If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

Quantification of the maternal–embryonal nutritional relationship of elasmobranchs: case study of wobbegong sharks (genus Orectolobus)

$48.00 plus tax (Refund Policy)

Download / Buy Article:

Abstract:

The present study used wobbegong sharks (genus Orectolobus) to assess the threshold value proposed by previous research to categorize strict lecithotrophic from incipient histotrophic species. Totals of 236 and 135 ornate wobbegong Orectolobus ornatus and spotted wobbegong Orectolobus maculatus, respectively, were collected from the New South Wales commercial fishery between June 2003 and May 2006. Eight pregnant gulf wobbegong Orectolobus halei were also recorded outside the sampling period for the first time. The three species were reproductively synchronous with a gestation of c. 10–11 months. Embryos started to be macroscopically visible during January and external yolk sacs were fully absorbed by June to July when embryos were c. 200 mm total length (LT). Internal yolk sacs were first observed during April to May when embryos were c. 160 mm LT, reached a peak during June and persisted in embryos immediately prior to parturition. The total wet mass from uterine egg to full-term embryos increased by 44–89% and 45–62%, whereas the total organic mass decreased by 32–33% and 26%, for O. ornatus and O. maculatus, respectively, suggesting that these species are strict lecithotrophic yolk-sac viviparous sharks with no maternal nutrient input. A review of the literature identified various issues and suggested that the previously proposed organic mass loss threshold value separating strict lecithotrophic species from incipient histotrophic species might not be appropriate. Instead, it is recommended that a combination of methods (e.g. estimation of organic mass gain or loss between ovarian egg and developed embryo, histology and electron microscopy of the uterus, radio-tracer assay and uterine fluid analysis throughout gestation) is used to discern between strict lecithotrophic and incipient histotrophic species.

Keywords: incipient matrotrophy; nutrients; reproduction; strict lecitothrophy

Document Type: Regular Paper

DOI: http://dx.doi.org/10.1111/j.1095-8649.2011.02938.x

Affiliations: 1: Industry and Investment NSW, Port Stephens Fisheries Institute, Taylors Beach Road, Taylors Beach, New South Wales 2316, Australia 2: Graduate School of the Environment, Macquarie University, Sydney, New South Wales 2109, Australia

Publication date: May 1, 2011

Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more