2006 Spawning Survey

Bronte Creek brown trout spawning survey, November 4 to 9, 2006
Vic Cairns and Ewan Alderson

A spawning survey was conducted on Bronte Creek along the 3.6 km section between Guelph Line and Cedar Springs Road on November 4th, 5th and 9th 2006. The November 4 survey was conducted by volunteers Vic Cairns and Ewan Alderson. Cairns repeated the survey on November 5 and November 9. Weather and water conditions were optimum for observing trout redds. The weather was dry, clear and sunny. Water level in Bronte Creek, measured at Carlisle, was at ~2.6m, which is ~10% above the mean water level for that period . Water clarity was good. Undisturbed gravel on the stream bottom was lightly covered with periphyton and contrasted with clean areas where the gravel had been recently disturbed. Alderson and Cairns walked the length of the creek section looking for light areas of disturbed gravel. Disturbed sites were examined carefully for evidence of a freshly excavated digging pit and an associated downstream tailspill, a mound of substrate formed as the trout digs the redd progressively upstream. Sites meeting these criteria were assumed to be trout redds. None of the sites was excavated to confirm the presence of eggs. The approximate location of each redd was marked on a paper map and geo referenced with a Garmin handheld GPS. Redd size was estimated.

There were 30 redds, observed along the 3.6km section of Bronte Creek in the 2006 survey. Sixteen redds were seen on November 4. Seven more redds were seen on November 5 and 7 more redds were seen on November 9. Redds were located along the margins of the creek, close to the stream bank in approximately 30 cm of water. There were no redds seen in the center of the channel or in deeper water. Redds were approximately 45-60 cm (18-24") in diameter and one redd was ~70-80 cm in diameter. The largest redd may have been made by a spawning rainbow trout or salmon. We did not see any trout or salmon in the surveyed section of the creek but one large salmon was seen in the creek downstream of the dam close to the Guelph Line. We did see a hognose sucker in the survey section.

The 30 redds counted in 2006 is consistent with the 33 redds counted in 2005 by Bill Christmas and volunteers. However, brown trout spawning occurs over 2-4 weeks and it is possible that spawning continued after the last survey on November 9. Unfortunately rain and high water levels prevented observations after that date.