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Large predators often play important roles in structuring marine communities. To understand the role that these predators play in ecosystems, it is crucial to have knowledge of their interactions and the degree to which their trophic roles are complementary or redundant among species. We used stable isotope analysis to examine the isotopic niche overlap of dolphins Tursiops cf. aduncus, large sharks (>1.5 m total length), and smaller elasmobranchs (sharks and batoids) in the relatively pristine seagrass community of Shark Bay, Australia. Dolphins and large sharks differed in their mean isotopic values for δ 13 C and δ 15 N, and each group occupied a relatively unique area in isotopic niche space. The standard ellipse areas (SEAc; based on bivariate standard deviations) of dolphins, large sharks, small sharks, and rays did not overlap. Tiger sharks Galeocerdo cuvier had the highest δ 15 N values, although the mean δ 13 C and δ 15 N values of pigeye sharks Carcharhinus amboinensis were similar. Other large sharks (e.g. sicklefin lemon sharks Negaprion acutidens and sandbar sharks Carcharhinus plumbeus) and dolphins appeared to feed at slightly lower trophic levels than tiger sharks. In this seagrass-dominated ecosystem, seagrassderived carbon appears to be more important for elasmobranchs than it is for dolphins. Habitat use patterns did not correlate well with the sources of productivity supporting diets, suggesting that habitat use patterns may not necessarily be reflective of the resource pools supporting a population and highlights the importance of detailed datasets on trophic interactions for elucidating the ecological roles of predators.

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BackgroundDysphagia following a cervical fusion is a known complication; however, this has not been examined in the trauma population. We sought to identify risk factors that can be optimized in this population.MethodsWe performed a retrospective chart review on consecutive trauma patients who underwent a cervical fusion from 2014 to 2017 at a single institution with multiple surgeons. We included patients more than 18-years-old who were admitted through the emergency department with a diagnosis of acute cervical injury and underwent a cervical fusion during the same admission. We excluded patients who remained intubated postoperatively or underwent a tracheostomy. The primary outcome was dysphagia as evaluated by a bedside swallow test on postoperative day one by the nursing staff. This was followed by a standardized assessment performed by a speech therapist on postoperative day two in some cases. Variables of interest included sex, age, mechanism of injury, surgical approach, cervical levels, and Charlson comorbidity index. Univariate analysis was also utilized.ResultsSixty patients met the study criteria. Nineteen patients (31.7%) developed dysphagia postoperatively. Mechanical falls were the most common injury mechanism (80%) and most surgical procedures were performed on the subaxial cervical spine (68.3%). Comparing the dysphagia groups, there was no significant difference among the confounding variables. Patients with dysphagia had an increased length of stay (10.6 ± 6.7 vs. 7.4 ± 3.1, p = 0.056) and were more likely to have had an anterior vs. posterior cervical fusion (63.2% vs. 34.1%, p = 0.056).ConclusionsWe found no statistically significant risk factors leading to postoperative dysphagia. The objective of this pilot is to find the baseline dysphagia rate and the potential modifiable factors in this unique patient population undergoing cervical fusion procedures.