Wednesday, Nov 22nd, 2017

Cooperation requested with trout tracking

Posted on January 24, 2012 Richard MacKenzie, [email protected]


Dalhousie University PhD candidate Aaron Spares holds a 40.4 cm sea-run brook trout caught under Antigonish Harbour ice January 2011. It was released after Spares recovered the surgically implanted internal tag he was using to track the fish locally. (Photo submitted)

Dalhousie University PhD candidate Aaron Spares is calling on the cooperation of local fishing enthusiasts who may catch one of his tagged fish.
Spares is the lead researcher on a project tracking the marine migration of sea-run brook trout to determine migration range, duration, movements, habitat use and feeding behaviour in relation to environmental conditions.
His locale of study is the Special Trout Management Area (STMA) which was implemented in 2001 in the West River and immediate estuary.
As part of the project, 43 trout were implanted with internal acoustic tags. Thirty-three trout were tagged on the West River side of the harbour and 10 on the south side.
The tags were inserted into the trout’s abdominal cavity through a small incision closed with two or three stitches. Each tag sends out sound signals every 90 seconds that code for an identification number, depth and temperature.
If a tagged trout swims near a listening receiver in Antigonish Harbour, the South, West or Wright River, the tag signals are recorded.
Noting that the fish can be identified by the stitches in its belly or red tag inserted near the dorsal fin, Spares is asking fishers who catch a tagged fish to please record the identification number (on the red tag), the fork-length (tip of nose to middle of tail), sex, date, time and location, before releasing and contact him with the information.
With retained fish, Spares asks that he be contacted before they’re frozen or eaten. Also, dead tagged fish may be dropped off to the Department of Fisheries and Oceans in Antigonish during regular business hours.
During the spring fishery, Spares is also looking for scales, frozen heads, stomachs and muscle tissue from catches.
A reward is being offered for receivers removed/relocated in the West River and Antigonish Harbour within the past year. Receivers should not be removed but an exact location and time of the finding should be forwarded to Spares.
So far, nine tagged fish have been recaptured.
Spares said people have been pretty cooperative so far.
“Most fishers are keen to cooperate and share knowledge,” Spares said. “Some have even cast a line to catch fish to be tagged. Most gladly offer samples from their catches and some have flipped a trout my way if I’m around.”
As for the receivers, Spares said some have been, unfortunately, tampered with.
“Some of my receivers have been removed by human hands so there are still those around who fail to see the benefit of knowing more of the whole story for these trout,” he said.
“Undoubtedly, there is resentment among some fishers for any science project related to fisheries management and this project definitely has application to this end.”
As for what conclusions he is hoping to draw, Spares said one of the things he hopes to answer is how long trout are in the harbour.
“As it appears now, they come down from freshwater in the fall (September to December) and stay all winter and spring until returning to freshwater in May-June,” Spares said.
“In addition, what are their movements? Do they go between rivers estuaries during marine migrations? What are their most active movement periods? Do they leave the harbour and enter the bay? Many of these questions have been answered already,” he said.
He also stressed the uniqueness of the study.
“This is the first study tracking sea-trout wintering in saltwater so the big question is; what are the environmental factors controlling their residency? Salt concentration, temperature, feeding grounds or a combination of all three?” Spares said.
“This is the second winter tracking season and I hope the data will double last year’s winter data.”
To reach Spares with requested information, fishers can email [email protected] or call 494-2357 during business hours or 735-2068 in the evenings.

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