Vol. 35: 71–80, 2018 ENDANGERED SPECIES RESEARCH Published February 19 https://doi.org/10.3354/esr00876 Endang Species Res OPENPEN ACCESSCCESS Reproductive biology and range extension for Mobula kuhlii cf. eregoodootenkee Matt K. Broadhurst1,2,*, Betty J. L. Laglbauer3, Katherine B. Burgess4, Melinda A. Coleman1 1NSW Department of Primary Industries, National Marine Science Centre, PO Box 4321, Coffs Harbour, NSW, Australia 2Marine and Estuarine Ecology Unit, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia 3Department of Oceanography and Fisheries, University of the Azores, Horta, Faial, Portugal 4School of Biomedical Sciences, University of Queensland, St Lucia, QLD, 4072, Australia ABSTRACT: Mobulids have been poorly studied, but most are listed by the International Union for the Conservation of Nature as Near Threatened or of greater concern. Here we fill critical know - ledge gaps surrounding reproduction for Mobula kuhlii cf. eregoodootenkee caught at 29° S — 200 km south of their proposed range — off eastern Australia by bather-protection gillnets de - ployed for 6 mo from December 2016. M. kuhlii cf. eregoodootenkee was the second most abundant netted species (all adults: n = 63), with catches peaking in April. There was no sexual segregation, but females (disc width [DW]: 92.5 to 130.0 cm, mean ± SD 112.8 ± 7.8 cm) were significantly larger than males (99.0 to 123.0 cm, 109.4 ± 6.3 cm). Of those caught, 45 died (71% mortality), of which 20 females and 11 males were assessed for reproduction. Nine females were pre-ovulatory and non-gravid with 7 to 23 oocytes in their left ovary, while 11 had 14 to 40 ovarian oocytes and 1 embryo (DW: 7.0 to 21.2 cm) in their left uterus. The diameter of the largest ovarian follicle in gravid females was not correlated with embryo size, indicating ovulation may not occur immediately after parturition. The development of the largest embryo (DW: 21 cm) suggests parturition occurs well above this size. Males had calcified claspers and exhibited large variation in their testes weights, which might imply seasonal fluctuation in sperm production. In addition to extending the distribution of the species and increasing maximum DW to 130 cm, the data provide further evidence of the low reproductive output of M. kuhlii cf. eregoodootenkee, and a need for their effective management. KEY WORDS: Elasmobranch · Embryo · Gillnet · Mobula · Reproduction INTRODUCTION and M. munkiana) are endemic to the western At- lantic, Indo-West Pacific and eastern tropical Pacific The family Mobulidae (mantas and devilrays) is oceans, respectively. distributed throughout tropical and warm-temperate Despite this taxonomic revision, further investiga- seas and historically has included 2 poorly studied tion is required to ascertain phylogeny. Specifically, genera: Manta and Mobula, comprising 2 and 9 spe- based on divergence between mitochondrial gen - cies, respectively (Notarbartolo-di-Sciara 1987, White omes and nuclear exon data in the lesser devilray M. et al. 2006). Recently, the entire family was updated kuhlii and the pygmy devilray M. eregoodootenkee to the singular Mobula with 8 species (White et al. falling within the range of intraspecific variation, the 2017). Of these, 5 (M. alfredi, M. birostris, M. mobu- latter was reclassified as M. kuhlii (White et al. 2017). lar, M. tarapacana and M. thurstoni) are cosmopoli- But there remain important morphological differ- tan, while the remaining 3 (M. hypostoma, M. kuhlii ences (e.g. among gill plates and body colouration) © The authors 2018. Open Access under Creative Commons by *Corresponding author: [email protected] Attribution Licence. Use, distribution and reproduction are un - restricted. Authors and original publication must be credited. Publisher: Inter-Research · www.int-res.com 72 Endang Species Res 35: 71–80, 2018 which warrant research to confirm whether M. ere- ing reproduction in mobulids, but the implication of goodootenkee is a valid species (Misty Paig-Tran & life histories characterized by a combination of bio- Summers 2013, Notarbartolo di Sciara et al. 2017). logical factors that could render the family suscepti- Here we refer to the species complex as M. kuhlii cf. ble to overfishing, our main aim here was to provide eregoodootenkee. the first quantitative assessment of reproduction in Nearly all mobulids, including M. eregoodooten- M. kuhlii cf. eregoodootenkee. kee, are listed as Near Threatened or of greater concern throughout their ranges (M. kuhlii is Data Deficient; IUCN 2017). Although the species are MATERIALS AND METHODS poorly studied, these broad classifications reflect very low reproductive output (uniparity and poten- This study used specimens caught as bycatch in 5 tially biennial or triennial parturition) and vulnera- bather-protection gillnets deployed at fixed loca- bility to various fishing gears (Couturier et al. 2012, tions during 6 mo from 8 December 2016 off north- Lawson et al. 2017). Mobulids frequently are caught ern NSW (28.77° S, 153.60° E to 29.10° S; 153.44° E; in gillnets and are targeted in developing countries Fig. 1). Each gillnet was 150 m long and 4 or 6 m for domestically consumed meat, or for their gill deep and comprised 600 mm knotted mesh (inside plates that typically are exported to China for use in stretched mesh opening) made from either 1.8 or traditional medicines (Couturier et al. 2012, Lawson 2.1 mm diameter (∅) braided polyethylene twine et al. 2017). Some mobulids, including M. kuhlii cf. attached to 20 mm ∅ polypropylene floatlines and eregoodootenkee, have been harvested for many 8 mm ∅ polyamide foot ropes at a hanging ratio of years throughout their Indo-Pacific distributions and 0.67. All nets were secured parallel to the 5 beaches there are concerns about over-exploitation (White et in 5 to 13 m of water with 30 kg anchors at each end al. 2006). A lack of data describing key life-history and had 5 surface floats (~300 mm ∅) attached to parameters, including reproduction, precludes in - ~2 m ropes (16 mm ∅ twisted polypropylene) be- formed population management, other than precau- tween the surface and the floatline, so the foot rope tionary recommendations. was always off the bottom. Attempts were made to M. kuhlii cf. eregoodootenkee may also be inciden- fish the nets continuously, while checking and tally caught in tuna and purse-seine fisheries off clearing them daily, and always with an onboard northern Australia (hypothesized to be the limit of its scientific observer trained in marine-vertebrate southern range; Compagno & Last 1999, Lawson et identification. al. 2017), since congenerics are encountered in simi- During gillnet checks (with the intervening period lar industrial fisheries elsewhere (Mas et al. 2015, defined as the ‘soaktime’), the water depth and tem- Francis & Jones 2017), but the species is not selected perature were recorded and any Mobula kuhlii cf. by any inshore commercial or recreational fishing eregoodootenkee were untangled from the netting. gears. Nevertheless, like M. kuhlii off South Africa The entanglement side was noted as east (seaward) (Dudley & Cliff 1993) M. kuhlii cf. eregoodootenkee or west (landward), and individuals were assessed is likely vulnerable to capture in bather-protection for status (alive or dead), sexed, measured for disc gillnets, which were first introduced to protect bathers width (DW) to the nearest 1 mm, and immediately against sharks in Queensland about 55 yr ago (Sump- released if alive. Badly decomposed specimens were ton et al. 2011). Catches in these gillnets typically are discar ded at sea. All other dead specimens were grouped as Mobula spp. (Sumpton et al. 2011). Simi- transported to a laboratory and stored in a freezer at lar gillnets have also been deployed off Sydney, New −20°C prior to assessment. Each collected specimen South Wales (NSW) for 80 yr; but al though M. was sexed, weighed (to the nearest 10 g) and meas- birostris is infrequently caught, the fished area does ured (DW) prior to dissection and removal of repro- not encompass the distribution of M. kuhlii cf. ere- ductive organs. goodootenkee (e.g. Krogh & Reid 1996). Data collected for males included the clasper Recently, in response to a cluster of shark−human length (inner) and stage of calcification, and the mass interactions, bather-protection gillnets were deploy- of the heaviest testis. For females, the weight of the ed off northern NSW during a 6-mo trial and in an functional left ovary and width of the oviducal gland area not previously subjected to any fishing effort by were recorded; the number of ovarian follicles was these or similar gears. M. kuhlii cf. eregoodootenkee counted; and the diameter of the largest follicle was the second most abundant netted species (23% (DOLF) was measured. Uteri were measured for of the total catch). Considering a lack of data describ- width before being dissected and any embryos Broadhurst et al.: Reproduction and range of M. kuhlii cf. eregoodootenkee 73 removed. Embryos were sexed, weighed, measured Table 1. Monthly data on catches of Mobula kuhlii cf. ere- (DW) and qualitatively described. All reproductive goodootenkee in bather-protection nets off northern New South Wales, Australia, between December 2016 and May weights and lengths were to the nearest 1 g and 2017: mean (±SD) water temperature, total number of indivi- 1 mm, respectively. duals caught, sex ratio, and number of individuals sampled. Size-frequency distributions of males and females na: not