Biennial reproductive cycle in an extensive matrotrophic viviparous batoid: the sandyback stingaree Urolophus bucculentus from south‐eastern Australia

Abstract

Urolophus bucculentus, the largest urolophid species found in southern Australia, exhibits a biennial reproductive cycle. Ovulation occurs during October to January followed by a 15-19 month period of gestation followed by parturition during April to May and a short rest period while the ovarian follicles continue to develop for subsequent ovulation. Male breeding condition peaks during April to June to coincide with the period of parturition. Urolophus bucculentus has the highest matrotrophic contribution reported for any urolophid species, with a mean wet mass gain from egg in utero (4 g) to full-term embryo in utero (250 g) of c. 6250% (maximum c. 7200%), and perhaps explains the biennial female reproductive cycle where 50% of females contribute to each year's recruitment. Litter size (one to five) increases with total length (L(T) ). Females reach a longer maximum L(T) (L(Tmax) ) than do males (885 v. 660 mm). The L(T) at maturity for males and females at 50% mature (L(T50) ) is c. 414 mm (63% of L(Tmax) ) for males and c. 502 mm (57% of L(Tmax) ) for females, length at maternity indicates that recruitment production occurs later in life at c. 632 mm L(T) (71% of L(Tmax) ).

Reproductive parameters of rhinobatid and urolophid batoids taken as by‐catch in the Queensland (Australia) east coast otter‐trawl fishery

“…Trygonoptera spp. generally have larger follicles suggesting less matrotrophic contribution and shorter periods of embryos in utero than Urolophus spp., which have smaller follicles suggesting higher matrotrophic contribution (Trinnie et al , , ). This is consistent with the larger follicle size reported in T .…”

Courtship and mating behaviour of manta rays Mobula alfredi and M. birostris in the Maldives

“…Amongst species that do not undertake post parturition parental care, biennial and triennial reproductive cycles have only been reported in reptiles (Cree et al, ; Ibargüengoytía & Cussac, ; Sever et al, ) and elasmobranchs (Castro, ; Colonello et al, ; Whitney & Crow, ). As a general point, rest periods between reproduction are thought to occur to allow females to recuperate energy reserves (Catry et al, ; Trinnie et al, ). In manta ray reproduction, females normally give birth to a single, large pup (Coles, ; Beebe & Tee‐Van, ; Bigelow & Schroeder, ), although rare cases of twins have been recorded (Marshall & Bennett, ), with size at birth ranging from 130–190 cm in disc width (Marshall & Bennett, ; OCA, 2010).…”

“…Amongst species that do not undertake post parturition parental care, biennial and triennial reproductive cycles have only been reported in reptiles (Cree et al, 1995;Ibargüengoytía & Cussac, 1996;Sever et al, 2000) and elasmobranchs (Castro, 2009;Colonello et al, 2006;Whitney & Crow, 2006). As a general point, rest periods between reproduction are thought to occur to allow females to recuperate energy reserves (Catry et al, 2006;Trinnie et al, 2012).…”

Regional differences in the reproductive parameters of the sparsely-spotted stingaree, Urolophus paucimaculatus, from south-eastern Australia

“…The methods applied for laboratory processing of the specimens followed those applied to other urolophid species by Trinnie et al (2009Trinnie et al ( , 2012. Each specimen was sexed, measured to the nearest millimetre (mm) for TL (tip of snout to end of caudal fin), disc length (DL, tip of snout to end of pectoral fin) and disc width (DW), and weighed for total body mass to the nearest gram (TW).…”

“…ANCOVA (with terms region, covariate ETL and region  ETL) was adopted to test for regional effects on the LFD-ETL relationship and ANCOVA (with terms region, covariate DOY and region  DOY) was adopted to test for regional effects on the LFD-DOY relationship in U ¼ 5 females. Determination of the periods of the female and male reproductive cycles The approach to the determination of the female reproductive cycle through first determining the period of gestation, then the period of ovarian cycle, and then the synchrony between these two periods followed (Trinnie et al 2009(Trinnie et al , 2012. In males, seasonal synchrony in breeding condition was examined by plotting mean gonadosomatic index (GSI) and hepatosomatic index (HSI) against month for mature males (on the basis of testis development as the index of maturity).…”