Environmental Influences on Long-term Movement Patterns of a Euryhaline Elasmobranch (Carcharhinus leucas) Within a Subtropical Estuary

2020 ◽  
Vol 43 (8) ◽  
pp. 2152-2169 ◽  
Author(s):  
R. D. Pillans ◽  
G. C. Fry ◽  
A. D. L. Steven ◽  
T. Patterson
Keyword(s):  
Environmental Influences ◽  
Movement Patterns ◽  
Carcharhinus Leucas ◽  
Subtropical Estuary

Occurrence, home range and movement patterns of juvenile bull (Carcharhinus leucas) and lemon (Negaprion brevirostris) sharks within a Florida estuary

2008 ◽  
Vol 59 (6) ◽  
pp. 489 ◽  
Author(s):  
B. G. Yeiser ◽  
M. R. Heupel ◽  
C. A. Simpfendorfer
Keyword(s):  
Home Range ◽  
Coastal Lagoons ◽  
Movement Patterns ◽  
Shark Species ◽  
Convex Polygons ◽  
Negaprion Brevirostris ◽  
Large Juvenile ◽  
Carcharhinus Leucas ◽  
Coastal Species

The movement patterns of large juveniles are poorly known for many shark species. With increasing pressure on shark populations these data are critical for the management of large coastal species. A series of acoustic receivers were positioned in Pine Island Sound, Florida, USA, to passively track the long-term movements of large juvenile bull (Carcharhinus leucas) and lemon (Negaprion brevirostris) sharks. Nineteen C. leucas and five N. brevirostris were monitored during 2003 and 2004. Individual C. leucas were present for 8 to 89 days, while N. brevirostris were present for 12 to 83 days. Weekly minimum convex polygons and kernel utilisation distributions were calculated to demonstrate the home range and core areas of use of both species. Spectral analysis demonstrated that several N. brevirostris showed repetitive diel north–south movement patterns over periods of up to 28 consecutive days. C. leucas demonstrated regular use of backwater habitats. Long-term use of estuarine areas by these large juvenile sharks suggests that estuarine coastal lagoons provide an important habitat for this portion of their life history and as such, protection of these habitats may assist in shark management and conservation.

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 Companions and Casual Acquaintances: The Nature of Associations Among Bull Sharks at a Shark Feeding Site in Fiji

2021 ◽  
Vol 8 ◽  
Author(s):  
Thibaut Bouveroux ◽  
Nicolas Loiseau ◽  
Adam Barnett ◽  
Natasha D. Marosi ◽  
Juerg M. Brunnschweiler
Keyword(s):  
Marine Reserve ◽  
Temporal Association ◽  
Feeding Site ◽  
Carcharhinus Leucas ◽  
Best Fitting ◽  
Social Associations ◽  
Simple Ratio ◽  
A Site ◽  
Predictor Factors

Provisioning activities in wildlife tourism often lead to short-term animal aggregations during the feeding events. However, the presence of groups does not necessarily mean that individuals interact among each other and form social networks. At the Shark Reef Marine Reserve in Fiji, several dozen bull sharks (Carcharhinus leucas) regularly visit a site, where direct feeding is conducted during tourism driven shark dives. On 3,063 shark feeding dives between 2003 and 2016, we visually confirmed the presence of 91 individual bull sharks based on external and long-lasting identification markings. We measured the intensity of associations between pairs of individuals by calculating the Simple Ratio Index (SRI) and calculated Generalized Affiliation Indices (GAIs) to distinguish true associations between dyads from structural predictor factors. Although the resulting mean SRIs were low, ranging from 0.01 to 0.12 (SRImean = 0.06; mean SRImax = 0.21), preferred long-term companionships were observed between individuals. Avoidances were also observed within pairs of individuals during the second half of the study. The best fitting model describing the temporal association patterns of bull sharks revealed a social structure which is characterized by preferred companionships and casual acquaintances. Our results suggest that the aggregation resulting from direct feeding has served to facilitate the development of social associations.

Habitat effects on home range and schooling behaviour in a herbivorous fish (Kyphosus bigibbus) revealed by acoustic tracking

2017 ◽  
Vol 68 (8) ◽  
pp. 1454 ◽  
Author(s):  
R. D. Pillans ◽  
R. C. Babcock ◽  
D. P. Thomson ◽  
M. D. E. Haywood ◽  
R. A. Downie ◽  
...  
Keyword(s):  
Home Range ◽  
Patch Reef ◽  
Movement Patterns ◽  
Herbivorous Fish ◽  
Ecological Role ◽  
Patch Reefs ◽  
Poor Understanding ◽  
Schooling Behaviour ◽  
Acoustic Tags

Large mobile herbivorous fish that specialise in browsing large brown algae are particularly important on coral reefs because their activities mediate algal–coral competition. Despite this important ecological role, we have a poor understanding of the movement patterns of such large herbivorous fish, including Kyphosus bigibbus. Nineteen K. bigibbus captured near adjacent but distinct patch reefs were tagged with internal acoustic tags and their movements monitored for up to 20 months by an array of 60 acoustic receivers. Home-range estimates showed that movements of individuals from each patch reef encompassed different spatial extents and resulted in differences in habitat used by the two groups of fish. The average 50 and 95% kernel utilisation distribution for long-term resident fish was 0.27±0.03 and 1.61±0.30km2 respectively, ranges that represent the largest values for a herbivorous coral reef fish recorded to date. There was a significantly higher degree of fidelity among fish from the same school, and to particular patch reefs, despite the proximity of the reefs and substantial overlap between schools of conspecifics. A coefficient of sociality was used on pairs of fish and showed that there was no evidence that individuals were consistently detected together when they were detected by receivers away from their home reef. The variability of movement patterns among individuals of K. bigibbus results in an increased niche footprint for this important browser, potentially increasing reef resilience.

Assessing variation in assemblages of large marine fauna off ocean beaches using drones

2020 ◽  
Vol 71 (1) ◽  
pp. 68 ◽  
Author(s):  
Brendan P. Kelaher ◽  
Andrew P. Colefax ◽  
Alejandro Tagliafico ◽  
Melanie J. Bishop ◽  
Anna Giles ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Bottlenose Dolphins ◽  
Spatial And Temporal Variation ◽  
Marine Animals ◽  
Marine Fauna ◽  
South Wales ◽  
Carcharhinus Leucas ◽  
Spatio Temporal ◽  
Marine Wildlife

The turbulent waters off ocean beaches provide habitat for large marine fauna, including dolphins, sharks, rays, turtles and game fish. Although, historically, these assemblages have proven difficult to quantify, we used a new drone-based approach to assess spatial and temporal variation in assemblages of large marine fauna off four exposed beaches in New South Wales, Australia. In total, 4388 individual large marine animals were identified from 216 drone flights. The most common taxa, bottlenose dolphins (Tursiops spp.) and Australian cownose rays (Rhinoptera neglecta), occurred in 25.5 and 19.9% of flights respectively. White (Carcharodon carcharias), bull (Carcharhinus leucas) and other whaler (Carcharhinus spp.) sharks were observed in <1% of flights. There was significant variation in the structure of assemblages of large fauna among beaches, with those adjacent to riverine estuaries having greater richness and abundance of wildlife. Overall, drone surveys were successful in documenting the spatio-temporal dynamics of an impressive suite of large marine fauna. We contend that emerging drone technology can make a valuable contribution to the ecological information required to ensure the long-term sustainability of sandy-beach ecosystems and associated marine wildlife.

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