title: Age and growth of the midwater crocodile shark Pseudocarcharias kamoharai.
abstract: Age and growth were analysed on the basis of 372 vertebrae from specimens of the crocodile shark Pseudocarcharias kamoharai (66·0-122·0 cm, total length, LT ) collected in the south-western Atlantic Ocean. Centrum edge analysis suggested the first four months of the year as the period of band completion, leading to acceptance of free-living bands as annual. A pre-birth ring is formed in embryos >31·0 cm LT , whereas the birthmark is deposited in newborns of 46·1 ± 1·1 cm LT (mean ± s.d.). Growth was parameterized using seven models and the AIC was used for selection of the most plausible model. The von Bertalanffy growth model received the greatest support from the data, providing the following growth parameters for combined sexes: L∞ = 129·2 cm, k = 0·137 year(-1) and t0 = -3·9 years. No significant differences were detected in growth by sex, but significant differences in age composition by sex were found in the sample. Overall age ranged from 2 to >13 years in females and from 1 to 8 years in males. Males achieved first maturity at 3·1 years and females at 5·1 years, with pregnancy appearing at 4·8 years. Similar to other lamnoid species, P. kamoharai is relatively fast growing.
authors.affiliation: Departamento de Pesca e Aquicultura (DEPAq), Universidade Federal Rural de Pernambuco (UFRPE), Dois Irmãos, Recife-PE CEP 52171-900, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Lessa
authors.affiliation: Departamento de Pesca e Aquicultura (DEPAq), Universidade Federal Rural de Pernambuco (UFRPE), Dois Irmãos, Recife-PE CEP 52171-900, Brazil.
authors.forename: H A
authors.initials: HA
authors.lastname: Andrade
authors.affiliation: Departamento de Pesca e Aquicultura (DEPAq), Universidade Federal Rural de Pernambuco (UFRPE), Dois Irmãos, Recife-PE CEP 52171-900, Brazil.
authors.forename: K L
authors.initials: KL
authors.lastname: De Lima
authors.affiliation: Departamento de Pesca e Aquicultura (DEPAq), Universidade Federal Rural de Pernambuco (UFRPE), Dois Irmãos, Recife-PE CEP 52171-900, Brazil.|Unidade Acadêmica de Serra Talhada (UAST), Universidade Federal Rural de Pernambuco (UFRPE), Serra Talhada-PE 56903-970, Brazil.
authors.forename: F M
authors.initials: FM
authors.lastname: Santana
mesh_terms: D000365:Age Determination by Skeleton; D000818:Animals; D001267:Atlantic Ocean; D049628:Body Size; D005260:Female; D008297:Male; D008954:Models, Biological; D011247:Pregnancy; D012754:Sharks / Q000254:growth & development*; D013131:Spine / Q000254:growth & development
keywords: AIC; IAPE; age verification; growth curve; model selection; pelagic sharks