Significance of wounding to female reproductive success in Hawaiian monk seals (Monachus schauinslandi) at Laysan Island

1993 ◽  
Vol 71 (3) ◽  
pp. 469-474 ◽  
Author(s):  
Lisa M. Hiruki ◽  
Ian Stirling ◽  
William G. Gilmartin ◽  
Thea C. Johanos ◽  
Brenda L. Becker
Keyword(s):  
Reproductive Success ◽  
Adult Male ◽  
Reproductive Rate ◽  
Lactation Period ◽  
Female Reproductive Success ◽  
Monachus Schauinslandi ◽  
Lower Survival Rate ◽  
Adult Females ◽  
Pup Survival ◽  
Monk 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.

Wounding in Hawaiian monk seals (Monachus schauinslandi)

1993 ◽  
Vol 71 (3) ◽  
pp. 458-468 ◽  
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.

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

Reproduction ◽  
1994 ◽  
Vol 100 (1) ◽  
pp. 225-230 ◽  
Author(s):  
S. Atkinson ◽  
B. L. Becker ◽  
T. C. Johanos ◽  
J. R. Pietraszek ◽  
B. C. S. Kuhn
Keyword(s):  
Adult Male ◽  
Monachus Schauinslandi ◽  
Reproductive Morphology ◽  
Monk Seals

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

2006 ◽  
Vol 32 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Katherine W. McFadden ◽  
Graham A. J. Worthy ◽  
Thomas E. Lacher
Keyword(s):  
Monachus Schauinslandi ◽  
Monk Seals

Female reproductive success in a species with an age-inversed hierarchy

2016 ◽  
Vol 11 (6) ◽  
pp. 433-446 ◽  
Author(s):  
Dorien DE VRIES ◽  
Andreas KOENIG ◽  
Carola BORRIES
Keyword(s):  
Reproductive Success ◽  
Female Reproductive Success

Status of the Hawaiian monk seal (Monachus schauinslandi) population

1995 ◽  
Vol 73 (6) ◽  
pp. 1185-1190 ◽  
Author(s):  
W. G. Gilmartin ◽  
L. L. Eberhardt
Keyword(s):  
Complex System ◽  
Sex Ratios ◽  
Current Trend ◽  
Survival Rates ◽  
Hawaiian Monk Seal ◽  
Monachus Schauinslandi ◽  
Young Females ◽  
Adult Females ◽  
Unknown Factor ◽  
Adult Sex Ratio

Restoration of the Hawaiian monk seal (Monachus schauinslandi) population to its former abundance poses a number of problems in managing a complex system. Sharp differences in history and current trend exist among the six major pupping sites. A severely unbalanced adult sex ratio has resulted in deaths from "mobbing" of estrus females at two sites. Some unknown factor apparently severely reduced the numbers of females at three of the sites and thus produced the observed excess of males. Sex ratios subsequently decreased, but losses of adult females continue at two sites. A simple model indicates that sex ratios at the two sites where mobbing is a problem would require more than 10 years to approach an equilibrium value. Data on trends from counts are compared with estimates from reproduction and survival rates and agree closely except at one site (Kure Atoll), where introductions of young females have been made.

Instability of Harems of Feral Horses in Relation To Season and Presence of Subordinate Stallions

Behaviour ◽  
1990 ◽  
Vol 112 (3-4) ◽  
pp. 149-161 ◽  
Author(s):  
Elizabeth Franke Stevens
Keyword(s):  
Reproductive Success ◽  
Social Interactions ◽  
Lifetime Reproductive Success ◽  
Late Winter ◽  
Island Population ◽  
Single Male ◽  
Seasonal Differences ◽  
Feral Horses ◽  
Adult Females ◽  
Abundance And Distribution

AbstractMale horses (Equus caballus) defend harems of females (bands) year-round and throughout their lifetimes. A male's lifetime reproductive success depends upon the number of females in his harem. Although harems have previously been reported as remaining stable over many years, during the two years of this study 30 % of the adult females in an island population of feral horses changed harems during late winter. The seasonal differences in harem stability resulted from seasonal differences in the abundance and distribution of food. The spacing between band members was greater and the frequency of social interactions between them was lower in winter than in summer. In addition, the amount of time devoted to grazing increased in winter. These differences are attributed to the lower availability of suitable vegetation duirng winter. Harem stability did not depend on the age of females, the size of the harem, nor the age of the harem stallion, but did depend on the presence of subordinate stallions attached to the band. All of the females that changed bands left single-male bands; multi-male bands were stable throughout the study.

Sign in / Sign up

Export Citation Format

Share Document