Hunting tactics of the lemon shark, Negaprion brevirostris, in shallow waters of an oceanic insular area in the western equatorial Atlantic

Ricardo C Garla,Otto B F Gadig,Domingos Garrone-Neto,Leonardo B Veras,José Garcia Junior

doi:10.1590/1982-0224-20160119

Abstract

ABSTRACT The hunting tactics of lemon sharks, Negaprion brevirostris, are described from underwater and cliff-top observations in the Fernando de Noronha Archipelago, western equatorial Atlantic, Brazil. Two main tactics were observed in the shallow waters of sandy beaches and reefs environments: (i) “substrate inspection” of crevices and holes over rocky and reef bottoms, and (ii) “sardine blitz”, which refer to striking schools of fishes (mainly sardines) in the surf zone. The first tactic was restricted to juveniles up to 2 m of total length, whereas subadult and adult sharks with total length larger than 2 m displayed the second. As lemon sharks use waters less than 5 m depth to hunt, perform social behaviours and predator avoidance, results highlight the importance of properly managing these habitats for their conservation, especially in areas where tourism has increased substantially.

Highlights

Sharks capture prey ranging from plankton to marine mammals using a wide variety of methods such as ram, biting, suction, and filter feeding (Motta, 2004)
The study was conducted between 2006 and 2013 in the Fernando de Noronha Archipelago (FEN), which is an isolated group of volcanic islands located in the western South Atlantic, 345 km off the north-eastern coast of Brazil (03°52’W, 32°25’S) (Fig. 1)
The two hunting tactics recorded in sites 1 and 2 were named as “substrate inspection” and “sardine blitz”

Summary

Introduction

Sharks capture prey ranging from plankton to marine mammals using a wide variety of methods such as ram, biting, suction, and filter feeding (Motta, 2004). A few other species may weaken or incapacitate prey before they consume it, such as the thresher sharks (Alopiidae) that employ tail-slaps to debilitate sardines (Oliver et al, 2013) and the great hammerhead, Sphyrna mokarran, which uses the head to blow and restrain prey on the substrate before biting (Strong et al, 1990). The direct observation of sharks in nature is not easy due to their high mobility, low densities, crepuscular and nocturnal habits, and the relatively concealing underwater environment.

Methods

Results

Conclusion