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Concrete infrastructure in coastal waters is increasing. While adding complex habitat and manipulating concrete mixtures to enhance biodiversity have been studied, field investigations of sub-millimetre-scale complexity and substrate colour are lacking. Here, the interacting effects of 'colour' (white, grey, black) and 'microtexture' (smooth, 0.5 mm texture) on colonisation were assessed at three sites in Australia. In Townsville, no effects of colour or microtexture were observed. In Sydney, spirorbid polychaetes occupied more space on smooth than textured tiles, but there was no effect of microtexture on serpulid polychaetes, bryozoans and algae. In Melbourne, barnacles were more abundant on black than white tiles, while serpulid polychaetes showed opposite patterns and ascidians did not vary with treatments. These results suggest that microtexture and colour can facilitate colonisation of some taxa. The context-dependency of the results shows that inclusion of these factors into marine infrastructure designs needs to be carefully considered. [ABSTRACT FROM AUTHOR]

Golden perch, Macquaria ambigua (Richardson), is a freshwater percichthyid native to inland eastern Australia. Growth and feeding of this fish in pond aquaculture conditions was studied in nursery phase at high (95,300/ha) and low (32,800/ha) density over 126 days. Mean growth of golden perch at both densities was similar, but there were significantly more small fish in the high-density treatment. Coefficient of variation was high in both treatments (72-79%). After 126 days, 67% of the fish in both treatments reverted to natural foods. Reversion from pelleted diet to natural foods was very rapid in the low-density treatment (<14 days), but slower in the high-density treatment. Golden perch were found to be selective feeders. The smallest fish selectively ate water fleas, Moina sp., from the zooplankton, and larger fish ate chironomids and caddis flies (Trichoptera). Golden perch, which fed predominantly on pellets, grew 54% faster than those eating natural foods. Three to four months of an intensive nursery period, followed by grading for grow-out, is recommended to separate fast growing pellet feeding fish from slower growing fish that have reverted to eating natural foods. [ABSTRACT FROM PUBLISHER]

Trials to wean golden perch, Macquaria ambigua ambigua, were conducted using two commercially-available prepared diets. Co-feeding with brine shrimp, Artemia salina, nauplii or abrupt transition to the prepared diets, were compared. Golden perch fingerlings (25-30mmtotal length) were most successfully weaned onto prepared diets using frozen ice blocks made of brine shrimp and commercial diet crumbles, with a 77% weaning rate. The weaning period was over ten days, with the volume of crumble to Artemia slurry in ice blocks increasing by 10% every day. Co-feeding was essential to successful weaning (>71%), as an abrupt transition from Artemia to crumble diet resulted in a high rate of failure to wean(< 52%), and subsequent starvation. However, growth of fish that successfully weaned in the abrupt weaning treatment was equal to that of those which underwent the gradual, co-feeding weaning treatment. This weaning strategy may be used for commercial aquaculture production of this species. [ABSTRACT FROM PUBLISHER]

The article discusses an investigation of bonamiasis in native oysters in Southern Australia, adapted from the 2016 newsletter "Animal Health Surveillance Quarterly." The recognition of Bonamia ostreae and Bonamia exitiosa as parasitic pathogens of oysters that cause high mortality rates and substantial economic losses to the global oyster industry is tackled. A project funded by the Fisheries Research and Development Corp. to identify the distribution and taxonomy of the species is explored.