by Karen Rutherford - DFO

Purpose of Project:
Release of mature Atlantic salmon (of Stewiacke River, NS origin) from the live gene bank to contribute to the recovery of the Inner Bay of Fundy salmon population. Adult releases are one component of the recovery process initiated by the Inner Bay of Fundy Planning Committee (IBOFPC).

Some salmon were tagged with ultrasonic pingers to determine if they remained in the river until after the normal spawning period. Confirmation of spawning is expected to occur in 2003 and 2004 by looking for juveniles. Tracking juveniles to the adults can be done using genetic information from tissue samples.

River of Choice:
Salmon River, Colchester, was identified as a prime candidate due to the size of the watershed (1,346,800 m2 of habitat), knowledge about summer water conditions, its similarities to portions of the Stewiacke River, evidence that there were few to no wild salmon remaining in the river (electrofishing surveys in summer 2002 by the Monitoring and Assessment Committee, IBOF Planning Group), and because the river discharges into the Minas basin (as does the Stewiacke).

Outline of tagging study:
1. Receivers were placed in the river as follows: soccer field - below head of tide; below railway bridge - just above head of tide; below Irving Pulp Mill (Lower fish release site); Black Rock Pool (upper fish release site); John Crowe's - upper Salmon River site below Kemptown; Black River; North River; and Cornwallis River (where originating biodiversity facility is located).

2. Ultrasonic pingers were implanted surgically into twelve fish on October 16.

3. Fish released at three locations on October 18:

  • 46 females and 44 males, including 6 pinger-tagged fish (3 of each sex) were released at Black Rock pool.

  • 45 females and 44 males, including 6 pinger-tagged fish (3 of each sex) were released below Irving Pulp Mill. iii 10 fish (5 males and 5 females) were released into Christie Brook (above the falls)

4. Receiver data downloaded on November 1, 25, 29, and when removed from the river in December. Last receivers were removed on Dec. 14 - 17.

Preliminary Results (assuming fish which travel below the lowest receiver have left the river):
1. One fish travelled downriver immediately, registered on the railway bridge and soccer field receivers until October 29, then left the river.

2. One fish stayed in the Irving Pulp Mill pool area until Nov 22, when it travelled downriver and left the river.

3. One fish stayed in the Black Pool area until Nov 13, then it travelled downriver and left the area.

4. Three fish travelled upriver, registering on the uppermost receiver below Kemptown. One of these fish travelled downriver again and registered on the Irving Pulp Mill receiver.

5. Remaining fish registered on receivers throughout the river.

6. No pinger tagged fish registered on receivers placed either in the Black River tributary, the North River or the Cornwallis River.

7. Portable tracking by J. Taylor, Fishery Officer, at various locations, did not locate any fish.

8. Record high rainfall resulted in flood conditions during Nov and Dec before freeze-up. Portable tracking and redd surveys could not be done during this time. One receiver (at John Crowe's) was buried under @ 1/3 m of silt for approximately one week and therefore not recording; one receiver at Irving Pulp Mill was upside down and possibly not recording.

The original hypothesis that adult salmon, not imprinted on Salmon River, Colchester, would remain in the river until after spawning, was supported with the tracking data. It is reasonable to expect that these salmon did actually spawn. Subsequent monitoring for juveniles in 2003 will be necessary to confirm these findings.

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