Age determination in fish fish. Johannes Reibisch, working for the Commission of Scientific Investigation of German Seas at Kiel, attempted to use Hoffbauer’s techniques to age plaice ("Plueronectes platessa") but found it difficult to accurately discern annuli. He decided to study a different structure and in 1899 he published the first procedures using otoliths as an aging structure. A fellow scientist also with the German Commission at Kiel, Friedriche Heincke, also frustrated with difficult scale annuli, further studied other structures to age fish. He discovered annuli in the vertebrae, opercula, and pectoral girdle and published his findings in Heicke 1905. The works of Hoffbauer,
Mogurnda clivicola Bulloo Rivers in Queensland away from the main population, in the very different habitat of larger, muddy-bottomed rivers. Flinders Ranges mogurndas are medium-sized fish, with a maximum total length around 13 cm. They are dark with a fine mottling of dark grey blotches on the upper side with semi-translucent fins. Usually their body is a paler colour underneath. These fish have a series of burnt orange-coloured stripes running backwards down their cheeks looking like warpaint. Roughly around the lateral line is a display of burnt orange-coloured spots interspersed with paler spots, with a single darker spot on the caudal peduncle.