US-AMLR Datasets Pinniped research Mike 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

4 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

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 ) * In collaboration with Chile * In collaboration with UCSC (NSF – funded) 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* ( )

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

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

8 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

9 Fur seal performance Assessing overall fur seal performance: an ordination approach using 17 indices Fur seal performance was best & 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? 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