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US-AMLR Datasets

US-AMLR Datasets. Pinniped research Mike Goebel. CEMP was established in 1984 in response to a developing krill fishery to:. “detect and record significant changes in critical components of the marine ecosystem ……”

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US-AMLR Datasets

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  1. US-AMLR Datasets Pinniped research Mike Goebel

  2. CEMP was established in 1984 in response to a developing krill fishery to: • “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.” CCAMLR Ecosystem Monitoring Program

  3. Pinniped species studied by US-AMLR • Fur seal • Elephant seal • Weddells • Leopards

  4. Predator performance – Fur seals • 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 *CEMP Indices

  5. Datasets collected – Pinnipeds • Data sets - Annual (1997/98 – Present): • DEMOGRAPHY - Mark-resight tag database • Adult females tagged 12-15% (3% Cape-wide) • Known-age 94% • Pregnancy and survival rates • 500 pups tagged annually* (~7% of pup production) • ECOLOGY • TDR deployments (Dec-Feb) • PTT/GPS deployments – (Dec, Jan, Feb) • Trip duration (CEMP) • Pup growth* (CEMP) • TROPHIC LINKS (Scats, Fatty acids, & Stable isotopes) • OTHER PINNIPEDS: • Mark resight data – leopards & elephant seals • Weaning mass – elephant seals Data sets - Periodic: ECOLOGY – Regional surveys (SSMUs) (1986, 1991, 1995, 2001, 2006) OCEANOGRAPHY - large seals as samplers – CTD* (2005-2009) * In collaboration with UCSC (NSF – funded) * In collaboration with Chile

  6. Fur seal population vital rates • Age-specific mortality • Net reproductive rate • Mean generation time • Intrinsic rate of growth • Age at 1st reproduction (AFR) • Adult females • survival: High • pregnancy rate: High • Juveniles • first year survival: Low • ~90% mortality by AFR

  7. 1999/00 Tooth data: 1982-1997 year classes Mark-resight data: 1998-2006 year classes Fur seal year class success 1982-2006 Recruitment and/or survival are variable ….that characteristic has not changed over three decades

  8. Krill demographics & fur seal performance Krill maturity & sex ratio Krill length in fur seal diet Fur seal trip duration • Trip durations are shortest when: • Krill length is >47mm • Low proportion of juvenile krill • High proportion of female krill

  9. 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

  10. Top-down impact on fur seal populations: 28-50% of all fur seal pups consumed by mid-Feb

  11. Fur seal phenology: Climate change effects? Trends in arrival and parturition for female fur seals Arrival and date of birth are becoming earlier.

  12. 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

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