US-AMLR Datasets
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Transcript of US-AMLR Datasets
US-AMLR Datasets
Pinniped researchMike Goebel
CCAMLR Ecosystem Monitoring Program
• “detect and record significant changes in critical components of the marine ecosystem ……”
• “distinguish between changes due to harvesting of commercial species and changes due to environmental variability, both physical and biological.”
CEMP was established in 1984 in response to a developing krill fishery to:
•Fur seal •Elephant seal•Weddells•Leopards
Pinniped species studied by US-AMLR
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Predator performance – Fur seals
*CEMP Indices
Summer (Local/Regional scale) Foraging success (4 indices, inc. trip duration*) Trophic links – food web & diet studies (5) Reproductive success (4, inc. pup growth*)
Winter (Scotia Sea - broader geographic scale) Annual survival , natality (4 indices) Pup production (2 indices) Arrival condition – timing of reproduction (2)
Multi-year Demography - Population vital rates
• Age at first reproduction
• Net reproductive rate
• Mean generation time
• Intrinsic rate of growth
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Datasets collected – Pinnipeds
Data sets - Annual (1997/98 – Present):
DEMOGRAPHY - Mark-resight tag databaseAdult females tagged 12-15% (3% Cape-wide)Known-age 94% Pregnancy and survival rates500 pups tagged annually* (~7% of pup production)
ECOLOGYTDR deployments (Dec-Feb)PTT/GPS deployments – (Dec, Jan, Feb)Trip duration (CEMP)Pup growth* (CEMP)
TROPHIC LINKS (Scats, Fatty acids, & Stable isotopes)
* In collaboration with Chile* In collaboration with UCSC (NSF – funded)
OTHER PINNIPEDS: Mark resight data – leopards & elephant sealsWeaning mass – elephant seals
Data sets - Periodic: ECOLOGY – Regional surveys (SSMUs) (1986, 1991, 1995, 2001, 2006)
OCEANOGRAPHY - large seals as samplers – CTD* (2005-2009)
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Fur seal population vital rates
•Age-specific mortality•Net reproductive rate•Mean generation time•Intrinsic rate of growth•Age at 1st reproduction (AFR)
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Juveniles• first year survival:Low• ~90% mortality by AFR
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Adult females• survival: High• pregnancy rate:High
Fur seal year class success 1982-2006
Recruitment and/or survival are variable
….that characteristic has not changed over three decades
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Tooth data:
1982-1997 year classes
Mark-resight data:
1998-2006 year classes
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Krill demographics & fur seal performance
Krill length in fur seal diet Krill maturity & sex ratio
Fur seal trip duration
Trip durations are shortest when:
• Krill length is >47mm• Low proportion of juvenile krill• High proportion of female krill
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JuvenileMaleFemale
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Fur seal performance
Assessing overall fur seal performance:
an ordination approach using 17 indices
Fur seal performance was best 2000-2002 & 2006 when:
• Krill length was >47mm• Low proportion of juvenile krill• High proportion of female krill
Top-down impact on fur seal populations:
28-50% of all fur seal pups consumed by mid-Feb
Fur seal phenology: Climate change effects?
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Mean age
Median date of births
Mean date of arrival
Arrival and date of birth are becoming earlier.
Trends in arrival and parturition for female fur seals
Uniqueness of US-AMLR pinniped datasets
• Number of indices, length of time series, having a large known age population, and a large mark-resight database
• Demography & vital rates for an Otariid
• Data are collected simultaneously with offshore data
• Leopard seal data
• Data sets are collected in a rapidly changing environment
• Colonizing events