Field-Based Feeding Performance and Kinematics of Bull Sharks, Carcharhinus leucas (Carcharhiniformes: Carcharhinidae)

2021 ◽  
Vol 109 (4) ◽  
Author(s):  
Joshua K. Moyer ◽  
Annabelle M. L. Brooks ◽  
Duncan J. Irschick
Keyword(s):  
Feeding Performance ◽  
Carcharhinus Leucas

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 Feeding patterns of two sympatric shark predators in coastal ecosystems of an oceanic island

2017 ◽  
Vol 74 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Clément Trystram ◽  
Karyne M. Rogers ◽  
Marc Soria ◽  
Sébastien Jaquemet
Keyword(s):  
Trophic Ecology ◽  
Dietary Habits ◽  
Stomach Contents ◽  
Nitrogen Isotope ◽  
Oceanic Island ◽  
Apex Predators ◽  
Coastal Habitat ◽  
Galeocerdo Cuvier ◽  
Carcharhinus Leucas ◽  
Bull Shark

Stomach contents and stable carbon and nitrogen isotope analyses (δ13C and δ15N) were used to investigate the trophic ecology of two apex predators, tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas), from Reunion Island to describe their dietary habits at both the population and individual levels. In this oceanic island, the tiger and bull sharks were more piscivorous and teutophagous than noted in previous research from other localities. The δ13C values suggested that bull sharks depended on more neritic organic matter sources than tiger sharks, confirming a coastal habitat preference for bull sharks. Moreover, the total length of the bull shark influenced δ13C values, with smaller individuals being more coastal than larger individuals. All indicators suggest that there is a higher degree of similarity between individual tiger sharks compared with the more heterogeneous bull shark population, which is composed of individuals who specialize on different prey. These results suggest that the two species have different functions in these coastal habitats, and thus, they must be considered independently in terms of conservation and management.

Feeding performance and blood parameters of male goat kids fed EasiFlo® cottonseed

2009 ◽  
Vol 81 (2-3) ◽  
pp. 137-145 ◽  
Author(s):  
S.G. Solaiman ◽  
N.K. Gurung ◽  
Q. McCrary ◽  
H. Goyal ◽  
W.H. McElhenney
Keyword(s):  
Blood Parameters ◽  
Feeding Performance

Feeding performance of juvenile marble goby (Oxyeleotris marmorata Bleeker, 1852) fed acidified diets

2018 ◽  
Vol 26 (4) ◽  
pp. 211-216
Author(s):  
Leong-Seng Lim ◽  
Chui-Fen Teoh ◽  
Gunzo Kawamura ◽  
Annita Seok-Kian Yong ◽  
Rossita Shapawi
Keyword(s):  
Body Length ◽  
Fish Meal ◽  
Control Diet ◽  
Dietary Treatment ◽  
Feeding Trial ◽  
Feeding Performance ◽  
Daily Ingestion ◽  
Ph Level ◽  
Ingestion Ratio ◽  
And Control

Abstract The present study aimed to evaluate the feeding performance of juvenile marble goby (Oxyeleotris marmorata) on acidified diets. Five fish meal-based diets at various pH levels (2.5, 3.2, 4.3, 5.3, and 6.0 (control)) were prepared, and each of them was fed to 10 wild-caught O. marmorata juveniles (body length 7.7–9.3 cm; each fish was placed in an aquarium, hence each dietary treatment was in 10 replicates) for 20 days. Throughout the feeding trial, O. marmorata juveniles showed clear increments in the daily ingestion ratio (IR) values of AD 2.5, AD 3.2, and AD 4.3. The control diet and AD 5.3 were almost totally rejected by the fish. On day 20, the IR of AD 2.5 (0.46) and AD 3.2 (0.36) were significantly higher (P < 0.05) than those of AD 5.3 (0.1) and the control diet (0.02). In addition, 70% of fish fed AD 2.5 achieved a high IR value (0.6 – 1.0), and this was the best result among all the treatments (AD 3.2, 60%; AD 4.3 50%; AD 5.3 and control, 10%). These results suggested that acidified diets can be used to wean O. marmorata juveniles, and the recommended pH level was 2.5.

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