Reproductive morphology and status of female Hawaiian monk seals (Monachus schauinslandi) fatally injured by adult male seals

We studied reproductive rate, length of lactation period, pup survival, and mortality of injured and uninjured female Hawaiian monk seals (Monachus schauinslandi) on Laysan Island, northwestern Hawaiian Islands, in 1983 – 1989. The severity and timing of nonfatal injuries were influential in determining their effect on female reproductive success. There was a tendency towards a shorter mean lactation period and lower survival rate of pups for females with major injuries than for uninjured females. Females with minor injuries were similar to uninjured females in terms of reproductive rate, length of lactation, and pup survival. For females injured shortly before the birth of their pup or during lactation, pup survival was lower than for uninjured females, whereas for females injured during the year prior to pupping, measures of reproductive success were not significantly different from those for uninjured females. Immature (aged 4 – 8 years) females entering the reproductive population were injured by adult male seals significantly more often than females aged 0 – 3 years, but at a similar rate to adult females. The major effect of injuries on female reproductive success is an increase in female mortality: 87.5 % of the adult females (n = 16) that died on Laysan Island in 1983 – 1989 sustained injuries from adult male seals.

Download Full-text

Wounding in Hawaiian monk seals (Monachus schauinslandi)

Canadian Journal of Zoology ◽

10.1139/z93-066 ◽

1993 ◽

Vol 71 (3) ◽

pp. 458-468 ◽

Cited By ~ 37

Author(s):

Lisa M. Hiruki ◽

William G. Gilmartin ◽

Brenda L. Becker ◽

Ian Stirling

Keyword(s):

Coral Reef ◽

Adult Male ◽

Marine Debris ◽

Adult Males ◽

Monachus Schauinslandi ◽

Aggressive Interactions ◽

Size Classes ◽

Adult Females ◽

Northwestern Hawaiian Islands ◽

Monk Seals

Injuries observed on endangered Hawaiian monk seals (Monachus schauinslandi) at Laysan Island and French Frigate Shoals in the northwestern Hawaiian Islands in 1988 and 1989 were classified into six major types, based on the source of the wounds: mating attempts by adult male monk seals; nonmating aggressive interactions with other seals; attacks by large sharks; attacks by cookiecutter sharks (Isistius brasiliensis); contact with coral reef or debris; and entanglement in netting or marine debris. At both locations, injuries inflicted by adult male seals during mobbing incidents, in which many males attempt to mate with one seal, were seen more frequently than other types of injuries in 1988 and 1989. Injury data from 1982 – 1987 at Laysan Island and from 1985 – 1989 at French Frigate Shoals were used to compare the distribution of mating injuries inflicted by adult males and injuries inflicted by large sharks over size and sex classes of seals. Mating injuries caused by adult male seals were seen primarily on adult females but were also seen on seals in other size classes. Mating injuries inflicted by adult males occurred earlier in the year and with greater frequency at Laysan Island than at French Frigate Shoals. Injuries inflicted by large sharks were observed more often on adult male seals than on seals in other size classes at Laysan Island; however, no such difference was seen among size classes at French Frigate Shoals.

Download Full-text

Geographic variation of persistent organic pollutants in Hawaiian monk seals Monachus schauinslandi in the main Hawaiian Islands

Endangered Species Research ◽

10.3354/esr00602 ◽

2014 ◽

Vol 24 (3) ◽

pp. 249-262 ◽

Cited By ~ 2

Author(s):

J Lopez ◽

KD Hyrenbach ◽

C Littnan ◽

GM Ylitalo

Keyword(s):

Geographic Variation ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Hawaiian Islands ◽

Monachus Schauinslandi ◽

Monk Seals

Download Full-text

Photogrammetric Estimates of Size and Mass in Hawaiian Monk Seals (Monachus schauinslandi)

Aquatic Mammals ◽

10.1578/am.32.1.2006.31 ◽

2006 ◽

Vol 32 (1) ◽

pp. 31-40 ◽

Cited By ~ 9

Author(s):

Katherine W. McFadden ◽

Graham A. J. Worthy ◽

Thomas E. Lacher

Keyword(s):

Monachus Schauinslandi ◽

Monk Seals

Download Full-text

Fostering Behavior and the Effect of Female Density in Hawaiian Monk Seals, Monachus schauinslandi

Journal of Mammalogy ◽

10.2307/1383115 ◽

1998 ◽

Vol 79 (3) ◽

pp. 1060 ◽

Cited By ~ 29

Author(s):

Daryl J. Boness ◽

Mitchell P. Craig ◽

Luciana Honigman ◽

Susan Austin

Keyword(s):

Monachus Schauinslandi ◽

Monk Seals

Download Full-text

Temporal and spatial variation in age-specific survival rates of a long-lived mammal, the Hawaiian monk seal

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2006.3737 ◽

2006 ◽

Vol 274 (1608) ◽

pp. 407-415 ◽

Cited By ~ 48

Author(s):

Jason D Baker ◽

Paul M Thompson

Keyword(s):

Survival Rates ◽

Adult Survival ◽

Age Classes ◽

Temporal And Spatial Variation ◽

Monachus Schauinslandi ◽

Breeding Sites ◽

Capture Recapture ◽

Temporal And Spatial ◽

Spatio Temporal ◽

Monk Seals

Estimates of variability in pinniped survival rates are generally based on observations at single sites, so it is not certain whether observed rates represent the whole population. Here, we provide a comprehensive analysis of spatio-temporal variation in age-specific survival rates for endangered Hawaiian monk seals ( Monachus schauinslandi ) based on capture–recapture analyses of more than 85% of the pups weaned in this population over the last two decades. Uniquely, these data have been collected from six subpopulations, encompassing all major breeding sites across its 1800 km long core range. Analyses of individual subpopulations revealed similar patterns in age-specific survival, characterized by the relatively low survival rates from weaning to 2 years of age, intermediate rates to 4 years of age, and then by relatively high ‘mature’ survival rates until 17 years of age, after which a senescent decline was observed. Juvenile, subadult and adult survival rates all varied significantly over time. Trends in survival among subpopulations were coherent with their relative geographical positions, suggesting regional structuring and connectedness within the archipelago. Survival rates for different age classes tended to be positively correlated, suggesting that similar factors may influence the survival for seals of all ages.

Download Full-text