Foraging behavior, habitat, health, and survival of resident and translocated Hawaiian monk seals at Nihoa Island, Hawaii

Translocations aimed at promoting population recovery for threatened and endangered species also can function as forced dispersals. To assess the efficacy of translocating Hawaiian monk seals (Monachus schauinslandi) and examine post-dispersal effects on monk seals, in 2008-2009, 12 weanling seals were translocated from French Frigate Shoals (FFS) to Nihoa Island (NIH). In addition, nine adult and eight weanling resident seals were captured at NIH. Satellite instrument attachment, biological sampling, and morphometry were conducted on seals at capture. Focal video camera drops also were conducted at 45 sites around NIH (\u3c 100 m) in 2010-2011. Translocated and resident weanlings primarily dove to 40-60 m and used sandy-bottomed habitat \u3c 13 km from NIH. In contrast, resident adults had greater variability in foraging behavior and habitat use. There also was a low prevalence of infectious disease in translocated and resident seals, excluding Chlamydophila abortus and enteric bacteria. First-year survival was greater for translocated weanlings (50%, n = 12) than non-translocated weanlings at FFS (31%, n = 36) but was slightly less than non-translocated weanlings at NIH (69%, n = 16). The results of this study supported four main conclusions that have important consequences on population-level trends: 1) translocations are a viable conservation strategy for monk seals, 2) there was a low risk of spreading pathogens, 3) an abundance of benthic monk seal foraging habitat may exist at NIH, and 4) individuals that disperse with limited foraging experience may adapt rapidly to their post-dispersal habitat

Persistent contaminants and herpesvirus OtHV1 are positively associated with cancer in wild California Sea Lions (Zalophus californianus)

This work was funded by the Geoffrey Hughes Fellowship, the National Institutes of Health (Fogarty International Center) and National Science Foundation joint program for the Ecology of Infectious Disease, the National Marine Fisheries Service Marine Mammal Heath and Stranding Program, and the Natural Environment Research Council grant number NE/R015007/.The prevalence of cancer in wild California sea lions (Zalophus californianus) is one of the highest amongst mammals, with 18–23% of adult animals examined post-mortem over the past 40 years having urogenital carcinoma. To date, organochlorines, genotype and infection with Otarine herpesvirus-1 (OtHV-1) have been identified in separate studies using distinct animals as associated with this carcinoma. Multi-year studies using large sample sizes to investigate the relative importance of multiple factors on marine mammal health are rare due to logistical and ethical challenges. The objective of this study was to use a case control approach with samples from 394 animals collected over 20 years in a multifactorial analysis to explore the relative importance of distinct factors identified to date as associated with sea lion cancer in the likelihood of sea lion carcinoma. Stepwise regression indicated that the best model to explain carcinoma occurrence included herpesvirus status, contaminant exposure, and blubber depth, but not genotype at a single microsatellite locus, PV11. The odds of carcinoma was 43.57 times higher in sea lions infected with OtHV-1 (95% CI 14.61, 129.96, p <0.001), and 1.48 times higher for every unit increase in the loge[contaminant concentrations], ng g–1 (an approximate tripling of concentration), in their blubber (95% CI 1.11, 1.97, p <0.007), after controlling for the effect of blubber depth. These findings demonstrate the importance of contaminant exposure combined with OtHV1 infection, in the potential for cancer occurrence in wild sea lions.Publisher PDFPeer reviewe

A Systematic Review of Changes in Marine Mammal Health in North America, 1972-2012: The Need for a Novel Integrated Approach

<div><p>Marine mammals are often cited as “sentinels of ocean health” yet accessible, synthesized data on their health changes that could effectively warn of ocean health changes are rare. The objectives of this study were to 1) perform a systematic review of published cases of marine mammal disease to determine spatial and temporal trends in disease from 1972–2012, including changes in regions and taxa affected and specific causes; and 2) compare numbers of published cases of neoplasia with known, hospital-based neoplasia records to explore the causes of discrepancy between numbers of published cases and true disease trends. Peer-reviewed literature was compiled, and data were collected from The Marine Mammal Center database in Sausalito, California for comparison of numbers of neoplasia cases. Toxicoses from harmful algal blooms appear to be increasing. Viral epidemics are most common along the Atlantic U.S. coastline, while bacterial epidemics, especially leptospirosis, are most common along the Pacific coast. Certain protozoal and fungal zoonoses appear to be emerging, such as <i>Toxoplasma gondii</i> in southern sea otters in California, and <i>Cryptococcus gattii</i> in cetaceans in the Pacific Northwest. Disease reports were most common from California where pinniped populations are large, but increased effort also occurs. Anthropogenic trauma remains a large threat to marine mammal health, through direct mortality and indirect chronic disease. Neoplasia cases were under-reported from 2003–2012 when compared to true number of cases, and over-reported in several years due to case duplication. Peer-reviewed literature greatly underestimates the true magnitude of disease in marine mammals as it focuses on novel findings, fails to reflect etiology of multifactorial diseases, rarely reports prevalence rather than simple numbers of cases, and is typically presented years after a disease first occurs. Thus literature cannot guide management actions adequately, nor inform indices of ocean health. A real-time, nationally centralized system for reporting marine mammal disease data is needed to be able to understand how marine mammal diseases are changing with ecosystem changes, and before these animals can truly be considered ‘sentinels of ocean health’.</p></div

Annual number of calculated cases by disease category and region extracted from published reports on marine mammal disease.

<p>For each disease category, regions representing less than 10% of the cumulative number of calculated cases were grouped (other). CA = California, GoM = Gulf of Mexico, NW = Pacific Northwest, AK = Alaska, NE = Northeast U.S., and SE = Southeast U.S.</p

Process for selection of publications included in the systematic review.

<p>Process for selection of publications included in the systematic review.</p

Nasopulmonary mites (Halarachnidae) of coastal Californian pinnipeds: Identity, prevalence, and molecular characterization.

Mites from the family Halarachnidae Oudemans 1906 are obligate endoparasites that colonize the respiratory tracts of free-living and captive marine mammals. Infestations can range from mild to severe and result in respiratory tract irritation or impairment. Nasopulmonary acariasis was determined to be a contributing cause of death among several southern sea otters Enhydra lutris nereis Merriam 1904 in a longitudinal study of otter mortality, and proximity to Pacific harbor seals Phoca vitulina richardii Gray 1864 was a significant risk factor for sea otter infestation. Beyond scattered opportunistic reports, each halarachnid mite species' affinity for particular hosts and the extent of mite transmission between host species is poorly understood. We investigated the identity and prevalence of nasopulmonary mites from Pacific harbor seals, California sea lions Zalophus californianus Lesson 1828, northern elephant seals Mirounga angustirostris Gill 1866, northern fur seals Callorhinus ursinus Linnaeus 1758, and Guadalupe fur seals Arctocephalus philippii townsendi Merriam 1897 to complement published nasopulmonary mite findings from sympatric southern sea otters during a comparable timeframe. Halarachnid mite infestation was common among California sea lions (74.1%), northern fur seals (73.3%), and northern elephant seals (46.6%), but was less common among harbor seals (18.7%) and Guadalupe fur seals (8.8%). Observed host-mite relationships suggest a distinct host specificity, with genus Orthohalarachne infesting otariids, and genus Halarachne infesting phocids and lutrinids along the California coast. Harbor seals and southern sea otters were the primary hosts of H. halichoeri, but one nothern elephant seal was infested with both H. miroungae and a single H. halichoeri. We also present the first high-resolution SEM images for H. miroungae and O. attenuata and possible evidence for a new host record for H. halichoeri

Calculated cases divided into those describing clinical disease (“disease”) and those with only the disease-causing agent isolated (“isolation”) for the infectious disease and biotoxicosis categories, 1972–2012.

<p>Calculated cases divided into those describing clinical disease (“disease”) and those with only the disease-causing agent isolated (“isolation”) for the infectious disease and biotoxicosis categories, 1972–2012.</p

Annual number of (a) calculated cases of neoplasia extracted from published reports on marine mammal disease and (b) individual California sea lions (<i>Zalophus californianus</i>) with urogenital carcinoma extracted from The Marine Mammal Center dataset.

<p>All calculated cases for California from 1979–2003 were from California sea lions with urogenital carcinoma originating from TMMC’s dataset, except for one case per year in 1984, 2000, and 2001.</p

Annual number of calculated cases of trauma extracted from published reports on marine mammal disease.

<p>Source of trauma was designated as anthropogenic or non-anthropogenic/unknown.</p