Abstract

We present results of an inwater research program focusing on basic ecology of juvenile hawksbill turtles (Eretmochelys imbricata) in the Cayman Islands. We made 206 captures of 135 hawksbills in Little Cayman and 103 captures of 97 hawksbills in Grand Cayman. The Cayman Islands aggregation demonstrated a broad size distribution (20.5–62.6 cm straight carapace length), slow growth rate (3.0 ± 0.9 cm/y), and multiple recaptures, suggesting long-term residence in some individuals. Demonstrated home range was small (mean distance from capture to recapture 545 ± 514 m, range 2–2080 m); although, an international tag return suggested a long-range developmental migration. Vertical features provided important habitat in Little Cayman, and larger turtles were generally captured in deeper waters. Behavior at sighting varied by habitat: resting, swimming, and feeding were observed in coral reef, reef wall, and hardbottom colonized by sponges and gorgonians, and resting was frequently observed in uncolonized hardbottom. Images obtained from underwater photographers show that hawksbills forage on sponges and occasionally on jellyfish. We observed an apparent commensal feeding relationship between hawksbills and 3 species of angelfish as well as aggressive interactions between hawksbills. We also documented causes of injury and mortality in the study area—including legal, illegal and incidental take, vessel collisions, hurricanes, and natural predation.

Abstract

Based on customs trade statistics from 1999 to 2008, a total of 1989 metric tons of shells of hard-shelled chelonians have been imported into Taiwan for consumption in the traditional Chinese medicine (TCM) market, with an average of 198.9 metric tons/y. The total amount of soft-shell turtle shells imported was 290 metric tons, averaging 29.0 metric tons/y. This volume indicates that millions of turtles and tortoises have been killed annually for the TCM market in Taiwan alone. The trade of turtle shells for TCM has existed in huge volumes for a long time, with no significant decrease in the market size through Convention on International Trade in Endangered Species of Wild Fauna and Flora listing of the main target species. Although the customs trade records were not species-specific, in the market survey conducted in 1996–2002, a total of 39 species of turtles and tortoises, mainly originating from China, Southeast and South Asia, were identified. Only 3 non-Asian species were found. The larger number and numerous species of origin in turtle-shell trade for the TCM market indicate blatant disregard by traders for law and authority of responsible agencies from both source and consumer countries. Observed levels of usage and trade of turtle shells appear to be highly unsustainable and may have a great impact on the chelonian fauna in source areas. For the sustainability of chelonian fauna in Asia, clear policies and close international cooperation for the regulation of turtle-shell trade are urgently needed.

Abstract

Although the olive ridley sea turtle (Lepidochelys olivacea) is the most abundant sea turtle in the world, the species has exhibited a significant decrease in the size of arribadas at Nancite Beach, Costa Rica, since its discovery in 1970. In the present study, we compiled data on number of nesting females per arribada from previous authors for the period 1971–1997 and collected new data using a total count methodology and a strip transect method for the arribadas during 1999–2007. We used generalized additive models to assess the trend of arribada size for the period 1971–2007. Our data indicate a significant reduction of 42%, 84%, and 90% in the number of nesting females per arribada in the periods 1971–1984, 1971–1992, and 1971–2007, respectively. Although we could not determine the specific reasons for this attrition we speculate that this decline may be driven by embryo-associated mortality due to a poor nest microenvironment in this beach. Our data confirm that the Nancite arribada population has undergone a significant decrease over the past 36 years but that the population currently appears to be at a stable low point. In addition, our data show that hatchling production may be increasing at this beach, which suggests the possibility that this population may recover over a few decades. The significant attrition observed in this study underscores the ephemeral nature of arribada populations in general and the need for the continued monitoring of the Nancite population.

Strange softshell turtles

large and flaccid,

stacked in plastic boxes

next to the sidewalk

on a cold hard butcher shop floor.

Maybe you were

raised on a farm,

where captive born turtles

knew nothing of freedom

fattened for the kill

your every need, supplied.

More likely though

you were trapped this summer,

wrenched from your native watery

the waters you will only know

in your last turtle dreams.

We are not your friends,

our actions do not deceive you.

Even I, empathetic to your plight

will never be trusted.

How frankly you stare,

how brave you seem

in spite of