Abstract Title

Session S-08D: Salmon Recovery: Implementation and Progress I

Proposed Abstract Title

Juvenile Chinook Outmigration in Howe Sound

Presenter/Author Information

Edith TobeFollow

Keywords

Species and Food Webs

Location

Room 6C

Start Date

1-5-2014 5:00 PM

End Date

1-5-2014 6:30 PM

Description

Chinook salmon populations returning to the Squamish River have been declining in recent years along with many other salmon populations in North America (DFO Science 1999). Howe Sound supported a major commercial fishery for chum, pink and Chinook salmon until declining returns resulted in the closure of the fishery in 1968. Since that time there have been significant efforts to limit exploitation and increase escapement through hatchery programs, especially for Squamish River Chinook. Despite these efforts this population is still struggling (Levings and Riddell 1992) for unknown reasons though poor marine survival could be a major contributing factor (DFO Science 1999, Wada and Sander 2005). Natural populations of salmon have differing life histories with variable timing of juvenile migration. This may result in greater survival rates due to less pressure on limited food and space resources (Beamish et al 2003) and a decreased likelihood that chance oceanic events will wipe out an entire brood year (Bottom et al 2005). Results from this study can be used to guide the establishment of hatchery release times that limit potential competition between wild and hatchery juveniles while also increasing our limited knowledge how hatchery programs effect wild salmon (Bottom et al 2005). Howe Sound is a necessary travel corridor for salmon returning to the Squamish River and its tributaries and may also play an important role for juvenile salmon during their outmigration and transition to the marine environment. Most studies of salmon distribution and survival are limited to freshwater life stages and consequently relatively little is known about survival and behaviour in marine waters (Beamish et al 2003). In addition, no broad scale juvenile fish sampling has occurred in Howe Sound since 1998 when a sampling methodology was established (Grout et al1998), through there have been many changes to the local environment. The primary objectives of this study are to better understand the spatial and temporal distribution of juvenile Chinook in Howe Sound and to identify key habitats or community assemblages preferred by these fish.

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May 1st, 5:00 PM May 1st, 6:30 PM

Juvenile Chinook Outmigration in Howe Sound

Room 6C

Chinook salmon populations returning to the Squamish River have been declining in recent years along with many other salmon populations in North America (DFO Science 1999). Howe Sound supported a major commercial fishery for chum, pink and Chinook salmon until declining returns resulted in the closure of the fishery in 1968. Since that time there have been significant efforts to limit exploitation and increase escapement through hatchery programs, especially for Squamish River Chinook. Despite these efforts this population is still struggling (Levings and Riddell 1992) for unknown reasons though poor marine survival could be a major contributing factor (DFO Science 1999, Wada and Sander 2005). Natural populations of salmon have differing life histories with variable timing of juvenile migration. This may result in greater survival rates due to less pressure on limited food and space resources (Beamish et al 2003) and a decreased likelihood that chance oceanic events will wipe out an entire brood year (Bottom et al 2005). Results from this study can be used to guide the establishment of hatchery release times that limit potential competition between wild and hatchery juveniles while also increasing our limited knowledge how hatchery programs effect wild salmon (Bottom et al 2005). Howe Sound is a necessary travel corridor for salmon returning to the Squamish River and its tributaries and may also play an important role for juvenile salmon during their outmigration and transition to the marine environment. Most studies of salmon distribution and survival are limited to freshwater life stages and consequently relatively little is known about survival and behaviour in marine waters (Beamish et al 2003). In addition, no broad scale juvenile fish sampling has occurred in Howe Sound since 1998 when a sampling methodology was established (Grout et al1998), through there have been many changes to the local environment. The primary objectives of this study are to better understand the spatial and temporal distribution of juvenile Chinook in Howe Sound and to identify key habitats or community assemblages preferred by these fish.