The recent growth rate and stable isotope composition of larval pilchards, (Sardinops sagax, 6-29 mm standard length), captured in surface and near-surface waters, were examined in coastal upwelling and non-upwelling regions of the EastAustralian Current over two cruises during the austral summer of 1998/1999. Compared to the nonupwelled regions, larvae were larger in the upwelling regions, and yet the back-calculated recent growth over 2 days before capture was significantly less on both cruises. This surprising result is consistent with slower larval growth of this species near coastal Japan and California, where strong year classes may form in offshore waters. δ 15 N ratios were significantly correlated with larval length, indicating ontogeny in their diet. In November, slower growers in upwelled waters were enriched in δ 15 N and depleted in δ 13 C, consistent with expected ratios from diets derived from deeper water. The pilchard's early life history off eastern Australia is proposed and compared with that off eastern Japan.
Larval fishes are a useful metric of marine ecosystem state and change, as well as species-specific patterns in phenology. The high level of taxonomic expertise required to identify larval fishes to species level, and the considerable effort required to collect samples, make these data very valuable. Here we collate 3178 samples of larval fish assemblages, from 12 research projects from 1983-present, from temperate and subtropical Australian pelagic waters. This forms a benchmark for the larval fish assemblage for the region, and includes recent monitoring of larval fishes at coastal oceanographic reference stations. Comparing larval fishes among projects can be problematic due to differences in taxonomic resolution, and identifying all taxa to species is challenging, so this study reports a standard taxonomic resolution (of 218 taxa) for this region to help guide future research. This larval fish database serves as a data repository for surveys of larval fish assemblages in the region, and can contribute to analysis of climate-driven changes in the location and timing of the spawning of marine fishes.
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