MEPS 343:221-228 (2007)  -  DOI:

Nanism (dwarfism) in fish: a comparison between red mullet Mullus barbatus from the southeastern and the central Mediterranean

Oren Sonin1, Ehud Spanier2,*, Dino Levi3, Bernardo Patti3, Pietro Rizzo3, Maria Gabriella Andreoli4

1Ministry of Agriculture and Rural Development, Department of Fisheries and Aquaculture, The Agricultural Center, PO Box 30, Beit Dagan 50250, Israel
2The Leon Recanati Institute for Maritime Studies and the Department of Maritime Civilizations, University of Haifa, Mount Carmel, Haifa 31905, Israel
3Istituto di Ricerche sulle Risorse Marine e l’ambiente (IRMA)—CNR, Via Vaccara 61, 91026 Mazara del Vallo (TP), Italy
4Instituto di Istologia ed Embryologia, Universitá di Palermo, Via Archirafi 22, 90123 Palermo, Italy
*Corresponding author. Email:

ABSTRACT: The gradient of environmental conditions from west to east in the Mediterranean results in very low primary productivity in the eastern area of this sea. This impoverishment is expressed also in higher trophic levels and has been accounted for by several faunistic phenomena. One of these is ‘Levantine nanism’ (dwarfism); this is characterized by smaller body size of specimens in the Levantine basin compared with conspecifics in the western Mediterranean. Nanism has been hypothesized for various taxonomic groups in the Mediterranean, but no quantitative study has yet been carried out to confirm it. In the present study male and female red mullet Mullus barbatus from trawl surveys carried out along the Mediterranean coast of Israel and the Strait of Sicily were sampled. Each fish was sexed, measured for total length (TL) and aged by otolith readings. ANCOVA analyses indicated that the TL of both males and females from Israel was significantly smaller at increasing ages than conspecifics of the same age and sex from Sicily. In addition, preliminary examination of sexual maturity of M. barbatus of both sexes indicated that the Israeli fish sexually mature at a smaller size than conspecifics of the same sex from Sicily. These findings can be explained by low productivity in the Levantine basin compared with the western Mediterranean. The low and unpredictable food supply in the southeastern Mediterranean may result in a form of r-strategy of the marginal eastern populations of this species that leads to early reproduction and smaller body size. The average higher water temperature may also partly explain Levantine nanism, as it may cause more intensive metabolic processes in the southeastern population, resulting in earlier sexual maturity and cessation of growth.

KEY WORDS: Nanism · Dwarfism · Total length · Sexual maturity · Otolith readings · Small body size · Mediterranean Sea · Mullus barbatus

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Cite this article as: Sonin O, Spanier E, Levi D, Patti B, Rizzo P, Andreoli MG (2007) Nanism (dwarfism) in fish: a comparison between red mullet Mullus barbatus from the southeastern and the central Mediterranean. Mar Ecol Prog Ser 343:221-228.

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