Sealion caused injuries to fish were quite prevalent, and recorded in a range of injuries from minor scratches to major puncture wounds, to bites penetrating well below the epithelial surface, exposing the underlying flesh. 

An estimated 15% of the Spring Chinook manifest pinniped injuries with the majority passing through in the last three weeks of May. 7% of Summer and 8% of Fall Chinook exhibited signs of pinniped injury. Pinniped injuries were not restricted to Chinook as pinniped injuries were also noted on sockeye, steelhead, and coho. 

While counts of observed pinniped feeding has historically been the primary data resource, injured fish, not consumed, but which are then at greater risk of not reaching their spawning grounds, is a significant causal insight.

A large percentage of the total fish imaged were very small. 

These were not smaller than usual adult salmonid as has been recently reported in the press, nor “jacks” returning after two years at sea, but rather 11% of the total fish imaged at the AFF were minijacks, juvenile salmonids <30 cm in forklength, which have reversed their outmigration and are heading back upriver having spent zero years in the ocean. 

The fact that the number of mini-jacks were high, may have been an aberration and a one year event, or may be something which needs to be closely monitored each year to better understand future return numbers.

Forklength (length from nose to tail) was calculated on 1244 Sockeye. 

The average forklength was 43.7 cm which is typical and consistent with historical size averages. However, when plotting the data collected on each fish of this large sample set, a different picture emerges. 

Two almost equal populations, one much larger than 43.7 cm and one much smaller than 43.7 cm were plotted. The two populations may represent different age populations: four year old returning sockeye vs three year old returning sockeye or genetically different species. 

This kind of macro insight can be very beneficial to fisheries managers, including when estimating the strength of the following years return run.