scholarly journals Movement patterns of juvenile hawksbill turtles Eretmochelys imbricata at a Caribbean coral atoll: long-term tracking using passive acoustic telemetry

2017 ◽  
Vol 32 ◽  
pp. 309-319 ◽  
Author(s):  
MG Chevis ◽  
BJ Godley ◽  
JP Lewis ◽  
J Jackson Lewis ◽  
KL Scales ◽  
...  
Keyword(s):  
Acoustic Telemetry ◽  
Movement Patterns ◽  
Eretmochelys Imbricata ◽  
Caribbean Coral ◽  
Passive Acoustic ◽  
Hawksbill Turtles

Short- and long-term movement patterns in the freshwater whipray (Himantura dalyensis) determined by the signal processing of passive acoustic telemetry data

2012 ◽  
Vol 63 (4) ◽  
pp. 341 ◽  
Author(s):  
Hamish A. Campbell ◽  
Matthew Hewitt ◽  
Matthew E. Watts ◽  
Stirling Peverell ◽  
Craig E. Franklin
Keyword(s):  
Signal Processing ◽  
Acoustic Telemetry ◽  
Movement Patterns ◽  
Wet Season ◽  
Aquatic Animals ◽  
Location Data ◽  
Linear Movement ◽  
Passive Acoustic ◽  
Free Ranging ◽  
Periodic Components

Patterns of movement in aquatic animals reflect ecologically important behaviours. Cyclical changes in the abiotic environment influence these movements, but when multiple processes occur simultaneously, identifying which is responsible for the observed movement can be complex. Here we used acoustic telemetry and signal processing to define the abiotic processes responsible for movement patterns in freshwater whiprays (Himantura dalyensis). Acoustic transmitters were implanted into the whiprays and their movements detected over 12 months by an array of passive acoustic receivers, deployed throughout 64 km of the Wenlock River, Qld, Australia. The time of an individual’s arrival and departure from each receiver detection field was used to estimate whipray location continuously throughout the study. This created a linear-movement-waveform for each whipray and signal processing revealed periodic components within the waveform. Correlation of movement periodograms with those from abiotic processes categorically illustrated that the diel cycle dominated the pattern of whipray movement during the wet season, whereas tidal and lunar cycles dominated during the dry season. The study methodology represents a valuable tool for objectively defining the relationship between abiotic processes and the movement patterns of free-ranging aquatic animals and is particularly expedient when periods of no detection exist within the animal location data.

Diving behavior and movements of juvenile hawksbill turtles Eretmochelys imbricata on a Caribbean coral reef

Coral Reefs ◽  
2008 ◽  
Vol 28 (1) ◽  
pp. 55-65 ◽  
Author(s):  
J. M. Blumenthal ◽  
T. J. Austin ◽  
J. B. Bothwell ◽  
A. C. Broderick ◽  
G. Ebanks-Petrie ◽  
...  
Keyword(s):  
Coral Reef ◽  
Diving Behavior ◽  
Eretmochelys Imbricata ◽  
Caribbean Coral ◽  
Caribbean Coral Reef ◽  
Hawksbill Turtles

The hawksbill turtle, Eretmochelys imbricata, in Queensland: population structure within a southern Great Barrier Reef feeding ground.

1992 ◽  
Vol 19 (4) ◽  
pp. 489 ◽  
Author(s):  
CJ Limpus
Keyword(s):  
Great Barrier Reef ◽  
Carapace Length ◽  
Regression Equations ◽  
Barrier Reef ◽  
Growth Data ◽  
Eretmochelys Imbricata ◽  
Nesting Beaches ◽  
Hawksbill Turtles ◽  
Feeding Grounds

Hawksbill turtles, Eretmochelys imbricata, live at low density on coral reefs in the southern Great Barrier Reef. The biomass of the species on Heron Reef was estimated at 0.82 kg ha-1. This is equivalent to 3.34 turtles km-1. The nesting beaches used by these E. imbricata are unknown. However, within the Great Barrier Reef and Coral Sea region, no regular nesting by the species occurs within 1200 km of these reefal feeding grounds. E. imbricata take up long-term residence in these feeding grounds at a minimum curved carapace length of 35.0cm. The E. imbricata feeding over these reefs ranged in size from these small immatures up to adults with curved carapace length of 87.5cm, but the maturity ratio was very strongly biased toward immatures (maturity ratio=0.01 adults). The sex ratio of all size classes was significantly skewed in favour of females (2.57 : 1 females : male overall) while 2% of the turtles were identified as intersex. Growth data from these turtles indicate that they will be decades old at first breeding. A key for sexing and assessing reproductive maturity of E. imbricata is provided. Regression equations for converting between curved carapace length and other standard measures including straight carapace measures, weight, head length and width and plastron length are described.

Long-term monitoring provides insight into estuarine top predator (Carcharhinus leucas) resilience following an extreme weather event

2020 ◽  
Vol 639 ◽  
pp. 169-183
Author(s):  
P Matich ◽  
BA Strickland ◽  
MR Heithaus
Keyword(s):  
Habitat Use ◽  
Acoustic Telemetry ◽  
South Florida ◽  
Behavioral Variability ◽  
Catch Per Unit Effort ◽  
Ontogenetic Shifts ◽  
Carcharhinus Leucas ◽  
Acute Disturbance ◽  
Cold Snap

Chronic environmental change threatens biodiversity, but acute disturbance events present more rapid and immediate threats. In 2010, a cold snap across south Florida had wide-ranging impacts, including negative effects on recreational fisheries, agriculture, and ecological communities. Here, we use acoustic telemetry and historical longline monitoring to assess the long-term implications of this event on juvenile bull sharks Carcharhinus leucas in the Florida Everglades. Despite the loss of virtually all individuals (ca. 90%) within the Shark River Estuary during the cold snap, the catch per unit effort (CPUE) of age 0 sharks on longlines recovered through recruitment within 6-8 mo of the event. Acoustic telemetry revealed that habitat use patterns of age 0-2 sharks reached an equilibrium in 4-6 yr. In contrast, the CPUE and habitat use of age 3 sharks required 5-7 yr to resemble pre-cold snap patterns. Environmental conditions and predation risk returned to previous levels within 1 yr of the cold snap, but abundances of some prey species remained depressed for several years. Reduced prey availability may have altered the profitability of some microhabitats after the cold snap, leading to more rapid ontogenetic shifts to marine waters among sharks for several years. Accelerated ontogenetic shifts coupled with inter-individual behavioral variability of bull sharks likely led to a slower recovery rate than predicted based on overall shark CPUE. While intrinsic variation driven by stochasticity in dynamic ecosystems may increase the resistance of species to chronic and acute disturbance, it may also increase recovery time in filling the diversity of niches occupied prior to disturbance if resistive capacity is exceeded.

scholarly journals Short- and long-term movement patterns of six temperate reef fishes (Families Labridae and Monacanthidae)

1995 ◽  
Vol 46 (5) ◽  
pp. 853 ◽  
Author(s):  
NS Barrett
Keyword(s):  
Natural Habitat ◽  
Movement Patterns ◽  
Reef Fishes ◽  
Long Term Results ◽  
Home Ranges ◽  
Temperate Reef ◽  
Effective Deterrent ◽  
Short And Long Term ◽  
Natural Boundaries

Movement patterns were studied on a 1-ha isolated reef surrounding Arch Rock in southern Tasmania. Short-term movements were identified from diver observations, and interpretation of long-term movements involved multiple recaptures of tagged individuals. Visual observations indicated that the sex-changing labrids Notolabrus tetricus, Pictilabrus laticlavius and Pseudolabrus psittaculus were all site-attached, with females having overlapping home ranges and males being territorial. In the non-sex-changing labrid Notolabrus fucicola and in the monacanthids Penicipelta vittiger and Meuschenia australis, there was no evidence of territorial behaviour and 1-h movements were in excess of the scale of the study. The long-term results indicated that all species were permanent reef residents, with most individuals of all species except M. australis always being recaptured within a home range of 100 m × 25 m or less. Only 15% of individuals of M. australis were always recaptured within this range category. The natural habitat boundary of open sand between the Arch Rock reef and adjacent reefs appeared to be an effective deterrent to emigration. The use of natural boundaries should be an important consideration in the design of marine reserves where the aim is to minimize the loss of protected species to adjacent fished areas.

WING MOVEMENTS AND LIFT REGULATION IN THE FLIGHT OF DESERT LOCUSTS

1993 ◽  
Vol 182 (1) ◽  
pp. 57-69 ◽  
Author(s):  
M. Wortmann ◽  
W. Zarnack
Keyword(s):  
Body Weight ◽  
Unsteady Aerodynamics ◽  
Movement Patterns ◽  
The Body ◽  
Three Dimensions ◽  
Body Angle ◽  
Wing Movement ◽  
Induced Changes ◽  
Lift Body

1. We simultaneously recorded lift/body weight, flight speed, body angle and 12 variables of wing movement for locusts performing tethered long-term flight with low movement scatter. The movements of the forewings and hindwings were recorded in three dimensions by means of miniature induction coils. 2. By adjusting the body angle, we could reproducibly manipulate lift generation as a consequence of induced changes in the wings' movement patterns. We were therefore able to analyse various relationships between the movement patterns and lift. 3. The most prominent variations of kinematic variables were observed for the forewing movements. The relative lift and the steady angle of pitch were positively correlated but there was a negative correlation between relative lift and pitching amplitude. We found no correlation between relative lift and flapping amplitude. Our results seem to correspond to a new theory about unsteady aerodynamics of oscillating aerofoils. 4. We sometimes observed variations in lagging. 5. The forewing downstroke was delayed by 0–8 ms following the hindwing downstroke. Relative lift was positively correlated to this delay.

scholarly journals Natal foraging philopatry in eastern Pacific hawksbill turtles

2017 ◽  
Vol 4 (8) ◽  
pp. 170153 ◽  
Author(s):  
Alexander R. Gaos ◽  
Rebecca L. Lewison ◽  
Michael P. Jensen ◽  
Michael J. Liles ◽  
Ana Henriquez ◽  
...  
Keyword(s):  
Genetic Research ◽  
Eastern Pacific ◽  
Marine Turtle ◽  
Natal Philopatry ◽  
Eretmochelys Imbricata ◽  
Turtle Species ◽  
Marine Turtles ◽  
Complex Processes ◽  
Natal Homing ◽  
Hawksbill Turtles

The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles ( Eretmochelys imbricata ) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.

scholarly journals Stingray Habitat Use Is Dynamically Influenced by Temperature and Tides

2022 ◽  
Vol 8 ◽  
Author(s):  
Chantel Elston ◽  
Paul D. Cowley ◽  
Rainer G. von Brandis ◽  
James Lea
Keyword(s):  
Habitat Use ◽  
Acoustic Telemetry ◽  
Monsoon Season ◽  
Abiotic Factors ◽  
Environmental Drivers ◽  
Shallow Waters ◽  
Shallow Marine ◽  
Tidal Cycles ◽  
Management Plans ◽  
Passive Acoustic

Abiotic factors often have a large influence on the habitat use of animals in shallow marine environments. Specifically, tides may alter the physical and biological characteristics of an ecosystem while changes in temperature can cause ectothermic species to behaviorally thermoregulate. Understanding the contextual and relative influences of these abiotic factors is important in prioritizing management plans, particularly for vulnerable faunal groups like stingrays. Passive acoustic telemetry was used to track the movements of 60 stingrays at a remote and environmentally heterogeneous atoll in Seychelles. This was to determine if habitat use varied over daily, diel and tidal cycles and to investigate the environmental drivers behind these potential temporal patterns. Individuals were detected in the atoll year-round, but the extent of their movement and use of multiple habitats increased in the warmer NW-monsoon season. Habitat use varied over the diel cycle, but was inconsistent between individuals. Temperature was also found to influence stingray movements, with individuals preferring the deeper and more thermally stable lagoon habitat when extreme (hot or cold) temperature events were observed on the flats. Habitat use also varied over the tidal cycle with stingrays spending a higher proportion of time in the lagoon during the lowest tides, when movement on the flats were constrained due to shallow waters. The interplay of tides and temperature, and how these varied across diel and daily scales, dynamically influenced stingray habitat use consistently between three species in an offshore atoll.

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