Mackalea Burn update

Those with a keen interest in the Spey may recall that in October 2014 we modified the culvert on the Mackalea Burn to provide fish passage under all flows. At spawning time last year many sea trout redds and a single salmon redd were identified in the burn upstream of the culvert.

The timber ramp installed on the Mackalea Burn steps

The timber ramp installed on the Mackalea Burn culvert steps

We normally start out electrofishing season by monitoring the burns stocked the previous autumn. Last week amongst others we resurveyed our two monitoring sites in the Mackalea Burn, which is a small Fiddich tributary. We have two sites in the burn that we have surveyed for the last three years. The upper site is located in rough grazing about 250m above the Fiddich confluence.

Upper site

Upper site in the Mackalea Burn. It is only a small burn, just over 2m wide and more suited to trout than salmon.

I normally refresh my memory regarding the previous years electrofishing prior to visiting a site but I hadn’t done on this occasion. The lower site is situated immediately below a B&B owned by a very keen angler who keeps an eye on the burn. I had informed him we would be onsite but was unprepared when he pointed out that there seemed to be a lot more fry than in the previous year. I thought that was the case although I hadn’t been involved in surveying that site last year but when I checked the figures he was right.

Mackalea sites electrofishing results presented in the usual fashion

Mackalea sites electrofishing results presented in the usual fashion (number per 100m2). Salmon fry were found in the burn for the first time with salmon parr from the stocking present in low density. The biggest change however was in the trout fry density. As is often the case the trout parr density follows the fry density from the previous year.

The trout fry density in the lower site was 8 times higher than recorded in 2013 and 100 times higher than in 2014.

The trout fry density (number per 100m2) in the lower site was 8 times higher than recorded in 2013 and 100 times higher than in 2014.

It was similar in the upper site where highre salmon fry numbers were present. It should be noted that in  site a little over 20m long we captured 164 trout fry in this sites along with 10 salmon fry. There mst be thousands of trout fry in the Mackalea Burn at present.

It was similar in the upper site where higher salmon fry numbers were present. It should be noted that in site a little over 20m long we captured 164 trout fry and 10 salmon fry along with parr. There must be thousands of trout fry in the Mackalea Burn at present.

Field biology is rarely an exact science so ideally you would use data or observations from a number of sources to build up understanding of the factors affecting fish populations. In this case we had the installation of fish passage at a previously difficult barrier, observations of fish passage, redd counts, a single salmon carcass, previous and current electrofishing data; all of which contribute to our assessment of the situation. Even the higher densities of salmon fry as we got further up the burn, and nearer the one salmon redd recorded in 2014, match the field observations.

One previous survey in 2002 had found good trout fry and parr densities but no salmon. We already knew from the B&B owners observations that sea trout could get up the Mackalea Burn if there was sufficient water to allow them to get over the steps but the water often isn’t there during the short spawning window especially this far east in the catchment. Time will tell if the fish passage improvements allow access every year as there was good water in late October 2014. Indeed myself and the B&B owner watched a sea trout jump clear over the steps without using the fish pass and there was a good run of sea trout in the river last year. However, all of these points suggest that the fish pass improvements have been sucessful, particularly the record of salmon fry for the first time.

We are grateful for the excellent relationship with the Spey Foundation sponsors Speyburn Distillery; an arrangement which made this fish pass project possible. We are also indebted to Moray Council roads department for the close cooperation on technical matters. If only all barriers were as easy to resolve!

 

There is 1 comment for this article
  1. Ross at 2:47 pm

    Excellent results! Keep up the good work!

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