The use of brushwood bundles as fish spawning media

Salford Quays is a redeveloped freshwater dockland, which initially constit uted part of the grossly polluted Manchester Docks, Manchester, UK. Such wa ter bodies are characterized by a lack of suitable spawning sites and litto ral refuges, and this will act to reduce fish recruitment. To redress this, a variety of artificial spawning substrates were introduced to these water s. Spawning structures were made from bundles of different types of thin br ushwood suspended from the dock walls. Roach, Rutilus rutilus (L.), spawned on bundles of willow, Salix alba (L.), and spruce, Pilea abies (L.), branc hes, whilst perch, Perca fluviatilis L., spawned on bundles of willow, syca more, Acer pseudoplatanus (L.), spruce and plastic netting. Unused bundles were made up of lime, Tilia platyphyloss (Scop.), pear willow, Pyrus salici tolia (Pall.), and laurel, Laurus nobilis (L.). Perch spawning began around 20 May and showed a preference for open structures (between one and three ribbons per bundle). Roach spawning began about 10 days after perch and sho wed a preference for dense bundles of spruce (geometric mean egg density 1. 5 cm(-2) spruce). The use of such structures in fisheries management is dis cussed.