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,
Eclecta aurorella by a slender white line. There is an irregularly triangular dark reddish-fuscous blotch, more ochreous-fuscous beneath, on the hindmargin, its apex extending to the disc at three-fifths from the base, its base extending from above the anal angle to beneath the apex, the lower side suffused, upper side connected in the disc with a dark reddish-fuscous acute diamond-shaped mark beneath the costa, beyond the connection margined with white. Within this triangle is a slender white twice sharply-toothed line proceeding from the middle of the upper side to the lower angle, and two small indistinct whitish spots on the hindmargin. The