Odontocete braintissues associated with auditory processing are hypertrophied and modified relative to their terrestrial counterparts. The relationship between the functional demand on these tissues and metabolic substrate requirements is unknown. Using positron emission tomography(PET), relative cerebral blood flow was measured in a bottlenose dolphin. Approximately 60 mCi N 13 H 3 was administered to the dolphin via a catheter inserted into the hepatic vein and threaded proximate to the vena cava. Radiolabel initially appeared as distributed focal points in the cerebellum. Increasing scan time resulted in an increase in the number of focal regions and in the diffusivity of label activity throughout the brain. The time course and spatial distribution of radiolabel was consistent with a cerebral blood supply dominated by the spinal meningeal arteries.Blood flow was predominantly observed in the cerebellum and neocortex, particularly the auditory and visual cortex. Differential brain glucose uptake, previously measured in a separate dolphin, showed good agreement with the differential supply of blood to braintissues. Rates of blood supply and glucose uptake in the auditory cortex, inferior colliculus, and cerebellum are consistent with a high metabolic demand of tissues which are important to the integration of auditory and other sensory inputs.

Rehabilitation of marine mammals is performed throughout the world, yet the impact of rehabilitation on individuals and populations is questionable given the lack of robust information on the rehabilitation process and post-release monitoring in most cases. The goals of this study were to perform a systematic review of existing literature on marine mammal rehabilitation between 2000–2023 to determine the current state of rehabilitation and to evaluate the rehabilitation and conservation factors that could be used to build a framework to assess the health of rehabilitation programs worldwide. A total of 418 publications encompassing 52 species of marine mammal were included in the systematic review. Rehabilitation efforts focused mostly on pinnipeds, and North America was the most represented region. Data are scarce for both short- and long-term post-release survival across species. Reports about species threatened with extinction were significantly more likely to include information about conservation parameters than those species of least concern. A meta-analysis demonstrated a fairly strong fit of the dimensions of the proposed framework for a rehabilitation health index. Further refinement would strengthen the utility of this tool for both rehabilitation and conservation programs.

Point of care (POC) hematology testing can be valuable in triage and field settings. We assessed the accuracy between the HemoCue^® WBC system and two comparative analyzers, as well as the precision of the HemoCue^® WBC system in five different pinniped species: Zalophus californianus, Arctocephalus townsendi, Callorhinus urcinus, Phoca vitulina, and Mirounga angustirostris for white blood cell (WBC) quantification. In Zalophus (n = 164; 106 from U.S. Navy Marine Mammal Program (Navy); 58 from The Marine Mammal Center (TMMC)), the HemoCue^® was compared to two hematology analyzers, Sysmex Xe-5000 and Vet ABC Plus. In Phoca (n = 50; TMMC), Callorhinus (n = 29; TMMC), Arctocephalus (n = 17; TMMC), and Mirounga (n = 67; TMMC), the HemoCue^® was compared to Vet ABC Plus only. Bland–Altman and Passing–Bablok agreement of HemoCue^® with Sysmex Xe-5000 and Vet ABC Plus analyzers were good for Zalophus, Arctocephalus, Phoca, and Mirounga but marginal with Callorhinus; bias = 0.56 × 10⁹/L (Zalophus; Navy), −2.13 × 10⁹/L (Zalophus; TMMC), −1.59 × 10⁹/L (Arctocephalus), −2.48 × 10⁹/L 0.917 (Phoca), −0.01 × 10⁹/L (Mirounga), and −6.05 × 10⁹/L (Callorhinus). The coefficient of variation from triplicate runs of samples were within acceptable limits for all species (2.50% ± 1.63 (Zalophus; TMMC), 3.09% ± 2.14 (Arctocephalus), 2.47% ± 1.35 (Callorhinus), 2.88% ± 1.75 (Phoca), and 3.44% ± 2.53 (Mirounga)), respectively. The presence of nucleated red blood cells (nRBC; 1–37 nRBC/100 WBC) did not significantly interfere with WBC counts in Zalophus, Callorhinus, and Phoca at the population level, but their presence should be evaluated at the individual level. The HemoCue^® provides an accurate method for WBC quantification with WBC counts up to 30 × 10⁹/L (upper limit of linearity of the analyzer) in Zalophus, Arctocephalus, Phoca, and Mirounga, but is less accurate in Callorhinus, and showed good precision in all species.

Neuromuscular blocking agents (NMBAs) are essential in intraocular surgeries to improve surgical conditions and ensure optimal ventilation. However, residual blockade can pose significant risks, particularly in pinnipeds due to their unique diving physiology. This case report describes the use of sugammadex for reversing rocuronium and AMG for monitoring neuromuscular block (NMB) in a California sea lion undergoing lensectomy. The objective is to evaluate the feasibility and safety of sugammadex for reversal of rocuronium-induced neuromuscular blockade and acceleromyography (AMG) for monitoring neuromuscular function in pinnipeds, with the goal of improving anesthetic management and recovery. Rocuronium (0.3 mg/kg IV) was used to achieve complete NMB, and an additional 0.1 mg/kg IV was administered to prolong the block. Sugammadex (1 mg/kg IV) reversed the NMB, with recovery within 90 s. Neuromuscular function was monitored using AMG, with the ulnar nerve of the foreflipper as the stimulation site. AMG allowed for an objective assessment of neuromuscular function, ensuring accurate titration of the NMBA and reversal agent. This is the first report documenting the use of sugammadex for the reversal of rocuronium and AMG for neuromuscular monitoring in a sea lion. This successful application highlights the potential of these techniques to improve anesthesia protocols, patient safety, and welfare in marine mammal medicine.

Domoic acid (DA) is a glutaminergic excitatory neurotoxin that causes morbidity and mortality of California sea lions ( Zalophus californianus ; CSL) and other marine mammals due to a suite of effects mostly on the nervous and cardiac systems. Between 1998 and 2019, 11,737 live-stranded CSL were admitted to The Marine Mammal Center (TMMC; Sausalito, CA, USA), over 2,000 of which were intoxicated by DA. A plethora of clinical research has been performed over the past 20 years to characterize the range of toxic effects of DA exposure on CSLs, generating the largest dataset on the effects of natural exposure to this toxin in wildlife. Here we review published methods for diagnosing DA intoxication, clinical presentation and treatment of DA-intoxicated CSL, and present a practical, reproducible scoring system called the neuroscore (NS) to help assess whether a DA-affected CSL is fit for release to the wild following rehabilitation. The largest proportion of DA-intoxicated CSL were adult females (58.6%). The proportions of acute and chronic cases were 63.5% and 36.5%, respectively, with 44% of affected CSL released and 56% either dying naturally or euthanized. The average time in rehabilitation was 15.9 days (range 0-169) for all outcomes. Logistic regression models were used to assess the relationships between outcome (released vs. euthanized or died) and multiple variables to predict the outcome for a subset of 92 stranded CSLs. The best performing model (85% prediction accuracy; area under the curve = 0.90) consisted of four variables: final NS, change in NS over time, whether the animal began eating in rehabilitation, and the state of nutrition on admission. These results suggest that a behavioral scoring system is a useful tool to assess the fitness for release of stranded DA-intoxicated CSL.