Patterns of recruitment and resource use in a shallow-water fish assemblage in Moreton Bay, Queensland

Abstract

Seven shallow-water sites in the western part of Moreton Bay, Queensland, Australia, were sampled by beam trawl on 7 occasions durlng 1987 and 1988. The sites differed significantly in their macrophyte and loose shell cover. The most abundant f~s h species was cardinal fish Apogon fasciatus, followed by fan-bellied leatherjacket Monacanthus chinensis, leatherlacket Paramonacanthus otisensis, trumpeter Pelates quadnlineatus and pony fish Leiognathus moretoniensls. Other species were comparatively rare. Small juveniles of the 5 specles recruited to the area, with all except L. moretoniensis being most abundant at the most vegetated site. Mean catch rates differed s~gn~flcantly between s~t e s , and patterns of habitat use, seasonality and d~e l behaviour varied between specles. There was evidenceof ontogenetic m~gration into deeper water in all specles, although this was weakest for A. fasciatus. Diets of the 5 species were distlngulshed by gravimetric, numerical and occurrence techniques. P quadrilineatus and L. moretoniensis took large amounts of polychaetes and copepods, M. chinensis and P otisensis consumed more amph~pods, molluscs and vegetation, and A. fasciatus exploited a wide slze range of prey, Including crabs, f~s h and small crustaceans. Interspecific diet overlap was greater in larger fish, but was less than intraspecif~c overlap between slze classes. Daytime feeders dominated the assemblage, but catch rates were higher at night. Overall patterns of resource use suggested species partitioning, but strong evidence of niche separat~on was obtalned only for L moretoniensis, which was distinct on all 3 major resource axes (food, habitat and time) Therefore, scope e x~s t e d for interspecific competition between members of the assemblage.

Primacy of seascape connectivity effects in structuring coral reef fish assemblages

“…Juvenile purple tuskfish Choero don cephalotes, grass and spangled emperor Lethrinus laticaudis and L. nebulosus, fanbelly leatherjacket Monacanthus chinensis and yellowtail barracuda Sphyraena obtusata occur in seagrass and migrate to reefs (and other structurally complex habitat) at larger sizes but often forage over seagrass (e.g. Blaber & Blaber 1980, Warburton & Blaber 1992, Wilson 1998, Fairclough et al 2008. Similarly, painted sweetlip Diagramma labiosum and bluebarred parrotfish Scarus ghobban recruit to shallow seagrass and adjacent reefs, move to reefs as adults and feed in adjacent seagrass and soft-bottom habitats (e.g.…”

Linking fish and prawns to their environment: a hierarchical landscape approach

“…At the species level, patch richness was only important for Pelates sexlineatus, which although a seagrass resident, has been found to have a more flexible dietary spectrum than many other seagrass specialists (Blaber & Blaber 1980, Warburton & Blaber 1992, thus allowing the species to benefit from utilising a wide range of seagrass patch types. For instance, dietary studies of P. sexlineatus associated with the seagrass Zostera capricorni along the coast of New South Wales, Australia, revealed a diet of 27 different prey items (Sanchez-Jerez et al 2002).…”

Bathymetric distribution and movements of red mullet Mullus surmuletus

“…However. inter-specific competition in this stratum might be low as a result either of a temporary adjustment in the occupation of the shallow zone (Warburton & Blaber 1992, Garcia-Rubies & Macpherson 1995 or of a shift in feeding habits (Labropoulou & Plaitis 1995, Labropoulou & Eleftherlou 1997. The movement of larger fish to greater depth could be a part of a strategy for better exploitation of the shallow zone by a greater number of species.…”

“…An ontogenetic movement (after maturation) to deeper water might have the advantage of reducing inter-specific competition (Warburton & Blaber 1992). Stratum I (Posidonia beds) is inhabited by a much greater number of species than the other strata (Tsimenides et al.…”

“…The fishes of the inshore zone also seem to undertake an ontogenetic migration to deeper water but there is a paucity of studies on the phenomenon and its causes (Macpherson & Duarte 1991, Warburton & Blaber 1992, Blaber et al 1995. However, there is disagreement as to the generality and the underlying cause of this phenomenon (Macpherson &Duarte 1991 andreferences therein, Swain 1993).…”