Brazilian Guitarfish — Led by Dr. Fabio Caltabellotta, Dr. Siders developed a Bayesian age-growth model for Pseudobatos horkelii, Pseudobatos percellens, and Zapteryx brevirostris in southern Brazil. The resulting model was used to estimate age and growth parameters for these three priority guitarfish species listed as Critically Endangered, Near Threatened, and Vulnerable by the International Union for the Conservation of Nature.
Published in: doi: 10.1111/jfb.14123 ![]() (Above) Bowtie sections of guitarfish vertebrae for the three Brazilian guitarfish species showing off the classic banding patterns left behind by annual growth spurts. (Left) Age-growth relationships for three Brazilian Guitarfish species. Age is on the x-axis in units of years and growth is on the y-axis in units of centimeters of total length.
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Brazilian Electric Ray — Led by Dr. Fernanda Rolim, a postdoc at Universidade Estadual Paulista in São Paolo, Brazil, Dr. Siders extended the Brazilian guitarfish model to estimate two-dimensional growth of Narcine brasiliensis, the Brazilian Electric Ray, in southern Brazil. The joint estimation of length-weight and age-growth parameters was added along with derivations of age at maturity, longevity, and mortality at age. A significant component was incorporating uncertainty in size at birth into the von Bertalanffy growth model.
Published in: doi: 10.1111/jfb.14378 |
![]() (Above) Silhouettes of Goblin Sharks through the ages. (top) 1898 in the description of the species by David Starr Jordan. (top middle) 1904 by King Bragança of Portugal. (top bottom) 1909 by Hussakof and the renaming of Mitsukurina to Scapanorhynchus for a time. (bottom) 1981 by Cadenat and Blache in Requins de Méditerranée et d' Atlantique.
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Goblin Shark — Led by Dr. Siders and Dr. Fabio Caltabellotta, we estimated the first age-growth relationship for Goblin Sharks (Mitsukurina owstoni), one of the largest deepwater sharks. Dr. Caltabellotta developed a method to highlight the classic banding pattern that allowed an age reading on a specimen caught in Brazil in 2008. Dr. Siders developed a Bayesian age-growth model that used back-calculated lengths at age from this specimen, data on maximum male sizes, and data on size at birth to estimate the first age-growth parameters for the species. We are excited to age more specimens in the future.
Published in: doi.org/10.1071/MF19370 |