The use of brushwood bundles as fish spawning media

Abstract

Salford Quays is a redeveloped freshwater dockland, which initially constituted part of the grossly polluted Manchester Docks, Manchester, UK. Such water bodies are characterized by a lack of suitable spawning sites and littoral refuges, and this will act to reduce fish recruitment. To redress this, a variety of artificial spawning substrates were introduced to these waters. Spawning structures were made from bundles of different types of thin brushwood suspended from the dock walls. Roach, Rutilus rutilus (L.), spawned on bundles of willow, Salix alba (L.), and spruce, Pilea abies (L.), branches, whilst perch, Perca fluviatilis L., spawned on bundles of willow, sycamore, Acer pseudoplatanus (L.), spruce and plastic netting. Unused bundles were made up of lime, Tilia platyphyloss (Scop.), pear willow, Pyrus salicitolia (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 showed 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 discussed.

Artificial macrophytes as fish habitat in a Mediterranean reservoir subjected to seasonal water level disturbances

“…Acute water level fluctuations can pose several threats to fish survival, leading to less diversified fish assemblages that are more susceptible to ecological impacts (Piet 1998;Rahel 2002). Therefore, artificial macrophytes, in adequate amounts and complexity, could increase fish survival in these reservoirs through many non-mutually exclusive ways, such as providing substrata for spawning (Nash et al 1999;Sandström and Karås 2002), creating refuge against predation (Hayse and Wissing 1996;Santos et al 2008) or enhancing food availability (Winfield 1986). Spawning requirements were not addressed in the present study, but we hypothesise that both predation risk and food restriction, which were the major attributes harshened by the drawdown, were the main driving forces of fish use of artificial macrophytes in Boadella Reservoir.…”

“…Seeding the reservoir withdrawal zones with grasses or replanting the fluctuating littoral areas with aquatic macrophytes is not successful for a number of reasons (Strange et al 1982;Engel 1995;Strakosh et al 2005;Smiley and Dibble 2006). Artificial structures have been experimentally deployed in reservoirs for a variety of purposes, such as to attract and concentrate fishery resources, enhance substrate for fish reproduction, increase shelter for juvenile or forage fish, and create new habitats in structure-less ecosystems (Nash et al 1999;Bolding et al 2004;Wills et al 2004), but their potential to mitigate the drawdown impacts on fishes is little known (but see Benoît and Legault 2002;Santos et al 2008).…”

Location and timing of the deposition of egg strands by perch (Perca fluviatilisL.): the roles of lake hydrology, spawning substrate and female size

“…Due to the continuous filling of the lake the rest of the dead common reed, worm weed and trees and branches are now mostly situated in very deep water in inappropriate temperature conditions, at least at the beginning of the perch spawning period. As the presence of live submerged vegetation is less predictable in time, moreover, it is not much suitable spawning substrate for perch (Čech et al, 2009, 2010), the installation of an artificial spawning substrate Dubois et al, 1996;Nash et al, 1999;Pedicillo et al, 2008;Probst et al, 2009), preferentially in depth layers of 3-8 m, would, in the near future, be an important means of both sustaining the stock of perch, the main predatory fish in the lake, and for overall management of the lake's ichthyofauna. The results from the above mentioned attempt (artificial spawning substrate installation) on the population of perch in Chabařovice Lake would be of crucial importance for other large water bodies forming in the region of North-West Bohemia, such as the opencast mine lake Most-Ležáky (area 311 ha; filling started in 2008), Medard-Libík (area 486 ha; filling started in 2010) or Jiří-Družba (area 1322 ha; filling will start in 2036).…”

“…Figures 2 and 4). Following the suggestion of Reyes et al (1992), Nash et al (1999Nash et al ( ) andČech et al (2009 it appears that dead submerged vegetation, such as common reed, worm weed and trees and branches, represents an ideal spawning substrate for perch because (1) it is a hard three-dimensional structure and, (2) there is much less oxygen requirement during night hours. Both factors are of crucial importance for the deposition of perch egg strands and their further development.…”

The use of artificial spawning substrates in order to understand the factors influencing the spawning site selection, depth of egg strands deposition and hatching time of perch (Perca fluviatilis L.)

“…to either control their population ("biomanipulation purposes"; Jones 1982), to more easily study its spawning biology (Zeh et al 1989;Huff et al 2004;Gillet, and Dubois 2007;Probst et al 2009) or to support the reproduction success of this species (Nash et al 1999;Pedicillo et al 2008). In Chabařovice Lake, the A.S.S.…”