In this study we consider the applicability of Bergmann's rule to the populations of small pelagic fish species in the Mediterranean Sea. Under Bergmann's rule, body size increases with decreasing temperature and increasing latitude. Although this mac-roecological pattern in body sizes is well established for many taxa of endotherms and ectotherms, it does not remain universal, and the proposed mechanisms underlying it are multiple and still lack consensus. Here we explored the occurrence of geographical body size clines using measurements of average body sizes of 10 species collected in pelagic trawl hauls carried out during acoustic surveys in the Mediterranean Sea. Bergmann's rule was evaluated by correlating body sizes with latitude and temperature for each species while accounting for potential confounding variables and sampling bias. For 5 species, namely anchovy, sardine, Atlantic chub mackerel, bogue and blue jack mackerel, we demonstrate that they follow Bergmann's rule, with a decline in average body size by about 3.01, 3.43, 3.67, 3.82 and 3.76 % per 1°C of warming, respectively, although this did not translate with an increase in size with latitude. The adherence of these 5 pelagic fish to Bergmann's rules strongly suggest that temperature is a major determinant of their body sizes and enables them to act as sentinel species for identifying the drivers and consequences of warming in the Mediterranean ecosystems.

Temperature strongly correlates with regional patterns of body size variation in Mediterranean small pelagic fish species

De Felice A;Basilone G;Costantini I;Leonori I;Barra M;Ferreri R;Malavolti S;Genovese S;
2021

Abstract

In this study we consider the applicability of Bergmann's rule to the populations of small pelagic fish species in the Mediterranean Sea. Under Bergmann's rule, body size increases with decreasing temperature and increasing latitude. Although this mac-roecological pattern in body sizes is well established for many taxa of endotherms and ectotherms, it does not remain universal, and the proposed mechanisms underlying it are multiple and still lack consensus. Here we explored the occurrence of geographical body size clines using measurements of average body sizes of 10 species collected in pelagic trawl hauls carried out during acoustic surveys in the Mediterranean Sea. Bergmann's rule was evaluated by correlating body sizes with latitude and temperature for each species while accounting for potential confounding variables and sampling bias. For 5 species, namely anchovy, sardine, Atlantic chub mackerel, bogue and blue jack mackerel, we demonstrate that they follow Bergmann's rule, with a decline in average body size by about 3.01, 3.43, 3.67, 3.82 and 3.76 % per 1°C of warming, respectively, although this did not translate with an increase in size with latitude. The adherence of these 5 pelagic fish to Bergmann's rules strongly suggest that temperature is a major determinant of their body sizes and enables them to act as sentinel species for identifying the drivers and consequences of warming in the Mediterranean ecosystems.
2021
Istituto di Scienze Marine - ISMAR
Istituto per le Risorse Biologiche e le Biotecnologie Marine - IRBIM
Istituto per lo studio degli impatti Antropici e Sostenibilità in ambiente marino - IAS
small pelagic fish
body size
Bergmann's rule
temperature-size rule
Mediterranean Sea
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/441663
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