When Going With the Flow Leaves You Stranded

By Erin Matthews

Chum salmon begin their life in a nest (called a Redd) built by their parents in a gravel bottomed stream usually in the lower sections of the river.  At barely an inch long, these newly hatched masters of evasion and disguise are only visible by a vigilant human observer.   Unlike other species of salmon, chum begin the long, treacherous,  journey to the ocean immediately after hatching—before they are even strong enough to swim against the currant!  They drift to the ocean, occasionally resting in off-channel habitat such as sloughs or ponds to rest, take shelter from the awesome power of the Skagit river currents, and to feed on bugs or plankton.  Those tiny fry that are lucky and strong enough to dodge birds, bigger fish, and other predators, spend a few months growing larger and stronger at the mouth of the river and estuary before leaving for the wide open ocean. 

But if a little chum takes refuge in a pond or slough, what happens if the river drops and strands them?  That is a question that the Skagit Fisheries Enhancement Group field staff were pondering on a lovely sunny Monday afternoon in early May.  At a stewardship site near Concrete WA called the Lower Baker Flood Plain, a team of staff, and volunteers dropped a research net into a pond that (despite being only a few meters from the banks of the river) had been disconnected from the Skagit for several weeks.  In a perfect, simple world, by early May all Skagit chum fry would be fat and happy living in the estuary where the Skagit River merges with Skagit Bay. 

Much to our surprise, we netted 17 chum in the shallow end of the pond.  Staff carefully recorded size and species of each individual fish, noting that these fish were especially large and well fed for their age, before releasing them back into the pond.  These little fish were doing well for now, no doubt benefiting from the nurturing environment of the pond which offered an abundance of shelter, food, and a water temperature cool enough for high dissolved oxygen levels but warm enough for the fry to grow larger faster than their counterparts in colder Skagit River water. 

Chum rarely rear in fresh water, and when they do they still must reach the ocean by the end of summer in order to survive.  Luckily for these fish, a heat wave washed over the Skagit in mid-May, which rapidly kick started spring snow melt and raised the water level of the Skagit enough to reconnect the pond and river, creating an exit for the fry.  If all goes well, the next time SFEG drops the research net into the Lower Baker Flood Plain pond we will not find any salmon.