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326C. IZZO & B. M. GILLANDERS1993); however, the incidence of embryonicdiapause, which appears to be characteristic of thisgroup, appears to form an annual breeding pattern.Kyne and Bennett (2002) suggest rhinobatids adoptembryonic diapause in an effort to provideseasonally favourable conditions for newborn rays.We suggest that embryonic diapause in T. fasciatamay be a mechanisms to combat juvenile mortality.Diapause may facilitate in furthering embryonicdevelopment; therefore, T. fasciata produce few,larger offspring that are less vulnerable to predationand do not require rapid growth (Cortés 2004).In conclusion, the southern fiddler ray is arelatively fast growing rhinobatid species thatachieves maturity late in its life. Whilst displaying alow fecundity, T. fasciata appears to investadditional parental care, giving birth to largeoffspring, thus reducing juvenile mortality. Theselife history traits are not indicative of a species thatwould be considered “at risk” to fisheries inducedpopulation declines (Walker 2004). Whilst currentReferencesAbdel-Aziz, S. H., Khalil, A. N. & Abdel-Maguid,S. A. 1993. Reproductive cycle of thecommon guitarfish, Rhinobatos rhinobatos(Linnaeus, 1758), in Alexandria waters,Mediterranean Sea. Australian Journal ofMarine and Freshwater Research, 44: 507-517.Beamish, R. J. & Fournier, D. A. 1981. A methodfor comparing the precision of a set of agedeterminations. Canadian Journal ofFisheries and Aquatic Science, 38: 982-983.Beamish, R. J. & McFarlane, G. A. 1983. Theforgotten requirement for age validation infisheries biology. Transactions of theAmerican Fisheries Society, 112: 735-743.Capapé, C. & Zaouali, J. 1994. Distribution andreproductive biology of the blackchin guitarfish,Rhinobatos cemiculus (Pisces: Rhinobatidae),in Tunisian Waters (Central Mediterranean).Australian Journal of Marine andFreshwater Research, 45: 551-561.Conrath, C. L. 2004. Reproductive biology. Pp. 133-164. In: Musick, J. A. & Bonfil, R. (Eds.).Elasmobranch Fisheries ManagementTechniques. APEC, Singapore.Cortés, E. 2004. Life history patterns, demography,and population dynamics. Pp. 449-469. In:Carrier, J., Musick, J. A. & Heithaus, M.(Eds.). Biology of Sharks and theirRelatives. CRC Press, San Diego.Diamond, S. L. 2003. Estimation of bycatch inshrimp trawl fisheries: a comparison ofcatch rates indicate that relative species abundanceremains stable throughout southern Australian, shiftsin fishing pressure could put this species at risk.Thus, the need for assessing the effects of currentby-catch rates of T. fasciata requires furtherinvestigations, with particular emphasis into thesurvival of discards.AcknowledgmentsWe would like to acknowledge the SARDIInshore Crustacean Sub-program and the crewsof the numerous prawn trawlers that assistedin specimen collection. We would also like tothank S. Donnellan for his critical appraisaland comments, which improved the quality ofthis manuscript. All animal procedures wereapproved by the Adelaide University animalethics committee (Project No. S-022-2006). Thisresearch was supported by funding awarded to thelead author from The Sir Mark Mitchell ResearchFoundation.estimation methods using field data andsimulated data. Fishery Bulletin, 101: 484-500.Dulvy, N. K., Ellis, J. R. Goodwin, N. B. Grant, A.Reynolds, J. D. & Jennings, S. 2004. Methodsof assessing extinction risk in marine fishes.Fish and Fisheries, 5(3): 255-276.Graham, K. J., Andrew, N. L. & Hodgson, K. E.2001. Changes in relative abundance of sharksand rays on Australian South East Fisherytrawl grounds after twenty years of fishing.Marine and Freshwater Research, 52: 549-561.Hyndes, G. A., Platell, M. E. Potter, I. C. &Lenanton, R. C. J. 1999. Does thecomposition of the demersal fish assemblagesin temperate coastal waters change with depthand undergo consistent seasonal changes?Marine Biology, 134: 335-352.Ismen, A., Yigin, C. & Ismen, P. 2007. Age, growth,reproductive biology and feed of the commonguitarfish (Rhinobatos rhinobatos Linnaeus,1758) in İskenderun Bay, the easternMediterranean Sea. Fisheries Research, 84:263-269.Kennelly, S. 1995. The issue of by-catch inAustralia's demersal trawl fisheries. Reviewsin Fish Biology and Fisheries, 5: 213-234.Kyne, P. M. & Bennett, M. B. 2002. Reproductivebiology of the eastern shovelnose ray,Aptychotrema rostrata (Shaw & Nodder,1794), from Moreton Bay, Queensland,Pan-American Journal of Aquatic Sciences (2008) 3(3): 321-327
Age, growth & reproduction in T. fasciata.327Australia. Marine and FreshwaterResearch, 53: 583-589.Last, P. R. & Stevens, J. D. 1994. Sharks and Raysof Australia. CSIRO, Melbourne, 513 p.Lessa, R. P. 1982. Biologie et dynamique despopulations de Rhinobatos horkelii (Mullerand Henle, 1841) du Plateau Continental duRio Grande do Sui Bresil. Ph.D. Thesis.Universite de Bretagne Occidentale, 929 p.Liu, K. M., Chiang, P. J. & Chen, C. T. 1998. Ageand growth estimates of the bigeye threshershark, Alopias superciliosus, in northeasternTaiwan waters. Fishery Bulletin, 96(3): 482-491.Márquez–Farias, J. F. 2007. Reproductive biology ofshovelnose guitarfish Rhinobatos productusfrom the eastern Gulf of California México.Marine Biology, 151: 1445-1454.Marshall, L. J., White, W. T. & Potter, I. C. 2007.Reproductive biology and diet of the southernfiddler ray, Trygonorrhina fasciata (Batoidea:Rhinobatidae), an important trawl bycatchspecies. Marine and Freshwater Research,58: 104-115Neer, J. A. & Cailliet, G. M. 2001. Aspects of thelife history of the Pacific electric ray, Torpedocalifornica (Ayres). Copeia, 3: 842-847.Prager, M. H., Saila, S. B. & Recksiek, C. W. 1989.FISHPARM: a mircocomptuer program forparameter estimation of nonlinear models infishery science, second edition. Old DominionUniversity Oceanography TechnicalReport 8: 7-10.Reardon, B. M. 2003. Southern Fiddler RayTrygonorrhina fasciata Müller and Henle,1841. Pp 137-138. In: Cavanagh, R. D., Kyne,P. M., Fowler, S. L., Musick, J. A. & Bennet,M. B. (Eds.). The Conservation Status ofAustralian Chondrichthyans: Report of theIUCN Shark Specialist Group Australiaand Oceania Regional Red List Workshop.Brisbane, Australia: The University ofQueensland, School of Biomedical Sciences.Rossouw, G. 1984. Age and growth of the sandshark, Rhinobatos annulatus, in Algoa Bay,South Africa. Journal of Fish Biology, 25(2):213-222.Seck, A. A., Diatta, Y., Diop, M., Guélorget, O.,Reynaud, C. & Capapé, C. 2004.Observations on the reproductive biology ofthe blackchin guitarfish, RhinobatosCemiculus E. Geoffroy Saint-Hilaire, 1817(Chondrichthyes, Rhinobatidae) from thecoast of Senegal (Eastern Tropical Atlantic).SCIENTIA gerundensis, 27: 19-30.Skomal, G. B. & Natanson, L. J. 2003. Age andgrowth of the blue shark (Prionace glauca) inthe North Atlantic Ocean. Fishery Bulletin,101: 627-639.Stevens, J. D., Bonfil, R. Dulvy, N. K. & Walker, P.A. 2000. The effects of fishing on sharks,rays, and chimaeras (chondrichthyans), andthe implications for marine ecosystems.Journal of Marine Science, 57: 476-494.Timmons, M., & Bray, R. N. 1997. Age, growth,and sexual maturity of shovelnose guitarfish,Rhinobatos productus (Ayres). FisheryBulletin, 95: 349-359.Villavicencio-Garayzar, C. J. 1995. Reproductivebiology of the banded guitarfish, Zapterixexasperata (Pisces: Rhinobatidae), in BahíaAlmejas, Baja California Sur, Mexico.Ciencias Marinas, 21(2): 141-153.von Bertalanffy, L. 1938. A quantitative theory oforganic growth. Human Biology, 10: 181–213.Walker, T. I. 2004. Elasmobranch FisheriesManagement Techniques. Pp. 285-323. In:Musick, J. A. & Bonfil, R. (Eds.).Elasmobranch Fisheries ManagementTechniques. APEC, Singapore.Walker, T. I. 2007. The state of research onchondrichthyan fishes. Marine andFreshwater Research, 58: 1-3.Walker, T. I., Hudson, R. J. & Gason, A. S. 2005.Catch evaluation of target, by-product and bycatchspecies taken by gillnets and longlinesin the shark fishery of south-eastern Australia.Journal of Northwest Atlantic FisheryScience, 35: 505-530.Wenbin, Z. & Shuyuan, Q. 1993. Reproductivebiology of the guitarfish, Rhinobatoshynnicephalus. Environmental Biology ofFishes, 38: 81-93.Received August 2008Accepted October 2008Published online October 2008Pan-American Journal of Aquatic Sciences (2008), 3(3): 321-327
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