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Fishery Bulletin 1 14(2) 
Time (months) 
Figure 3 
Monthly proportion of sexual maturity stages for (A) female and (B) male bullnose ray (Myliobatis frem- 
invillei ) captured by the artisanal fishery of La Pared, Venezuela, during 2 periods: 2005-2007 and 2013. 
size at sexual maturity for the southern eagle ray in 
Northern Patagonia was 48.7 and 45.0 cm DW for fe- 
males and males, respectively. In central California, for 
the bat ray, sexual maturity has been estimated to oc- 
cur at 45.0-62.2 cm DW for males and 50% maturity 
of females has been reached at an estimated 88.1 cm 
DW (Martin and Cailliet, 1988). Differences in DW at 
sexual maturity for species occurring in diverse regions 
have also been reported for other species of Myliobati- 
dae, and several factors may determine such dispari- 
ties, such as real variations in populations, sample size, 
sampling bias, as well as errors in the assignation of 
maturity stages and the use of different estimation 
methods (Tagliafico et al., 2012). 
No patterns were detected in the reproductive cycle 
of bullnose ray. As with our observations of gravid and 
postgravid females in July, Cervigon and Alcala (1999) 
reported capture of gravid females in June and Octo- 
ber. The low numbers of gravid females in our study 
may indicate a spatial segregation of the sexes, with 
females giving birth in waters outside the operational 
area of the fishery. 
The maximum size of embryos registered in this 
study (20.6 cm DW) is similar to the previously report- 
ed range (21.5-21.7 cm DW; Cervigon and Alcala, 1999) 
and to the size of neonates (25.0 cm, McEachran and 
de Carvalho, 2002; 22.0-23.0 cm, Gomez et al., 2010). 
Also, the maximum fecundity encountered in this study 
(n=6) is comparable to the previously reported numbers 
of 6-8 embryos (Cervigon and Alcala, 1999; McEachran 
and de Carvalho, 2002). An outlier specimen, a female 
captured with a single embryo of 9.0 cm, is suspected 
to have aborted pups during its capture as a result of 
stress. Similar values for size and number of embryos 
have been indicated for the bat ray (n- 2-5; size: 22.0- 
30.5 cm) (Martin and Cailliet, 1988). 
Venezuelan fishery resources are showing signs of 
overexploitation (Mendoza 2 ), and a lack of management 
for Myliobatiformes (i.e., the spotted eagle ray [Aetoba- 
tus narinari ], southern stingray [Dasyatis americana ], 
and longnose stingray [D. guttata ]) has been reported 
previously (Tagliafico et al., 2012, 2013b). Precaution- 
ary management measures may be necessary to en- 
sure ongoing population viability of the bullnose ray. 
In this study, we provide results regarding CPUE, DW 
at maturity, size structure by sex, and the sex ratio 
for this species, all of which are important param- 
eters for demographic modeling and stock assessment 
that are necessary in order to develop management 
recommendations. 
Previous studies have highlighted that most of the 
elasmobranchs accessible to the world’s fisheries are 
under threat (Dulvy et al., 2014), and this group, with 
low resilience to fishing (Cheung et al., 2005) and a 
protracted period of 14 years for a stock to rebuild 
2 Mendoza, J. J. 2015. Rise and fall of Venezuelan industri- 
al and artisanal marine fisheries: 1950-2010. Fish. Cent., 
Univ. British Columbia, Work. Pap. Ser. #2015-27, 16 p. 
[Available at website.] 
