Counting Noses: Not an Easy Feat

Counting Noses: Not an Easy Feat

By Kim Steinhardt and Gena Bentall


How many southern sea otters are there? Is the number rising or falling? Where are they on the road to recovery? What are the biggest threats they face?

These and many more questions like them are central to the sea otter conservation story, a story that began with humans hunting them to near extinction by the early 1900s. Researchers, conservation activists, and marine, fishery, and wildlife management specialists all seek to have a solid foundation of reliable data on which to develop and support science-based policy decisions affecting the recovery of sea otters.

The most southerly of the three sea otter subspecies, the southern sea otter, once populated the coast all the way south into Baja California before being hunted down to a remnant few by the turn of the century. This keystone species was reduced to perhaps 30 or 40 individuals by 1911, and even now—more than one hundred years later—the southern sea otter still numbers only a little over 3,000. This small population is distributed along the central California coastline from about Pigeon Point in San Mateo County, to the north, to Gaviota State Beach in Santa Barbara County, to the south, with a small translocated population at San Nicolas Island, off Ventura County. Growth at the center of this mainland range (Seaside to Cayucos) is likely to be limited, as the sea otter populations there are thought to be at carrying capacity—the number the current habitat resources can support. Sustained growth and recovery will require expansion in the numbers of sea otters at the north and south range fronts.

In order to effectively direct conservation efforts and scientific study, we must have a better understanding of whether the numbers of sea otters in California are growing, declining, or staying steady.

Researchers track population trends with an annual census in which they survey the numbers of sea otters in California. Teams of well-trained and experienced counters go out into the field each spring and make a coordinated and thorough count, seeking sea otters along the coast of California on foot and from airplanes. Counting every sea otter nose along hundreds of miles of their coastal range—from rugged Año Nuevo to the sandy dunes of Pismo Beach, the wild seas of Pt. Conception, and the remote island of San Nicolas—is a bit of a tricky undertaking.

This annual effort, coordinated by the U.S. Geological Survey Western Ecological Research Center, involves participants from California Department of Fish and Wildlife, Monterey Bay Aquarium, US Fish and Wildlife Service, Sea Otter Savvy, and others.

Each annual survey results in a “raw number”—the actual number of sea otters counted. Many factors may influence the accuracy of the raw number from year to year, including kelp species composition and abundance, viewing conditions, observer experience, and the movements and distribution of the sea otters themselves. Any of these factors, alone or in combination, may affect the observers’ ability to visually locate sea otters. For example, in years when there is a very low abundance of giant kelp (Macrocystis pyrifera) canopy, sea otters tend to be more widely scattered, increasing the likelihood that observers will miss some otters as they scan. For this reason, no single year’s raw count is a reliable indicator of growth or decline from the previous year. The official data point for each year is based on an average of counts from three consecutive years. For example, the data point for 2017 is based on the averaged raw counts from 2015, 2016, and 2017. This running three-year average is referred to as the “population index,” and it is the metric used by the U.S. Fish and Wildlife Service to track the status of the population.

Census Table11 1015x1024 Counting Noses: Not an Easy Feat

Viewed alongside each other for multiple years, the population index data points indicate trends of growth or decline in the southern sea otter population, but that is not to say anomalously high or low raw counts aren’t worthy of notice and concern. In the case of the last two years—2016 and 2017—we have extremes at both ends of the spectrum: a record high raw number in 2016 and a steep drop in 2017. Both are reason to be attentive. While the current population index shows a 3 percent decline from last year, we will have to wait until 2018 to know if the raw count from 2017 indicates a more concerning longer-term trend.

To understand the importance researchers and policymakers place on the running average, we need to recognize the limitations of the individual yearly raw number. A sharp increase or decrease in the raw count may in fact prove to be an indicator of real trends in the population over the course of several years, or it may turn out to be the fleeting result of observer error due to poor conditions or other factors influencing the accuracy of the count that year. To get a meaningful view of population trends, we need to look beyond what’s right in front of our noses and take in the bigger picture.

Counting noses: a tricky business indeed.

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Media Contact:

Friends of the Sea Otter


Leigh Anne Tiffany, Defenders of Wildlife; 202-772-0259


CARMEL, Calif. (Sept. 29, 2017) – The southern sea otter population dropped in the last year, according to the United States Geological Survey (USGS) 2017 spring survey published yesterday. The results are especially alarming following an overall positive growth through 2016, which culminated in a population size that – if maintained for three consecutive years – could have led to southern sea otters being delisted under the Endangered Species Act (ESA).

While the U.S. Fish and Wildlife Service (FWS) noted a 3 percent decline in sea otter numbers, their statement fails to tell the whole story.  The FWS was correct in that the three-year average reflects only a 3 percent decline, but they did not note that the raw numbers of sea otters counted during the spring survey declined by 927 sea otters between the mainland and San Nicolas Island – an over 25 percent decline from the raw numbers of sea otters counted last year.

Jennifer Covert, Board Chair of Friends of the Sea Otter, issued this statement:

“This dramatic decline in the sea otter population raw count calls into question our optimism over the potential recovery of this species, and is a wake-up call to redouble our efforts to understand this downward trend and to save these important and beautiful creatures.

Emily Burke, California program assistant for Defenders of Wildlife, issued this statement:

“As go sea otters, so goes our nearshore marine ecosystem. This staggering decline in their population after years of growth is concerning, and signals that it is too early to declare the sea otter fully recovered.”


The 2017 USGS southern sea otter survey results showed the raw count population size dropped to 2,688 an over 25 percent decline from last year. The 2016 survey recorded a raw count population size of 3,615, the highest survey result ever. The decline in population survey results is the largest numerical and percentage decline in consecutive years since the annual survey began in 1985.

The causes of population decline unfortunately remain uncertain. One likely factor is the increased incidence of attacks by white sharks on sea otters at the southern end of the sea otter range. While scientists are unable to confirm why the rate of shark attacks has increased, it could be the result of sharks spending more time in nearshore waters because of the recent increase in their primary prey, pinnipeds like northern elephant seals.

Additionally, shifts in ocean current patterns due to climate change may be changing the distribution of marine ecosystem food chains. With a thick fur coat and no blubber layer, sea otters are not a traditional source of prey for sharks. While sea otters have always been mistaken for traditional prey sources and attacked, the substantial increase in shark attacks is likely an artifact of changes in shark distribution patterns. Other factors in the sea otter decline may include a decrease in the number of sea urchins—one of sea otters’ preferred prey items—following a few years of relatively large urchin populations, as well as compromised water quality in the nearshore environment due to pollution and agricultural runoff.

FSO and Defenders of Wildlife maintain that regardless if the population exceeds 3,090 for three consecutive years, the sea otter is unlikely to meet the full criteria for delisting and recovery under the ESA. The 2017 spring survey results reinforce FSO’s and Defenders of Wildlife’s position that additional range expansion and healthy and sustained population size significantly above the recovery threshold of 3,090 are necessary for the population to be considered for a recovery determination.

The magnitude of the population decline emphasizes the importance of providing full protection of sea otters under the ESA and the Marine Mammal Protection Act. FSO encourages the public to avoid engaging in activities that could result in harassment or harmful interactions with sea otters. For additional information regarding appropriate sea otter viewing guidelines, please refer to the Sea Otter Savvy program at


Friends of the Sea Otter (FSO) is an advocacy group, founded in 1968, dedicated to actively working with state and federal agencies and other groups to maintain, increase and broaden the current protections for the sea otter, a species currently protected by state and federal laws, and with two geographic populations on the Endangered Species list. We wish to inspire the public at large to increase awareness about the otters’ unique behavior and habitat, and to take action to recover this remarkable species. For more information, visit

Defenders of Wildlife is dedicated to the protection of all native animals and plants in their natural communities. With nearly than 1.2 million members and activists, Defenders of Wildlife is a leading advocate for innovative solutions to safeguard our wildlife heritage for generations to come. For more information, visit and follow us on Twitter @DefendersNews.

Not Again! When Will We Learn?

Not Again! When Will We Learn?

On May 19th, a tragic  event unfolded along the Santa Barbara coastline that serves as a serious reminder to the world – oil spills and wildlife don’t mix.  Needless to say, oil spills’ impacts reach farther than just killing wildlife.  They close beaches, put livelihoods on hold, minimize ocean recreation, and they simply scar the land, ocean and its inhabitants, impacting people who come to enjoy these special areas.

Friends of the Sea Otter knows all too well the deadly consequences oil spills have upon sea otters due to the Exxon Valdez oil spill that occurred just slightly more than a quarter decade ago in 1989.  Sea otters die of hypothermia or ingesting the oil, which then gets into their internal organs and causes damage.  These similar impacts happen to other animals.

The deadly toll in this recent oil spill includes marine birds, marine mammals, other marine vertebrates, and marine invertebrates.  It is so disheartening to see the images flooding the news, social media, other media sites of oiled animals!

As of Thursday, June 4, 173 birds have been collected – 58 live, 115 dead – and 100 mammals – 42 live, 58 dead, and more than 14,000 gallons of oily water mixture has been collected.

There have been many things that have come up as to why this happened and why the initial response was inadequate.  These are all important things to address.  What is more important is the constant goal of preventing it from happening in the first place.  One area of emphasis is the need to move away from oil exploration and development in sensitive habitats like this.  Problems are always going to happen with these methods of extracting oil.  We need to focus on alternative energy and put our foot down in saying enough is enough.  We should have learned from the Gulf Oil Spill from five years ago.  We had ample time to learn from that tragic event, and we haven’t. And, until we really say “No More!”, we will continue to get news reports about these tragic, yet preventable events. Let’s learn this time and not repeat historic mistakes like these.

FSO’s 2015 Hero Series: Don Baur

FSO’s 2015 Hero Series: Don Baur

FSO’s 2015 Hero Series

A Behind the Scenes Look at the Individuals Dedicated to the Cause

Friends of the Sea Otter (FSO) is the only organization in the world dedicated to the protection of sea otters on a global scale.  We do this through effective advocacy, litigation, public education, and the development of strong alliances and partnerships.  We are committed to protecting this threatened species wherever sea otters are found worldwide.  Why?  Because the health of the nearshore coastal ecosystem is dependent upon their survival.  The sea otter is a keystone species, meaning what happens to the sea otter, happens to the ecosystem. It is our duty to protect this marine mammal.  But who exactly is behind the scenes fighting for this keystone species?  Meet Friends of the Sea Otter’s feature Hero of 2015: Don Baur.

 Don Baur FSOs 2015 Hero Series: Don Baur

Ranked as one of  “America’s Leading Environmental Lawyers” and a partner at the law firm of Perkins Coie, LLP, Don Baur is an integral part of Friends of the Sea Otter’s success.  Close friends with FSO founder, Margaret Owings, Mr. Baur has been advocating for sea otters for over 30 years.  One of his most recent and celebrated successes representing FSO is the removal of the 20+ year No Otter Zone that prohibited the free movement of sea otters throughout their natural habitat in Southern California.  Don helped spearhead the removal of this impediment to sea otter recovery, a critical decision that will help the threatened species expand its range over time.

It’s no coincidence that Don headlines the FSO Hero Series.  Without his guidance, passionate approach, and legal expertise, FSO would not have garnered the triumphant successes that it has had over the past three decades.  Don’s input and dedication to protecting the natural environment are instrumental in the success of the organization.  His expertise includes extensive experience in all relevant federal laws, including the Endangered Species Act, the Marine Mammal Protection Act, the National Environmental Policy Act, the Clean Water Act, and coastal/ocean and public land laws.  Previously an attorney for the U.S. Fish and Wildlife Service and General Counsel of the Marine Mammal Commission, Don’s efforts on ocean conservation include his service on the Board of the National Marine Sanctuary Foundation, his position as a professor of Ocean Law at the Vermont Law School for the last two decades, and as the lead editor and author of legal treatises on both endangered species and ocean law.

Thanks in part to the expertise, leadership, and experience of Don Baur, ocean enthusiasts and sea otter lovers alike can be confident that no rock will be left unturned to ensure protection for these threatened animals.  Don Baur states,  “The fact that the sea otter species has been able to fight off extinction is due, in no small measure, to the extraordinarily effective conservation program mounted by FSO.  This species still remains at great risk, however, and FSO and its supporters have major challenges ahead.  The recovery of this species will depend on sustained advocacy for the foreseeable future.”  Where there are legal challenges regarding the protection of sea otters, you can be sure that FSO will be there to confront them.

Sea Otters Quietly Battling Climate Change

 Sea Otters Quietly Battling Climate Change

Global Warming Warriors: A new study reveals sea otters help to mitigate climate change by protecting kelp forests that promote carbon sequestration, as seen above. (Photo: Peggy Patterson)

In a world where climate policy usually moves at the speed of a sea slug rather than that of a sailfish, sea otters are quietly having a positive influence on climate change mitigation…on their own terms. A recent study published by UC Santa Cruz scientists, Jim Estes and Chris Wilmers, found that sea otters are contributing heavily to the uphill battle against climate change. How is this possible, you ask?
To understand, we have to dive deeper, and examine the intricacy of our ocean’s capabilities. Similar to jungles and trees, kelp forests help sequester carbon from the atmosphere, slowing the atmospheric accumulation of greenhouse gasses. This is a very powerful component of kelp forests, which also harbor a vast array of marine life. But much like bulldozers in the Amazon, kelp forests have their threats as well. What could pose such a threat? Sea urchins, ravenous creatures that devastate kelp beds, not only destroy habitats for marine life living amongst kelp forest, but can now be considered facilitators in accelerating climate change. These animals are capable of doing extreme damage to kelp forests in very small time frames.

Enter the Otter

Sea otters have long been considered protectors of the kelp forests, and for good reason. The sea otter’s diet relies heavily on sea urchins that can consume 30 feet of kelp forest in less than a month. So what does this underwater relationship look like? Simply put: the sea otter consumes the sea urchin which indirectly results in safeguarding the kelp forests (that harbor life and also sequestrate carbon). The higher the otter populations, the denser the kelp forests; the denser kelp forests, the more carbon captured. The study shows that kelp forests that have flourishing otter populations are capable of absorbing 12 times more carbon than areas that were not overpopulated with sea urchins. Although their new role as a “global warming warriors” might be new to them, this study shows that the vital role sea otters play in their underwater ecosystems now transcends the ocean and impacts the entire planet. Conserving and restoring otter populations makes for a healthier planet. Read more about the study here.

USGS Report Shows Stagnant Population for Sea Otters

The U.S. Geological Survey’s spring census report on sea otter populations was released today. Signs show that the population index of sea otters has increased compared to 2010, however not to the levels we would like to see.  The USGS lists this year’s population index for the southern sea otter at 2,792, an almost 2% increase in the marine mammals’ population index since 2010.

Although a halt in the decrease of the population seems encouraging, these numbers are not strong enough to celebrate. This survey strongly helps reinforce the need to increase the southern sea otters’ range geographically. Small population growth in the center of their geographic range, where maximum sea otter populations exist, suggests that populations could be leveling off.

The survey also reports that 335 otters died last year, close to 12% of the current population. Harmful algal toxins, parasites and infectious diseases, mating trauma, emaciation, bacterial infections, heart disease and boat strikes were some of the main causes of death for the southern sea otter. As well, on top of these causes, the report shows an increase in the number of sea otters attacked and killed by Great White sharks last year, the highest on record. More studies will be needed to determine the recent spike in shark attack rates, but it should be noted that this is an alarming trend.

Friends of the Sea Otter is cautiously optimistic of these results as the increase in population numbers is not yet a sustained trend and recovery is slow. The highest mortality number on record occurred last year, which is still a major concern for us. As well, we are not any closer to discovering the array of reasons for this increase in mortality and we would like to emphasize that disease and pollution are just a piece of this complex puzzle.  Moreover, we need to understand what is causing these populations to stagnate. As studies reveal more information, Friends of the Sea Otter will ensure that our members and followers will be updated accordingly.