Alaska is not renowned for its good weather but there are exceptions!
Older age classes of fish (age-1s) are still resident in the nearshore embayments around Kodiak Island, but they are tricky to sample-----they’re generally too deep for the seine and too shallow for trawl nets. We also want to be careful not to harm sensitive habitat types (boulders, reefs, macroalgae) where these small fish live.
Enter the ‘baited camera.’
Baited cameras have been in use around the world, especially around fragile tropical reef areas. Our research team has been using underwater cameras to survey juvenile Pacific cod since 2006, and they will continue to be a valuable tool for tracking cohorts of juvenile fish in coastal nurseries.
Here is one of a set of identical baited cameras we are using this summer in Kodiak, AK. The lightweight aluminum frames and autonomous cameras allow us to deploy multiple cameras at once before retrieval.
Two size groups of juvenile Pacific cod generally approach the bait bag---age-0 fish (insert figure 1 image here) and age-1 fish (insert Fig 3). Scientists determine what age group an approaching fish fits into based on their relative size compared to the bait box and parallel supporting bars.
Cameras are deployed for 15-minute periods and then hauled back and redeployed at another site further away. Data gathered in this type of survey do not provide true counts of fish in an area, but allow us to analyze relative trends in abundance and habitat use.
Age-0 Pacific cod are smaller (5-9 cm) and generally restricted to shallow depths. This set was deployed along the 3 m depth contour.
We’ll be back in August to conduct more baited camera surveys of the same region and will expand the survey to other parts of Alaska in 2019.
Meet the Blogger
Ben Laurel
Ben Laurel has spent more than 20 years studying early life stages of cold-water commercial fish. Ben began his science career as a graduate student in Newfoundland, Canada following the collapse of the Atlantic cod fishery. He currently leads several field and laboratory research projects involving graduate students and technical staff. He is interested in Pacific cod and how this species is responding to climate change in Alaskan waters.
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