Introduction

Electric Fishing Fry Index Survey

January 2023

Hannah Winchester

Westcountry Rivers Trust Electric Fishing Survey Report – PRK 2022

Westcountry Rivers Trust is an environmental charity established in 1995 to restore, protect and improve the rivers, streams, and water environments in the region for the benefit of wildlife and people.

This report has been written and prepared by: Hannah Winchester

Published by: Westcountry Rivers Trust

Rain Charm House, Kyl Cober Parc, Stoke Climsland, Callington, Cornwall, PL17 8PH.

Tel: 01579 372140

Email: info@wrt.org.uk

Web: www.wrt.org.uk

Charity no. 1135007

Company no. 06545646

Executive Summary

Westcountry Rivers Trust (WRT) undertook electric fishing (EF) surveys throughout the small streams of the Plymouth River Keepers project area, within Northwest Plymouth during the summer of 2022. The surveys are the second year of a three-year monitoring effort funded as part of the wider Plymouth River Keepers project (PRK). Salmon were absent at all survey sites, along with complete absence of any fish species at some of the survey sites. The only species that were present at some sites were brown trout and European eel. Overall, brown trout abundance was lower and European eel were absent at more sites than the 2021 surveys. It should be noted that summer 2022 was the driest since 1995 as well as the second hottest year on record. Conservation strategies, such as the Defend/Repair/Attack approach, can be applied on a sub catchment level with recommended fisheries management actions suggested to either improve or maintain salmonid habitat and numbers.

1. Introduction

The Westcountry Rivers Trust (WRT) undertook eight semi-quantitative fry index electric fishing surveys on the small streams within the PRK project area within the Tamar catchment in September 2022 (see Figure 1). This was three less sites than in 2021, due to such low flows of a dry summer with the headwaters of these streams becoming very shallow and small. Severe low flow increases risk of damage to fish health if surveys were to go ahead. The three streams have been named Reach 1, 2, and 3 within the wider PRK project. This was the second year of fish monitoring undertaken by WRT and forms part of establishing a long-term dataset of semi-quantitative fry numbers.

Sites were selected based on potential fisheries improvement works that are scheduled be carried out within the project area. Monitoring will aid in understanding if improvements have been effective in increasing fish numbers and/or presence of already absent species. It is hoped that these sites will continue to be surveyed every year to build a strong baseline dataset for the catchment.