Marine Mammal Health

A special issue of Oceans (ISSN 2673-1924).

Deadline for manuscript submissions: closed (15 September 2022) | Viewed by 38698

Special Issue Editors

Sea Change Health, Kentfield, CA 94904, USA
Interests: marine mammal disease; epidemiology; anesthesia; conservation; innovation
Sea Change Health, Kentfield, CA 94904, USA
Interests: marine mammal health; conservation; strandings; medicine

Special Issue Information

Dear Colleagues,

Marine mammals are uniquely adapted species and sentinels of the ocean. A growing body of knowledge exists on marine mammal health and disease, but a knowledge gap remains. Innovations in medicine expand this knowledge base and provide additional tools to both inform and improve the welfare and wellbeing of marine mammals worldwide.

This Special Issue on “Marine Mammal Health” of the Oceans journal seeks original contributions in the field of all disciplines relating to marine mammal health, disease and medicine. The aim of this Special Issue is to address relevant topics that improve marine mammal health. Topics relevant to this Special Issue include but are not limited to marine mammal health, disease, medicine, physiology, conservation, and One Health. Articles on topics of interest to clinicians, scientists, policymakers, and the general public will be considered for publication.

Dr. Shawn Johnson
Dr. Claire Simeone
Guest Editors

Manuscript Submission Information

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Keywords

  • health
  • disease
  • medicine
  • physiology
  • conservation
  • One Health

Published Papers (15 papers)

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Research

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20 pages, 2232 KiB  
Article
Contribution to the Knowledge of Cetacean Strandings in Chile between 2015 and 2020
Oceans 2024, 5(1), 1-20; https://doi.org/10.3390/oceans5010001 - 03 Jan 2024
Viewed by 780
Abstract
Strandings caused by anthropogenic factors are one of the most worrying threats in relation to the conservation of cetacean species, and in the case of Chile, due to its geography and large extension of the coastline, monitoring and access to these events is [...] Read more.
Strandings caused by anthropogenic factors are one of the most worrying threats in relation to the conservation of cetacean species, and in the case of Chile, due to its geography and large extension of the coastline, monitoring and access to these events is difficult, making their study more complex. Chile has a shortage of specialized scientific forensic research facilities for cetaceans; however, for this study, it was able to collect data recorded from official institutions and sporadic scientific biological sampling oriented to investigate the causes of death or stranding. According to the Chilean government official database, we described that the main causes of unusual mortality events (UME) and mass strandings from 2015 and 2016 were acute poisoning by biotoxins and strandings by multiple possible causes, respectively, while individual strandings would have their causes in anthropogenic activities, such as entanglements in fishing and aquaculture gears and collisions with vessels. The predominant species in mass strandings was the sei whale (Balaenoptera borealis). The geographical area of greatest prominence in mass strandings was the Aysén Region in the Central Patagonia of Chile, while the species mostly involved in individual strandings along the south-central, central, and northern coasts of Chile was the small porpoise (Phocoena spinipinnis). The most common gross pathological findings were advance decay of the carcasses and non-specific wounds of different natures. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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18 pages, 5092 KiB  
Article
When and Where Did They Strand? The Spatio-Temporal Hotspot Patterns of Cetacean Stranding Events in Indonesia
Oceans 2022, 3(4), 509-526; https://doi.org/10.3390/oceans3040034 - 04 Nov 2022
Cited by 3 | Viewed by 2758
Abstract
Analyses of the spatial and temporal patterns of 26 years of stranding events (1995–2011 and 2012–2021, n = 568) in Indonesia were conducted to improve the country’s stranding response. The Emerging Hot Spot Analysis was used to obtain the spatial and temporal hotspot [...] Read more.
Analyses of the spatial and temporal patterns of 26 years of stranding events (1995–2011 and 2012–2021, n = 568) in Indonesia were conducted to improve the country’s stranding response. The Emerging Hot Spot Analysis was used to obtain the spatial and temporal hotspot patterns. A total of 92.4% events were single stranding, while the remaining were of mass stranding events. More stranding events were recorded between 2012 and 2021 in more dispersed locations compared to the previous period. Within the constraints of our sampling limitations, East Kalimantan and Bali were single stranding hotspots and consecutive hotspots. East Java and Sabu-Raijua in East Nusa Tenggara were mass stranding hotspots. Temporally, Raja Ampat (West Papua) experienced a significant increase in case numbers. The presence of active NGOs, individuals or government agencies in some locations might have inflated the numbers of reported cases compared to areas with less active institutions and/or individuals. However, our results still give a good understanding of the progression of Indonesia’s stranding responses and good guidance of resource allocation for the stranding network. Several locations in Indonesia that need more efforts (e.g., more training workshops on rescue and necropsies) have been identified in this paper. Suggestions to improve data collection (including georeferencing tips) have also been included. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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15 pages, 5040 KiB  
Article
Age and Sexual Maturity Estimation of Stranded Striped Dolphins, Stenella coeruleoalba, Infected with Brucella ceti
Oceans 2022, 3(4), 494-508; https://doi.org/10.3390/oceans3040033 - 31 Oct 2022
Cited by 1 | Viewed by 2303
Abstract
Age parameters in cetaceans allow examining conservation and studying individuals with growth affection. The age and sexual maturity of 51 stranded Stenella coeruleoalba striped dolphins from the Eastern Tropical Pacific (ETP) of Costa Rica, most suffering brucellosis (95.6%), were assessed. In order to [...] Read more.
Age parameters in cetaceans allow examining conservation and studying individuals with growth affection. The age and sexual maturity of 51 stranded Stenella coeruleoalba striped dolphins from the Eastern Tropical Pacific (ETP) of Costa Rica, most suffering brucellosis (95.6%), were assessed. In order to ascertain the dolphins’ ages, we measured the length and growth of dentin-layer group counts (GLGs) and assessed flipper bone radiography without (FBSA) and with a formula (FBF). Sexual maturity was determined through gonadal histology and sexual hormone serum levels. Compared with a model based on S. coeruleoalba ages estimations in other latitudes, the striped dolphin studied displayed deficient growth parameters, with considerable variability in length, teeth, and flippers bone development. Close to 43% (n = 15) of GLGs’ measurements were below the body length average ranges for the predicted age, suggesting developmental abnormalities. Likewise, 34.4% and 31.2% of the dolphins assessed by FBSA and FBF were also below the body length based on age prediction curves, also indicating developmental abnormalities. This information is supported by the poor correlation between GLGs, FBSA, and FBF. Inconsistencies between sexually mature males and females related to GLGs, FBSA, and FBF were evident. Although the different oceanic settings of the ETP, such as contamination, food access, diseases, and other parameters, may influence size variation, our data also suggest that long-lasting debilitating brucellosis may account for detrimental growth in the ETP striped dolphins. Our study highlights the possible deleterious consequences of chronic infectious diseases in the cetacean populations already confronting distressful conditions. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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16 pages, 1433 KiB  
Article
Erythrocyte, Whole Blood, Plasma, and Blubber Fatty Acid Profiles in Oceanaria-Based versus Wild Alaskan Belugas (Delphinapterus leucas)
Oceans 2022, 3(4), 464-479; https://doi.org/10.3390/oceans3040031 - 30 Sep 2022
Cited by 1 | Viewed by 2259
Abstract
This investigation compared the fatty acid (FA) levels found in erythrocyte (RBC) membranes, plasma, whole blood (WB), and blubber from wild Alaskan (Bristol Bay) belugas (Delphinapterus leucas) (BBB, n = 9) with oceanaria-based belugas (OBB, n = 14) fed a controlled [...] Read more.
This investigation compared the fatty acid (FA) levels found in erythrocyte (RBC) membranes, plasma, whole blood (WB), and blubber from wild Alaskan (Bristol Bay) belugas (Delphinapterus leucas) (BBB, n = 9) with oceanaria-based belugas (OBB, n = 14) fed a controlled diet consisting of primarily herring (Clupea harengus) and capelin (Mallotus villosus). FA patterns in RBCs, WB, and plasma varied considerably between BBB and OBB animals. Focusing on RBC FA levels of known dietary origin, the OBBs had markedly higher levels of 20:1n9,11 and 22:1n9,11. RBC levels of these fatty acids were 1% and 0.2% in the BBBs, but 8.2% and 4.5%, respectively, in the OBBs (p < 0.05 both). These long-chain mono-unsaturated FAs (LC-MUFAs) are rich in herring and capelin but not in the prey species (i.e., salmonids, smelt, cod, and shrimp) generally available to BBBs. As for the marine omega-3 poly-unsaturated fatty acids [PUFAs; 20:5n3 (eicosapentaenoic acid) and 22:6n3 (docosahexaenoic acid)], the former was higher in the OBBs vs. BBBs (16% vs. 11%, p < 0.05), but the latter was low and similar in both (3.8% vs. 4%). Similar patterns were seen in the other sample types, except that DHA% was higher in BBB than OBB animals in both plasma (12.6% vs. 8.7%) and in blubber (12% vs. 4.9%) (p < 0.05). A physiologically important omega-6 PUFA, 20:4n6 (arachidonic acid) was approximately 2× higher in BBB than OBB within RBC (22% vs. 12%), WB (16% vs. 7%), plasma (11.5% vs. 4.6%) and blubber (4.6% vs. 2.4%), respectively. While blubber FAs have been evaluated historically and relatively easy to procure with biopsy darts in the field, this study proposes that blood-based FAs collected during health assessments or subsistence hunts, especially RBC or WB FAs, may be more convenient to handle using dried blood spot cards (DBS) with limited cold storage and simplifies shipping requirements, and may more accurately reflect tissue FA status. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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25 pages, 4718 KiB  
Article
Strandings in St Vincent Gulf Bioregion, South Australia: 12-Year Study Monitors Biology and Pathology of Cetaceans
Oceans 2022, 3(4), 439-463; https://doi.org/10.3390/oceans3040030 - 26 Sep 2022
Cited by 3 | Viewed by 2411
Abstract
The semi-enclosed environment of the St Vincent Gulf Bioregion and its fauna are impacted by many human activities. Long-term monitoring of cetaceans is vital. Records of collected specimens (173) and those not examined by the South Australian Museum (98 non-specimens) from 2009–2020 were [...] Read more.
The semi-enclosed environment of the St Vincent Gulf Bioregion and its fauna are impacted by many human activities. Long-term monitoring of cetaceans is vital. Records of collected specimens (173) and those not examined by the South Australian Museum (98 non-specimens) from 2009–2020 were analyzed. Necropsies were carried out on most carcasses using gross, histopathological, and diagnostic assessment of pathogens, organs, and skin lesions. The relative age and circumstance of death were assigned. Baleen whales (five species) and odontocetes (eight species) were studied. Indo-Pacific bottlenose dolphins (Tursiops aduncus) and common dolphins (Delphinus delphis) were frequently recorded and analyzed in detail. Anthropogenic cases were prevalent (21%). Many dolphins (62%) were immature males. Disease (73%) was the most frequently recorded circumstance of death. The most common pathological change was inflammatory disease, including infectious pneumonia. In Indo-Pacific bottlenose dolphins, infectious disease was more prevalent in the greater St Vincent Gulf Bioregion than in the Adelaide Dolphin Sanctuary. Microbe testing confirmed 32 species of bacteria, 2 fungi, and 1 virus. Nematodes and trematodes were recorded throughout the study, sometimes in association with microbes. Toxoplasma gondii was observed in an Indo-Pacific bottlenose dolphin. Severe traumatic injury was recorded in many dolphins, including anthropogenic cases. A tumor (leiomyoma) was described from a single common dolphin. This study provides an important baseline for the future monitoring of emerging infectious and chronic diseases, and anthropogenic threats in the region. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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18 pages, 950 KiB  
Article
Divergent Gene Expression Profiles in Alaskan Sea Otters: An Indicator of Chronic Domoic Acid Exposure?
Oceans 2022, 3(3), 401-418; https://doi.org/10.3390/oceans3030027 - 08 Aug 2022
Viewed by 2441
Abstract
An opportunistic investigation into ecosystem instability in Kachemak Bay (KBay), Alaska, has led us to investigate exposure to toxic algae in sea otters. We used gene expression to explore the physiological health of sea otters sampled in KBay in May 2019. We found [...] Read more.
An opportunistic investigation into ecosystem instability in Kachemak Bay (KBay), Alaska, has led us to investigate exposure to toxic algae in sea otters. We used gene expression to explore the physiological health of sea otters sampled in KBay in May 2019. We found altered levels of gene transcripts in comparison with reference sea otters from clinically normal, oil-exposed, and nutritionally challenged populations sampled over the past decade. KBay sea otters were markedly divergent from the other groups for five genes, which indicated the involvement of neurological, cardiac, immune, and detoxification systems. Further, analyses of urine and fecal samples detected domoic acid in the KBay sea otters. In combination, these results may point to chronic, low-level exposure to an algal toxin, such as domoic acid. With a warming climate, the frequency and severity of harmful algal blooms in marine environments is anticipated to increase, and novel molecular technologies to detect sublethal or chronic exposure to algal toxins will help provide an early warning of threats to the stability of populations and ecosystems. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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12 pages, 1819 KiB  
Article
Increased Incidence of Entanglements and Ingested Marine Debris in Dutch Seals from 2010 to 2020
Oceans 2022, 3(3), 389-400; https://doi.org/10.3390/oceans3030026 - 05 Aug 2022
Cited by 3 | Viewed by 3760
Abstract
In recent decades, the amount of marine debris has increased in our oceans. As wildlife interactions with debris increase, so does the number of entangled animals, impairing normal behavior and potentially affecting the survival of these individuals. The current study summarizes data on [...] Read more.
In recent decades, the amount of marine debris has increased in our oceans. As wildlife interactions with debris increase, so does the number of entangled animals, impairing normal behavior and potentially affecting the survival of these individuals. The current study summarizes data on two phocid species, harbor (Phoca vitulina) and gray seals (Halichoerus grypus), affected by marine debris in Dutch waters from 2010 to 2020. The findings indicate that the annual entanglement rate (13.2 entanglements/year) has quadrupled compared with previous studies. Young seals, particularly gray seals, are the most affected individuals, with most animals found or sighted with fishing nets wrapped around their necks. Interestingly, harbor seals showed a higher incidence of ingested debris. Species differences with regard to behavior, foraging strategies, and habitat preferences may explain these findings. The lack of consistency across reports suggests that it is important to standardize data collection from now on. Despite increased public awareness about the adverse environmental effects of marine debris, more initiatives and policies are needed to ensure the protection of the marine environment in the Netherlands. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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12 pages, 1702 KiB  
Article
Entanglement of Steller Sea Lions in Marine Debris and Fishing Gear on the Central Oregon Coast from 2005–2009
Oceans 2022, 3(3), 319-330; https://doi.org/10.3390/oceans3030022 - 20 Jul 2022
Cited by 1 | Viewed by 2077
Abstract
Entanglement in marine debris and fishing gear is an increasing problem for the world’s pinnipeds and a contributing factor in Steller sea lion (Eumetopias jubatus) injury and mortality. From 2005–2009, we surveyed (n = 389 days) two haul-outs on the central [...] Read more.
Entanglement in marine debris and fishing gear is an increasing problem for the world’s pinnipeds and a contributing factor in Steller sea lion (Eumetopias jubatus) injury and mortality. From 2005–2009, we surveyed (n = 389 days) two haul-outs on the central Oregon coast containing a combined median of 402 animals (range 33–1240, or ca. 1–19% of the Oregon coast population). We recorded 72 individuals entangled in marine debris (n = 70) or with ingested salmon hook-and-line fishing gear (n = 2). Of the identifiable neck entanglements, black rubber bands were the most common neck-entangling material (62%), followed by plastic packing bands (36%), nets (1.2%), yellow rubber bands (0.4%), and a flying disc (0.4%). The estimated prevalence of entanglement for individuals in Oregon was 0.34%. Juveniles were the most frequently entangled age class (60%), followed by adult females (28%), and subadult males (12%). Supply chain and industry-based solutions are needed to prevent entangling debris from entering the ocean, along with eliminating, modifying, or cutting entangling loops of synthetic material. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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14 pages, 5830 KiB  
Article
Whale-Associated Microbial Communities Remain Remarkably Stable despite Massive Water Community Disruption in a Managed Artificial Marine Environment
Oceans 2022, 3(3), 289-302; https://doi.org/10.3390/oceans3030020 - 06 Jul 2022
Viewed by 2064
Abstract
Highly managed and built environments such as zoos and aquaria provide a rich source of standardized environmental monitoring data over periods of years to decades. A fifty percent water change in an 11.4-million-liter indoor artificial sea water system housing three species of marine [...] Read more.
Highly managed and built environments such as zoos and aquaria provide a rich source of standardized environmental monitoring data over periods of years to decades. A fifty percent water change in an 11.4-million-liter indoor artificial sea water system housing three species of marine mammals was conducted over a two-month period. Using 16S rRNA gene sequencing, the microbial community structure of the system water and three host sites (feces, skin, and exhaled breath “chuff”) of whales housed in the system were characterized. Diversity measures confirmed massive disruption to the water community structure as an expected result of the water change. Host site-associated communities remained remarkably stable. Improved understanding of host microbial community dynamics in response to environmental system perturbations allows for sound management decisions toward optimizing conditions for resident animals. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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18 pages, 4501 KiB  
Article
Sowerby’s Beaked Whales (Mesoplodon bidens) in the Skagerrak and Adjacent Waters: Historical Records and Recent Post-Mortem Findings
Oceans 2022, 3(3), 250-267; https://doi.org/10.3390/oceans3030018 - 23 Jun 2022
Cited by 1 | Viewed by 3556
Abstract
In contrast to sparse historical observational records, five Sowerby’s beaked whales (SBW) stranded and died in Swedish waters between 2015 and 2020. Here we summarize historical records of SBWs in the Skagerrak basin and adjacent waters. The three recent stranding events from Sweden [...] Read more.
In contrast to sparse historical observational records, five Sowerby’s beaked whales (SBW) stranded and died in Swedish waters between 2015 and 2020. Here we summarize historical records of SBWs in the Skagerrak basin and adjacent waters. The three recent stranding events from Sweden are described, and the post-mortem findings, including diet analysis, from the five SBWs are presented. Of 30 historical records of SBWs observations since 1869, 13 (43%) were documented between 2010 and 2021, and records between July and November were the most frequent. The recent stranding events occurred in October 2015 (n = 1), August 2019 (n = 3) and July 2020 (n = 1). Four of the SBWs were examined through necropsy, and one was sampled in the field. They were all sub-adults and included a single female and four males. The causes of death were emaciation, euthanasia due to traumatic injury, and live stranding of undetermined cause. Two SBWs each had a focal bone lesion consistent with osteomyelitis. Other findings included pox-like dermatitis, trauma, focal granulomas in a lymph node and intestine, and ulceration of the stomach. CT scans were performed on the heads of two animals, with inconclusive results. Three SBWs had hard parts in the gastrointestinal tract that mainly consisted of otoliths from several fish species. An eDNA-analysis confirmed and supplemented the diet analysis, revealing 17 fish species in total, including species not previously described as prey for SBW, such as Pleuronectidae spp. The apparent increase in observational records since 2010 may indicate a shift in SBW distribution or changing threats to these animals. Our results support and expand theories on SBW movements and provide data on the biology and health of this poorly known species, which are valuable for conservation and legislation efforts. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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19 pages, 2958 KiB  
Article
Temporal and Spatial Evaluation of Mono(2-ethylhexyl) Phthalate (MEHP) Detection in Common Bottlenose Dolphins (Tursiops truncatus) from Sarasota Bay, Florida, USA
Oceans 2022, 3(3), 231-249; https://doi.org/10.3390/oceans3030017 - 23 Jun 2022
Cited by 1 | Viewed by 2051
Abstract
Phthalates are endocrine-disrupting chemicals added to plastics, personal care products, cleaning solutions, and pesticides. Extensive use has led to its exposure to wildlife, including common bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, Florida, USA; however, there are gaps in knowledge regarding [...] Read more.
Phthalates are endocrine-disrupting chemicals added to plastics, personal care products, cleaning solutions, and pesticides. Extensive use has led to its exposure to wildlife, including common bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, Florida, USA; however, there are gaps in knowledge regarding whether sample timing or geographic location influence exposure. Dolphins were evaluated for temporal and spatial variability in urinary mono(2-ethylhexyl) phthalate (MEHP) detection (2010–2019). Significant fluctuations in detectable MEHP concentrations were found across the dataset. All samples from 2014 and 2015 (n = 12) had detectable MEHP concentrations; thus, data were classified into cohorts to explore the significance of prevalent MEHP detection (“Cohort 1” (n = 10; 2010–2013), “Cohort 2” (2014–2015), and “Cohort 3” (n = 29; 2016–2019)). Compared to Cohorts 1 and 3, Cohort 2 had higher detectable MEHP concentrations (Dunn’s; p = 0.0065 and p = 0.0012, respectively) and a greater proportion of detectable MEHP concentrations (pairwise comparisons using Benjamini–Hochberg adjustments: p = 0.0016 and p = 0.0059, respectively). MEHP detection also varied across spatial scales. Dolphins with detectable MEHP concentrations had ranges primarily within enclosed embayments, while dolphins with nondetectable MEHP concentrations extended into open waters, potentially indicating geographically linked exposure risk. This study suggests that researchers and management agencies should consider a population’s ranging pattern, geographic habitat characteristics, and sample timing when assessing small cetacean health in relation to contaminant exposure. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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15 pages, 5934 KiB  
Article
Pathological Studies and Postmortem Computed Tomography of Dolphins with Meningoencephalomyelitis and Osteoarthritis Caused by Brucella ceti
Oceans 2022, 3(2), 189-203; https://doi.org/10.3390/oceans3020014 - 09 May 2022
Cited by 4 | Viewed by 3148
Abstract
Cetacean neurobrucellosis is a common cause of strandings in Costa Rica diagnosed by serology, bacteriology, and histopathology. Pathological studies were performed on 18 dolphins. Twelve were scanned by postmortem computed tomography (PMCT) as a complementary tool for describing neurobrucellosis and osteoarticular alterations associated [...] Read more.
Cetacean neurobrucellosis is a common cause of strandings in Costa Rica diagnosed by serology, bacteriology, and histopathology. Pathological studies were performed on 18 dolphins. Twelve were scanned by postmortem computed tomography (PMCT) as a complementary tool for describing neurobrucellosis and osteoarticular alterations associated with Brucella ceti infections. The central nervous system (CNS) and the skeleton of five dolphins not infected with B ceti did not reveal alterations by PMCT scanning. Seven Brucella-infected dolphins showed at least bilateral ventriculomegaly associated with hydrocephalus and accumulation in CSF in the lateral ventricles. We performed semiquantitative grading of the inflammatory process in the different areas of the CNS and evaluated the thickness of the cellular infiltrate in the meninges and the perivascular cuffs. The results for the severity grading were graphed to provide an injury profile associated with each area of the CNS. Age is not a decisive factor regarding neurobrucellosis presentation. The severity of ventriculomegaly by PMCT does not directly correlate with the severity of the inflammatory index determined by histopathological parameters of the brain cortex and other CNS regions, suggesting that these processes, although linked, are multifactorial and need further characterization and validation to establish better cutoffs on the PMCT. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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12 pages, 1213 KiB  
Article
Evaluation of the HemoCue® WBC System as a Point of Care Diagnostic Tool for White Blood Cell Quantification in Pinnipeds
Oceans 2022, 3(1), 72-83; https://doi.org/10.3390/oceans3010007 - 14 Mar 2022
Cited by 1 | Viewed by 2787
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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Review

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16 pages, 899 KiB  
Review
A Review of Northern Fur Seal (Callorhinus ursinus) Literature to Direct Future Health Monitoring Initiatives
Oceans 2022, 3(3), 303-318; https://doi.org/10.3390/oceans3030021 - 07 Jul 2022
Viewed by 2111
Abstract
Northern fur seals (Callorhinus ursinus, NFS) are a vulnerable species broadly distributed throughout the north Pacific. Although commercial hunting stopped in 1984, the population has continued to decline for unknown reasons. The goal of this scoping review was to synthesize and [...] Read more.
Northern fur seals (Callorhinus ursinus, NFS) are a vulnerable species broadly distributed throughout the north Pacific. Although commercial hunting stopped in 1984, the population has continued to decline for unknown reasons. The goal of this scoping review was to synthesize and review 50 years of literature relevant to the health of NFS to inform the development of health surveillance recommendations. Search criteria were developed and applied to three databases, followed by title and abstract screening and full text review. Articles published between 1 January 1972 and 31 December 2021 were included. Articles were categorized by health determinant, and further as relating to ten subcategories of disease. Data were summarized descriptively. A total of 148 publications met the criteria for inclusion. Infectious disease reports were common, primarily relating to metazoan parasite presence. The presence of zoonotic pathogens such as Coxiella burnetii and Brucella spp. is of public health interest, although a failure to link disease research to individual animal or population health outcomes was consistent across the literature. A shift away from the single agent focus of disease programs toward more holistic, health-oriented perspectives will require broader interdisciplinary collaboration. These findings can inform stakeholders and help them to prioritize and strategize on future NFS health research efforts. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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Other

Jump to: Research, Review

9 pages, 659 KiB  
Brief Report
Clinical Observations Associated with Phenobarbital Serum Monitoring to Manage Epilepsy in a California Sea Lion with Domoic Acid Toxicosis
Oceans 2022, 3(3), 331-339; https://doi.org/10.3390/oceans3030023 - 27 Jul 2022
Viewed by 1840
Abstract
The marine algal toxin domoic acid is an important threat to marine mammal health, and exposure can lead to both acute neurologic signs and a chronic epileptic syndrome in California sea lions (Zalophus californianus). Phenobarbital has been used for several decades [...] Read more.
The marine algal toxin domoic acid is an important threat to marine mammal health, and exposure can lead to both acute neurologic signs and a chronic epileptic syndrome in California sea lions (Zalophus californianus). Phenobarbital has been used for several decades to manage seizures, although reports are limited correlating dosing, serum monitoring and clinical efficacy in this species. This report details serum monitoring over 33 months in an 8-year-old male sea lion. Seizure control was achieved when phenobarbital concentrations were above 18 μg/mL, and sedation and ataxia were noted when concentrations were above 35 μg/mL. There was no clinically significant difference between phenobarbital concentrations resulting from once-daily versus twice-daily dosing. Serum levels remained detectable as far as 101 days after administration, and remained stable during periods of prolonged anorexia, although dramatic decreases in serum concentrations were noted immediately after normal eating resumed. For this animal, a serum phenobarbital target range of 20–30 μg/mL was achievable with a dose of 1.5 mg/kg once daily followed by therapeutic monitoring, and this is a reasonable recommended concentration and initial dose for clinicians treating this species. Long-term seizure control may be difficult to achieve with anti-epileptic drugs such as phenobarbital alone, and further research is needed to make novel options useful for clinical management of biotoxin-related neurologic disease in this aquatic species. Full article
(This article belongs to the Special Issue Marine Mammal Health)
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