451 
National Marine 
Spencer F. Baird /* ' V 
Fisheries Service 
Fishery Bulletin 
First U S Commissioner Tl U 
NOAA 
ft- established in 1831 
of Fisheries and founder iff! 
of Fishery Bulletin 
Trophic ecology of the smooth hammerhead shark 
C Sphyrna zygactta) off the coast of northern Peru 
Adriana Gonzatez-Pestana {contact author) 1 ' 2 ' 3 
Nicolas Acuna-Perales 1 ' 4 
Javier Coasaca-Cespedes 1 ' 2 
Francisco Cordowa-Zawaleta 1 ' 3 
Joanna Alfare-Shigitefo 1 - 2 ' 6 
Jeffrey C. Mangel 1 '® 
Pepe Espinoza 2 ' 1 
Email address for contact author: adriana@prodelphinus.org 
Abstract— -The smooth hammerhead 
(Sphyrna zygaena ) is the third most 
captured shark species in Peru, a 
nation with one of the largest shark 
fisheries in the Pacific Ocean. We 
sought to better understand the tro¬ 
phic ecology of this shark in north¬ 
ern Peru by analyzing stomach 
contents. From 2013 through 2015, 
we collected 485 samples of gut con¬ 
tents from sharks measuring 53-294 
cm in total length. Our results show 
that the smooth hammerhead is a 
top predator with a diet dominated 
by jumbo flying squid (Dosidicus gi- 
gas) and the Patagonian squid (Do- 
ryteuthis ( Amerigo ) gahi). Smooth 
hammerheads displayed different di¬ 
ets with different body size, and this 
finding indicates that sharks change 
their distribution and habitat during 
development. This study represents 
the most comprehensive investiga¬ 
tion to date of the trophic ecology 
of smooth hammerhead in waters 
off Peru. We propose that these wa¬ 
ters represent an important eastern 
Pacific Ocean feeding ground for 
smooth hammerhead. Because this 
species is commercially important 
and also preys upon other commer¬ 
cial species, these findings could 
contribute to the design and imple¬ 
mentation of plans for ecosystem- 
based fisheries management. 
Manuscript submitted 14 October 2016. 
Manuscript accepted 7 June 2017. 
Fish. Bull. 115:451-459 (2017). 
Online publication date: 31 July 2017. 
doi: 10.7755/FB. 115.2 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
1 ProDelphinus 
Calle Jose Galvez 780-e 
Lima 18, Peru 
2 Universidad Cientifica del Sur 
Panamericana Sur Km 19 
Villa El Salvador, Lima 42, Peru 
3 James Cook University 
1 James Cook Dr. 
Townsville City, Queensland 4811, Australia 
4 Universidad Ricardo Palma 
Avenida Alfredo Benavides 5440 
Santiago de Surco, Lima 33, Peru 
The smooth hammerhead (Sphyrna 
zygaena) is distributed from Califor¬ 
nia to Chile within the eastern. Pa¬ 
cific Ocean. This species reaches a 
maximum size of 370-400 cm in total 
length (TL), and is one of the largest 
fishes in the southeast Pacific Ocean 
(Fowler et al., 2005). At birth, neo¬ 
nates measure 50-61 em-TL (Fowler 
et al., 2005). Neonate and juvenile 
smooth hammerheads use shallow 
coastal waters as nursery grounds 
and as they grow larger they move to 
more offshore oceanic waters (Smale, 
1991; Diemer et al., 2011; Francis, 
2016). The distribution of adults 
worldwide, however, is still unknown 
(Francis, 2016). 
Abundance of this species is de¬ 
creasing and the species is classified 
as vulnerable in the IUCN Red List 
of Threatened Species (Casper et al., 
2005). As of September 2014, the spe- 
5 Universidad Nacional Agraria La Molina 
Avenida La Molina s/n 
La Molina, Lima 12, Peru 
6 Center for Ecology and Conservation 
College of Life and Environmental Sciences 
University of Exeter. Penryn Campus 
Penryn, Cornwall TRIO 9FE, United Kingdom 
7 Instituto del Mar del Peru 
Esquina Gamarra y General Valle s/n 
Chucuito, Callao 05, Peru 
cies has been included in Appendix 
II of the Convention on Internation¬ 
al Trade in Endangered Species of 
Wild Fauna and Flora (https://cites. 
org/eng/app/appendices.php). Smooth 
hammerhead fins are prized in Asian 
markets and sharks are increasingly 
targeted in some areas. Peru is one 
of the top 12 countries that supply 
shark fins to Asian markets (Cheung 
and Chang, 2011). The smooth ham¬ 
merhead is commonly caught in the 
southeast Pacific Ocean but the im¬ 
pact of these fisheries on its popula¬ 
tion is unknown (Fowler et al., 2005). 
Peru also reports the highest accu¬ 
mulated historical shark landings in 
the Pacific Ocean and smooth ham¬ 
merhead is identified as the third 
most captured shark species by the 
fisheries of Peru and the most fre¬ 
quently captured shark species off 
northern Peru (Gonzalez-Pestana et 
