1. An understanding of the vertical movements of elasmobranchs across their range is crucial to defining critical habitat use, its overlap with anthropogenic activities and subsequently managing such interactions. 2. In this study, satellite telemetry was used to investigate the vertical habitat use of three oceanic manta rays (Mobula birostris) tagged on the northern coast of Peru.

The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and Ecuador is believed to be the largest in the world (Harding & Beirwagen, 2009). This species is considered to be the largest within the group of manta rays, as they attains at least 670 cm disc width (reported to 910 cm) (White et al., 2006) and there is a record of an individual weighing 2000 kg (Kunjipalu & Boopendranath, 1981). This species is ovoviviparous (matrotrophic viviparious) (Herbert, 2012). A single pup follows a gestation period of approximently one year, (Marshall et al., 2008, Mendonça et al., 2012). Sucessive pregnancies are speculated to be separated by a refactory period of two or more years (Mendonça et al., 2012). The objective of this study is to record the measurements of a M. birostris fetus of a female caught accidentally in the region of Tumbes, Peru. This is the first record of morphological and morphometric data regarding a manta fetus in Peru.

Abnormal embryonic development may result from mutations caused by genetics, environmental conditions or viruses. This study reports cases of cyclopia and a mouth malformation in two embryonic blue shark Prionace glauca collected off southern Brazil (South-western Atlantic). Such malformations are likely to reduce the chances of survival of embryos and neonates.

The largetooth sawfish (Pristis pristis) is listed as Critically Endangered on the IUCN Red List (Kyne et al. 2013). This species has been recorded in the Eastern Tropical Pacific, where its range has been described as extending from Mazatlan, Mexico, to northern Peru (Chirichigno & Cornejo 2001). Recent research efforts suggest that largetooth sawfish are now extremely rare or locally extinct on Mexico’s Pacific coast (Bonfil et al. 2018). There is no current information on the status of largetooth sawfish in Panama or Colombia; the most recent record of a largetooth sawfish captured on Colombia’s Pacific coast occurred in 2007 (Chasqui et al. 2017). In Ecuador, the species had been considered extirpated. However, in 2014, a large largetooth sawfish was captured by local fisherman in southern Ecuador, taken to the fishing port of Salinas and then released by the environmental agency (Barriga 2012; Rosas-Luis 2014). In Peru, recent reports of largetooth sawfish have been rare, but two captures of largetooth sawfish by fishermen (2014 and 2015) in northern Peru were reported (Mendoza et al. 2017). This confirms that the species is still occasionally encountered in this region.