Initial investigation of the North East Pacific salmon feeding waters with Slocum gliders

With the decline in the number of salmon returning to theWest Coast of Canada despite efforts to improve land-based habitat and increase hatchery releases, attention is turning to the condition of salmon ocean habitat for a reason. The offshore ocean habitat of salmon is complex and needs to be monitored continuously to facilitate an understanding of the dynamics. In preparation for long term monitoring an initial investigation was conducted to explore the suitability of ocean gliders for such a task. Three specific glider missions were executed with Slocum gliders: a long-range transit mission, a water property change mission, and a plankton bloom mission. The gliders were remotely navigated through the three missions using real-time satellite data. The long-range transit mission demonstrated successful near shore launch and recovery coupled with an extended deep sea mission. The water property change mission explored the water properties of a second year Haida Eddy. The plankton bloom mission tested the glider´s ability to collect data associated with biological productivity by navigating the glider inside a second year Haida Eddy that was fertilized with iron to stimulate a plankton bloom. The data collected on the three missions is discussed in the context of images of temperature, salinity, sound velocity, water density, CDOM, and chlorophyll. These three missions demonstrated a glider´s ability to collect high quality data that is requisite for understanding the dynamics of ocean waters and for developing effective management protocols for ocean salmon habitat.