Abstract: Distances between capture and recapture locations of tagged immature hawksbill turtles Eretmochelys imbricata (Linnaeus) are analyzed for four near-shore survey sites at Mona and Monito Islands, Puerto Rico. Data were obtained for 87 turtles ranging in size from 20.0 to 56.7 cm straight-line carapace length. Net displacements by individual turtles averaged 0.45 km (S.D.=0.66, range 0.00–5.22) for mean inter-capture intervals of 465 days (S.D.=331, range 9–1118). Measured displacements were not correlated with turtle size and did not differ significantly between survey sites. Movements of three immature turtles fitted with sonic tags were monitored by acoustical tracking in reef habitats along the southwestern coast of Mona Island. The area utilized by the turtles during the 11–16 days of tracking measured 0.07–0.21 km2. It is concluded that immature hawksbill turtles maintain a limited home range area and appear resident at the feeding grounds of Mona and Monito Islands for periods of at least several years.
Abstract: 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.
Abstract: We present diving data for four whale sharks in relation to a predictable food pulse (reef fish spawn) and an analysis of the longest continuous fine-resolution diving record for a planktivorous shark. Fine-resolution pressure data from a recovered pop-up archival satellite tag deployed for 206 days on a whale shark were analysed using the fast Fourier Transform method for frequency domain analysis of time-series. The results demonstrated that a free-ranging whale shark displays ultradian, diel and circa-lunar rhythmicity of diving behaviour. Whale sharks dive to over 979.5 m and can tolerate a temperature range of 26.4 degrees C. The whale sharks made primarily diurnal deep dives and remained in relatively shallow waters at night. Whale shark diving patterns are influenced by a seasonally predictable food source, with shallower dives made during fish spawning periods.
