Age and growth of some delphinids in south-eastern Brazil

• Published in: Journal of the Marine Biological Association of the United Kingdom
• Main Authors: Siciliano, Salvatore, Ramos, Renata Maria A., Di Beneditto, Ana Paula M., Santos, Marcos César O., Fragoso, Ana Bernadete, Brito, José Lailson, Azevedo, Alexandre F., Vicente, André F. C., Zampirolli, Emerson, Alvarenga, Fernando S., Barbosa, Lupércio, Lima, Neuza Rejane W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2007
• Subjects: Killer Whale
• Online Access: http://dx.doi.org/10.1017/s0025315407053398; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315407053398

This study provides the first compilation on age and growth of some delphinids in south-eastern Brazil (18°25′S–25°45′S). A total of 154 delphinids were reported: 44 Atlantic spotted dolphin Stenella frontalis 36 bottlenose dolphin Tursiops truncatus 26 ‘Brazilian’ common dolphin Delphinus sp.; 20 rough-toothed dolphin Steno bredanensis 16 Fraser's dolphin Lagenodelphis hosei 3 false killer whale Pseudorca crassidens 3 unidentified Stenella sp.; 2 pantropical spotted dolphin Stenella attenuata 2 short-finned pilot whale Globicephala macrorhynchus 1 spinner dolphin Stenella longirostris and 1 striped dolphin Stenella coeruleoalba . Age was estimated by counting the number of growth layer groups present in the dentine in 74.5% of the sample. The growth of 92 individuals of the first five species was determined by the Gompertz model to length-at-age data. Stenella frontalis —the oldest specimen was 23 y and the asymptotic length of 224.4 cm predicted by growth curve occurred at about 20 y; T. truncatus —the oldest specimen was 26 y and the asymptotic length of 301.3 cm predicted by growth curve occurred at about 20 y; Delphinus sp.—the oldest dolphin was 18 y and the asymptotic length of 215.9 cm predicted by growth curve occurred at about 5–6 y; S. bredanensis —the oldest specimen was 24 y and the asymptotic length of 258.1 cm predicted by growth curve occurred at about 10 y; L. hosei —the oldest specimen was 19 y and the asymptotic length of 231.2 cm predicted by growth curve occurred at about 7–8 y. Only age was estimated for the other species. The age-at-length data for S. frontalis , Delphinus sp., S. bredanensis and L. hosei were consistent, suggesting a good agreement with previous work on these species. For T. truncatus , the age at asymptotic length obtained in this study might be confirmed by increasing the sample size. The information currently presented will contribute to further life history research of delphinids on the western south Atlantic coast.