Tuesday, December 29, 2015

Happy Holidays from the 2015-16 Farallon Winter Crew

Greetings everyone!

All is well out here on the Farallon Islands. We have been spending a lot of our time dodging rain drops and trying not to get blown off this rock. As mentioned in the previous blog we've been experiencing large swells out here and they have continued to impress. We'd like to take this opportunity to introduce this year's team.

Rainbow coming out of Indian Head Rock on West End Island. December 2015
Ryan Berger – Lead Winter Farallon Biologist:

The longer Ryan performs this work the more questions arise about the marine environment. Just when he thinks he has started to figure out certain aspects of this ecosystem he is humbled by the way it continues to throw him for a loop. This is the value of long term datasets and even after 6 years of studying marine mammals on the Farallones there is still so much to learn. Ryan is excited to begin working with this year’s crew and can’t wait for the surprises that will unfold this season. This year has the potential to be the biggest El Nino event since the 1997-98 season and after experiencing prolonged drought on the Farallones new challenges should arise over the next few months.

Ryan on the island helping with FWS facilities operations.

Taylor Nairn – Winter Farallon Research Assistant 2016:

Taylor earned her degree in Environmental Science with a concentration in Natural Resource Management and Conservation. She currently works for the Beach Watch program at the Greater Farallones Association, a 22 year ecosystem monitoring program that collects baseline data on beaches in the Greater Farallones National Marine Sanctuary. She is also highly trained in oil spill response. When not documenting wildlife and checking data, she enjoys surfing, road trips, and live music. Taylor is incredibly excited about her time on SEFI; she looks forward to gaining more intimate knowledge of our California Current system and wildlife, and looking forward to more adventures in island biogeography that this opportunity could bring.

Taylor on the National Marine Sanctuaries R/V Fulmar during an ACCESS cruise.
Cassie Bednar – Winter Farallon Research Assistant 2016:

Cassie is from the San Francisco Bay Area. She graduated from UC Santa Cruz with a B.S. in Marine Biology and recently received her M.S. in Environmental Studies from San Jose State University. She spent two seasons working for Point Blue Conservation Science observing seabird breeding and foraging behavior along the north central coast of CA and on Santa Cruz Island off the coast of Santa Barbara, CA. When she is not working she enjoys backpacking, photography, crafting and weightlifting. She is looking forward to living and working on SEFI this coming winter season and to expand her experience working with marine mammals.

Cassie conducting field research along the California coast.

Ross Nichols – Winter Farallon Research Assistant 2016:

Ross was born and raised near Monterey Bay in California. He graduated from UC, Santa Cruz, where he studied Marine Biology with a focus in marine mammals. He worked as a research assistant with the Pinniped Cognition and Sensory Systems Lab, under Dr. Colleen Reichmuth, from 2012-2015, where he worked with various pinniped species. He enjoys the outdoors, and loves to go backpacking, mountain biking, and kayaking whenever he can. Some of his favorite pastimes are SCUBA diving and listening to podcasts. Ross strives to expand his knowledge about marine carnivores and the marine environment, and is excited about the upcoming 2015-2016 winter field season with SEFI.

Ross doing some scope work at the Lighthouse.
Scarlett Hutchin – Winter Farallon Research Assistant 2016:

Scarlett Hutchin completed a Postgraduate Certificate at Oxford University this year, where she studied Manx shearwater foraging behaviour in the Irish Sea using GPS tracking.  After completing internships and volunteer placements on various islands in the UK and one in the Seychelles, Scarlett a spent summer on SEFI in 2013 and has been looking for a way to come back to this extraordinary place ever since.  She originally trained in metalwork conservation and is leaving behind a career as a sculpture conservator in London in order to embark on new adventures.  When she’s not working with seabirds and marine mammals or cleaning historic bronzes, Scarlett mostly likes to eat and climb.

Scarlett collecting tag resight data on the resident elephant seals.
Speaking of eating, we had a quiet Christmas out here in the middle of the Pacific. We did a proper feast that consisted of a 20 lb turkey, mashed potatoes, yams, stuffing in a pumpkin, steamed carrots, salad, garlic bread, marzipan, apple pie and mulled cider.

Farallon Winter 2015-16 Christmas dinner.
In closing this blog the elephant seal breeding season is starting to ramp up. We now have 10 cows in our breeding colonies and the first pup of the season was born on December 26th. This cow arrived to the island on December 22nd. In comparison to last year the first cow arrived on December 18th and pupped on the 22nd. This year's first pup was born 4 days later compared to last year. More exciting news to come! Check back soon!

First pup of the season born to the first cow that arrived to the island!

Friday, December 11, 2015

The Power of the Sea

Giant Swells breaking across Sewer Gulch
Break, break, break
On thy cold gray stones, O Sea!
And I would that my tongue could utter
The thoughts that arise in me.

Alfred Lord Tennyson, Poet, 1842

20ft waves wipe out Study Point Peninsula in Maintop Bay

It's Alaska big out here!

Jonathan Shore, Wildlife Refuge Specialist, Farallon National Wildlife Refuge, today

In 15 years of coming to the Farallones, I've seen a lot of storms - but today was a real treat. In the morning it was ~18feet swell out of the West Northwest with king tide and wind waves on top of that. A real incredible show, particularly on the north side of the island. These great photos were taken by intern RJ Roush. These events are always amazing - I find myself behaving like a 10 year old "Wow! look at that one!" They are humbling, as we move into winter in this unique El Nino year we will likely see more of them. The video below is a montage - I believe our first ever on Los Farallones, hey even Rocky had a montage. This is something I have never seen before myself, and only viewed in an old photograph that hung on the wall here when I first started coming to the island and has disappeared. What you are looking at here at one picture per second is a massive wave hitting Sea Lion Islet on the NW side of the island, with spray engulfing it completely. And a bonus rainbow!

Sea Lion Islet gets swallowed in this montage video

We figure from topographic maps that Sea Lion Islet is ~80ft tall! Wow! (again...)
Observations like this remind us of the raw power of the "Pacific" ocean, our unique position to be on the Refuge everyday, and our ability to view sightings like these in a long term context. And also why I'm glad we don't have a boat landing scheduled for anytime soon...

Russ Bradley
Farallon Program Manager, Point Blue


Friday, December 04, 2015

A Warming Ocean Brings the Tropics to the Farallones--But It's Not Fun in the Sun for Everyone

The month of October had something of a tropical feel at Southeast Farallon Island--no, its barren rocks and few Monterey Cypress were not suddenly replaced by white sand beaches and palm trees, but recently, wildlife more characteristic of tropical latitudes have been visiting the island. Throughout October, we witnessed species like Brown Boobies, Common Dolphins, and Ocean Sunfish in unprecedented numbers around the Farallon Islands. These animals are typically associated with warm-water marine environments and rarely occur this far north along the California coast in the fall. What could explain the abundances of unusual species? Not surprisingly, a recent spike in local sea surface temperatures may be contributing to this phenomenon.

A handsome male Brown Booby visiting the Farallones. More typical in tropical regions, these birds have been showing up in increasing numbers in recent years around the islands. Photo: Jim Tietz. 

Sea surface temperature (SST) from water samples obtained from shore is measured daily at Southeast Farallon Island, as part of Point Blue’s effort to monitor the surrounding oceanic conditions. The practice dates back to 1925, long before biologists had a presence on the island. The historic average daily SST for October is 13.6 degrees Celsius. This year, the month’s SST registered at 16.6 degrees! That makes it the warmest-ever October on the island, nearly 0.5 degrees higher than the previous warmest October. 
Historic average daily sea surface temperature (SST) for the month of October from Southeast Farallon Island. There is no SST from 1943-1954 and 1971.
The marine ecosystem is heavily influenced by temperature--relatively minor temperature changes can alter nutrient availability, which has effects throughout the ocean food web. With such abnormally warm conditions, warm-water species are turning up in unprecedented numbers, likely in search of food that usually would not be available in the colder waters of the California Current around the Farallon Islands. 

Brown Boobies congregating on Sugar Loaf rock. Before recent years, seeing this many birds together on the island was unheard of. Photo: Jim Tietz.
 Brown Boobies have been one of the most apparent tropical visitors. Found throughout tropical oceans, this large seabird breeds as far north as the Coronados Islands in Mexican waters just south of the California border. Historically, Brown Boobies would only rarely venture further north up the California coast. Between 1968 and 1999, there were only 11 records from Southeast Farallon Island. Since 2000, a few individuals have been seen in most years, usually during the fall. But when a spell of relatively high water temperatures began late last year, booby numbers started to noticeably increased. That trend continued through this October, when we regularly saw dozens of birds roosting on Sugar Loaf rock, with as many as 30 in a single day.

Number of Brown Boobies seen on Southeast Farallon per year, 2000-present. There has been a notable increase in sightings since 2014. In 2015, 39 birds have been seen to date.

Colorful and gregarious Common Dolphins, more typical in the waters offshore of Southern California, have also visited in exceptional numbers. They have been frequently seen near the island on our daily whale surveys, in fast-moving pods of several hundred individuals. In October alone, 2,900 Common Dolphins were seen. That’s nearly equal to the total number of dolphins seen between 2000 and 2014--about 3,300 were seen in that 15-year span. Additionally, this influx of warm-water Common Dolphins has corresponded with a decrease in sightings of cetacean species associated with colder waters, such as Pacific White-sided Dolphins and Northern Right-whale Dolphins. A typical fall may witness as many as a few hundred white-sided dolphins and several dozen right-whale dolphins, but neither species has been seen from the island this season.

Number of Common Dolphins seen from Southeast Farallon Island per year, 2000-2015. Totals for 2015 are through November 15th. This year has seen substantially more Common Dolphins than previous years. Note the year-to-year trend since 2000 nearly mirrors Brown Booby sightings in that span.

These unusual conditions are not confined to the Farallon Islands. Temperatures across the eastern Pacific Ocean have been markedly increasing over the past few years, with a well-documented impact on marine ecosystems along the west coast of North America. Since late 2013, a mass of warm water known as “The Blob” has persisted from Alaska to Mexico, raising regional sea surface temperatures several degrees Celsius above the norm. In addition to The Blob, however, an even larger phenomenon is looming--El Niño. Over the past year, scientists have observed the onset of an El Niño event that was forecasted to peak this fall and winter, further warming the eastern Pacific. Early evidence indicates this years’ edition could be among the strongest on record, possibly surpassing the massive El Niño of 1997-98. 

Past El Niño events are readily apparent in long-term SST data from the Southeast Farallon Island. The historic 1997-98 El Niño coincided with some of the warmest average monthly temperatures around the island. The average SST from September of 1997, at 16.7 °C, was even higher than this October’s, while average temperatures from November of that year registered at a balmy 16.3 °C. The previous warmest October on record, in 1982, also corresponded with the start of a very strong El Niño. Thus, it appears this fall’s warm spell is a clear indicator of the arrival of this years’ much-heralded El Niño.

Late-October El Niño status compared between 1997 and 2015 events. Images depict satellite-derived data of sea surface height anomalies, which correlate with relative upper ocean temperatures. The 1997 El Niño was the strongest on record. Image: NASA/JPL

While it has been fascinating to see unusual wildlife around the Farallones, the El Niño may bring more serious consequences to the marine ecosystem. Abnormally warm temperatures can limit nutrient availability and thus disrupt ocean food webs. With the persistence of the Blob and the arriving El Niño, there have already been significant impacts on marine life in the region. The Blob was linked to a decline in krill abundances last year, which in turn led to massive die-offs of Cassin’s Auklets--a small, krill-eating seabird--along the coast in the winter. California sea lions in the southern part of the state have been strained of late, as their typical prey has been pushed hundreds of miles north by warm waters. Many sea lions are being forced to travel further north in search of food, or else starve, as indicated by reports of thousands of emaciated individuals stranded on beaches this year. Related to this trend, we have seen California sea lions in record numbers on the Southeast Farallon Island this fall (learn more about it in a previous blog post: http://www.losfarallones.blogspot.com/2015/10/zalophus-invade-farallones.html). Additionally, warm ocean conditions spurred a harmful algae bloom on an unprecedented scale in coastal waters this summer. Toxins produced by the algae have been linked to another wave of seabird mortalities and sea lion strandings, and have wreaked havoc on some fisheries, causing West Coast states to postpone the winter crabbing season.

A Common Dolphin adult and calf. While recent conditions around the Farallones have suited this warmer-water cetacean, other species have struggled from a disruption to their usual food resources. Photo: Protected Resources Division, Southwest Fisheries Science Center, La Jolla, California.
On a broad scale, the ultimate consequences of this El Niño may be a mixed bag. If it turns out to be as strong as predicted, this El Niño may further exacerbate many of the ongoing stresses in the marine ecosystem. We may see more hardships for many animals if their food availability continues to be disrupted by warm conditions. There could be substantial economic impacts as well if fisheries struggle. On the other hand, El Niño is forecasted to bring much-needed rain to California over the winter, though this may come with damaging floods and mudslides.

In the end, it is hard to predict what the exact impacts of this El Niño will be. The context of climate change is important to consider, as rising global temperatures have already begun to alter marine ecosystems throughout the world. It remains to be seen how El Niño events and climate change may interact and influence each other, and whether that will further exacerbate stresses in marine systems. It is also possible the trends we have been observing on the Farallones will be more commonplace in the future if warming trends persist—perhaps Brown Boobies and other warm-water species will have a regular presence in years to come, while the island’s breeding seabirds may decline. Whatever this El Niño has in store, the continued observations of Farallon biologists are essential to better understand how environmental change will influence wildlife around the islands and throughout the region.

You can learn more about the recent changes in the ocean ecosystem and how Point Blue researchers are monitoring them through these articles:

Sunday, November 29, 2015

Conservation Conundrum: The interaction of Burrowing Owls, Ashy Storm-Petrels, and House Mice

    Fall on the Farallon Islands may bring up exciting ideas about songbirds, seabirds, cetaceans, or pinnipeds, but Southeast Farallon Island’s most abundant species each fall is the non-native house mouse (Mus musculus). In 2010, population estimates recorded house mouse density to be ten times greater than densities reported on the mainland or on other islands. House mouse populations on SEFI are cyclic, peaking in the fall and plummeting in late winter and early spring. This cyclic pattern is the foundation of an interesting food web quandary involving two SEFI natives that are also California Species of Special Concern: Burrowing Owls (Athene cunicularia) and Ashy Storm-Petrels (Oceanodroma homochroa).  

    Burrowing Owls are small, long-legged raptors that migrate to SEFI each fall. From as early as the late 19th century up until the present day, Burrowing Owls have been observed on SEFI. They are generalists that feed primarily at night on rodents, invertebrates, and birds. 
    In the fall, house mouse populations increase on Southeast Farallon Island at the same time that Burrowing Owls are arriving. Based on Burrowing Owl pellet dissection, we can see that in the fall the majority of their diet biomass comes from mice. As the mouse population declines towards the end of winter, our research has found that Burrowing Owls switch to preying on Ashy Storm-Petrels which arrive mid-winter to breed. In the 2010-2011 season, a graduate student from San Jose State University did a diet study on Burrowing Owls providing evidence of this prey switching mechanism happening among SEFI’s Burrowing Owls.

This figure from Sara Chandler’s thesis work shows biomass of four different prey items in Burrowing Owl diets observed through dissection of collected pellets from September 30, 2010 to May 15, 2011. The switch from using mice as the main diet source to Ashy Storm-Petrels over time is clearly evident.

    Switching to eating Ashy Storm-Petrels is problematic.  The worldwide population of Ashy Storm-Petrels numbers approximately 10,000, and half of those birds breed on SEFI. This small seabird is slow-breeding, long-lived, and can only produce one chick each year. When several Burrowing Owls overwinter and each depredates dozens of Ashy Storm-Petrels, the long-term impact on the breeding population is significant. 

Ashy Storm-Petrel adult at its nest. Photo by Annie Schmidt.
    In order to monitor the fall and winter population of Burrowing Owls on SEFI, Point Blue Conservation Science has had an owl intern survey for Burrowing Owls each fall. In 2007, we began to capture and band Burrowing Owls, in addition to daytime surveying, to get better population estimates.    

    SEFI provides an ideal habitat for Burrowing Owls, which roost in rocky crevices as well as Rhinoceros and Cassin’s Auklet burrows. Burrowing Owls are incredibly cryptic, blending in very well with their surroundings. Each day, the owl intern searches these rocky crevices and burrows for owls and their regurgitated pellets. If an owl is found, we make an effort to identify the individual by the unique combination of numbers and letters on its leg band. These pellets are later dissected to get more information on owl diet over time. 

  Burrowing Owl in front of its rocky crevice roost. Photo by Jim Tietz

The house mouse is the most abundant species on the island in fall. Photo by Jim Tietz.

    If mice are eradicated from SEFI, it is likely that the overwintering Burrowing Owl population would decline. Owls that currently arrive in the fall find plenty of mice to eat and therefore have reason to overwinter. However, if the owls arrived in fall to a mouse-less island, the biomass provided by the invertebrate prey would be insufficient to sustain them through the fall and early winter. The owls would be forced to migrate elsewhere in search of a more abundant prey base. Burrowing Owls that do not overwinter are not preying on Ashy Storm-Petrels. Currently, the USFWS is developing a proposal to eradicate the house mouse from the Farallon Islands, which, if successfully implemented, would likely be an effective long term benefit for the declining Ashy Storm-Petrel population.

    So far during the fall of 2015, we have documented 23 Burrowing Owl arrivals and have banded 19 of them. One owl observed had been banded in  2013. In the past two months, 53 Burrowing Owl Pellets have been collected. Currently, there are at least 4 Burrowing Owls still on the island that may attempt to overwinter. Since 2007, the number of arrivals each year has averaged around 17 Burrowing Owls. An exception to this average was in 2012 when there were 54 individuals. We will continue to survey for Burrowing Owls for the years to come in order to collect data on their life histories and the impacts they have on Southeast Farallon Island’s ecosystem.

An unbanded Burrowing Owl stands about 10 inches tall. Photo by Jim Tietz.

A just-banded Burrowing Owl about to be released. Photo by Natalie Okun.

Figure 1 comes from: Chandler, S. L.  Burrowing owl (Athene cunicularia) diet and abundance at a stopover wintering ground on Southeast Farallon Island, California (Unpublished master's thesis). San Jose State University, San Jose, California.

Posted by Natalie Okun, fall Burrowing Owl intern