer)


 About the Program

The goal of the Discovery Passage Plankton Monitoring Program is to develop a simple tool to help monitor marine productivity and use this information to adjust enhanced coho releases from Fisheries and Oceans Quinsam Hatchery.  

The monitoring program is being used to assess:

  1. Is poor survival due to a mismatch of smolt release timing and food availability in the near shore marine environment?
  2. Is good survival correlated to improved food quality and availability at the time of smolt release?
  3. Can chlorophyll a (a pigment in phytoplankton) be used as an indicator of increasing phytoplankton levels followed by increasing zooplankton levels in Discovery Passage? 

To address these questions, chlorophyll a levels are compared to phytoplankton levels and zooplankton composition (type/species) and abundance. This information is compared to the stomach contents of juvenile coho salmon to correlate what the fish are eating compared to what is available in the nearshore marine environment. 

This pilot project has completed its fifth year of five years, and the data collected has confirmed that there is no predictability to the productivity cycles and food availability and, therefore, monitoring is the best way to ensure that juvenile coho get maximum benefit from well-timed release dates.  Other interesting and important findings include: 

  • Juvenile coho stomach content analysis indicates that wild and hatchery reared salmon may prefer different zooplankton upon immediate arrival in the marine environment.
  • Staggered release dates may help ensure that some populations are released when food sources are good.
  • Chlorophyll a values are an effective way to monitor phytoplankton levels; however, these values are not a predictor of ensuing zooplankton levels and composition.

Knowledge of zooplankton levels and composition at time of juvenile salmon go into the marine environment is a useful tool in helping to predict poor or good survival of that year class.  This knowledge can be used in helping to establish what the brood returns will be and provide more information necessary to establish numbers necessary for brood selection.

While the project has focused on coho out-migrating from two neighboring rivers, this study’s findings can be applied to the specific needs of other Pacific salmon species especially those salmon that travel through the Discovery Passage area and to rivers throughout BC.



May 2010 - StreamTalk - article:  A way to increase coho returns? Matching release time with food availability (Page 7)

Project Reports

March 19, 2010 - Courier-Islander - article: Tiny coho get better start thanks to study