E 2009, by the American Society of Limnology and Oceanography, Inc. Connecting recruitment of Antarctic krill and sea ice

• Main Authors: John Wiedenmann, B Katherine A. Cresswell, Marc Mangel B
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarctic Peninsula; Meredith; The Antarctic; Antarc*; Antarctic Krill; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.158.4183; http://www.soe.ucsc.edu/~msmangel/Wiedenmann%20et%20al%20LO.pdf

We develop an age-structured model for two krill populations near the Antarctic Peninsula and estimate the relative recruitment events that reproduce observed trends in krill abundance and age structure. Estimates of recruitment in both regions show a nonlinear relationship between recruitment and sea ice area in the combined Bellingshausen and Amundsen Seas from the previous winter and spring, with large recruitment events occurring over a narrow range of ice area, and minimal recruitment otherwise. This finding may allow for an adaptive approach in which future catch limits are adjusted based on predictions of biomass. This result also suggests that the ecosystem may change dramatically once average ice area drops below the recruitment threshold. The West Antarctic Peninsula (WAP) is one of the most rapidly changing regions on the planet (Vaughn et al. 2003). Air temperatures warmed by over 3uC and summer surface ocean temperatures warmed by over 1uC over the past 50 years (Meredith and King 2005). Sea ice concentration also showed a decline, although the timing and magnitude of this decline remain debated. Based on