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Fishery Bulletin 1 14(1) 
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Species 
Figure 3 
Average body sizes in cm, with standard errors indicated by er- 
ror bars, of shark and ray species caught in 3 depth ranges, (A) 
<50 m, (B) 50—100 m, and (C) >100 m), along the Pacific coast of 
Costa Rica in 2010-2012. Body size is presented as total length in 
sharks and disc width in rays. The following species abbreviations 
are used: RLO (Pacific sharpnose shark [Rhizoprionodon longu- 
rio]), SLE (scalloped hammerhead [ Sphyrna lewini]), MHE (brown 
smoothhound [Mustelus henlei]), MLU (sicklefin smoothhound 
[. Mustelus lunulatus ]), ECO (prickly shark [ Echinorhinus cookei ]), 
SCA (Pacific angel shark [Squatina californica ]), DLO (longtail 
stingray [Dasyatis longa]), ANA (spotted eagle ray [Aetobatus lati- 
ceps]), RST (golden cownose ray [ Rhinoptera steindachneri]), UAS 
(Panamic stingray [Urotrygon aspidura]), UCH (blotched sting- 
ray [Urotrygon chilensis ]), UCI (denticled roundray [ Urotrygon 
cimar]), UMU (Spiny stingray [Urotrygon munda]), UNA (dwarf 
stingray [ Urotrygon nana]), URO (thorny stingray [Urotrygon rog- 
ersi]), GMA (California butterfly ray [ Gymnura marmorata ]), REQ 
(equatorial skate [Raja equatorialis]), RVE (rasptail skate [Raja 
velezi]), RCO (Cortez skate [Raja cortezensis ]), RLE ((whitesnout 
guitarfish [Rhinobatos leucorhynchus]), ZXY (witch guitarfish 
[Zapteryx xyster]), DOM (bullseye electric ray [Diplobatis om- 
mata]), NEN (giant electric ray [Narcine entemedor]), NVE (ver- 
miculate electric ray [Narcine vermiculatus]), and TPE (Peruvian 
torpedo [Torpedo peruviana]). 
Pacific angel shark, and the Peruvian torpedo. 
Within this group, the Peruvian torpedo had 
the strongest positive correlation with depth, 
whereas the witch guitarfish and Pacific angel 
shark had the strongest negative correlation 
with depth. The deepwater assemblage was 
weakly associated with the night, the rainy 
season, and the years 2010 or 2012. 
Discussion 
Elasmobranch diversity and distribution patterns 
The results of our study revealed that elas- 
mobranch bycatch of the shrimp trawl fishery 
in Costa Rica comprised 25 species, which ac- 
count for more than 35% of the species rich- 
ness reported for the Pacific coast of Costa 
Rica (Bussing and Lopez, 2009). Most of these 
bycatch species have wide distribution rang- 
es that include the entire ETP. Consequently, 
the few studies available on elasmobranch 
bycatch from shrimp fisheries in this region 
reveal similar species compositions (Gulf of 
California, Mexico: Lopez-Martinez et al., 
2010; Pacific coast of Colombia: Mejia-Falla 
and Navia 1 ) (Table 5). The strong similar- 
ity between elasmobranch bycatch in Costa 
Rica and Colombia (14 species in common) 
reflects the biogeographic patterns proposed 
by Robertson and Cramer (2009). Costa Rica 
and Colombia form part of the Panamic bio- 
geographic province that is composed solely of 
tropical fishes (Robertson and Cramer, 2009), 
and the Gulf of California belongs to the Cor- 
tez biogeographic province, which is charac- 
terized by the convergence of temperate, sub- 
tropical, and tropical marine fish fauna (Mora 
and Robertson, 2005; Rodriguez-Romero et 
al., 2008). 
Our results revealed that the elasmobranch 
assemblage varies along the Pacific coast of 
Costa Rica (-1254 km of coastline). This vari- 
ation is probably due to differences in ocean- 
ographic conditions along the coastline, with 
the north affected by upwelling and the cen- 
tral and South Pacific affected by freshwater 
inflows. Delta-GLMs indicated that latitude 
was an important predictor of elasmobranch 
presence in deepwater and monitoring sur- 
veys; however, these differences may reflect 
the higher sampling efforts in deep waters 
of the northern and southern Pacific areas. 
Therefore, the effect of latitude on elasmo- 
branch diversity needs to be interpreted with 
caution. The uneven sampling effort along the 
coast was the result of an overall dependence 
on the presence of commercial shrimp trawl- 
