Crucial Collection: Les Murray's Translations From the Natural World

This is a brief article outlining the importance of Les Murray's Translations From the Natural World (Carcanet Press, 1995) to contemporary poetry.

Article - "Those darling young women in their flying machines", 1977

A retrospective article written by Dorothy Rungeling as she recalls the the International Air Races that often began or ended in Welland-Port Colborne Airport. The article was published in the Welland Evening Tribune, 9 September 1977.

Performance of juvenile Murray cod, Maccullochella peelii peelii (Mitchell), fed with diets of different protein to energy ratio

The results of a 56-day experiment on juvenile Murray cod, Maccullochella peelii peelii, an Australian native fish with a high aquaculture potential, of mean weight 14.9 ± 0.04 g, fed with five experimental diets, one a series of 40% protein content and lipid levels of 10, 17 and 24% (P40L10, P40L17 and P40L24), and another of 50% protein and 17 and 24% (P50L17 and P50L24) lipid are presented. The specific growth rate (SGR) (% day−1) of fish maintained on different diets ranged from 1.18 to 1.41, and was not significantly different between dietary treatments, except P40L10 and the rest. However, there was a general tendency for SGR to increase with increasing dietary lipid content at both protein levels. The food conversion ratio (FCR) for the 40% protein series diets were poorer compared with those of the 50% protein diets, and the best FCR of 1.14 was observed with the P50L17 diet. The protein efficiency ratio (PER), however, was better in fish reared on low protein diets. The net protein utilization (NPU) also did not differ significantly (P > 0.05) in relation to dietary treatment. As in the case of PER the highest NPU was observed in Murray cod reared on diet P40L24 and the lowest in fish fed with diet P50L24. The carcass lipid content reflected that of the diets, when significant increases in the lipid content was observed in relation to dietary lipid content at both protein levels. However, body muscle lipid content did not increase with increasing dietary lipid content, and was significantly lower than in the whole body. The fatty acids found in highest concentration amongst the saturates, monoenes and polyunsaturates (PUFAs) were 16 : 0, 18 : 1n-9 and 22 : 6n-3, respectively, and each of these accounted for more than 60% of each of the group's total. The muscle fatty acid content was affected by the dietary lipid content; for example the total amount (in μg mg−1 lipid) of monoenes ranged from 72 ± 5.1 (P40L10) to 112 ± 10 (P40L24) and 112 ± 2.8 (P50L17) to 132 ± 11.8 (P50L24) and the n-6 series fatty acids increased with increasing dietary lipid content, although not always significant. Most notably, 18 : 2n-6 increased with the dietary lipid level in both series of diets.

Growth and nutrient utilization of Murray cod Maccullochella peelii peelii (Mitchell) fingerlings fed diets with varying levels of soybean meal and blood meal

The Australian native freshwater fish Murray cod, Maccullochella peelii pellii (Mitchell), currently supports a fledgling inland aquaculture industry, which is thought to have considerable growth potential. The aim of this study was to evaluate the suitability of two alternate protein sources [blood meal (BM) and defatted soybean meal (SBM)] as substitutes for fish meal at various levels of inclusion in diets for juvenile Murray cod. The growth performance of juvenile Murray cod in response to nine isonitrogenous and isocalorific diets (50% protein, 14% lipid, 20.2 kJ g⁻¹) consisting of a control diet in which protein was supplied from fish meal, and test diets in which the fish meal protein was substituted at levels of 8%, 16%, 24%, and 32% with BM or SBM was evaluated from a 70-day growth experiment. The per cent apparent dry matter (% ADC_dm) and percentage protein digestibility (% ADC_p) of the test diets were also determined using Cr₂O₃ as a marker. Survival in all the SBM dietary treatments was high but that of fish on the BM dietary treatments was significantly (P < 0.05) lower than in all the other dietary treatments. Specific growth rate (% day−1) of Murray cod fed SBM incorporated diets ranged from 1.63 ± 0.06 to 1.78 ± 0.10 and even at the highest level tested (32% of the dietary protein from SBM) was not significantly different (P > 0.05) from the fish fed the control diet (1.65 ± 0.09). Feed conversion ratios of the SBM dietary treatments ranged from 1.36 ± 0.08 to 1.45 ± 0.07. The protein efficiency ratios and protein conversion efficiencies of Murray cod in the soybean meal treatments were also good and for a majority of the SBM diets were better than those for the control diet. Per cent ADC_dm and ADC_p of the SBM diets tested ranged from 70.6 ± 1.46 to 72.3 ± 1.81% and 88.6 ± 0.57 to 90.3 ± 0.17%, respectively, and was not significantly different (P > 0.05) from the control diet (% ADC_dm 74.3 ± 1.63; % ADC_p 91.3 ± 0.55). The reasons for significantly poor survival and growth of Murray cod reared on BM incorporated diets, and relatively poor digestibility of these diets are discussed. The study shows that for Murray cod diets in which fish meal protein is substituted up to 32% performance or carcass composition is not compromised.

Microsatellite loci for studies of wild and hatchery Australian Murray cod Maccullochella peelii peelii (Percichthyidae)

Murray cod is a species of conservation concern that is subject both to wild harvest and to aquaculture production. Six polymorphic microsatellite loci have been developed for this species, which will facilitate studies of wild-stock structure, will help the management of hatchery diversity, and will aid genetic improvement programmes. The markers exhibited nonindependence of genotypes between loci and deviations from Hardy–Weinberg expectations, although these most probably reflect practices at the hatchery from which the genotyped individuals were sourced.

Phylogeography of the widespread Australian freshwater prawn, Macrobrachium australiense (Decapoda, Palaemonidae)

Aim: To investigate the phylogeographic structure of the widespread freshwater prawn, Macrobrachium australiense, within and between major Australian drainage basins using mitochondrial sequence data. This will enable the investigation of historical connections between major drainages and examination of hypotheses of biogeographic associations among Australian freshwater basins.

Location: Inland, eastern and northern Australia.

Methods: Sequencing 16S rRNA and ATPase 6 protein coding mitochondrial DNA genes from M. australiense from 19 locations from inland, eastern and northern Australia.

Results: Within drainage basins, haplotype trees are monophyletic, with the exception of the Finke River from the Lake Eyre Basin. Macrobrachium australiense from the two main inland drainages, the Murray–Darling and Lake Eyre Basin are divergent from each other and do not form a monophyletic group, instead the Murray–Darling Basin haplotypes clade with eastern coastal haplotypes. Haplotypes from neighbouring eastern coastal drainages were found to be quite divergent from each other.

Main conclusions: The phylogeographic relationships among M. australiense suggest that the two major inland drainages, the Murray–Darling Basin and the Lake Eyre Basin, are not biogeographically closely associated to each other. Instead the Murray–Darling Basin is more closely allied with the eastern coastal drainages across the Great Dividing Range. Despite their proximity the neighbouring southeast Queensland coastal Mary and Brisbane Rivers are also biogeographically divergent from each other. The results also indicate that the Finke River appears to have been isolated from the remainder of the Lake Eyre Basin catchment for a significant period of time.

Performance of intensively farmed Murray cod Maccullochella peelii peelii (Mitchell) fed newly formulated vs. currently used commercial diets, and a comparison of fillet composition of farmed and wild fish

Murray cod is a top-order carnivore with high culture potential. Currently, there are no commercial diets formulated specifically for Murray cod. In this study, results of two growth trials on Murray cod (80–83.5-g mean initial weight), conducted in commercial settings, using two laboratory-formulated diets (DU1 and DU2; 48.9% and 49.1% protein, and 16.9% and 16.1% lipid, respectively, on a dry matter basis), and two commercial diets, formulated for other species (salmon – CD/S and barramundi – CD/B) but used in Murray cod farming are presented. The two commercial diets had less protein (46.6% and 44.4%) but higher lipid (21.7% and 19.5%). The energy content of the feeds tested was similar (about 20–22 kJ g−1). The growth performance and feed utilization of Murray cod did not differ significantly amongst the diets, but the food conversion ratio and % protein efficiency ratio in fish fed the DU1 and DU2 diets were consistently better. There was significantly less carcass and muscle lipid deposition in fish fed with the latter diets. Of the fatty acids in muscle, the lowest amounts (in μg mg lipid−1) of n-3 (262.5±2.9), n-6 (39.8±0.9) and polyunsaturated fatty acid (PUFA) (302.3±3.8) were observed in fish fed CD/S, and the highest in fish fed DU2 and CD/B. Fatty acids 16:0 and 18:0, 18:1n-9 and 16:1n-7, and 22:6n-3, 20:5n-3, 22:5n-3 and 18:2n-6 were the dominant fatty acids amongst the saturates, monoenes and PUFA, respectively, and accounted for 80.8–88.7% of all identified fatty acids (23) in muscle of Murray cod. The study showed that Murray cod could be cultured successfully on a diet (DU2) containing 20% soybean meal without compromising growth and/or carcass quality. Differences in the proximate composition and fatty acid composition of muscle of wild and farmed Murray cod were observed, the most obvious being in the latter. Wild Murray cod had significantly less (P<0.05) saturates (192.6±1.84 vs. 266.3±3.51), monoenes (156.5±8.7 vs. 207.6±6.19), n-3 (145.2±5.24 vs. 261.8±3.2) but higher n-6 (144.3±2.73 vs. 48.3±1.38) in muscle (all values are in μg mg lipid−1) than in farmed fish. Wild fish also had a much lower n-3 to n-6 ratio (1.0±0.03 vs. 5.4±0.09).

Performance of murray cod, Maccullochella peelii peelii (Mitchell) in response to different feeding schedules

The Australian freshwater fish Murray cod, Maccullochella peelii peelii (Mitchell) is gaining popularity as a suitable species for intensive culture, particularly in closed systems. The aim of this study was to evaluate the performance of Murray cod in response to different feeding schedules. Growth, survival, food conversion and a range of other related parameters including carcass proximate composition were evaluated for fish in five feed management regimes. The feeding regimes used in the experiment were hand fed to satiation twice daily (SAT), a pre-determined ration of 1.2% of the body weight day−1 which was hand fed twice daily (HFR), and belt fed through the day only (B/D), belt fed through the night only (B/N) and belt fed for 24 h (B/DN). Each of the five feeding regimes was randomly allocated to three tanks (triplicates). All of the feeding regimes used a commercially prepared diet formulated specifically for Murray cod, containing ≈50% protein and ≈16% lipid. The experiment was conducted for 84 days. Specific growth rate ranged from 0.89±0.01 to 1.07±0.04% day−1. Food conversion ratio (FCR) ranged from 1.09±0.02 to 0.92±0.03. The fastest growth and greatest final body weight were observed in the SAT treatment; however, the highest FCR, visceral fat index (VFI %) and hepatosomatic index (HSI %) were also observed in this treatment. Significant differences were found in specific growth rate and final mean weight between fish in the B/D and SAT treatments. B/N and B/DN feeding regimes appeared to result in the most favourable fish performance.