Juvenile Salmon Residency in a Marsh Area of the Fraser River Estuary

Abstract

Large numbers of juvenile chinook salmon (Oncorhynchus tshawytscha), chum salmon (O. keta), and pink salmon (O. gorbuscha) were present within tidal channels of a marsh area in the Fraser Estuary between March and June 1978. The tidal channels investigated dewatered at low tide, necessitating daily emigrations by juvenile salmon out of the channels. While pink fry emigrated from tidal channels at the early and middle stages of ebbing tides, most chum and chinook fry emigrated near the later stages of ebbing tides. Mark–recapture studies demonstrated that chinook and chum fry resided temporarily in the marsh prior to migrating into the Pacific Ocean and returned to the same channel on several tidal cycles. Pink fry were abundant in the channels, but appeared to be transient. Chinook and chum showed an increase in average length which was attributable to estuarine growth.Key words: chinook salmon, chum salmon, pink salmon, juvenile residency, marsh tidal channel, Fraser Estuary, estuary growth

Effects of high temperatures on threatened estuarine fishes during periods of extreme drought

“…Jonsson and Jonsson, 2009;Martins et al, 2012), much less is known about the effects on anadromous and semi-anadromous species that are less important economically, yet contribute greatly to aquatic biodiversity. For anadromous and semi-anadromous fishes, estuaries provide critical rearing grounds and migratory corridors that connect the marine environment with freshwater watersheds (Levy and Northcote, 1982;Ray, 2005). Given the importance of estuaries worldwide for resident and migratory fishes, it is crucial to understand the effects of water temperature on these systems.…”

Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007

“…Subyearling salmon have been found in shallow water or nearshore habitats of the Fraser River estuary (Levy and Northcote 1982) and the Nanaimo estuary (Healey 1978) in British Columbia, the nearshore waters of Puget Sound (Brennan et al 2004;Beamer et al 2005), the Sacramento-San Joaquin estuary (Kjelson et al 1982), the Sixes and Coquille estuaries (Reimers et al 1979), the Salmon River estuary (Bottom et al 2005a), and Yaquina Bay (Meyers and Horton 1982) on the Oregon coast. Although specific fish/habitat linkages are not always evident, especially in highly migratory species such as Pacific salmon (Simenstad and Cordell 2000), it is likely that salmon with ocean-type life history patterns depend on shallow, estuarine habitats for rearing and refuge (Fresh et al 2005).…”

Floodgate Operations and Fish Communities in Tidal Creeks of the Lower Fraser River (British Columbia, Canada)

“…We found that higher flows in the Fraser River were associated with floodgates being closed more. The hydrology of the Fraser River is characterized by snowmelt-driven high flow in the spring and early summer, with typical daily mean discharge rates around 8000 m 3 /s at its peak, compared to 700 m 3 /s in low flow months (i.e., winter) (Levy and Northcote 1982). Indeed, many floodgates were closed during the freshet (i.e., for the first half of July 2014 and in 2015 for part of May and June).…”

“…Due to the timing of sampling, our study did not fully assess the impacts of floodgate operations on juvenile salmon. Although tidal creeks and wetlands can be key rearing habitats for juvenile coho and Chinook salmon in the spring and early summer, most individuals are unlikely to remain in these habitats by late summer (Levy and Northcote 1982;Craig et al 2014;Scott et al 2016). Our fish sampling regime was focused on the late summer and thus provided a snapshot of impacts for this season when hypoxic conditions occur near floodgates (Gordon et al 2015;Scott et al 2016).…”

“…Although we know that many floodgates may remain closed for weeks to months during seasonal high flows (i.e., the freshet) (Thomson 2005), there are limited data on floodgate operations for the rest of the year. Tidal creeks and wetlands represent important rearing habitats for juvenile coho and Chinook salmon (Oncorhynchus kisutch, O. tshawytscha) (Levy and Northcote 1982;Craig et al 2014); however, floodgates can diminish water quality and restrict access to these habitats (Gordon et al 2015;Scott et al 2016). Given aging infrastructure and increased flood risk due to sea level rise and changing river hydrographs, the region is undergoing a strategic flood management planning process (Fraser Basin Council 2014).…”