ANNUAL REPRODUCTIVE CYCLE OF THE FEMALE HAWAIIAN MONK SEAL (<i>MONACHUS SCHAUINSLANDI</i>)

Johanos, Thea C.; Becker, Brenda L.; Ragen, Timothy J.

doi:10.1111/j.1748-7692.1994.tb00386.x

Cited by 65 publications

(57 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some individual tiger sharks clearly arrive at FFS during the albatross fledgling season from June through July (Hyrenbach et al 2002, Lowe et al 2006, Meyer et al 2010. However, overall the seasonal peaks of sharks utilizing other islands do not correlate with periods of breeding or pupping in potential prey items such as seals, birds or turtles (Balazs 1976, Johanos et al 1994, Hyrenbach et al 2002. Simultaneous tracking of tiger sharks and green sea turtles off of Australia also reveals limited correlation in movements between this predatorprey pair (Fitzpatrick et al 2012).…”

Section: Discussionmentioning

confidence: 99%

Telemetry and random‐walk models reveal complex patterns of partial migration in a large marine predator

Papastamatiou

Meyer

Carvalho

et al. 2013

Ecology

148

163

View full text Add to dashboard Cite

Abstract. Animals are often faced with complex movement decisions, particularly those that involve long-distance dispersal. Partial migrations, ubiquitous among all groups of vertebrates, are a form of long-distance movement that occurs when only some of the animals in a population migrate. The decision to migrate or to be a resident can be dependent on many factors, but these factors are rarely quantified in fishes, particularly top predators, even though partial migrations may have important implications for ecosystem dynamics and conservation. We utilized passive acoustic telemetry, with a Brownian bridge movement model and generalized additive mixed models, to explore the factors regulating partial migration in a large marine predator, the tiger shark, throughout the Hawaiian Islands. Although sharks tended to utilize a particular ''core'' island, they also demonstrated inter-island movements, particularly mature females that would swim from the northwestern Hawaiian Islands to the main Hawaiian Islands (MHI). Immigration to another island was a function of season, sea surface temperature (SST), and chlorophyll a concentration. Our results predict that 25% of mature females moved from remote French Frigate Shoals atoll to the MHI during late summer/early fall, potentially to give birth. Females with core home ranges within the MHI showed limited movements to the NWHI, and immigration to an island was better explained by SST and chlorophyll a concentration, suggesting a foraging function. Dispersal patterns in tiger sharks are complex but can be considered a mix of skipped-breeding partial migration by mature females and individual-based inter-island movements potentially linked to foraging. Therefore, sharks appear to use a conditional strategy based on fixed intrinsic and flexible extrinsic states. The application of Brownian bridge movement models to electronic presence/ absence data provides a new technique for assessing the influence of habitat and environmental conditions on patterns of movement for fish populations.

show abstract

Section: Discussionmentioning

confidence: 99%

Telemetry and random‐walk models reveal complex patterns of partial migration in a large marine predator

Papastamatiou

Meyer

Carvalho

et al. 2013

Ecology

148

163

View full text Add to dashboard Cite

show abstract

“…Female monk seals give birth to single pups and nurse them for five to six weeks during a protracted reproductive season, with most births occurring during March to August ( Johanos et al 1994). In this study, pups were double-tagged on their rear flippers with unique plastic tags (and, since 1990, also marked with injected passive integrated transponders-PIT tags; Wright et al 1998) soon after weaning.…”

Section: Methodsmentioning

confidence: 99%

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

Baker

Thompson

2006

Proc. R. Soc. B.

View full text Add to dashboard Cite

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.

show abstract

“…We assumed this hunting duration because seals were probably hunted when the females were on land nursing their pups, as they would have been most vulnerable and visible to hunters during this time. In other species of monk seals, nursing is known to occur for approximately 30-50 days, with some degree of overlap among individuals ( Johanos et al 1994). Thus, a range of 30-90 days probably covers the length of time at which peak hunting occurred for Caribbean monk seals.…”

Section: Methodsmentioning

confidence: 99%

Extinction rate, historical population structure and ecological role of the Caribbean monk seal

McClenachan

Cooper

2008

Proc. R. Soc. B.

View full text Add to dashboard Cite

The productivity and biomass of pristine coral reef ecosystems is poorly understood, particularly in the Caribbean where communities have been impacted by overfishing and multiple other stressors over centuries. Using historical data on the spatial distribution and abundance of the extinct Caribbean monk seal (Monachus tropicalis), this study reconstructs the population size, structure and ecological role of this once common predator within coral reef communities, and provides evidence that historical reefs supported biomasses of fishes and invertebrates up to six times greater than those found on typical modern Caribbean reefs. An estimated 233 000-338 000 monk seals were distributed among 13 colonies across the Caribbean. The biomass of reef fishes and invertebrates required to support historical seal populations was 732-1018 g m K2 of reefs, which exceeds that found on any Caribbean reef today and is comparable with those measured in remote Pacific reefs. Quantitative estimates of historically dense monk seal colonies and their consumption rates on pristine reefs provide concrete data on the magnitude of decline in animal biomass on Caribbean coral reefs. Realistic reconstruction of these past ecosystems is critical to understanding the profound and long-lasting effect of human hunting on the functioning of coral reef ecosystems.

show abstract

ANNUAL REPRODUCTIVE CYCLE OF THE FEMALE HAWAIIAN MONK SEAL (MONACHUS SCHAUINSLANDI)

Cited by 65 publications

References 12 publications

Telemetry and random‐walk models reveal complex patterns of partial migration in a large marine predator

Telemetry and random‐walk models reveal complex patterns of partial migration in a large marine predator

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

Extinction rate, historical population structure and ecological role of the Caribbean monk seal

Contact Info

Product

Resources

About