Microhabitat segregation in three rocky intertidal fish species in Portugal: does it reflect interspecific competition?

Abstract

Recruits of Lipophrys pholis, Coryphoblennius galerita and Gobius cobitis spend the low tide under water in pools, and in the case of G. cobitis also in channels. The pools used by the two blenniids show greater similarity than those used by G. cobitis. Larger juveniles and adults of C. galerita continue to use the same type of pools, which are temporarily abandoned by the males during the breeding season when they use emersed holes and crevices as nests. The much faster growing L. pholis and G. cobitis leave the pools in their first autumn, when they are c. 7 cm long. Whereas G. cobitis >7 cm move to channels and large upper pools, with a smooth substratum, sand and boulders, L. pholis begin to use emersed crevices where they spend low tide often in large groups. When L. pholis or C. galerita were added or removed selectively from pools, their numbers returned to pre-experimental levels after 2 weeks, suggesting that, although intraspecific competition may be strong, interspecific competition was unlikely to explain these results fully. 2001 The Fisheries Society of the British Isles

Phylogeny of the shanny, Lipophrys pholis, from the NE Atlantic using mitochondrial DNA markers

“…Although several studies have been carried out on the morphology (Arruda, 1979;Bath, 1976;Lowe, 1843), ecology (Faria and Almada, 2001;Almada and Faria, 2000), ontogeny (Faria et al, 2002), and its diet composition (Maze et al, 1999) not much has been done on the genetics (Guillemaud et al, 2000).…”

Temporal asymmetries in the feeding patterns along the tidal cycle in two sympatric littoral blennies

“…In each dive two transects were inspected on two different rockwalls, almost parallel to the coast, that stay exposed during lowtide (see Faria and Almada, 2001 for habitat descriptions). A diver swam slowly and at a regular speed over each transect.…”

“…Gibson, 1972;Milton, 1983;Almada, 1999, 2001), and there have been attempts to access possible resource partitioning among them (e.g. Milton, 1983;O'Farrell and Fives, 1990;Faria and Almada, 2001). This resource partitioning may be expressed in trophic differences; however, it seems also to be expressed through differences in ontogeny: L. pholis grows faster and reaches a larger size than C. galerita, which leads the two species to use different types of shelter and prey (Milton, 1983;Faria and Almada, 2001;Monteiro et al, 2005).…”

“…When they are about 1 year old, L. pholis reach the upper size of adult C. galerita (Faria et al, 1996). At this stage L. pholis leaves the pools that are shared by the juveniles of both species, seeking new shelters in crevices and spaces under boulders, in the lower shore, where they hide in groups (Qasim, 1957;Gibson, 1972;Faria and Almada, 2001). This shift in low-tide shelter is accompanied by a shift in diet, the larger L. pholis now eating larger prey (Monteiro et al, 2005).…”

“…Qasim, 1957;Gibson, 1972;Milton, 1983;Faria et al, 2001), so little consideration has been given to the possibility that partitioning of resources among the two species may occur through spatial and temporal differences in behaviour during high-tide. Burrows et al (1999), using underwater TV observations, suggested that the shanny, Lipophrys pholis, shows the highest level of activity during the rising and high-tide periods, and that its feeding movements are concentrated around crevices.…”