Mesohabitat use by bullhead (Cottus gobio)

Abstract

Habitat composition and connectivity within a stream vary with changing flows but the influence of changing flow on habitat use by fish is not well understood. Meso-and microhabitat surveys were used to investigate habitat use by bullhead (Cottus gobio Linnaeus) in response to discharge variation in a small tributary of the Upper Severn, England. Mesohabitat mapping surveys were carried out over a range of summer flows (0.016-0.216 m 3 s -1 ) and were coupled with direct underwater observations (snorkelling) of fish location. Five mesohabitat types-glides, runs, riffles, chutes and pools-were present in the reach at all flows surveyed and 'backwaters' were found at three flows. The macro-morphology of the reach comprised six riffle-pool sequences divided into 27 mesohabitats with the maximum diversity (23 mesohabitats) at intermediate flows (Q 43 ) and only 15 mesohabitats at Q 95 . Despite low numbers of fish (N = 78), bullhead displayed a strong association (51% of the fish) with glidesrelatively deep habitats having high rates of velocity increase with flow. However, 54% of the fish were observed in two large, persistent mesohabitats, a glide (34%) and a pool (20%), both located below a faster flowing mesohabitat. Habitat use curves based upon micro-habitat data showed bullhead favoured low velocities (\0.30 m s -1 ), depths less than 0.30 m and a cobble substratum. This study illustrates the value of cross-scale investigations in linking fish ecology, flow and physical habitat variability and suggests mesohabitat size, persistence and arrangement may influence fish distribution.

Assessment of the conservation status of endemic sculpinCottus haemusi(Cottidae) in the river Vit (Danube Tributary), northwest Bulgaria

“…In accordance with previously reported results we observed that the Vit sculpin has a preference for substrata dominated by cobbles and pebbles (e.g. Smily, 1957;Jansen et al, 2000;Carter et al, 2004;Van Liefferinge et al, 2005;Gosselin et al, 2010). Cottus poecilopus also prefers cobbles and boulders (Kotusz et al, 2004).…”

“…Legalle et al (2005) found that bullheads were associated with shallow depths and high velocities. On the contrary, Perrow et al (1997) and Gosselin et al (2010) observed a positive correlation between bullheads and greater depths and slow velocity. In fact, there is an ontogenetic shift and seasonal changes in the preferences of sculpins for water depth, velocity and size of the substrata (Carter et al, 2004;Van Liefferinge et al, 2005) and the bullhead may be more flexible in its habitat requirements than generally assumed (Utzinger et al, 1998;Jansen et al, 2000).…”

“…In fact, there is an ontogenetic shift and seasonal changes in the preferences of sculpins for water depth, velocity and size of the substrata (Carter et al, 2004;Van Liefferinge et al, 2005) and the bullhead may be more flexible in its habitat requirements than generally assumed (Utzinger et al, 1998;Jansen et al, 2000). Most studies have found that bullheads avoid muddy bottoms and homogeneous areas and wider sections of the river (Legalle et al, 2005;Gosselin et al, 2010). C. gobio occurs within a relatively wide temperature gradient.…”

“…The habitat preferences of Cottus species have been described in several studies (e.g. Tomlinson and Perrow, 2003;Carter et al, 2004;Kotusz et al, 2004;Legalle et al, 2005;Legalle, 2008;Gosselin et al, 2010). Investigation of the abundance, age and growth rate of sculpins revealed variation not only between species, but also between populations from different locations (e.g.…”

Conservation of the freshwater pearl mussel (Margaritifera margaritifera) in the river Rede, UK: Identification of instream indicators for catchment-scale issues

“…At each location, 5 transects were established, along which substrate, embeddedness and instream vegetation were recorded every metre. Substrate categories were identified visually according to particle size as described in Gosselin et al (2010). Substrate embeddedness was also recorded at each transect point in order to estimate the stability of substrate and its potential to become clogged up by fine sediment (Sylte and Fischenich 2002).…”