WTT Blog - Tagged with ecology

Typical! Not two weeks after completing my round-up for the Science Spot in Salmo trutta, the annual glossy WTT publication that our members receive, an interesting paper on IMWs (Intensively Monitored Watersheds) lands on my desk. While not exactly on topic, it includes interesting snippets that would have embellished my article. However, as I wrote in the Salmo piece, the means by which knowledge is transferred nowadays means: I can (and have already) tweeted about this paper (but not included any precis or personal view of its content); I can (here, now) blog about it and impart some detail; or I can sit on it for 12 months and tell you all about it in the 2017 issue of Salmo!

IMWhats? In the Pacific Northwest, a vast tract of land with a very loosely defined boundary but it’s roughly 67 times the size of Wales if you’re interested in that sort of thing, there are at least 17 IMWs. They are an attempt to test the effectiveness of a broad range of stream restoration actions for increasing the freshwater production of anadromous salmon and steelhead and to better understand fish–habitat relationships. This is no mean feat, and the paper by Bennet and his colleagues reports on the lessons learned so far.

On my WTT-inspired ramblings recently, I came across a shocking sight, above. Shocking because firstly, I was expecting to see a village pond complete with a raft of local ducks bobbing around, not a barren mudscape stuck behind a defunct dam; and secondly, because I immediately started to wonder where all that accrued sediment was being washed away to….. and where it was being deposited… and might it not be being dumped upon some salmonid redds at a rather inopportune time?

The first National Crayfish Conference to be organized in five years was held at Giggleswick School, almost on my doorstep. As I have supervised three PhD, and countless MSc and BSc student projects on invasive crayfish species during my 10 years at Queen Mary University of London, it seemed sensible to attend. I was granted time to do so on the WTT’s behalf since white clawed crayfish, the species we consider indigenous, and brown trout can both be considered flagship or sentinel species; that is their abundance / population health can tell us something about the quality of the ecosystem in which they reside. There are also other parallels of course, more of which below.

It is believed that brown trout and perch were introduced into Malham Tarn by the Cistercian monks in the 12th century. Further stocking of brown trout for recreational fishing started around 1860, continuing off and on until 1994 when the National Trust pushed for a more natural brown trout fishery. Indeed stocking ceased in 2001 and, since 2002, a strict catch and release policy for all fish has been in place.

A few years ago, Jon Payne, now working for one of the fisheries teams at the Environment Agency, looked at the life history and growth rates of brown trout in Malham Tarn and showed very rapid growth compared to other European populations. OK, it’s a limestone lake so the underlying nutrient base for productivity is good, but the elevation and location might suggest pretty harsh growing conditions for fish.