Hawksbill turtles Eretmochelys imbricata in El Salvador: nesting distribution and mortality at the largest remaining nesting aggregation in the eastern Pacific Ocean

Abstract

has a series of nesting beaches that together host the highest remaining nesting abundance of hawksbill turtles Eretmochelys imbricata in the eastern Pacific Ocean. However, the distribution of hawksbill turtle nesting and causes of hawksbill mortality along the Salvadoran coast are yet to be described. Here, we report on life history information of this population, including body size of nesting hawksbill turtles and clutch size, and mortality along nesting habitat at the following 3 areas in El Salvador: Los Cóbanos Reef Marine Protected Area (Los Cóbanos), Bahía de Jiquilisco-Xiriualtique Biosphere Reserve (Bahía), and Punta Amapala. In 2008, we recorded 310 nesting events by hawksbill turtles over 51.6 km of nesting habitat, giving an overall nesting density of 6.0 nests km-1 ; nearly 62% of total nesting activity and the highest reproductive output occurred in the Bahía. Morphometric data were collected from 26 nesting turtles that ranged from 74 to 88 cm curved carapace length (mean ± SD; 81.6 ± 3.6 cm) and 63 to 76 cm curved carapace width (70.1 ± 3.4 cm). Between 2004 and 2008, a total of 24 hawksbill turtles died in the mangrove and estuarine habitats of the Bahía (18 attributed to blast fishing) and in 2008, 8 hawksbill turtles died due to bycatch in bottom-set gillnets in Los Cóbanos. Given the severely depleted status of hawksbill turtles in the eastern Pacific, conservation action is urgently needed to mitigate their incidental capture in artisanal fisheries gear at primary nesting and foraging areas in El Salvador.

Living on the Edge: Hawksbill turtle nesting and conservation along the Eastern Pacific Rim

“…The 580 program was re-initiated in 2014 and has continued to function since that time. Nonetheless, the presence of local gangs (referred to in El Salvador as "Maras") on the beaches that are often involved in the illegal collection and sale of turtle eggs, discourages program collaborators from patrolling certain beaches and/or during certain times (Liles et al, 2011). This reduces our ability to collect information on the species and protect a greater percentage of nests (poaching at Los Cobanos is approximately 40% of total nests annually).…”

“…Coupled with most of the beaches being extremely remote and difficult to access, these realities render ongoing monitoring efforts unfeasible. Indeed, identifying and protecting hawksbill nesting grounds throughout the eastern Pacific remains challenging due to the disparate, lowdensity, cryptic nesting demonstrated by the species Gaos et al, 2010;Liles et al, 2011Liles et al, , 2015a as these nesting characteristics necessitate logistical, temporal and/or financial investments that often are unattainable by researchers. Regardless, efforts to identify nesting habitats can be facilitated by focusing acute, rapid assessments during the peak nesting seasons (Fig.…”

“…Furthermore, whereas hawksbills in the eastern Pacific were previously referred to as a single population (Gaos et al, , 2012a(Gaos et al, , 2012bLiles et al, 2011Liles et al, , 2015aLiles et al, , 2015bWallace et al, 2011), recent genetic research has revealed the existence of multiple stocks in the region, as well as a unique reproductive ecotype represented by hawksbills nesting in mangrove estuaries . These findings have heightened interest in understanding differences in nesting levels and conservation scenarios at the various rookeries.…”

“…Notwithstanding this perspective, the discovery of important remnant nesting and foraging strongholds beginning in 2007 Gaos & Urteaga, 2010;Liles et al, 2011;Gaos & Yañez, 2012) led to a regional data sharing workshop in 2008, where data were compiled and subsequently published, providing the first comprehensive analysis of hawksbill nesting (as well as in-water sightings, strandings and bycatch records) observations in the region .…”

Shoalgrass Halodule wrightii (Ascherson, 1868) meadows in El Salvador: distribution and associated macroinvertebrates at the estuary complex of Bahia de Jiquilisco

“…Despite these multiple stressors, opportunities for conservation exist. Bahía de Jiquilisco is under the protection of diverse national laws and international agreements and is increasingly recognized for its importance as a refuge for critically endangered (Liles et al, 2011, which further heightens its standing as a priority on the national conservation agenda. Additionally, when water conditions are suitable for its survival, H. wrightii is tolerant to disturbances and can quickly recolonize denuded areas, which underscores its potential for recovery and offers opportunities to extend its distribution in Bahía de Jiquilisco.…”