Flipper Tags Research Articles

Assessing Hot-Iron and Cryo-Branding for Permanently Marking Southern Elephant Seals

The process of marking otherwise indistinguishable animals as individuals (and following them through subsequent phases of their lives) has been central to numerous advances in animal ecology, management, and conservation (Caughley and Gunn 1996). Indeed, because accurate survival estimates are important for assessing the conservation status of animals, the quality, durability, and readability of marks applied are essential characteristics that must be taken into consideration when choosing a marking technique. When identifying marks are lost, survival estimates are biased (Eberhardt et al. 1979, Seber and Felton 1981, Frazer 1983, Lebreton et al. 1992); therefore, permanent and legible marks, such as brands, often represent more valuable approaches. There are several other methods of marking animals (Erickson et al. 1993), but some of these methods are either temporary (e.g., tags) or the identifiers may become difficult to read over time. For example, passive integrating transponder tags require all unmarked animals to be scanned with a tag-reading head placed close (usually within 20 cm) to the animal’s body so the tag signal has a good chance of being received, and flipper tags require the observer be close to the animal (Clarke and Kerry 1998, Galimberti et al. 2000). Such problems in large vertebrates are largely overcome by branding because the marks are external and visible from a distance (Harwood et al. 1976, Harkonen et al. 1999, Pomeroy et al. 1999, Harkonen and Harding 2001, Raum-Suryan et al. 2002). The southern elephant seal (Mirounga leonina) is one species of large vertebrate marine predator that has provided important ecological, behavioral, and conservation information for Antarctic ecosystems through the marking of individuals (Hindell et al. 2003, McMahon et al. 2003, Bradshaw et al. 2004, McMahon and Burton 2005). Additionally, many southern elephant seal populations have declined in recent times (McMahon et al. 2005a,b), so longterm assessments of their status continue to be required. The Australian Antarctic Division hot-branded southern elephant seals at Heard and Macquarie islands in the 1950s and 1960s (Chittleborough and Ealey 1951, Ingham 1967) and again in the 1990s (van den Hoff et al. 2004) for demographic studies. However, none of those studies evaluated the long-term effects (i.e., survival probability) hot-iron branding may have on the elephant seals being studied. Therefore, we assessed the consequences of branding on survival by comparing estimates of survival probability for branded versus tagged-only seals. We also assessed the effectiveness of cryo-branding because some research suggests that this type of branding may be less invasive than hotiron branding (Schwartzkopf-Genswein et al. 1997b).

Movement Patterns of Green Turtles (Chelonia mydas) in Cuba and Adjacent Caribbean Waters Inferred from Flipper Tag Recaptures

To study the movement patterns of Green Seaturtle (Chelonia mydas) populations in the Caribbean region using Cuban habitats, tag-recapture data from local (Cuban National Tagging Program 1989–2002) and international programs (1959–2002) were compiled and compared. Of the 742 turtles tagged in Cuba at fishing areas, nesting beaches and head-start facilities, 5.5% were recaptured, mostly outside of Cuban waters and with a majority of these (76.9%) off the coast of Nicaragua. Green Seaturtles tagged elsewhere and recaptured in Cuba included head-started juveniles from Grand Cayman (45% of the total), Mexico (2.3%), and Florida (1.8%); wild juveniles from the Bahamas (14.1%), Bermuda (5.4%), and Florida (1.5%); and adults from Tortuguero (26%), Florida, USA (1.3%), Mexico (1%), Venezuela (1.3%), and U.S. Virgin Islands (0.3%). Recaptures of tags placed at sites north of Cuba (Bermuda and the Bahamas) clustered in the northeast region of Cuba, whereas those from the south (Grand Cayman) were recaptured in southern areas. Recaptures from Tortuguero tags were concentrated in the southeast and westward regions of Cuba. Turtles from the Bahamas, Grand Cayman, and Bermuda showed the highest recapture rates in Cuban habitats, with 3.2, 1.9, and 1.0% of the total number of tags applied, respectively. These results for a broad range of populations and across life stages underscore the regionwide significance of Cuban sites as critical habitats or migratory corridors.

Flipper tagging with archival data recorders for short-term assessment of diving in nesting female turtles

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 2:7-13 (2006) - doi:10.3354/esr002007 Flipper tagging with archival data recorders for short-term assessment of diving in nesting female turtles Tomoharu Eguchi1,*, Jeffrey A. Seminoff1, Steven A. Garner2, Jeanne Alexander-Garner2, Peter H. Dutton1 1NOAA—National Marine Fisheries Service, Southwest Fisheries Science Center, 8604 La Jolla Shores Drive, La Jolla, California 92037, USA 2West Indies Marine Animal Research and Conservation Service, 202 Prosperity, Frederiksted, St. Croix, US Virgin Islands 00840, USA *Email: tomo.eguchi@noaa.gov ABSTRACT: Archival data recorders (ADRs) were deployed on nesting female leatherback turtles Dermochelys coriacea to record short-term diving behavior. Plastic cattle ear tags were used as a platform to which an archival depth recorder was attached. The tags were applied to the hind flippers of 10 turtles, ranging from 141.9 to 160.6 cm in curved carapace length at Sandy Point National Wildlife Refuge, St. Croix, US Virgin Islands. We later retrieved 7 of the original 10 tags at the beach; durations of deployment ranged from 22 to 90 h. The recorded number of dives per deployment ranged from 118 to 310. Maximum dive depths ranged from 175.6 to 479.7 m (mean 275.4, SE 41.7, n = 7), and maximum dive durations ranged from 16.3 to 27.8 min (mean 21.3, SE = 1.5, n = 7). Dive data indicated that post-nesting females dove deeper, less frequently, and longer than pre-nesting females—depth: mean post 78.6 m, 95% CI (56.0, 101.2) versus mean pre 45.4 m, 95% CI (37.1, 53.8); frequency: mean post 2.4 dives h–1, 95% CI (1.8, 2.9) versus mean pre 5.4 dives h–1, 95% CI (5.0, 5.8); duration: mean post 13.1 min, 95% CI (11.2, 15.1) versus mean pre 6.1 min, 95% CI (5.5, 6.6). A pre-nesting female was defined as one that attempted to nest but returned to the sea without laying eggs. This ADR deployment method provides a simpler and less intrusive alternative to other tag attachment methods, such as harness and tethers, when the research questions require only short deployment time of archival recorders. KEY WORDS: Dermochelys coriacea · Diving behavior · Archival tag · Flipper tag · Time-depth recorder · ADR Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 2. Online publication date: May 03, 2006 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2006 Inter-Research.

Migration of green turtles Chelonia mydas from Tortuguero, Costa Rica

During 1955–2003, flipper tags were attached to 46,983 green turtles and ten turtles were fitted with satellite transmitters at Tortuguero, Costa Rica. Eight satellite-tracked turtles stayed within 135 km of the beach and probably returned to nest after release. The internesting area is more extensive than previously documented. Post-nesting migration routes of satellite-tracked turtles varied. Seven turtles swam close to the coast and three turtles swam through oceanic waters before moving toward nearshore areas. Sea surface height anomaly maps indicate that oceanic movements were consistent with the southwestern Caribbean gyre. Circling and semi-circling turtles could have been disoriented but submergence and surface times suggest they may have been feeding in Sargassum sp. concentrations. Rapid post-nesting migrations (mean 2.2 km hr−1) ended on benthic feeding grounds in shallow waters (<20 m) off Belize (n=1), Honduras (n=1) and Nicaragua (n=8). The spatial distribution of migration end points (n=10) and tag returns (n=4,669) are similar. Fishermen in Nicaragua target green turtles along migratory corridors and on foraging grounds. Management efforts are urgently needed in Nicaragua, particularly in the high-density feeding areas south and east of the Witties (N14°09 W82°45). The proximity of foraging grounds to the nesting beach (mean 512 km) may permit female turtles to invest more energy in reproduction and hence the Tortuguero population may have greater potential for recovery than other green turtle nesting populations. Recovery of the Tortuguero green turtle population will benefit countries and marine ecosystems throughout the Caribbean, especially Nicaragua.

Migration of hawksbill turtles Eretmochelys imbricata from Tortuguero, Costa Rica

The hawksbill turtle Eretmochelys imbricata is a widely distributed and critically endangered species that feeds on sponges and fills an important ecological role in the coral reef ecosystem. At Tortuguero, Costa Rica, trend analyses indicate considerable decline in nesting estimated at 77.2–94.5% between 1956 and 2003, as a result of excessive turtle fishing. We analyzed flipper tag returns, satellite telemetry and genetic samples to determine movements and habitat use of adult female Tortuguero hawksbills. Tag returns and satellite telemetry show hawksbills migrate to foraging grounds in Nicaragua and Honduras. Genetic analysis indicates the hawksbills may also migrate to Cuban, Puerto Rican, and possibly Mexican waters. We conclude hawksbills represent an internationally shared resource. There is a close correlation between tag recapture sites, hawksbill foraging grounds and coral reef distribution. Caribbean coral reef decline may reduce food availability and negatively impact hawksbill turtles. Conversely, hawksbill decline may shift the balance on coral reefs by reducing predation pressure on sponges and hence make coral reefs less resilient to natural and anthropogenic threats. Strategies aiming to conserve hawksbills and coral reefs must consider both the extensive hawksbill migrations and the close relationship between the species and the coral reef ecosystem.

Monitoring green turtles (Chelonia mydas) at a coastal foraging area in Baja California, Mexico: multiple indices to describe population status

From June 1995 to August 2002 we assessed green turtle (Chelonia mydas) population structure and survival, and identified human impacts at Bahía de los Angeles, a large bay that was once the site of the greatest sea turtle harvest rates in the Gulf of California, Mexico. Turtles were captured live with entanglement nets and mortality was quantified through stranding surveys and flipper tag recoveries. A total of 14,820 netting hours (617·5 d) resulted in 255 captures of 200 green turtles. Straight-carapace length and mass ranged from 46·0–100·0 cm (mean=74·3±0·7 cm) and 14·5–145·0 kg (mean=61·5±1·7 kg), respectively. The size–frequency distribution remained stable during all years and among all capture locations. Anthropogenic-derived injuries ranging from missing flippers to boat propeller scars were present in 4% of captured turtles. Remains of 18 turtles were found at dumpsites, nine stranded turtles were encountered in the study area, and flipper tags from seven turtles were recovered. Survival was estimated at 0·58 for juveniles and 0·97 for adults using a joint live-recapture and dead-recovery model (Burnham model). Low survival among juveniles, declining annual catch per unit effort, and the presence of butchered carcasses indicated human activities continue to impact green turtles at this foraging area.

Movement patterns of green turtles in Brazilian coastal waters described by satellite tracking and flipper tagging

The movements of 8 green turtles Chelonia mydas in Brazilian coastal waters were tracked using transmitters linked to the Argos system for periods of between 1 and 197 d. These were the first tracking data gathered on juveniles of this species in this important foraging ground. Infor- mation was integrated with that collected over a decade using traditional flipper-tagging methods at the same site. Both satellite telemetry and flipper tagging suggested that turtles undertook 1 of 3 general patterns of behaviour: pronounced long range movements (>100 km), moderate range move- ments (<100 km) or extended residence very close to the capture/release site. There seemed to be a general tendency for the turtles recaptured/tracked further afield to have been among the larger turtles captured. Satellite tracking of 5 turtles which moved from the release site showed that they moved through coastal waters; a factor which is likely to predispose migrating turtles to incidental capture as a result of the prevailing fishing methods in the region. The movements of the 3 turtles who travelled less than 100 km from the release site challenge previous ideas relating to home range in green turtles feeding in sea grass pastures. We hypothesise that there may be a fundamental difference in the pattern of habitat utilisation by larger green turtles depending on whether they are feeding on seagrass or macroalgae. Extended tracking of 2 small turtles which stayed near the release point showed that small juvenile turtles, whilst in residence in a particular feeding ground, can also exhibit high levels of site-fidelity with home ranges of the order of several square kilometers.

Plastic flipper tags are inadequate for long-term identification of the flatback sea turtle (Natator depressus)

Two styles of plastic tags were used on flatback sea turtles (Natator depressus). In parallel with conventional metal flipper tagging, and internal PIT tagging methodologies, a total of 476 plastic tags were applied to 428 individual females in the 1991, 1992, 1993 and 1998 nesting seasons at Wild Duck Island, Queensland. Data are reported up to and including the 2000 nesting season demonstrating that plastic tags are inadequate for the long-term identification of these turtles, with failures of approximately 80% within three years of application.

Nesting Ecology of the Leatherback Turtle, Dermochelys coriacea, at Parque Nacional Marino Las Baulas, Costa Rica: 1988–1989 to 1999–2000

Abstract We collected data on nesting ecology and identified individual turtles that nested at Parque Nacional Las Baulas, Costa Rica, one of the few remaining nesting sites for Pacific leatherbacks, from 1988–1989 to 1999–2000. We tagged individual female turtles with flipper tags and later with Passive Integrated Transponder (PIT) tags that permitted permanent identification. During the full calendars years of 1990 and 1995, over 93% of nests were laid between the beginning of October and the end of February. We found that 92.4 ± 1% of nesting attempts resulted in successful oviposition, with a mean clutch size of 64.7 ± 1.4 yolked and 38.5 ± 1.0 yolkless eggs (n = 1389). Mean standard curved carapace length and curved carapace width during the surveyed years ranged from 144.4 ± 0.6 cm to 147.6 ± 0.3 cm and from 103.9 ± 0.3 cm to 105.5 ± 0.6 cm, respectively. Reproductive output as determined by estimated clutch frequency (ECF) ranged from 4.3 ± 0.2 to 7.9 ± 0.3 clutches per female per nesting season. T...

EFFECTS OF RESEARCH HANDLING ON THE ENDANGERED HAWAIIAN MONK SEAL

AbstractWe examined the effects of research handling on free‐ranging endangered Hawaiian monk seals, Monachus schauinslandi, by analyzing differences in subsequent year survival, migration, and condition between handled seals and controls during 1983–1998. Each of 549 handled seals was matched to a control seal of the same age, sex, location, and year. Handling included instrumentation with tel metry devices (n= 93), blood sampling (n= 19), and tagging (n= 437). No significant differences were found between handled seals and their controls in one‐year resighting rates, observed migration rates, or condition. Resighting rates of handled and control seals were high (80%‐100%). Available sample sizes were sufficient to detect reasonably small (9%‐20%) differences in resighting rates had they existed among instrumented or tagged seals and controls (α= 0.05, power = 0.90). Too few seals were captured for blood sampling to detect even large differences in their resighting rates. However, blood samples were drawn from most instrumented seals, and there was no indication that this larger group suffered harmful effects. Duration of restraint during flipper tagging had no effect on subsequent probability of resighting. Our analysis suggests that conservative selection procedures and careful handling techniques have no deleterious effects on Hawaiian monk seals.

Intraseasonal Nesting Activity of Loggerhead Sea Turtles (Carettacaretta) in Southeastern North Carolina

Abstract Intraseasonal nesting patters were determined for loggerhead sea turtle (Caretta caretta) nesting on Bald Head Island, North Carolina, one of the northernmost nesting concentrations along the east coast of North America. One hundred and twenty-seven nesting females were tagged with Inconel flipper tags and photographed, accounting for 83% of the 318 nests produced during the 1991 and 1992 nesting seasons. No female nested in both years. Nest production was similar both years. Most females (55.9%) nested once, 5.5% nested twice, 15.0% nested three times, 7.9% nested four times, 12.6% nested five times and 3.1% nested six times. The internesting interval averaged 13.7 d (range 10–18) in 1991 and 14.2 d (range 11–18) in 1992, and it was significantly influenced by seawater temperature. Intraseasonal nest site fidelity was signifcant; most multiple-nesting females (67.9%) confined their nesting activities within 4.8 km. Loggerheads in the northernmost part of their nesting range in the western North ...

Effect of tagging marine turtles on nesting behaviour and reproductive success

We studied green, Chelonia mydas, and loggerhead, Caretta caretta, turtles nesting on the island of Cyprus to determine the effects of flipper tagging on postovipositional behaviour and reproductive success. Tagging was undertaken immediately after oviposition (64 green turtles; 111 loggerheads). On 12 occasions, loggerheads immediately stopped covering the eggs and proceeded directly to the sea. No green turtles abandoned nesting. In all other cases, where sufficient data were collected, the duration of the two postovipositional phases of nesting behaviour (covering and camouflaging) and the speed of descent to the sea did not differ between tagged and untagged turtles. The durations of behaviours also did not differ between females not tagged, tagged once or tagged twice. There was no effect of tagging on the likelihood of hatching or on the hatching success of clutches in either species.

Estimation of tag loss in marine turtle research

From the results from long-term multiple tagging studies of marine turtles in eastern Australia, the probability of tag loss was estimated for standard monel and titanium turtle tags applied at different tagging positions on Caretta caretta and Chelonia mydas in nesting and feeding-ground studies. Tag loss was variable, being a function of tag design, tagging position, species, study type and tag age. Tag loss was greatest from the more distal tagging positions on the trailing edge of the front flippers. Rear flipper tags were lost at a higher rate than tags in the axillary-tagging position on the front-flipper. Tag loss was greater for turtles tagged in nesting studies than in feeding-ground studies. Monel tags, in general, were lost at a greater rate than titanium tags. There was a species contribution to titanium tag loss but not to monel tag loss. The probabilities of tag loss calculated for this study can be used as correction factors for tag loss in those marine-turtle studies where recapture rates have been measured.

Losses of Monel Flipper Tags from Loggerhead Sea Turtles, Caretta caretta

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