Vertical distribution of two sympatric labrid fishes in the Western Mediterranean and Eastern Atlantic rocky subtidal: local shore topography does matter |
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| Authors: | Marco Milazzo Angelo Palmeri Jesús M Falcón Fabio Badalamenti Jose A Garcìa‐Charton Mauro Sinopoli Renato Chemello Alberto Brito |
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| Institution: | 1. Dipartimento di Scienze della Terra e del Mare, Università di Palermo, Palermo, Italy;2. Instituto Espanol de Oceanografia (IEO), Calle General Gutiérrez, Santa Cruz de Tenerife, Spain;3. Grupo de Investigación BIOECOMAC, Departamento de Biología Animal (Ciencias Marinas), Facultad de Biología, Universidad de la Laguna, La Laguna, Canary Islands, Spain;4. Laboratorio di Ecologia, CNR‐IAMC, Castellammare del Golfo (TP), Italy;5. Departamento de Ecología e Hidrología, Facultad de Biología, Universidad de Murcia, Campus de Espinardo, Murcia, Spain;6. Grupo de Investigación BIOECOMAC, Departamento de Biología Animal (Ciencias Marinas), Facultad de Biología, Universidad de la Laguna, La Laguna, Canary Islands, Spain |
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| Abstract: | Changes in the shore topography (e.g. slope) occur at a scale of hundreds of meters in several locations in the Lusitanian and the Mediterranean Sea provinces. We tested whether differences in the bottom inclination might affect the vertical distribution patterns of two sympatric coastal labrid fishes, the rainbow wrasse Coris julis and the ornate wrasse Thalassoma pavo. Visual censuses were used to determine the distribution and abundance of these labrid species in high (≥30°) and low (≤3°) slope rocky substrates covered by brown macroalgae and at two different depths (shallow, 4–7 m, and deep 14–20 m). Pectoral fin aspect ratio was used as an estimate of swimming performance to potentially explain the patterns observed. Despite the intrinsic biogeographical differences in the overall density of T. pavo and C. julis, on steep coasts the ornate wrasse dominated in shallow waters, whereas the two species coexisted both in shallow and deeper depths on gentle slope coasts. These distribution patterns were consistent across locations, and fin aspect ratio was not a good predictor of between‐habitat use for wrasses. We show that, under specific topographical conditions, the depth segregation pattern seems to be an interactive segregation (likely related to resource competition) rather than a result of selective segregation due to morphological differences in the pectoral fin. Significant ecological changes might occur in locations where the density of T. pavo has recently increased as a result of water warming. |
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| Keywords: | Bottom inclination depth segregation ecoregion fin ratio fish Labridae Lusitanian Sea Mediterranean Sea |
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