The 70 year old lady next to me watching this scene was from Germany.
The Atlantic Alewife herring [1] were running up the river to spawn - and to feed the Great Blue heron [2] and the terns.
Very dramatic life and death stuff going on here.
The German lady, her eyes wide and glistening, said to me "really blows your mind, doesn't it?"
My answer?
Absolutely!
Here is a link to the University of Massachusetts study of anadromous fish including a census of fish that are video recorded at fish ladders.
Here is a selection of text from the report in which the data for 10 minute periods of video recording is produced.
System Number of 10
minute
intervals
possible
Number of 10
minute
intervals in
which fish
were counted
Average
number of fish
per 10 minute
interval
Estimate of run
size (number
of fish passing
upriver)
Town Brook 5040 321 24.97 125,840
Charles River 2016 126 21.44 43,230
Back River 5040 284 13.71 69,052
Bourne River 5040 315 10.34 53,151
Sorry, the table blew up when posted here, but the last number - 125,840, 43,230 is the number of fish passing the video camera.
The video cameras are solar powered and connected to the internet.
When I spoke with one of the U Mass men who I met on the fish ladder, I understood that the video camera had shape recognition software which allowed the distinction of alewife from shad from etc. So the species of fish coming up the ladder - as well as the count of each type of fish, was recorded - although on the UMass website for this project [3]I don't see any discussion of identification of species.
Very, Very cool.
This fish spawning study is what the internet, computers, solar power, and video cameras are so good for.....
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