Tuesday, December 8, 2009
Wednesday, December 9, 2009
Thursday, December 10, 2009
Friday, December 11, 2009
Saturday, December 12, 2009
Sunday, December 13, 2009

December 11, 2009

Today was our third day in the field. We had a good day again today and collected samples from 5 adult females and their pups. This is the last day that we are planning to catch adult animals, but will spend tomorrow collecting samples from additional pups. Our field team has become very efficient, with everyone learning new skills and knowledge. Considering this was the first time several of the Peruvian biologists on our team were involved with catching adult fur seals, we are all very happy with how proficient everyone has become. We adjusted our target this morning and were hoping to be able to examine 15 adult animals this year. Everyone was very dedicated to reaching this goal and we stayed on the beach until nearly sunset in order to achieve it. We are hoping to return next year to examine more adults and strengthen the data we have gained on the population health. The experience everyone gained this year will help us be more efficient in the field next year. The data we gain this year from all the tests we will run looking for diseases, toxins, etc. will also help us refine our methods next year to be sure we are gaining the best information possible.

We are very happy with the number of adults and pups we were able to examine this year. The pups we look at tomorrow should round out a fairly complete set of data for juvenile fur seals. About a month ago, we weren’t even sure if we would be able to examine any pups. Since early this summer, there has been a great deal of concern based on climate models that a strong El Niño Southern Oscillation (ENSO) event was developing. The ENSO phenomenon is a change in ocean currents that results in abnormally warm water along the Pacific coast of South America. At PSJ specifically, this change in water temperature disrupts the fish populations and decreases the number of anchovetas available as food for the wildlife. Ocean temperatures are normally a cold 50°F, but during an ENSO they can reach into the high 60s. The last severe ENSO event was in 1997/98 and was so decreased the fur seal population from around 25,000 animals to 5,000. The beach full of fur seals where we have been working this week was essentially empty except for carcasses and an entire breeding season was essentially skipped. It took years for the population to recover and for the beach to become full again.

These El Niño events are a normal part of nature and affect all the wildlife at PSJ, such as Humboldt penguins, pelicans, cormorants, sea lions, and other species. The populations do slowly recover over time and are adapted to withstand these events at a population level. However, we don’t know how well they can withstand the events when other threats are also present (such as illegal hunting, overfishing the ocean, disease, and environmental contamination). The data collected during this study on disease and toxin exposure prior to an ENSO, will help us evaluate such concerns following the next ENSO whenever it occurs. Looking at recent trends, severe El Niño events are also occurring more frequently and with greater severity, allowing less time for populations to recovery between events. Climate change may be to blame. Regardless of the cause, the mortality from ENSO events could have severe consequences for fur seal conservation efforts.

Fortunately it appears that the early predictions did not hold true this year. The populations are vibrant and at high numbers. Marco Cardena is the lead biologist on-site at PSJ year round. He and the other staff take census counts of the animals observed on the various beaches. I work with Marco on another project evaluating the health of the Humboldt penguins at PSJ. When I was at PSJ in June of this year working on penguins, we had several conversations about how the air temperatures and humidity seemed different this year. We were both very concerned that a bad El Niño was around the corner. We’re both very relieved that our suspicions were wrong.

More tomorrow….

Mike Adkesson, DVM, DACZM
Veterinarian – Chicago Zoological Society