Dixon Lane-Meadow Creek, MT, United States
Dixon Lane-Meadow Creek, MT, United States

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Baker J.D.,National Oceanic and Atmospheric Administration | Harting A.L.,Harting Biological Consulting | Johanos T.C.,National Oceanic and Atmospheric Administration | Littnan C.L.,National Oceanic and Atmospheric Administration
Endangered Species Research | Year: 2016

The type and quantity of survey data, and consequently, applicable methods for estimating abundance, vary throughout the range of the Endangered Hawaiian monk seal Neo mon - achus schauinslandi. Here we present a new approach to combine disparate data and methods to estimate the range-wide abundance of this species, along with associated uncertainty. We quantified subpopulation abundance using total enumeration, closed population capture-recapture methods, empirically derived relationships between survey effort and proportion of the population detected, minimum tallies, or standardized land surveys corrected to account for seals in the water. We used a Monte Carlo approximation to generate a distribution of range-wide abundance, by summing randomly drawn values from distributions of site-specific abundance. Data to estimate range-wide abundance were available for 2013, 2014, and 2015; our estimates were 1291, 1309, and 1324 individuals, respectively. Although the point estimates increased over 2 yr, the confidence intervals for all estimates overlapped. We recognize that these estimates are subject to some varying degree of negative bias, which precludes drawing unequivocal conclusions regarding current population trends. However, after a prolonged history of population decline in this species, the lack of evidence for further decline during 2013 to 2015 is encouraging. Additional years of consistent monitoring will enable reliable assessment of the trend in total Hawaiian monk seal abundance. © the US Government 2016.

Harting A.L.,Harting Biological Consulting | Johanos T.C.,National Oceanic and Atmospheric Administration | Littnan C.L.,National Oceanic and Atmospheric Administration
Endangered Species Research | Year: 2014

The cumulative benefits derived from historic small-scale, opportunistic interventions for the Hawaiian monk seal Monachus schauinslandi were assessed using multiple methods. The analysis focused on interventions undertaken to enhance survival of individual seals by reducing or eliminating immediate mortality risks. These interventions included dehookings, disentanglements, removing seals from high predation zones, medical interventions, and related activities. A total of 885 interventions occurred range-wide from 1980 to 2012. These included 645 inter -ventions classified as mitigating medium- to high-risk threats, involving 532 different seals. In the Northwest Hawaiian Islands, where most of these interventions took place, we found a significant relationship between the number of interventions conducted annually and duration of field effort. The survival and reproduction of the intervention seals were tracked through multiple generations, using (1) known survival and reproduction of intervention seals, and (2) expected survival and reproduction as determined using demographic rates estimated for the population at large. This analysis indicated that 17-24% of the 2012 population comprised either intervention seals or descendants of intervention seals. If seals included in a multiyear (1984-1992) re habilitation and captive care effort are also included, this proportion increases to 32%. These findings demonstrate the important link between the sustained population assessment field effort, the number of interventions that are enabled in association with those efforts, and the current status of the monk seal population. In contrast to a metaphorical 'silver bullet' whereby a result is achieved through a single (or a few) highly impactive tools, we liken our success in applying multiple interventions to a fusillade of many silver BBs1. © Inter-Research 2014.

Baker J.D.,National Oceanic and Atmospheric Administration | Harting A.L.,Harting Biological Consulting | Wurth T.A.,Joint Institute for Marine and Atmospheric Research | Johanos T.C.,National Oceanic and Atmospheric Administration
Marine Mammal Science | Year: 2011

Total estimated abundance of Hawaiian monk seals was just 1,161 individuals in 2008 and this number is decreasing. Most monk seals reside in the remote Northwestern Hawaiian Islands (NWHI) where the decline is approximately 4%/yr, whereas relatively fewer seals currently occupy the main Hawaiian Islands (MHI). It is widely accepted that the MHI population is increasing, although there are no formal estimates of total abundance, population growth rate or vital rates. This lack of information has hampered efforts to anticipate future scenarios and plan conservation measures. We present the first estimates of MHI monk seal survival and age-specific reproductive rates. Using these rates, a conservative estimate of current MHI abundance and a previously published stochastic simulation model, we estimate the MHI population growth rate and projected abundance trend. Analogous estimates for the NWHI are derived from a much richer data set. Estimated survival from weaning to age 1 yr is 77% in the MHI, much higher than recent NWHI estimates ranging from 42% to 57%. Moreover, MHI females begin reproducing at a younger age and attain higher birth rates than observed in the NWHI. The estimated MHI intrinsic rate of population growth is 1.07 compared to a 0.89-0.96 range in the NWHI. Assuming an initial abundance of 152 animals in the MHI, projections indicate that if current demographic trends continue, abundance in the NWHI and MHI will equalize in approximately 15 yr. These results underscore the imperative to mitigate the NWHI decline while devoting conservation efforts to foster population growth in the MHI, where documented threats including fishery interactions, direct killing, and disease could rapidly undo the current fragile positive trend. 2010 by the Society for Marine Mammalogy Published 2010. This article is a US Government work and is in the public domain in the USA.

Gilmartin W.G.,Hawaii Wildlife Fund | Sloan A.C.,National Oceanic and Atmospheric Administration | Harting A.L.,Harting Biological Consulting | Johanos T.C.,National Oceanic and Atmospheric Administration | And 3 more authors.
Aquatic Mammals | Year: 2011

Observed high pup and juvenile mortality, as a result of starvation conditions that were prevalent in the Hawaiian monk seal (Monachus schauin-slandi) population in the Northwestern Hawaiian Islands (NWHI), led to the development of a reha-bilitation and reintroduction program for under-weight monk seals. During 1984-1995, the pro-gram collected 98 young female monk seals whose mortality appeared certain (underweight and in some cases ill) from French Frigate Shoals (FFS) and attempted to nourish and rehabilitate these animals to enable their release as healthy individ-uals. Six additional young females of normal size were relocated from FFS (5) and Oahu (1) to Kure Atoll where their survival rate was expected to be higher than at their birth islands. The goal of the program was salvaging the reproductive potential of young female monk seals to aid in the recov-ery of this endangered species. Of the 104 animals collected, 17 died in captivity, 13 were converted to permanent captivity (for health or behavioral reasons), and the remaining 74 were released at Kure Atoll or Midway Islands within 14 mo of col-lection. Survival during the first year post-release was compromised, compared to native seals (born at the release site) but was similar to survival of natives in the second year. The released monk seals migrated among the three westernmost atolls at a higher rate than native seals. Monk seal moni-toring continued through 2005 when 32 animals were known to be alive; they, with their offspring, constituted at least 12 to 14% of the animals in the three western NWHI populations. Captive-care management strategies were developed in a rapid response and varied greatly as did the success. These results are critical to the development of future captive-care initiatives that may be neces-sary to mitigate the continuing high loss of young monk seals in the NWHI.

Baker J.D.,National Oceanic and Atmospheric Administration | Harting A.L.,Harting Biological Consulting | Barbieri M.M.,National Oceanic and Atmospheric Administration | Johanos T.C.,National Oceanic and Atmospheric Administration | And 2 more authors.
Journal of Wildlife Diseases | Year: 2016

Understanding disease transmission dynamics, which are in part mediated by rates and patterns of social contact, is fundamental to predicting the likelihood, rate of spread, impacts, and mitigation of disease outbreaks in wildlife populations. Contact rates, which are important parameters required for epidemiologic models, are difficult to estimate. The endangered Hawaiian monk seal (Neomonachus schauinslandi) may be particularly vulnerable to morbillivirus outbreaks, due to its low abundance, lack of genetic diversity, and history of isolation from mammalian diseases. Morbillivirus epizootics have had devastating effects on other seal populations. We constructed social networks based on visual observations of individually identifiable monk seals associating onshore to estimate contact rates, assuming random mixing, and also to investigate contact patterns of different age and sex classes. Contact rates estimated from two island populations in 4 yr were remarkably similar, indicating any two individuals have about a one in 1,000 chance of making contact on any given day. Further, contact patterns within and among age and sex classes were statistically different from random. The methods we used could be broadly applied to empirically derive contact rates using association data. These rates are critical for epidemiologic modelling to simulate wildlife disease outbreaks and to inform science-based prevention and mitigation programs. © Wildlife Disease Association 2016.

Schultz J.K.,Hawaii Institute of Marine Biology | Baker J.D.,National Oceanic and Atmospheric Administration | Toonen R.J.,Hawaii Institute of Marine Biology | Harting A.L.,Harting Biological Consulting | Bowen B.W.,Hawaii Institute of Marine Biology
Conservation Biology | Year: 2011

The Hawaiian monk seal (Monachus schauinslandi) is one of the most critically endangered marine mammals. Less than 1200 individuals remain, and the species is declining at a rate of approximately 4% per year as a result of juvenile starvation, shark predation, and entanglement in marine debris. Some of these problems may be alleviated by translocation; however, if island breeding aggregates are effectively isolated subpopulations, moving individuals may disrupt local adaptations. In these circumstances, managers must balance the pragmatic need of increasing survival with theoretical concerns about genetic viability. To assess range-wide population structure of the Hawaiian monk seal, we examined an unprecedented, near-complete genetic inventory of the species (n =1897 seals, sampled over 14 years) at 18 microsatellite loci. Genetic variation was not spatially partitioned ( w=-0.03, p = 1.0), and a Bayesian clustering method provided evidence of one panmictic population (K =1). Pairwise F STcomparisons (among 7 island aggregates over 14 annual cohorts) did not reveal temporally stable, spatial reproductive isolation. Our results coupled with long-term tag-resight data confirm seal movement and gene flow throughout the Hawaiian Archipelago. Thus, human-mediated translocation of seals among locations is not likely to result in genetic incompatibilities. © 2010 Society for Conservation Biology.

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