The sagittal otolith of 348 species, belonging to 99 families and 22 orders of marine Teleostean fishes from the north and central eastern Atlantic and western Mediterranean were described using morphological and morphometric characters. The morphological descriptions were based on the otolith shape, outline and sulcus acusticus features. The morphometric parameters determined were otolith length (OL, mm), height (OH, mm), perimeter (P; mm) and area (A; mm 2 ) and were expressed in terms of shape indices as circularity (P 2 /A), rectangularity (A/(OL×OH)), aspect ratio (OH/OL; %) and OL/fish size. The present Atlas provides information that complements the characterization of some ichthyologic taxa. In addition, it constitutes an important instrument for species identification using sagittal otoliths collected in fossiliferous layers, in archaeological sites or in feeding remains of bony fish predators.

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Otolith atlas for the western Mediterranean, north and central eastern Atlantic

A review of 862 otolith-oriented papers published since the time of the 1998 Otolith Symposium in Bergen, Norway suggests that there has been a change in research emphasis compared to earlier years. Although close to 40% of the papers could be classifed as 'annual age and growth' studies, the remaining papers were roughly equally divided between studies of otolith microstructure, otolith chemistry and non-ageing applications. A more detailed breakdown of subject areas identified 15 diverse areas of specialisation, including age determination, larval fish ecology, population dynamics, species identification, tracer applications and environmental reconstructions. For each of the 15 subject areas, examples of representative studies published in the last 6 years were presented, with emphasis on the major developments and highlights. Among the challenges for the future awaiting resolution, the development of novel methods for validating the ages of deepsea fishes, the development of a physiologically- based otolith growth model, and the identification of the limits (if any) of ageing very old fish are among the most pressing.

Otolith science entering the 21st century

Otolith morphometrics have been shown to provide a practical basis for stock discrimi- nation and subsequent fisheries management. However, the determinants of otolith shape are not fully understood and analysis does not distinguish between genotype and environmentally induced differences. In this context, understanding how those 2 components act synergetically on the otolith shape is fundamental. The use of non-indigenous fish of multiple origins provides an interesting tool for evaluating the relative importance of genetic and environmental components in determining otolith shape. This paper investigates to what extent a dual regulation (i.e. genetic and environmen- tal) of the otolith shape from an introduced coral reef snapper (Lutjanus kasmira) exists, in order to determine how each component specifically acts on otolith morphology. Using geometric morpho- metrics, we discriminated between native and introduced range as well as between individuals belonging to different lineages (i.e. origins) but growing under the same environmental conditions (individuals cohabiting within the same shoals in the wild). Here we show that both genetic and envi- ronmental influences play a substantial role in determining the shape of the otolith. More specifically, while environment induces an overall change in otolith shape, genetically induced changes locally affect otolith shape. In addition, data suggest that both nuclear and mitochondrial components act synergetically. This information is fundamental if otolith shape is to be used as an effective tool for management of fisheries resources in the future.

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Environmental and genetic determinant of otolith shape revealed by a non-indigenous tropical fish.

We present an automatic system for describing and identifying fish otolith shapes combining information technologies with modern advances in signal analysis. As a major novelty with respect to past studies the system includes wavelets (WT) and curvature space scale (CSS) analyses that have been shown to provide local morphologic information and characteristics (landmarks) of the sagitta otolith outline for non-specialists. By applying this electronic catalogue directly the system is very helpful for determining teleostean fish size, population and species. Both the electronic catalogue and the shape analysis are implemented through the AFORO database, which at present contains more than 1250 high resolution images of the left sagitta from 292 species and 94 families of teleostan fishes sampled mainly in Mediterranean and Antarctic waters.

/pdf/a-web-based-environment-for-shape-analysis-of-fish-otoliths-3ncq7r7yx6.pdf

A web-based environment for shape analysis of fish otoliths. The AFORO database

Application of elliptical Fourier analysis of otolith form as a tool for stock identification

The effects of sex, stock, and environment on the shape of known-age Atlantic cod (Gadus morhua) otoliths from the Faroe Islands were investigated. Moreover, the feasibility of otolith shape analys...

Effects of sex, stock, and environment on the shape of known-age Atlantic cod (Gadus morhua) otoliths

Traditional age reading is a rather subjective method that lacks true reproducibility, producing ageing error that propagates up to stock assessment. One alternative is represented by the use of ot...

Estimating population age structure using otolith morphometrics: a test with known-age Atlantic cod (Gadus morhua) individuals

The three-dimensional (3-D) shape and density distribution of a cod otolith was determined using a newly developed micro X-ray tomograph. The technique requires no special treatment of the otolith and could yield the entire 3-D growth history in a single analysis. 999 The Fisheries Society of the British Isles

P. Doering-Arjes

Papers

Effects of sex, stock, and environment on the shape of known-age Atlantic cod (Gadus morhua) otoliths

Estimating population age structure using otolith morphometrics: a test with known-age Atlantic cod (Gadus morhua) individuals

A new method for three‐dimensional otolith analysis

Fish ageing by otolith shape analysis : Final report to the European Commission