AN INTRODUCTION AND BACKGROUND TO THE BAITFISH RESEARCH PROJECT IN EASTERN INDONESIA

Pole-and-line fishing for tuna is a multi-million dollar industry in eastern Indonesia that employs many people, supports several canneries and generates export income

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

The most abundant fish species was cardinal fish Apogon fasciatus, followed by fan-bellied leatherjacket Monacanthus chinensis, leatherjacket Paramonacanthus otisensis, trumpeter Pelates quadrilineatus and pony fish Leiognathus moretoniensis. Small juveniles of these species recruited to the area, with all except L. moretoniensis being most abundant at the most vegetated site. Mean catch rates differed significantly between sites, and patterns of habitat use, seasonality and diel behaviour varied between species. There was evidences of ontogenetic migration into deeper water in all species, although this was weakest for A. fasciatus. P. quadrilineatus and L. moretoniensis took large amounts of polychaetes and copepods, M. chinensis and P. otisensis consumed more amphipods, molluscs and vegetation, and A. fasciatus exploited a wide size range of prey, including crabs, fish and small crustacenas. Interspecific diet overlap was greater in larger fish, but was less than intraspecific overlap between size 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 separation was obtained only for L. moretoniensis, which was distinct on all three major resource axes (food, habitat, time). Scope thus existed for interspecific competition between members of the assemblage. -from Author

Paradigms in estuarine ecology - a review of the Remane diagram with a suggested revised model for estuaries

Most estuarine ecology textbooks have included the so-called Remane diagram which is derived from German studies in the Baltic Sea region during the early part of the 20th Century. The model shows how aquatic species diversity changes from freshwater to more marine areas. In essence it aims to show the relative proportions of each component of the fauna (freshwater, brackish and marine) and how these change along a salinity gradient. These combined components decrease in diversity with a progression from both the freshwater and marine ends of the spectrum, with the 5-7 salinity area being dominated by a small number of true brackish/estuarine species. The way in which the Remane diagram has been interpreted (and misinterpreted) and used (and misused) in the literature is discussed here. We primarily investigate whether the model needs to be modified to help provide an understanding of current biotic distribution patterns within estuaries and how these patterns might be influenced by climate change. Using global estuarine examples for a variety of taxa we discuss the appropriateness of the Remane model beyond the zoobenthos (on which the model was originally based) and provide a revised model that is more suited to estuaries worldwide. Comment is also provided on the way in which a more appropriate estuarine biodiversity model can influence future estuarine ecotone and ecocline studies