4 research outputs found
Improving sightings-derived residency estimation for whale shark aggregations: A novel metric applied to a global data set
The Largetooth Sawfish, Pristis pristis (Linnaeus, 1758), is not extirpated from Peru: new records from Tumbes
The Largetooth Sawfish, Pristis pristis, was for a long time considered extirpated from Peru. However, here we report the capture of 2 individuals from the north coast of Peru, indicating that this species is still extant in Peruvian waters. Both individuals were adult-sized and their encounters occurred during the austral summer, which could indicate a seasonal presence in those waters. Gillnets are still a major threat for the species as both specimens were incidentally captured with this gear. Our finding highlights the need for continuous research, awareness, and legal protection of this species
First reports of Megamouth Shark, Megachasma pelagios Taylor, Compagno & Struhsaker, 1983 (Lamniformes, Megachasmidae), in Peru
Megamouth Shark, Megachasma pelagios Taylor, Compagno & Struhsaker, 1983, is one of the least-known shark species worldwide. We report the encounters of four megamouth sharks: one caught in a driftnet off Piura (November 2016; sex indeterminate), one landed in Los Organos (July 2018; female), one stranded in El Ñuro (July 2018; sex indeterminate, ca 300 m total length), and one caught in a purse seine off Lambayeque (June 2019; female, total length ca 300 cm). These are the first records from Peru and expand the species’ known southern limit by 415 km. With the addition of M. pelagios, there are 67 species of sharks in Peru
Distribution of whale shark (Rhincodon typus) off northern Peru based on habitat suitability
In the south-eastern Pacific Ocean, few studies of whale sharks (Rhincodon typus) exist. In Peru, the northern coast has been identified as the area with the highest presence of whale sharks, yet their ecology in this area is poorly defined. This study predicts the spatial distribution of whale sharks off coastal northern Peru (03°00′S–04°30′S) during La Niña and El Niño seasonal conditions, utilizing maximum entropy modelling. Between 2009 and 2018 (except for 2011), 347 whale sharks were geo-referenced in northern Peru with greatest data recordings in the austral summer and spring during La Niña events. Depth was the most important predictive variable for spatial distribution of whale sharks, followed by chlorophyll-a. Sharks were predicted in shallower coastal waters in which chlorophyll-a values are higher. Habitat suitability was higher in the northern coastal part of the study area. Spring presents the most suitable environmental conditions for whale sharks, both during La Niña and El Niño conditions. The probability of whale shark presence in the north of Peru increases at higher chlorophyll-a and sea surface temperature values. Therefore, whale sharks appear to aggregate seasonally in northern Peru, potentially exploiting rich foraging grounds. In these areas of high suitability, whale sharks are susceptible to fisheries, bycatch, ship collisions, unmanaged tourism, and pollution; thus, management actions should focus in these areas. This study represents a first step to understand the distribution and habitat suitability of whale shark in Peruvian waters. Further studies should identify suitable habitat for whale sharks in offshore areas. Also, these should focus on the connectivity of these aggregations with other localities in the south-eastern Pacific in order to contribute to regional strategies for the conservation of this iconic species in this particular region