Belize Zoo

Elasmobranchs often exhibit nocturnal or crepuscular activity, with shark diel patterns being better understood than ray diel patterns. We used accelerometry and hidden Markov models (HMMs) to classify female southern stingray ( Hypanus americanus Hildebrand & Schroeder, 1928) activity states across diel periods and environmental conditions in Belize. Three state (low, medium, and high activity) HMMs were constructed for all individuals together and separately ( N = 9). Combined, stingrays were most likely to be highly active at night and in low and medium activity states in the morning. However, there was individual variation in diel activity. In contrast, all stingrays consistently used shallow water (<4 m) during periods of high activity. Temperature had less influence on activity patterns, although three individuals exhibited high activity in cooler water. Generally, high stingray activity was driven by diel cycles and depth. Future research should link activity states to specific behaviours, include a larger sample size, extend tag deployment durations, and explore the impact of predator and prey dynamics on stingray activity.

Spatial comparisons of reef shark abundance inside and outside marine protected areas (MPAs) are common and generally report positive MPA effects, yet few studies have tracked abundance trends over long time periods. This is problematic because inside:outside comparisons at a single point in time cannot evaluate whether populations are declining. In Belize, the Caribbean reef shark Carcharhinus perezi is one of the most fished shark species and is more abundant inside MPAs. Although the relative abundance of C. perezi was stable inside Glover’s Reef Marine Reserve (GRMR) from 2001 to 2013, using standard baited remote underwater video station surveys, we document a decline in relative abundance inside the no-take marine reserve from 2009 to 2019. We used a negative binomial generalized linear model and model averaging to test the effect of year, depth, and water temperature on C. perezi and nurse shark Ginglymostoma cirratum relative abundance. While model-averaged results indicated a C. perezi decline, G. cirratum remained stable from 2009 to 2019. We hypothesize that the C. perezi decline is a result of fishing along the edge of GRMR, while G. cirratum stability is related to their behavior and nationwide protection. Given the dynamic nature of fisheries regulations, economic pressures, and site-specific environmental conditions, our results emphasize the need for standardized long-term monitoring of reef sharks inside and around MPAs globally.

Long-term monitoring is essential for the identification of population trends, and to understand how these trends are affected by climate variability. The El Niño Southern Oscillation (ENSO) is the strongest global interannual pattern of climate variability, resulting in the disruption of the annual phenological cycles of sea turtles. Among sea turtles, the Olive Ridley (Lepidochelys olivacea) is the most abundant, and on many beaches their nests are relocated to hatcheries as part of conservation management, especially in northern Central America. However, Olive Ridley nesting abundance trends in northern Central America and the effects of ENSO variability on these trends are still not fully understood. Here, we present the first long-term study of this subject. We predicted an upward trend in Olive Ridley nesting abundance on the Pacific coast of Guatemala, and a negative effect of increasing ENSO variability on nesting abundance. As proxies for nesting abundance, we analysed two different data sets; a 16-year period of Olive Ridley nesting data, using nesting tracks from one index beach (Hawaii in Guatemala), and the yearly number of eggs buried in the 25–35 hatcheries that operate along the Pacific coast of Guatemala. Revised Multivariate ENSO Index values were applied to estimate annual ENSO variability. During this 16-year study period, ENSO variability was distributed in eight neutral years, two normal El Niño years, four normal La Niña years and two extreme ENSO events; an extreme La Niña in 2010 and an extreme El Niño in 2015. We found a clear overall upward trend in Olive Ridley numbers of nesting tracks and eggs buried in hatcheries but no clear effect of ENSO variability on these nesting abundance proxies. However, a decrease in the net change of eggs buried in hatcheries occurred the respective years after the two extreme ENSO events during the study period. In the second year after those events, the net change of eggs buried in hatcheries bounced back to resume the overall positive trend. Our results suggest a clear upward trend, resilient to ENSO variability, of the nesting abundance of the Pacific coast Olive Ridley population in Guatemala. Community-based hatchery management efforts seem to be effective for Olive Ridley conservation on the Pacific coast of Guatemala. However, longer term monitoring including additional nesting beaches in northern Central America are necessary to further elucidate the effects of ENSO variability on the nesting abundance of Olive Ridley.

Abstract Mesoamerica is the world's third largest biodiversity hotspot and has c. 4,000 wildlife species protected under CITES. Despite the high biodiversity in the region, there is limited global attention, data and funding for conservation. The continued exploitation of wildlife species for the trade requires a more proactive approach to address emerging trends, and low-cost and effective solutions to prevent species decline. Over a 5-month period in 2017, we used expert-driven horizon scanning, facilitated online, to identify emerging trends of the illegal wildlife trade in Mesoamerica. We found that the main emerging trends included digital and technological advancements, greater regional access to the global community, developments in trafficking techniques and growing demand for certain species. Our findings demonstrate that horizon scanning can be used as a tool for identifying emerging trends of illegal wildlife trade in data-poor contexts. We recommend that horizon scanning is used regularly for systematic monitoring of trends and to prioritize resources for immediate and emerging trends in illegal wildlife trade.

There were 479 reported whale shark Rhincodon typus encounters between 1999 and 2011 at the island of Utila, which forms part of the Meso-American Barrier Reef System (MBRS) in the western Caribbean Sea. The majority of R. typus were found to feed on small bait fish associated with various tuna species. Ninety-five individual R. typus, ranging from 2 to 11 m total length (LT ), were identified through their unique spot patterns. A significant male bias (65%) was present. There was no significant difference between the mean ± s.d. LT of female (6·66 ± 1·65 m) and male (6·25 ± 1·60 m) R. typus. Most R. typus were transient to Utila, with 78% sighted only within a single calendar year, although some individuals were sighted in up to 5 years. Mean residency time was modelled to be 11·76 days using maximum likelihood methods.

Whale sharks (Rhincodon typus) are seasonal visitors to four sites in the Western Caribbean, 3 of which are encompassed by the Mesoamerican Barrier Reef. Predictable encounters with the world's largest fish have raised this species' profile globally and led to several research and conservation efforts that aim to elucidate the need for information for the species management and balance the growing demand for highly lucrative encounter tourism. Tagging studies have demonstrated that the whale shark population is relatively small and likely forms a single population. Individuals move throughout the region between 3 of 4 known feeding sites and are capable of timing their movements to pulses of productivity. Whale shark tourism's dramatic growth has led to a range of protective measures and scientific studies both precautionary and reactionary that require better harmonization throughout the region to be effective. This paper will provide an overview of the status of whale shark research and conservation efforts in the Western Caribbean and identify future management needs to minimize anthropogenic impacts and enable continued whale shark visitation at key feeding sites.