We simulated the reintroduction of Mediterranean monk seal Monachus monachus individuals to create new populations using the Cabo Blanco colony (Western Sahara/Mauritania) as the source population. We evaluated potential negative impacts of removing weaned pups on population growth in the Cabo Blanco population and projected a range of plausible outcomes for reintroduced populations under 4 vital rate scenarios. Lifetables of simulated reintroduced populations were parameterized with published survival and reproductive rate estimates from the 2 extant monk seal populations in the eastern Atlantic: Cabo Blanco and Madeira. Two scenarios simulated enhanced neonatal survival to represent potentially higher survival of pups born on open beaches at reintroduction sites compared to the relatively low observed survival of pups born in caves at Cabo Blanco and Madeira. Reintroduction scenarios simulated the translocation of 6 weaned pups per year (4 females and 2 males) for 5 yr from Cabo Blanco to a reintroduction site, and both populations were subsequently projected an additional 5 yr. Simulations indicated that this level of removal would have relatively minor effects on the Cabo Blanco population, which could theoretically sustain considerably more removals and continue increasing in abundance. All simulated reintroduced populations were extant after the 10 yr projections, and the median of an aggregate distribution of final abundance from all scenarios was 27 seals (5 and 95 percentiles 15 and 52 seals, respectively). Our results support the viability of establishing new monk seal populations without causing undue harm to the Cabo Blanco colony.

We provide the first comprehensive demographic assessment of the Endangered Mediterranean monk seal Monachus monachus population residing in the Madeira Archipelago to identify factors that may impede population growth. Encounter data was obtained for this small, elusive population from 2012 to 2021 using a variety of non-invasive methods. From birth to age 2 mo, when pups molt, survival averaged 0.57. From birth to 1 yr and from 1-2 yr, estimated survival rates were 0.47 and 0.85, respectively. Beyond 2 yr, survival estimates differed by sex: 0.98 for females and 0.90 for males. These survival rates are similar to published estimates from the Cabo Blanco (Western Sahara/Mauritania) population. This is remarkable given that Cabo Blanco is situated adjacent to the extremely productive Canary Current system, whereas the marine environment of Madeira is far less productive. Instead of reducing survival, low marine productivity in Madeira appears to manifest in strikingly depressed reproductive rates. We estimated a mean gross reproductive rate of just 0.31; less than half the value (0.71) reported for Cabo Blanco. The youngest parturient females in Madeira were 6 yr old, whereas 3 yr olds give birth at Cabo Blanco. Despite low fecundity, the monk seal population in Madeira has been recovering, aided by a series of conservation measures implemented since 1988. Our results document that abundance increased from 19 seals in 2013 to 27 in 2021. Despite this undeniable success, the monk seals of Madeira remain vulnerable and require continued monitoring and protection in order to persist.

Identifying, assessing, and ranking the impact of individual threats is fundamental to the conservation and recovery of rare and endangered species. In this analysis, we quantify not only the frequency of specific causes-of-death (CODs) among Main Hawaiian Island (MHI) monk seals, but also assess the impact of individual CODs on the intrinsic growth rate, lambda, of the MHI population. We used gross necropsy results, histopathology, and other evidence to assign probabilities of 11 COD types to each mortality and then used Monte Carlo sampling to evaluate the influence of each COD on lambda. By right censoring realizations involving specific CODs, we were able to estimate lambda (and its associated uncertainty) when CODs were selectively removed from influencing survival. Applying the analysis to all known and inferred deaths believed to have occurred 2004-2019, the CODs with the largest influence on lambda were anthropogenic trauma, anthropogenic drowning, and protozoal disease. In aggregate, anthropogenic CODs had a larger effect on the growth rate than either natural or disease CODs. Possible bias associated with differential carcass detection, recovery, and COD classification are discussed.

We provide the first complete set of survival rate estimates for the Endangered Mediterranean monk seal Monachus monachus from birth into adulthood, as well as the first age-specific reproductive rates for the species. From 2002 to 2016, we obtained individual seal live encounter data through non-invasive monitoring techniques that were analyzed to estimate vital rates of Mediterranean monk seals of the Cabo Blanco (Western Sahara/Mauritania) population. From birth to age 2 mo, when pups molt, survival averaged 0.59, ranging from 0.41 to 0.74 among cohorts. From birth to 1 yr and from 1 to 2 yr, median estimated survival rates were 0.46 and 0.75, respectively. Beyond 2 yr, survival estimates differed by sex: 0.94 for males and 0.97 for females. From 2005 to 2016, we estimated a mean gross reproductive rate of 0.71. The youngest parturient females were 3 yr old. Fitted age-specific reproductive rates increased beginning at age 3 yr and exceeded 0.80 from age 6 to 17 yr. Despite low survival during the first 2 mo of life, the aggregate vital rates of the population are favorable for growth; a Leslie matrix containing our survival and fecundity estimates yielded an intrinsic growth rate of 1.058. Increasing abundance and favorable vital rates are a testament to the efficacy of the many measures taken to promote the conservation of this population.

We used sighting reports, including decades of citizen-reported Hawaiian monk seal (Neomonachus schauinslandi) sightings, to describe female breeding biology and reproductive success in the main Hawaiian Islands. We first used this data set to describe the timing of events in the female reproductive cycle. We then conducted an expert review of patterns in sighting histories to detect unobserved pupping events. Finally, we estimated the age-specific reproductive curve for female monk seals in the main Hawaiian Islands. Charting reproductive cycles showed indications of the robust condition of female monk seals in the main Hawaiian Islands; they nursed pups 12% longer than their counterparts in the Northwestern Hawaiian Islands and regained condition to molt more quickly after weaning a pup. By examining sighting histories, we were able to infer 25 unobserved pupping events that had previously gone uncounted. We accounted for additional uncertainty with a randomization procedure. After accounting for unobserved pupping events, the age-specific reproductive rate of main Hawaiian Islands monk seals exceeded 0.70 for prime aged females (8-18 years). This is the highest reproductive rate reported for any of the Hawaiian monk seal breeding sites, illustrating the important role of the main Hawaiian Islands population in Hawaiian monk seal recovery.

Where disease threatens endangered wildlife populations, substantial resources are required for management actions such as vaccination. While network models provide a promising tool for identifying key spreaders and prioritizing efforts to maximize efficiency, population-scale vaccination remains rare, providing few opportunities to evaluate performance of model-informed strategies under realistic scenarios. Because the endangered Hawaiian monk seal could be heavily impacted by disease threats such as morbillivirus, we implemented a prophylactic vaccination programme. We used contact networks to prioritize vaccinating animals with high contact rates. We used dynamic network models to simulate morbillivirus outbreaks under real and idealized vaccination scenarios. We then evaluated the efficacy of model recommendations in this real-world vaccination project. We found that deviating from the model recommendations decreased the efficiency; requiring 44% more vaccinations to achieve a given decrease in outbreak size. However, we gained protection more quickly by vaccinating available animals rather than waiting to encounter priority seals. This work demonstrates the value of network models, but also makes trade-offs clear. If vaccines were limited but time was ample, vaccinating only priority animals would maximize herd protection. However, where time is the limiting factor, vaccinating additional lower-priority animals could more quickly protect the population.

There is considerable temporal and spatial variability in the reproductive rates of Hawaiian monk seals (HMS; Neomonachus schauinslandi). Poor reproductive performance limits the recovery of this endangered species; however, causal factors are not fully understood. There is serologic evidence that HMS are exposed to pathogens that can impact reproductive success, but the prevalence of placental infections in HMS has not been evaluated. Placental tissues (n=50), including tissues from 25% of known HMS births, were opportunistically collected in 2011 from six Northwestern Hawaiian Islands and three main Hawaiian Islands. Reproductive histories of the sampled females were representative of the breeding population, as determined through comparisons in age of primiparity and mature reproductive rate. Placental tissues were examined histologically and screened by PCR for Coxiella burnetii, Brucella spp., Chlamydia spp., Leptospira spp., herpesviruses, and Toxoplasma gondii. There was no histologic evidence of placental pathology, and molecular analyses were negative. These negative results can be used to estimate pathogen prevalence in the nonsampled population. For an approximate population size of 1,300 HMS, we can estimate with 99% confidence that the prevalence of each pathogen tested is 9% or less. This is low relative to other pinnipeds and indicates that factors other than reproductive pathology, such as resource limitation, may drive variability in HMS reproductive rates. Further investigation into the cumulative impacts of resource limitation and other stressors on HMS reproduction is warranted.

We developed a stochastic susceptible-exposed-infectious-removed (SEIR) model to simulate a range of plausible morbillivirus outbreak scenarios in a randomly mixing population of 170 endangered Hawaiian monk seals (Neomonachus schauinslandi). We then modeled realistic vaccination and quarantine measures to determine the potential efficacy of such mitigation efforts. Morbillivirus outbreaks represent substantial risk to monk seals-91% of simulated baseline outbreaks grew (R0>1), and in one-third of the scenarios all, or nearly all, individuals were infected. Simulated vaccination efforts in response to an outbreak were not effective in substantially reducing infections, largely because of the prolonged interval between vaccination and immunity. Prophylactic vaccination, in contrast, could be an effective tool for preventing outbreaks. Herd immunity is practically achievable because of the small sizes of monk seal populations and the animals' accessibility on shore. Adding realistic spatial structure to the model, as informed by movement of seals tracked in the main Hawaiian Islands with the use of telemetry, greatly reduced the simulated impact of outbreaks (≤10 seals were infected in 62% of spatially structured simulations). Although response vaccination remained relatively ineffective, spatial segregation allowed herd immunity to be achieved through prophylactic vaccination with less effort. In a randomly mixing population of 170 seals, 86% would need to be vaccinated to achieve herd immunity in 95% of simulated outbreaks, compared to only approximately 60% in three spatially segregated subgroups with the same combined abundance. Simulations indicate that quarantining a modest number (up to 20) of ill seals has the potential to extinguish even fast-growing outbreaks rapidly. The efficacy of quarantine, however, is highly dependent upon rapid detection and response. We conclude that prophylactic vaccination combined with a quarantine program supported by vigilant surveillance and rapid, reliable diagnosis could greatly mitigate the threat of a morbillivirus outbreak in Hawaiian monk seals.

ABSTRACTObtaining a range‐wide abundance estimate for the Hawaiian monk seal (Neomonachus schauinslandi; monk seal) has formerly not been possible because of data limitation at sites where the only available data are infrequent counts. We describe a new method for obtaining abundance estimates for these sites that relies upon the proportion of the non‐pup population observed in standardized counts at other sites with known abundance. We converted these proportions (p), compiled over all sites and years having full population enumeration, to haulout correction factors (CF), where CF = 1/p. We then applied these CF values to counts at sites with unknown population size to provide a bounded distribution of population estimates. We used 2,179 CFs from 44 site‐years at intensively studied sites. We used these CFs for population estimation at 2 sites, Necker and Nihoa Islands, Hawaii, USA, where infrequent counts occurred and total abundance was unknown. The resulting population estimates ( and 5 and 95 percentiles) indicated that abundance had increased at Nihoa from 2001 ( = 31 non‐pups, 5–95% = 21–47) to 2015 ( = 116, 5–95% = 79–177), but there was no increase evident at Necker. We conducted method validation by randomly selecting 1–5 of the observed counts at site‐years with full enumeration, applying the CFs to the observed count, and testing whether the true (known) value lay within the 5–95% range of the resulting distribution of estimates. When we used only 1 count, the method succeeded in capturing the true value in >85% of 1,000 randomizations for single islands and 65–87% of the randomizations in atolls. Performance markedly improved when we used >1 randomly selected count to estimate population size. For the monk seal, this methodology represents a significant advancement because it enables a more complete estimate of the species’ abundance and a better assessment of the relative importance of different regions of its range to the overall recovery initiative. © 2017 The Wildlife Society.

The type and quantity of survey data, and consequently, applicable methods for estimating abundance, vary throughout the range of the Endangered Hawaiian monk seal Neomonachus 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.

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.

Marine Mammal ScienceVolume 30, Issue 3 p. 1165-1174 Notes Range-wide movement patterns of Hawaiian monk seals Thea C. Johanos, Corresponding Author Thea C. Johanos Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1601 Kapiolani Boulevard, Honolulu, Hawaii 96814, U.S.ACorresponding author (e-mail: thea.johanos-kam@noaa.gov).Search for more papers by this authorAlbert L. Harting, Albert L. Harting Harting Biological Consulting, 8898 Sandy Creek Lane, Bozeman, Montana 59715, U.S.ASearch for more papers by this authorTracy A. Wurth, Tracy A. Wurth Joint Institute for Marine and Atmospheric Research, 1000 Pope Road, Honolulu, Hawaii 96822, U.S.ASearch for more papers by this authorJason D. Baker, Jason D. Baker Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1601 Kapiolani Boulevard, Honolulu, Hawaii 96814, U.S.ASearch for more papers by this author Thea C. Johanos, Corresponding Author Thea C. Johanos Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1601 Kapiolani Boulevard, Honolulu, Hawaii 96814, U.S.ACorresponding author (e-mail: thea.johanos-kam@noaa.gov).Search for more papers by this authorAlbert L. Harting, Albert L. Harting Harting Biological Consulting, 8898 Sandy Creek Lane, Bozeman, Montana 59715, U.S.ASearch for more papers by this authorTracy A. Wurth, Tracy A. Wurth Joint Institute for Marine and Atmospheric Research, 1000 Pope Road, Honolulu, Hawaii 96822, U.S.ASearch for more papers by this authorJason D. Baker, Jason D. Baker Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1601 Kapiolani Boulevard, Honolulu, Hawaii 96814, U.S.ASearch for more papers by this author First published: 06 December 2013 https://doi.org/10.1111/mms.12084Citations: 11Read the full textAboutRelatedInformationPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessClose modalShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume30, Issue3July 2014Pages 1165-1174 RelatedInformation

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, disentangle- ments, 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 re- production as determined using demographic rates estimated for the population at large. This analysis indicated that 1724% of the 2012 population comprised either intervention seals or de- scendants of intervention seals. If seals included in a multiyear (19841992) re habilitation and cap- tive 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 interven- tions that are enabled in association with those efforts, and the current status of the monk seal pop- ulation. 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 fusil- lade of many silver BBs 1 .

We propose a two-stage translocation strategy to conserve metapopulations of endangered species. The concept takes advantage of variation in vital rates among subpopulations to increase individual fitness, improve species status, and maintain metapopulation structure for long-term resiliency. We simulate two-stage translocation scenarios for conserving the Hawaiian monk seal Monachus schauinslandi, a critically endangered species which exhibits highly variable juvenile, but consistently favorable adult, survival rates. Moving young seals from areas of lower to higher juvenile survival and subsequently returning them to their source site once they have reached an appropriate age improves population reproductive value. We present a decision framework for implementing two-stage translocation in a manner that minimizes risks while increasing the likelihood of desired outcomes. Two-stage translocation may be effective for metapopulations of other rare species which exhibit variation in vital rates among subpopulations and a life-stage bottleneck due to factors that are not amenable to in situ mitigation.

P>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.

Observed high pup and juvenile mortality, as a result of starvation conditions that were prevalent in the Hawaiian monk seal (Monachus schauinslandi) population in the Northwestern Hawaiian Islands (NWHI), led to the development of a rehabilitation and reintroduction program for underweight monk seals. During 1984-1995, the program 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 individuals. 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 recovery 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 collection. 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 monitoring 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 necessary to mitigate the continuing high loss of young monk seals in the NWHI.

Abstract:  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 FST comparisons (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.

We evaluated reproductive patterns of the Hawaiian monk seal (Monachus schauinslandi) using a combination of fitted age-specific reproductive curves and analysis of reproductive patterns of individual females. We review the difficulties inherent in the acquisition and modeling of reproductive data with emphasis on the significance of reproductive senescence to populations with dissimilar age/sex compositions. Validation of the fitted reproductive parameters was accomplished by Monte Carlo sampling of parameter distributions to compare the expected number of pups with the observed production. Although the fitted reproductive functions appear to provide an acceptable fit to the raw reproductive data, we found that the fitted curves did a poor job of predicting the actual pup production in individual years because of high variability among years. To further verify, and elaborate on, the patterns in the pooled (multi-seal, and multi-year) rates, we examined attributes of the reproductive performance of individual seals. The attributes included age of primiparity, reproductive rates computed over several age ranges, and the relationship between reproductive performance and seal longevity. Analysis of individual seal patterns reinforced the conclusion that reproductive senescence is operative in monk seal populations.