eCite Digital Repository
Non-lethal assessment of the reproductive status of broadnose sevengill sharks (Notorynchus cepedianus) to determine the significance of habitat use in coastal areas
Citation
Awruch, CA and Jones, SM and Garcia Asorey, M and Barnett, A, Non-lethal assessment of the reproductive status of broadnose sevengill sharks (Notorynchus cepedianus) to determine the significance of habitat use in coastal areas, Conservation Physiology, 2, (1) Article 013. ISSN 2051-1434 (2014) [Refereed Article]
 | PDF 2Mb |
Copyright Statement
Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/
DOI: doi:10.1093/conphys/cou013
Abstract
Identification of the importance of habitats that are frequently used by any species is essential to a complete understanding
of the species’ biology and to incorporate their ecological role into conservation and management programmes. In this context,
the present study investigated whether Tasmanian coastal waters have any reproductive relevance for the broadnose
sevengill shark (Notorynchus cepedianus). Although this species is a large coast-associated apex predator in these areas, there
is a complete gap in understanding the role that these coastal systems could play in its reproduction. Reproductive hormones
were used as a non-lethal method to address the reproductive biology of this species. Females seemed to have at least a biannual
reproductive cycle, being pregnant for ~1 year and spending at least 1 year non-pregnant, with the ovulatory cycle
separated from gestation. Mature females were found to be ovulating, in the initial stages of pregnancy, resting or starting a
new vitellogenic cycle. Notorynchus cepedianus did not use these coastal habitats for mating or as a pupping ground. Although
the mating season was distinguished between September to April, only 22% of males showed mating scars during the peak of
the mating period and no near-term pregnant females were observed. Thus, despite these coastal waters being an important
foraging ground for this species, these areas did not have any reproductive relevance. In consequence, future management
and conservation planning programmes need to identify whether there are other areas in Tasmania that play a critical role for
reproductive purposes in this species. Finally, although previous studies have linked reproductive hormones with external
examination of the gonads to validate the use of steroids as a non-lethal tool to address reproduction, the present study used
this methodology without killing any animals. This has important implications for conservation programmes
of threatened
and endangered species worldwide where the methodology cannot be validated.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | elasmobranchs, maturity, steroid hormones, viviparity |
| Research Division: | Environmental Sciences |
| Research Group: | Environmental management |
| Research Field: | Conservation and biodiversity |
| Objective Division: | Environmental Management |
| Objective Group: | Marine systems and management |
| Objective Field: | Marine biodiversity |
| UTAS Author: | Awruch, CA (Dr Cynthia Awruch) |
| UTAS Author: | Jones, SM (Professor Susan Jones) |
| UTAS Author: | Barnett, A (Dr Adam Barnett) |
| ID Code: | 92220 |
| Year Published: | 2014 |
| Web of Science® Times Cited: | 21 |
| Deposited By: | Zoology |
| Deposited On: | 2014-06-10 |
| Last Modified: | 2017-11-01 |
| Downloads: | 392 View Download Statistics |
Repository Staff Only: item control page