Leung, Amanda Jhu-Xhin and Then, Amy Yee-Hui and Loh, Kar-Hoe (2023) Reproductive biology, length-weight relationship and diet of co-occurring butterfly rays, Gymnura poecilura and Gymnura zonura, in Malaysian waters. Journal of Fish Biology, 102 (3). pp. 564-574. ISSN 0022-1112, DOI https://doi.org/10.1111/jfb.15288.
Full text not available from this repository.Abstract
Recent IUCN assessments had resulted in up listing of the status of butterfly rays due to concerns of overfishing, but inadequate biological understanding of these rays prevents meaningful conservation and management measures. Therefore, this study was undertaken to address knowledge gaps in the reproductive biology and diet of longtail butterfly ray (Gymnura poecilura) and zone tail butterfly ray (Gymnura zonura) in Malaysian waters. From surveys of landing sites and fish markets from years 2017 to 2022, size (disc width, DW), weight and maturity were recorded, and stomachs were collected from 94 G. poecilura (N = 39 females and 55 males) and 20 G. zonura (N = 10 females and 10 males) specimens. The length-weight relationships were significantly different between sexes for G. poecilura. The size at maturity (DW50) was estimated to be 476.0 mm (females), 385.0 mm (males) for G. poecilura and 442.0 mm (combined) for G. zonura. The number of embryos ranged from 1 to 6, and the embryo size was between 73.90 to 130.44 mm DW. Dietary analysis of stomach contents revealed that fish prey was dominant in both G. poecilura 94.4% Index of Relative Importance (IRI)] and G. zonura (100% IRI). Ontogenetic shift was seen in G. poecilura that fed on more variety of prey items, including shrimps, squids and crabs with an increase in body size. Both species co-occur all along coastal Malaysia although G. zonura is rarely encountered from fisheries surveys along the Strait of Malacca. Given similar habitat associations and dietary habits, G. poecilura may be able to outcompete G. zonura across their shared habitat range. The validity of G. japonica and G. micrura records in Malaysia remains questionable and requires future investigation.
| Item Type: | Article |
|---|---|
| Funders: | WWF-Malaysia, PV049‐2019, Universiti Malaya, RP018C-16SUSC |
| Uncontrolled Keywords: | Diet composition; Indo-Pacific; Ontogenetic shift; Sexual dimorphism; Size at maturity |
| Subjects: | Q Science > QL Zoology |
| Divisions: | Faculty of Science > Institute of Biological Sciences Deputy Vice Chancellor (Research & Innovation) Office > Institute of Ocean and Earth Sciences |
| Depositing User: | Ms Zaharah Ramly |
| Date Deposited: | 29 Nov 2023 03:30 |
| Last Modified: | 29 Nov 2023 03:30 |
| URI: | http://eprints.um.edu.my/id/eprint/39172 |
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