308 
Fishery Bulletin 1 10(3) 
ever, are usually less than 140 cm DW (McEachran and 
de Carvalho, 2002). Aetobatus narinari has a matro- 
trophic mode of embryonic gestation and fetal nutri- 
tion occurs by lipid histotrophy; and this species has 
low fecundity with 1-4 pups per litter (McEachran 
and de Carvalho, 2002). Length at maturity has been 
estimated for A. ocellatus in the western Pacific and 
Indian Oceans, but to our knowledge there is only one 
previous report for A. narinari in the Atlantic Ocean 
(Dubick, 2000). 
The spotted eagle ray is categorized as near threat- 
ened throughout its range by the IUCN and studies 
on its catch, abundance, and reproductive biology have 
been recommended. However, the conservation status 
of this species complex needs to be reviewed in light 
of the recent taxonomic changes (White et al., 2010). 
The spotted eagle ray is considered of minor com- 
mercial importance, but it is caught as bycatch with 
different fishing-gear types, such as trawls, trammel 
nets, and longlines (Trent et ah, 1997; Stobutzki et 
al., 2002; Grijalba-Bendeck et ah, 2007). In the south- 
eastern Gulf of Mexico, Cuevas-Zimbron et al. (2011) 
reported a small-scale, directed fishery for A. narinari. 
In Venezuela, A. narinari is considered a common 
species, particularly in insular areas with coral reef 
cover, such as the Los Roques Archipelago in the 
north central part of this country (Cervigon, 2005) 
and the islands of Coche, Cubagua, and Margarita off 
the northeastern coast. Aetobatus narinari is readily 
marketable fresh or salted and is particularly ap- 
preciated in eastern Venezuela where it is the main 
part of a typical dish (Cervigon and Alcala, 1999). 
At Margarita Island, we studied a small, directed 
fishery to generate information that may contribute 
to the management and conservation of this little 
known and potentially vulnerable species. 
Materials and methods 
Study area and fishing fleet 
The insular state of Nueva Esparta in northeastern 
Venezuela is formed by the islands of Coche, Cubagua, and 
Margarita. Margarita and Coche each have an important 
concentration of small-scale fishing communities. Puerto 
Fermin, also known as El Tirano, is a traditional fishing 
community in northeastern Margarita. Fisheries at 
Puerto Fermin mainly use trap gear, but a small number 
of boats target A. narinari around the nearby Los Frailes 
Archipelago (63°46'-63°43'N latitude, 11°14'-11 0 12'W 
longitude). This specialized fleet is composed of 6 wooden 
boats with outboard engines, known locally as peneros, 
with 2 boats that fish only occasionally and the other 4 
boats that fish every month. This fleet uses bottom-set 
giilnets that vary between 200 and 500 m in length, 
between 8 and 10 m in height, and between 30 and 39 cm 
in mesh size. Nets are set in the evening between 1600 
and 1830 hours and lifted the following day between 
0500 and 0900 hours. Detailed descriptions of boats 
and fishing gear for this area may be found in Mendez- 
Arocha (1963), Gines et al. (1972), Iriarte (1997), and 
Gonzalez et al. (2006). 
Field sampling and biological data 
Fishing for the spotted eagle ray is carried out every 
month during a period of ~10 days around the full moon. 
Samples were taken during such periods over the 29 
months between August 2005 and December 2007. We 
registered the number of boats fishing daily, the number 
of individuals landed, and their weight in kilograms. The 
retained indices of relative abundance were the number 
of individuals captured per trip and total kilograms 
collected per trip. 
To determine the size of A. narinari , DW was meas- 
ured as a proxy for total length in ray (total length can- 
not be reliably measured because tails can be damaged 
during capture) (Last and Stevens, 2009); therefore, 
unless otherwise specified, all subsequent references 
to length in this article refer to DW. Specimens were 
weighed with a field balance with a weighing capacity of 
200 kg and a precision of 1 kg. Sexes were differentiated 
by the presence of claspers in males and their absence 
in females. 
Male sexual maturity was verified by checking clasp- 
ers visually and by touch. Individuals were considered 
mature when claspers were strongly calcified, rotated 
easily around the base, had an extensible distal ex- 
treme (Pratt, 1979; Conrath, 2005), and showed the 
presence of seminal fluid (Bizarro et al., 2007). 
Female maturity was identified by macroscopic ob- 
servation of reproductive organs in fish at the landing 
site in Puerto Fermin. Individuals were considered 
mature (nongravid) or immature based on the pres- 
ence or absence of fully developed ova in the ovaries 
(Conrath, 2005). When possible, embryos from gravid 
females were counted, sex was determined, and DW 
measured (in centimeters). Postgravid females were 
recognized by the presence of a well-developed, large, 
highly vascularized uterus (Conrath, 2005) that, in 
most cases, contained intrauterine milk or histotro- 
phe. Some of these postgravid females were considered 
gravid if fishermen indicated that abortions occurred 
during hauling of the specimens. 
Other measurements, such as clasper length, follicle 
diameter, uterus width, gonad weight, and liver weight 
could not be obtained because of the speed at which 
animals were cut and sold on arrival at the landing site 
in Puerto Fermin. The swift cutting and selling of rays 
also prevented biological measurements of some of the 
landed individuals and embryos. 
Data analysis 
Population structure was analyzed by sex from length- 
frequency data. Length-weight relationships, of the 
form Wt = oDW b exp e , were established for males and 
females separately, where a is the intercept, b is the 
slope, exp 1 ’ represents the residual error, and Wt stands 
