Growth estimates of young‐of‐the‐year broadnose sevengill shark, Notorynchus cepedianus , a top predator with poorly calcified vertebrae

Jaureguizar, A.J., Cortés, F., Braccini, J.M., Wiff, R. and Milessi, A.C. (2022) Growth estimates of young‐of‐the‐year broadnose sevengill shark, Notorynchus cepedianus , a top predator with poorly calcified vertebrae. Journal of Fish Biology . Early View.

Abstract

The broadnose sevengill shark, Notorynchus cepedianus (Péron, 1807), is a large marine top predator in temperate coastal ecosystems. Some aspects of its life history have been determined, but its growth pattern is yet to be fully understood. The authors used a multi-modelling approach and a sensitivity test to estimate growth parameters from young-of-year (YOY) length data collected off San Antonio Cape (SAC), Argentina, a critical habitat in the Southwest Atlantic Coastal Zone (SACZ). The best selected model, a sex-combined logistic growth model, estimated an asymptotic length (L∞) of 92.58 cm TL (95% C.I.: 86.48–105.89 cm), a growth coefficient (K) of 0.006818 days −1 (95% C.I.: 0.004948–0.008777) and a size at birth (L0) of 40.73 cm. The predicted annual growth (i.e., L1 – L0) was 43.2 cm TL. Males had smaller L0, higher K and achieved larger sizes after 1 year. The YOY in SAC attained a larger L1 and grew faster than their Australian and South African wild counterparts. The consistent year-round presence of YOY in the SAC highlights the importance of this area as a pupping ground and potential nursery for N. cepedianus; this has direct implications for the allocation of research and management effort for the conservation of this species in the Southwest Atlantic.

Item Type:	Journal Article
Murdoch Affiliation(s):	Harry Butler Institute
Publisher:	Wiley
Copyright:	© 2021 Fisheries Society of the British Isles.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/63532

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