Changes in the fish community of Loch Leven: untangling anthropogenic pressures

Abstract

Changes in the fish community of Loch Leven: untangling anthropogenic pressures. Hydrobiologia, 681 (1). 73-84. 10.1007/s10750-011-0925-8 Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. This paper has not been submitted elsewhere in identical or similar form, nor will it be during the first three months after its submission to Hydrobiologia. 2 AbstractLoch Leven, U.K, contains brown trout (Salmo trutta), eel (Anguilla anguilla), minnow (Phoxinus phoxinus), perch (Perca fluviatilis), pike (Esox lucius) and threespined stickleback (Gasterosteus aculeatus), with brook lamprey (Lampetra planeri) and stone loach (Barbatula barbatula) also present in its tributaries. Arctic charr (Salvelinus alpinus), Atlantic salmon (Salmo salar) and flounder (Platichthys flesus) are now extinct. The brown trout population has supported a world-renowned recreational fishery for over a century, although a decline in fishery performance led to extensive stocking between 1983 and 2006, including with non-native rainbow trout (Oncorhynchus mykiss). This review combines historical information with contemporary gill-net and hydroacoustic surveys. In 2008, brown trout, perch and three-spined sticklebacks were abundant, but pike and stone loach were rare. The obstruction of migratory routes was probably responsible for the loss of Atlantic salmon and flounder, while a lowering of water level likely caused the extinction of Arctic charr and contributed to a reduction in pike abundance. Perch abundance has fluctuated markedly, being influenced by disease and eutrophication, although a present reduction in nutrients and associated recovery of macrophytes are likely to benefit this species. Although the brown trout population has undoubtedly shown a long-term decline, individuals are currently in excellent condition.3

From regionally predictable to locally complex population structure in a freshwater top predator: river systems are not always the unit of connectivity in Northern Pike Esox lucius

“…In recent years, several Esocid populations are considered under threat of local extinction due to habitat degradation (e.g., in connection with damming; Winfield et al. and other types of river regulation), through fisheries capture, either targeted (Hunt et al. ) or as by‐catch (Colotelo et al.…”

Lake management: is prevention better than cure?

“…In addition, Dudley et al (2012) observed that macrophyte diversity tended to increase with decreasing TP load to the lake, although no statistical relationship was presented. Similarly, an apparent increase in fish body size was recorded following improvements in water quality (Winfield et al 2012). Increases in the diversity of zooplankton, leading to increases in Daphnia, and of macroinvertebrates, also occurred when the water quality improved (Gunn et al 2012).…”

Impacts of acidification on brown trout Salmo trutta populations and the contribution of stocking to population recovery and genetic diversity

“…Such genetically divergent populations are very important when it comes to conserving overall S. trutta diversity (Kelson et al, ; Vøllestad, ). The existence of the Loch Mannoch population derived exclusively, or nearly so, from a Leven‐based farm strain is of increased conservation importance as both Solway or Howietoun farms are no longer in existence, the latter as of 2017 (J. Taggart, University of Stirling, personal communication), and there are continued threats to the native Loch Leven stock (Winfield et al, ).…”