“The joy of paper acceptance” or “The GEMM Lab’s recent scientific contributions”

Dr. Leigh Torres, Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Oregon State University

The GEMM Lab is always active – running field projects, leading outreach events, giving seminars, hosting conferences, analyzing data, mentoring young scientists, oh the list goes on! (Yes, I am a proud lab PI). And, recently we have had a flurry of scientific papers either published or accepted for publication that I want to highlight. These are all great pieces of work that demonstrate our quality work, poignant and applied science, and strong collaborations. For each paper listed below I provide a short explanation of the study and implications. (Those names underlined are GEMM Lab members, and I provided a weblink where available.)

 

Sullivan, F.A. & Torres, L.G. Assessment of vessel disturbance to gray whales to inform sustainable ecotourism. The Journal of Wildlife Management, doi:10.1002/jwmg.21462.

This project integrated research and outreach regarding gray whale behavioral response to vessels. We simultaneously tracked whales and vessels, and data analysis showed significant differences in gray whale activity budgets when vessels were nearby. Working with stakeholders, we translated these results into community-developed vessel operation guidelines and an informational brochure to help mitigate impacts on whales.

 

Hann, C., Stelle, L., Szabo, A. & Torres, L. (2018) Obstacles and Opportunities of Using a Mobile App for Marine Mammal Research. ISPRS International Journal of Geo-Information, 7, 169. http://www.mdpi.com/2220-9964/7/5/169

This study demonstrates the strengths (fast and cheap data collection) and weaknesses (spatially biased data) of marine mammal data collected using the mobile app Whale mAPP. We emphasize the need for increased citizen science participation to overcome obstacles, which will enable this data collection method to achieve its great potential.

 

Barlow, D.R., Torres, L.G., Hodge, K., Steel, D., Baker, C.S., Chandler, T.E., Bott, N., Constantine, R., Double, M.C., Gill, P.C., Glasgow, D., Hamner, R.M., Lilley, C., Ogle, M., Olson, P.A., Peters, C., Stockin, K.A., Tessaglia-Hymes, C.T. & Klinck, H. (in press) Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endangered Species Research. https://doi.org/10.3354/esr00891.

This study used genetics, acoustics, and photo-id to document a new population of blue whales around New Zealand that is genetically isolated, has high year-round residence, and shows limited connectivity to other blue whale populations. This discovery has important implication for population management, especially in the South Taranaki Bight region of New Zealand where the whales forage among industrial activity.

 

Burnett, J.D., Lemos, L., Barlow, D.R., Wing, M.G., Chandler, T.E. & Torres, L.G. (in press) Estimating morphometric attributes of baleen whales with photogrammetry from small UAS: A case study with blue and gray whales. Marine Mammal Science.

Here we developed methods to measure whale body morphometrics using images captured via Unmanned Aerial Systems (UAS; ‘drones’). The paper presents three freely available analysis programs and a protocol to help the community standardize methods, assess and minimize error, and compare data between studies.

 

Holdman, A.K., Haxel, J.H., Klinck, H. & Torres, L.G. (in press) Acoustic monitoring reveals the times and tides of harbor porpoise distribution off central Oregon, USA. Marine Mammal Science.

Right off the Newport, Oregon harbor entrance we listened for harbor porpoises at two locations using hydrophones. We found that porpoise presence at the shallow rocky reef site corresponds with the ebb tidal phase, while harbor porpoise presence at the deeper site with sandy bottom was associated with night-time foraging. It appears that harbor porpoise change their spatial and temporal patterns of habitat use to increase their foraging efficiency.

 

Derville, S., Torres, L.G., Iovan, C. & Garrigue, C. (in press) Finding the right fit: Comparative cetacean distribution models using multiple data sources. Diversity and Distributions.

Species distribution models (SDM) are used widely to understand the drivers of cetacean distribution patterns, and to predict their space-use patterns too. Using humpback whale sighting datasets in New Caledonia, this study explores the performance of different SDM algorithms (GAM, BRT, MAXENT,  GLM, SVM) and methods of modeling presence-only data. We highlight the importance of controlling for model overfitting and thorough model validation.

 

Bishop, A.M., Brown, C., Rehberg, M., Torres, L.G. & Horning, M. (in press) Juvenile Steller sea lion (Eumetopias jubatus) utilization distributions in the Gulf of Alaska. Movement Ecology.

This study examines the distribution patterns of juvenile Steller sea lions in the Gulf of Alaska to gain a better understanding of the habitat needs of this vulnerable demographic group within a threatened population. Utilization distributions were derived for 84 tagged sea lions, which showed sex, seasonal and spatial differences. This information will support the development of a species recovery plan.

This comic seemed appropriate here. Thanks for everyone’s hard work!

Forecasting blue whale presence: Small steps toward big goals

By Dawn Barlow, MSc student, Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

In 2013, Leigh first published a hypothesis that the South Taranaki Bight region between New Zealand’s North and South Islands is important habitat for blue whales  (Torres 2013). Since then, we have collected three years of data and conducted dedicated analyses, so we now understand that a unique population of blue whales is found in New Zealand, and that they are present in the South Taranaki Bight year-round (Barlow et al. in press).

A blue whale surfaces in the South Taranaki Bight. Photo by Leigh Torres.

This research has garnered quite a bit of political and media attention. A major platform item for the New Zealand Green Party around the last election was the establishment of a marine mammal sanctuary in the South Taranaki Bight. When the world’s largest seismic survey vessel began surveying the South Taranaki Bight this summer for more oil and gas reserves using tremendously loud airguns, there were rallies on the lawn in front of Parliament featuring a large inflatable blue whale that the protesters affectionately refer to as “Janet”. Needless to say, blue whales have made their way into the spotlight in New Zealand.

Janet the inflatable blue whale accompanies protesters on the lawn in front of Parliament in Wellington, New Zealand. Image credit: Greenpeace.

Now that we know there is a unique population of blue whales in New Zealand, what is next? What’s next for me is an exciting combination of both ecology and conservation. If an effective sanctuary is to be implemented, it needs to be more than a simple box drawn on a map to check off a political agenda item—the sanctuary should be informed by our best ecological knowledge of the blue whales and their habitat.

In July, Leigh and I will attend the Society for Conservation Biology meeting in Wellington, New Zealand, and I’ll be giving a presentation titled “Cloudy with a chance of whales: Forecasting blue whale presence based on tiered, bottom-up models”. I’ll be the first to admit, I am not yet forecasting blue whale presence. But I am working my way there, step-by-step, through this tiered, bottom-up approach. In cetacean habitat modeling, we often assume that whale distribution on a foraging ground is determined by their prey’s distribution, and that satellite images of temperature and chlorophyll-a provide an accurate picture of what is going on below the surface. Is this true? With our three years of data including in situ oceanography, krill hydroacoustics, and blue whale distribution and behavior, we are in a unique position to test some of those assumptions, as well as provide managers with an informed management tool to predict blue whale distribution.

What questions will we ask using our data? Firstly, can in situ oceanography (i.e., thermocline depth and temperature, mixed layer depth) predict the distribution and density of blue whale prey (krill)? Then, can those prey patterns be accurately predicted in the absence of oceanographic measurements, using just satellite images? Next, we’ll bring the blue whales back into the picture to ask: can we predict blue whale distribution based on our in situ measurements of oceanography and prey? And finally, in the absence of in situ measurements (which is most often the case), can we forecast where the whales will be based just on remotely-sensed images of the region?

The transducer pole in the water off the RV Star Keys (left) deployed with the echosounder to collect prey availability data, including this image (right) of krill swarms near feeding blue whales. Photo by Leigh Torres.

So, cloudy with a chance of whales? Well, you’ll have to stay tuned for that story in the coming months. In the meantime, I can tell you that as daunting as it is to aggregate so many data streams, each step of the way has a piece of the story to tell. I can’t wait to see how it falls together, both from an ecological modeling perspective and a conservation management objective.

A blue whale surfaces in front of a floating production storage and offloading (FPSO) vessel which services the oil rigs in the South Taranaki Bight. Photo by Dawn Barlow.

 

References:

Torres, L. G. (2013). Evidence for an unrecognised blue whale foraging ground in New Zealand. New Zealand Journal of Marine and Freshwater Research47(2), 235-248.

Barlow, D. R., Torres, L. G., Hodge, K. B., Steel, D. Baker, C. S., Chandler, T. E., Bott, N., Constantine, R., Double, M. C., Gill, P., Glasgow, D., Hamner, R. M., Lilley, C., Ogle, M., Olson, P. A., Peters, C., Stockin, K. A., Tessaglia-Hymes, C. T., Klinck, H. (in press). Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endangered Species Research. 

Assessing suitable sea otter habitat along Oregon’s coast

By Dominique Kone, Masters Student in Marine Resource Management

When considering a species reintroduction into an area, it is important to assess the suitability of the area’s habitat before such efforts begin. By doing this assessment at the outset, managers and conservationists can gain a better understanding of the capacity of the area to support a viable population overtime, and ultimately the success of the reintroduction. However, to do a habitat assessment, researchers must first have a base understanding of the species’ ecological characteristics, behavior, and the physical habitat features necessary for the species’ survival. For my thesis, I plan to conduct a similar assessment to identify suitable sea otter habitat to inform a potential sea otter reintroduction to the Oregon coast.

Source: The Tribune.

To start my assessment, I conducted a literature review of studies that observed and recorded the various types of habitats where sea otters currently exist. In my research, I learned that sea otters use in a range of environments, each with a unique set of habitat characteristics. With so many features to sort through, I have focused on specific habitat features that are consistent across most of the current range of sea otters – from Alaska to California – and are important for at least some aspects of sea otters’ everyday life or behavior, specifically foraging. Focusing my analysis on foraging habitat makes sense as sea otters require around 30% of their body weight in food every day (Costa 1978, Reidman & Estes 1990). Meaning sea otters spend most of their day searching for food.

Here, I present four habitat features I will incorporate into my analysis and explain why these features are important for sea otter foraging behavior and survival.

Habitat Features:

  1. Kelp: Sea otters are famously known for the benefits they provide to kelp forests. In the classic three-trophic-level model, sea otters allow for the growth of kelp by keeping sea urchins – consumers of kelp – in check (Estes & Palmisano 1974). Additionally, sea otters and kelp have a mutually-beneficial relationship. Sea otters will often wrap themselves amongst the top of kelp stocks while feeding, resting, or grooming to prevent being carried away by surface currents. Meanwhile, it’s thought that kelp provide a refuge for sea otters seeking to avoid predators, such as sharks, as well as their prey.
Source: The Telegraph.
  1. Distance from Kelp: The use of kelp, by sea otters, is relatively straight-forward. Yet, kelp can still have an influence on sea otter behavior even when not used directly. A 2014 study found that sea otters along the southern California coast were almost 10 times more likely to be located within kelp habitat than outside, while outside kelp beds sea otter numbers declined with distance from the edge of kelp canopies. Sea otters will often forage outside or next to kelp canopies when prey’s available, and even sometimes to socialize in age- or sex-specific rafts (Lafferty & Tinker 2014). These findings indicate that sea otters can and do regularly disperse away from kelp habitat, but because they’re so dependent on kelp, they don’t stray very far.

 

  1. Seafloor Substrate: Sea otters forage over a variety of sediment substrates, including rocks, gravel, seagrass, and even sometimes sand. For example, sea otters hunt sea urchins over rocky substrates, while in other areas they may hunt for crabs in seagrass beds (Estes & Palmisano 1974, Hughes et al. 2014). The type of substrate sea otters forage in typically depends on the substrate needs of their target prey species. Despite some variability across their range, sea otters predominantly forage in rocky substrate environments. Rocky substrate is also necessary for kelp, whose holdfasts need to attach to hard, stable surfaces (Carney et al. 2005).
Source: Save our Seas Foundation.
  1. Depth: Seafloor depth plays a pivotal role in sea otter foraging behavior and therefore acts as a natural boundary that determines how far away from shore sea otters distribute. Many of the prey species sea otters eat – including sea urchins, crabs, and snails – live on the seafloor of the inner continental shelf, requiring sea otters to dive when foraging. Interestingly, sea otters exhibit a non-linear relationship with depth, where most individuals forage at intermediate depths as opposed to extremely shallow or deep waters. One study found the average foraging depth to be around 15 meters (Lafferty & Tinker 2014). This behavior results in a hump-shaped distribution of diving patterns as illustrated in Figure 1 below.
Figure 1. Average probability of occurrence as a function of depth for female (A) and male (B) sea otters as predicted by a synoptic model of space-use (Tinker et al. 2017).

Of course, local conditions and available habitat are always a factor. For example, a study found that sea otters along the coast of Washington foraged further from shore and in slightly shallower environments than sea otters in California (Laidre et al. 2009), indicating that local topography is important in determining distribution. Additionally, diving requires energy and limits how deep sea otters are able to forage for prey. Therefore, diving patterns are not only a function of local topography, but also availability of prey and foraging efficiency in exploiting that prey. Regardless, most sea otter populations follow this hump-shaped diving pattern.

Source: Doretta Smith.

These features are not a complete list of all habitat characteristics that support viable sea otter populations, but seem to be the most consistent throughout their entire range, as well as present in Oregon’s nearshore environment – making them ideal features to include in my analysis. Furthermore, other studies that have predicted suitable sea otter habitat (Tinker et al. 2017), estimated carrying capacity as a product of suitable habitat identification (Laidre et al. 2002), or simply observed sea otter foraging behavior (Estes & Palmisano 1974), have echoed the importance of these four habitat features to sea otter survival.

As with most reintroduction efforts, the process of identifying suitable habitat for the species of interest can be complicated. No two ecosystems or habitats are exactly alike and each comprise their own unique set of physical features and are impacted by environmental processes to varying degrees. The Oregon coast consists of a unique combination of oceanographic conditions and drivers that likely impact the degree and amount of available habitat to sea otters. Despite this, by focusing on the habitat features that are consistently preferred by sea otters across most of their range, I will be able to identify habitat most suitable for sea otter survival in Oregon. The questions of where this habitat is and how much is available are what I’ll determine soon, so stay tuned.

References:

Carney, L. T., Robert Waaland, J., Kilinger, T., and K. Ewing. 2005. Restoration of the bull kelp Nereocystis luetkeana in nearshore rocky habitats. Marine Ecology Progress Series. 302: 49-61.

Costas, D. P. 1978. The ecological energetics, waters, and electrolyte balance of the California sea otter (Enhydra lutris). Ph.D. dissertation, University of California, Santa Cruz.

Estes, J. A. and J. F. Palmisano. 1974. Sea otters: their role in structuring nearshore communities. Science. 185(4156): 1058-1060.

Hughes et al. 2014. Recovery of a top predator mediate negative eutrophic effects on seagrass. Proceedings of the National Academy of Sciences. 110(38): 15313-15318.

Lafferty, K. D. and M. T. Tinker. 2014. Sea otters are recolonizing southern California in fits and starts. Ecosphere. 5(5): 1-11.

Laidre et al. 2002. Estimates of carrying capacity for sea otters in Washington state. Wildlife Society Bulletin. 30(4): 1172-1181.

Laidre et al. 2009. Spatial habitat use patterns of sea otters in coastal Washington. Journal of Mammalogy. 90(4): 906-917.

Tinker et al. 2017. Southern sea otter range expansion and habitat use in the Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2017-1001 (OCS Study BOEM 2017-022), 76 p., http://doi.org/10.3133/ofr20171001.

Reidman, M. L. and J. A. Estes. 1990. The sea otter (Enhydra lutris): behavior, ecology, and natural history. United States Department of the Interior, Fish and Wildlife Service, Biological Report. 90: 1-126.

 

 

Managing Oceans: the inner-workings of marine policy

By Alexa Kownacki, Ph.D. Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

When we hear “marine policy” we broadly lump it together with environmental policy. However, marine ecosystems differ greatly from their terrestrial counterparts. We wouldn’t manage a forest like an ocean, nor would we manage an ocean like a forest. Why not? The answer to this question is complex and involves everything from ecology to politics.

Oceans do not have borders; they are fluid and dynamic. Interestingly, by defining marine ecosystems we are applying some kind of borders. But water (and all its natural and unnatural content) flows between these ‘ecosystems’. Marine ecosystems are home to a variety of anthropogenic activities such as transportation and recreation, in addition to an abundance of species that represent the three major domains of biology: Archaea, Bacteria, and Eukarya. Humans are the only creatures who “recognize” the borders that policymakers and policy actors have instilled. A migrating gray whale does not have a passport stamped as it travels from its breeding grounds in Mexican waters to its feeding grounds in the Gulf of Alaska. In contrast, a large cargo ship—or even a small sailing vessel—that crosses those boundaries is subjected to a series of immigration checkpoints. Combining these human and the non-human facets makes marine policy complex and variable.

The eastern Pacific gray whale migration route includes waters off of Mexico, Canada, and the United States. Source: https://www.learner.org/jnorth/tm/gwhale/annual/map.html

Environmental policy of any kind can be challenging. Marine environmental policy adds many more convoluted layers in terms of unknowns; marine ecosystems are understudied relative to terrestrial ecosystems and therefore have less research conducted on how to best manage them. Additionally, there are more hands in the cookie jar, so to speak; more governments and more stakeholders with more opinions (Leslie and McLeod 2007). So, with fewer examples of successful ecosystem-based management in coastal and marine environments and more institutions with varied goals, marine ecosystems become challenging to manage and monitor.

A visual representation of what can happen when there are many groups with different goals: no one can easily get what they want. Image Source: The Brew Monks

With this in mind, it is understandable that there is no official manual on policy development.  There is, however, a broadly standardized process of how to develop, implement, and evaluate environmental policies: 1) recognize a problem 2) propose a solution 3) choose a solution 4) put the solution into effect and 4) monitor the results (Zacharias pp. 16-21). For a policy to be deemed successful, specific criteria must be met, which means that a common policy is necessary for implementation and enforcement. Within the United States, there are a multiple governing bodies that protect the ocean, including the National Oceanic and Atmospheric Administration (NOAA), Environmental Protection Agency (EPA), Fish and Wildlife Service (USFWS), and the Department of Defense (DoD)—all of which have different mission statements, budgets, and proposals. To create effective environmental policies, collaboration between various groups is imperative. Nevertheless, bringing these groups together, even those within the same nation, requires time, money, and flexibility.

This is not to say that environmental policy for terrestrial systems, but there are fewer moving parts to manage. For example, a forest in the United States would likely not be an international jurisdiction case because the borders are permanent lines and national management does not overlap. However, at a state level, jurisdiction may overlap with potentially conflicting agendas. A critical difference in management strategies is preservation versus conservation. Preservation focuses on protecting nature from use and discourages altering the environment. Conservation, centers on wise-use practices that allow for proper human use of environments such as resource use for economic groups. One environmental group may believe in preservation, while one government agency may believe in conservation, creating friction amongst how the land should be used: timber harvest, public use, private purchasing, etc.

Linear representation of preservation versus conservation versus exploitation. Image Source: Raoof Mostafazadeh

Furthermore, a terrestrial forest has distinct edges with measurable and observable qualities; it possesses intrinsic and extrinsic values that are broadly recognized because humans have been utilizing them for centuries. Intrinsic values are things that people can monetize, such as commercial fisheries or timber harvests whereas extrinsic values are things that are challenging to put an actual price on in terms of biological diversity, such as the enjoyment of nature or the role of species in pest management; extrinsic values generally have a high level of human subjectivity because the context of that “resource” in question varies upon circumstances (White 2013). Humans are more likely to align positively with conservation policies if there are extrinsic benefits to them; therefore, anthropocentric values associated with the resources are protected (Rode et al. 2015). Hence, when creating marine policy, monetary values are often placed on the resources, but marine environments are less well-studied due to lack of accessibility and funding, making any valuation very challenging.

The differences between direct (intrinsic) versus indirect (extrinsic) values to biodiversity that factor into environmental policy. Image Source: Conservationscienceblog.wordpress.com

Assigning a cost or benefit to environmental services is subjective (Dearborn and Kark 2010). What is the benefit to a child seeing an endangered killer whale for the first time? One could argue priceless. In order for conservation measures to be implemented, values—intrinsic and extrinsic—are assigned to the goods and services that the marine environment provides—such as seafood and how the ocean functions as a carbon sink. Based off of the four main criteria used to evaluate policy, the true issue becomes assessing the merit and worth. There is an often-overlooked flaw with policy models: it assumes rational behavior (Zacharias 126). Policy involves relationships and opinions, not only the scientific facts that inform them; this is true in terrestrial and marine environments. People have their own agendas that influence, not only the policies themselves, but the speed at which they are proposed and implemented.

Tourists aboard a whale-watching vessel off of the San Juan Islands, enjoying orca in the wild. Image Source: Seattle Orca Whale Watching

One example of how marine policy evolves is through groups, such as the International Whaling Commission, that gather to discuss such policies while representing many different stakeholders. Some cultures value the whale for food, others for its contributions to the surrounding ecosystems—such as supporting healthy seafood populations. Valuing one over the other goes beyond a monetary value and delves deeper into the cultures, politics, economics, and ethics. Subjectivity is the name of the game in environmental policy, and, in marine environmental policy, there are many factors unaccounted for, that decision-making is incredibly challenging.

Efficacy in terms of the public policy for marine systems presents a challenge because policy happens slowly, as does research. There is no equation that fits all problems because the variables are different and dynamic; they change based on the situation and can be unpredictable. When comparing institutional versus impact effectiveness, they both are hard to measure without concrete goals (Leslie and McLeod 2007). Marine ecosystems are open environments which add an additional hurdle: setting measurable and achievable goals. Terrestrial environments contain resources that more people utilize, more frequently, and therefore have more set goals. Without a problem and potential solution there is no policy. Terrestrial systems have problems that humans recognize. Marine systems have problems that are not as visible to people on a daily basis. Therefore, terrestrial systems have more solutions presented to mitigate problems and more policies enacted.

As marine scientists, we don’t always immediately consider how marine policy impacts our research. In the case of my project, marine policy is something I constantly have to consider. Common bottlenose dolphins are protected under the Marine Mammal Protection Act (MMPA) and inhabit coastal of both the United States and Mexico, including within some Marine Protected Areas (MPA). In addition, some funding for the project comes from NOAA and the DoD. Even on the surface-level it is clear that policy is something we must consider as marine scientists—whether we want to or not. We may do our best to inform policymakers with results and education based on our research, but marine policy requires value-based judgements based on politics, economics, and human objectivity—all of which are challenging to harmonize into a succinct problem with a clear solution.

Two common bottlenose dolphins (coastal ecotype) traveling along the Santa Barbara, CA shoreline. Image Source: Alexa Kownacki

References:

Dearborn, D. C. and Kark, S. 2010. Motivations for Conserving Urban Biodiversity. Conservation Biology, 24: 432-440. doi:10.1111/j.1523-1739.2009.01328.x

Leslie, H. M. and McLeod, K. L. (2007), Confronting the challenges of implementing marine ecosystem‐based management. Frontiers in Ecology and the Environment, 5: 540-548. doi:10.1890/060093

Munguia, P., and A. F. Ojanguren. 2015. Bridging the gap in marine and terrestrial studies. Ecosphere 6(2):25. http://dx.doi.org/10.1890/ES14-00231.1

Rode, J., Gomez-Baggethun, E., Krause, M., 2015. Motivation crowding by economic payments in conservation policy: a review of the empirical evidence. Ecol. Econ. 117, 270–282 (in this issue).

White, P. S. (2013), Derivation of the Extrinsic Values of Biological Diversity from Its Intrinsic Value and of Both from the First Principles of Evolution. Conservation Biology, 27: 1279-1285. doi:10.1111/cobi.12125

Zacharias, M. 2014. Marine Policy. London: Routledge.

 

Robots are taking over the oceans

By Leila Lemos, PhD Student

In the past few weeks I read an article on the use of aquatic robots in the ocean for research. Since my PhD project uses technology, such as drones and GoPros, to monitor body condition of gray whales and availability of prey along the Oregon coast, I became really interested by the new perspective these robots could provide. Drones produce aerial images while GoPros generate an underwater-scape snapshot. The possible new perspective provided by a robot under the water could be amazing and potentially be used in many different applications.

The article was published on March 21st by The New York Times, and described a new finned robot named “SoFi” or “Sophie”, short for Soft Robotic Fish (Figure 1; The New York Times 2018). The aquatic robot was designed by scientists at the Massachusetts Institute of Technology (MIT) Computer Science and Artificial Intelligence Lab, with the purpose of studying marine life in their natural habitats.

Figure 1: “SoFi”, a robotic fish designed by MIT scientists.
Source: The New York Times 2018.

 

SoFi’s  first swim trial occurred in a coral reef in Fiji, and the footage recorded can be seen in the following video:

 

SoFi can swim at depths up to 18 meters and at speeds up to half-its-body-length a second (average of 23.5 cm/s in a straight path; Katzschmann et al. 2018). Sofi can swim for up to ~40 minutes, as limited by battery time. The robot is also well-equipped (Figure 2). It has a compact buoyancy control mechanism and includes a wide-view video camera, a hydrophone, a battery, environmental sensors, and operating and communication systems. The operating and communication systems allow a diver to issue commands by using a controller that operates through sound waves.

Figure 2: “SoFi” system subcomponents overview.
Source: Katzschmann et al. 2018.

 

The robot designers highlight that while SoFi was swimming, fish didn’t seem to be bothered or get scared by SoFi’s presence. Some fish were seen swimming nearby the robot, suggesting that SoFi has the potential to integrate into the natural underwater environment and therefore record undisturbed behaviors. However, a limitation of this invention is that SoFi needs a diver on scene to control the robot. Therefore, SoFi’s study of marine life without human interference may be compromised until technology develops further.

Another potential impact of SoFi we might be concerned about is noise. Does this device produce noise levels that marine fauna can sense or maybe be stress by? Unfortunately, the answer is yes. Even if fish don’t seem to be bothered by SoFi’s presence, it might bother other animals with hearing sensitivity in the same frequency range of SoFi. Katzschmann and colleagues (2018) explained that they chose a frequency to operate SoFi that would minimally impact marine fauna. They studied the frequencies used by the aquatic animals and, since the hearing ranges of most aquatic species decays significantly above 10 KHz, they selected a frequency above this range (i.e., 36 KHz). However, this high frequency range can be sensed by some species of cetaceans and pinnipeds, but negative affects on these animals will be dependent on the sound amplitude that is produced.

Although not perfect (but what tool is?), SoFi can be seen as a great first step toward a future of underwater robots to assist research efforts.  Battery life, human disturbance, and noise disturbance are limitations, but through thoughtful application and continued innovation this fishy tool can be the start of something great.

The use of aquatic robots, such as SoFi, can help us advance our knowledge in underwater ecosystems. These robots could promote a better understanding of marine life in their natural habitat by studying behaviors, interactions and responses to threats. These robots may offer important new tools in the protection of animals against the effects caused by anthropogenic activities. Additionally, the use of aquatic robots in scientific research may substitute remote operated vehicles and submersibles in some circumstances, such as how drones are substituting for airplanes sometimes, thus providing a less expensive and better-tolerated way of monitoring wildlife.

Through continued multidisciplinary collaboration by robot designers, biologists, meteorologists, and more, innovation will continue allowing data collection with minimal to non-disturbance to the wildlife, providing lower costs and higher safety for the researchers.

It is impressive to see how technology efforts are expanding into the oceans. As drones are conquering our skies today and bringing so much valuable information on wildlife monitoring, I believe that the same will occur in our oceans in a near future, assisting in marine life conservation.

 

 

References:

Katzschmann RK, DelPreto J, MacCurdy R, Rus D. 2018. Exploration of Underwater Life with an Acoustically Controlled Soft Robotic Fish. Sci. Robot. 3, eaar3449. DOI: 10.1126/scirobotics.aar3449.

The New York Times. 2018. Robotic Fish to Keep a Fishy Eye on the Health of the Oceans. Available at: https://www.nytimes.com/2018/03/21/science/robot-fish.html.

There is no such thing as “throwing it away”: Why I try to reduce my plastic consumption

By Dawn Barlow, MSc student, Department of Fisheries and Wildlife

Several years ago, I had a profound experience on a remote little coral island in the Kingdom of Tonga, in the middle of the South Pacific. I was a crew member aboard a 46’ sailboat, traveling in Tonga and Fiji. This trip was a time when I became very aware of my consumption because when living on a boat, you carry your waste with you. The South Pacific is a region of little islands scattered across wide ocean spaces, and my eyes were opened to island culture. An island is analogous to a large boat—your waste cannot go far. The idea of “throwing it away” began to seem suspect. Does anything really “go away”?

A seemingly pristine beach on Tungua Island, Kingdom of Tonga. Upon closer inspection, we realized the volume of plastics that could be found even on an island this remote. Photo by D. Barlow.

After spending a night at anchor in the Kingdom of Tonga when I listened through the hull to signing humpback whales and felt their deep tones vibrate our mast, I thought I was in a place as pure and untouched as I would ever experience. The next morning, we ventured to shore on an island that we could circumnavigate in less than an hour on foot. But the soft sand was strewn with more than just conch and cowrie shells. It was also strewn with plastic. I began to pick up the trash items on the beach, and before long I had a large bag filled to the brim with plastic. The captain humored me when I wanted to bring it back to the boat. But what was I going to do with it then? These remote island places have very little infrastructure—they can’t recycle it there. So should I take it to another island where it would likely get barged out and dumped back in the ocean? Or a landfill? What struck me most was the realization that none of these products were manufactured on these islands. Some of this plastic may have been imported to the nearest island with a town or city, while some likely had drifted across the sea to this landing spot. All the plastics that I picked up on that one, small island were just a tiny portion of ocean plastic that wash ashore on the world’s beaches, a tiny glimpse of a much larger issue.

Eight million tons of plastics make their way into the oceans each year. Let that number sink in. There is no such thing as “throwing it away”, because “away” does not exist. “Away” is the ocean.

“What lies under”. Image credit: Ferdi Rizkiyanto.

Before sitting down to write this, I participated in a beach cleanup event here in my local community in Newport, Oregon. Today along the whole Oregon Coast, over 3,000 volunteers removed more than 15,000 pounds of litter and marine debris from the coastal places they love. A few weeks ago Surfrider Foundation screened the documentary Straw, directed by Linda Booker. Following the well-attended screening, a panel of community members from Surfrider, the Oregon Coast Aquarium, and Thomson Sanitary Services answered questions from the audience. In a lively discussion, we learned about why China is no longer accepting our recyclables and consequently we can only recycle plastics #1 and #2 here in Oregon, about how marine animals are rehabilitated after becoming entangled in plastic waste, about how Surfrider is encouraging local businesses to switch to paper straws and only offer them by request. As daunting as it is to think about the scale of our plastic consumption and the damage it causes, I am encouraged by the engagement and bottom-up movement in my community.

My life is shaped by the ocean—it is my inspiration, my work, my passion, my place of adventure and joy, the place that humbles me and heals me. Imagining the relationship between the products I use and the ocean is what makes me think twice before consuming. If I am driving in my car and want to stop for coffee but don’t have a reusable mug with me, I consider “if I were on a boat, would I drink coffee out of a single-use cup and then throw it away, toss it over the rail?” Of course not. So I invite you to think about the plastic in your life—it is everywhere. Think about how that plastic relates to what you love. Will it make its way into the stomach of a baby albatross, a sea turtle, the filter-feeding shellfish and large predatory fish that you love to eat?

Lifestyle changes can be simple and impactful. As a consumer, use your purchase power—when you have the option to buy a product wrapped in plastic or one that is not, opt for no plastic. Show manufacturers what you value. Bring reusable bags to the grocery store. Use waxed paper instead of plastic saran wrap. Talk to others, share your choices with them, encourage them to minimize their plastic use. And if you need context or motivation, imagine the relationship between the products you consume and the places that you love.

 

Sea Otter Management in the U.S.

By Dominique Kone, Masters Student in Marine Resource Management

Since the first official legal protections in 1911, the U.S. has made great strides in recovering sea otter populations. While much of this progress is due to increased emphasis on understanding sea otter behavior, biology, and ecology, there are also several policies that have been just as instrumental in making sea otter conservation efforts successful. Here, I provide a brief overview of the current legal and regulatory policies used to manage sea otters in the U.S. and explain why having a base understanding of these tools can help our lab as we look into the potential reintroduction of sea otters to the Oregon coast.

Sea otter with pup, Prince William Sound, Alaska. Source: Patrick J. Endres

When we talk about sea otter management in the U.S., the two most obvious laws that come to mind are the Marine Mammal Protection Act (MMPA) and the Endangered Species Act (ESA). In short, the MMPA seeks to prevent the take – including kill, harass, capture, or disturb – or importation of marine mammals and marine mammal products[1]. While the ESA seeks to protect and recover imperiled species – not just marine mammals – and the ecosystems which they depend upon[2]. Both laws are similar in the sense that their primary objectives are to protect and recover at-risk species. However, marine mammals will always be protected under the MMPA, but will only be protected under the ESA if the species is considered threatened or endangered.

On the federal level, the U.S. Fish and Wildlife Service (the Service) is primarily responsible for managing sea otter populations. In the U.S., we manage sea otter populations as five distinct stocks, which differ in their population size and geographic distribution – located in California, Washington, and Alaska state waters (Fig. 1). Because sea otters are divided into these single stocks, management decisions – such as recovery targets or reintroductions – are made on a stock-by-stock basis and are dependent on the stock’s population status. Currently, two of these stocks are federally-listed as threatened under the ESA. Therefore, these two stocks are granted protection under both the ESA and MMPA, while the remaining three stocks are only protected by the MMPA (at the federal level; state management may also apply).

Figure 1. Distribution (approximations of population centers) of sea otter stocks in the U.S. (SW = Southwest Alaskan; SC = Southcentral Alaskan; SE = Southeast Alaskan; WA = Washington, SCA = Southern/Californian)

While the MMPA and ESA are important federal laws, I would be remiss if I didn’t mention the important role that state laws and state agencies have in managing sea otters. According to the MMPA and ESA, if a state develops and maintains a conservation or recovery program with protections consistent with the standards and policies of the MMPA and/or ESA, then the Service may transfer management authority over to the state1,2. However, typically, the Service has opted to manage any stocks listed under the ESA, while states manage all other stocks not listed under the ESA.

Sea otter management in the states of Washington and California is a clear example of this dichotomy. The Washington sea otter stock is not listed under the ESA, and is therefore, managed by the Washington Department of Fish and Wildlife (WDFW), which developed the stock’s recovery plan[3]. In contrast, sea otters along the California coast are listed as threatened under the ESA, and the Service primarily manages the stock’s recovery[4].

Interestingly, sea otter management in Alaska is an exception to this rule. The Southeast and Southcentral sea otter stocks are not listed under the ESA, yet are still managed by the Service. However, the state recognizes sea otters as a species of greatest conservation need in the state’s Wildlife Action Plan, which acts as a recommendation framework for the management and protection of important species and ecosystems[5]. Therefore, even though the state is not the primary management authority for sea otters by law, they still play a role in protecting Alaskan sea otter populations through this action plan.

Table 1. Federal and state listing status of all sea otter stocks within U.S. coastal waters.

States have also implemented their own laws for protecting at-risk species. For instance, while the Washington sea otter stock is not listed under the ESA, it is listed as endangered under Washington state law4. This example raises an important example demonstrating that even if a stock isn’t federally-listed, it may still be protected on the state level, and is always protected under the MMPA. Therefore, if the federal and state listing status do not match, which is the case for most sea otter stocks in the U.S. (Table 1.), the stock still receives management protection at some level.

So why does this matter?

Each of the previously mentioned laws are prohibitive in nature, where the objectives are to prevent and discourage activities which may harm the stock of interest. Yet, agencies may grant exceptions – in the form of permits – for activities, such as scientific research, translocations, commercial/recreational fisheries operations, etc. The permit approval process will oftentimes depend on: (1) the severity or likelihood of that action to harm the species, (2) the species’ federal and state listing status, and (3) the unique approval procedures enforced by the agency. Activities that are perceived to have a high likelihood of harming a species, or involve a species that’s listed under the ESA, will likely require a longer and more arduous approval process.

A sea otter release in Monterey Bay, California. Source: Monterey Bay Aquarium Newsroom.

Understanding these various approval processes is vitally important for our work on the potential reintroduction of sea otters to Oregon because such an effort will no doubt require many permits and a thoughtful permit approval process. Each agency may have their own set of permits, administrative procedures, and approval processes. Therefore, it behooves us to have a clear understanding of these various processes relative to the state, agency, or stock involved. If, hypothetically, a stock is determined as a suitable candidate for reintroduction into Oregon waters, having this understanding will allow us to determine where our research can best inform the effort, what types of information and data are needed to inform the process, and to which agency or stakeholders we must communicate our research.

 

References:

[1] Marine Mammal Protection Act of 1972

[2] Endangered Species Act of 1973

[3] State of Washington. 2004. Sea Otter Recovery Plan. Washington Department of Fish and Wildlife: Wildlife Program

[4] U.S. Fish & Wildlife Service. 2003. Final Revised Recovery Plan for the Southern Sea Otter (Enydra lutris nereis).

[5] Alaska Department of Fish and Game. 2015. Alaska wildlife action plan. Juneau.

 

The Land of Maps and Charts: Geospatial Ecology

By Alexa Kownacki, Ph.D. Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

I love maps. I love charts. As a random bit of trivia, there is a difference between a map and a chart. A map is a visual representation of land that may include details like topology, whereas a chart refers to nautical information such as water depth, shoreline, tides, and obstructions.

Map of San Diego, CA, USA. (Source: San Diego Metropolitan Transit System)
Chart of San Diego, CA, USA. (Source: NOAA)

I have an intense affinity for visually displaying information. As a child, my dad traveled constantly, from Barrow, Alaska to Istanbul, Turkey. Immediately upon his return, I would grab our standing globe from the dining room and our stack of atlases from the coffee table. I would sit at the kitchen table, enthralled at the stories of his travels. Yet, a story was only great when I could picture it for myself. (I should remind you, this was the early 1990s, GoogleMaps wasn’t a thing.) Our kitchen table transformed into a scene from Master and Commander—except, instead of nautical charts and compasses, we had an atlas the size of an overgrown toddler and salt and pepper shakers to pinpoint locations. I now had the world at my fingertips. My dad would show me the paths he took from our home to his various destinations and tell me about the topography, the demographics, the population, the terrain type—all attribute features that could be included in common-day geographic information systems (GIS).

Uncle Brian showing Alexa where they were on a map of Maui, Hawaii, USA. (Photo: Susan K. circa 1995)

As I got older, the kitchen table slowly began to resemble what I imagine the set from Master and Commander actually looked like; nautical charts, tide tables, and wind predictions were piled high and the salt and pepper shakers were replaced with pencil marks indicating potential routes for us to travel via sailboat. The two of us were in our element. Surrounded by visual and graphical representations of geographic and spatial information: maps. To put my map-attraction this in even more context, this is a scientist who grew up playing “Take-Off”, a board game that was “designed to teach geography” and involved flying your fleet of planes across a Mercator projection-style mapboard. Now, it’s no wonder that I’m a graduate student in a lab that focuses on the geospatial aspects of ecology.

A precocious 3-year-old Alexa, sitting with the airplane pilot asking him a long list of travel-related questions (and taking his captain’s hat). Photo: Susan K.

So why and how did geospatial ecology became a field—and a predominant one at that? It wasn’t that one day a lightbulb went off and a statistician decided to draw out the results. It was a progression, built upon for thousands of years. There are maps dating back to 2300 B.C. on Babylonian clay tablets (The British Museum), and yet, some of the maps we make today require highly sophisticated technology. Geospatial analysis is dynamic. It’s evolving. Today I’m using ArcGIS software to interpolate mass amounts of publicly-available sea surface temperature satellite data from 1981-2015, which I will overlay with a layer of bottlenose dolphin sightings during the same time period for comparison. Tomorrow, there might be a new version of software that allows me to animate these data. Heck, it might already exist and I’m not aware of it. This growth is the beauty of this field. Geospatial ecology is made for us cartophiles (map-lovers) who study the interdependency of biological systems where location and distance between things matters.

Alexa’s grandmother showing Alexa (a very young cartographer) how to color in the lines. Source: Susan K. circa 1994

In a broader context, geospatial ecology communicates our science to all of you. If I posted a bunch of statistical outputs in text or even table form, your eyes might glaze over…and so might mine. But, if I displayed that same underlying data and results on a beautiful map with color-coded symbology, a legend, a compass rose, and a scale bar, you might have this great “ah-ha!” moment. That is my goal. That is what geospatial ecology is to me. It’s a way to SHOW my science, rather than TELL it.

Would you like to see this over and over again…?

A VERY small glimpse into the enormous amount of data that went into this map. This screenshot gave me one point of temperature data for a single location for a single day…Source: Alexa K.

Or see this once…?

Map made in ArcGIS of Coastal common bottlenose dolphin sightings between 1981-1989 with a layer of average sea surface temperatures interpolated across those same years. A picture really is worth a thousand words…or at least a thousand data points…Source: Alexa K.

For many, maps are visually easy to interpret, allowing quick message communication. Yet, there are many different learning styles. From my personal story, I think it’s relatively obvious that I’m, at least partially, a visual learner. When I was in primary school, I would read the directions thoroughly, but only truly absorb the material once the teacher showed me an example. Set up an experiment? Sure, I’ll read the lab report, but I’m going to refer to the diagrams of the set-up constantly. To this day, I always ask for an example. Teach me a new game? Let’s play the first round and then I’ll pick it up. It’s how I learned to sail. My dad described every part of the sailboat in detail and all I heard was words. Then, my dad showed me how to sail, and it came naturally. It’s only as an adult that I know what “that blue line thingy” is called. Geospatial ecology is how I SEE my research. It makes sense to me. And, hopefully, it makes sense to some of you!

Alexa’s dad teaching her how to sail. (Source: Susan K. circa 2000)
Alexa’s first solo sailboat race in Coronado, San Diego, CA. Notice: Alexa’s dad pushing the bow off the dock and the look on Alexa’s face. (Source: Susan K. circa 2000)
Alexa mapping data using ArcGIS in the Oregon State University Library. (Source: Alexa K circa a few minutes prior to posting).

I strongly believe a meaningful career allows you to highlight your passions and personal strengths. For me, that means photography, all things nautical, the great outdoors, wildlife conservation, and maps/charts.  If I converted that into an equation, I think this is a likely result:

Photography + Nautical + Outdoors + Wildlife Conservation + Maps/Charts = Geospatial Ecology of Marine Megafauna

Or, better yet:

📸 + ⚓ + 🏞 + 🐋 + 🗺 =  GEMM Lab

This lab was my solution all along. As part of my research on common bottlenose dolphins, I work on a small inflatable boat off the coast of California (nautical ✅, outdoors ✅), photograph their dorsal fin (photography ✅), and communicate my data using informative maps that will hopefully bring positive change to the marine environment (maps/charts ✅, wildlife conservation✅). Geospatial ecology allows me to participate in research that I deeply enjoy and hopefully, will make the world a little bit of a better place. Oh, and make maps.

Alexa in the field, putting all those years of sailing and chart-reading to use! (Source: Leila L.)

 

How important are foundational, novel and review papers?

By Leila Lemos, PhD Student

As I wrote in my last blog post, I am in the process of studying for my preliminary exams that will happen in late March (written exams) and late April (oral exam).

My committee members provided me with reading lists of material they thought was important for me to know in order for me to become a PhD candidate. This will serve as the basis for my dissertation research, and provides the framework for how my contribution will advance the field. In the last month, I have been reading many, many articles, book chapters, theses, etc. to build this foundation.

One of the first steps was to organize all of the readings for my prelims on
a big board that would help me visualize what has been done and
what is still missing for each of the committee members

 

The material I am reading is a mixture of foundational and novel material, which are equally important. Foundational articles tell us about the origin of a specific field or theme, and help me to understand fundamental concepts and theories. It is really interesting to see what the pioneer researchers in the field first thought and how they tested their hypotheses many years ago. It is also remarkable to read novel papers and see how these foundational ideas have evolved and developed into new hypotheses, leading to new studies and experiments which push the boundaries of what we already know.

Review papers can also give a sense of this timeline by compiling studies on a particular topic. By assembling all of the available findings in my field, it becomes clear what questions remain unanswered, justifying the goals of my research, and establishing the project’s theoretical and methodological framework.

In my PhD project we are attempting to address some of the unanswered questions related to stress responses in baleen whales. Reading about other studies, their results, and the diverse techniques that have been applied to other taxa makes me really excited about what I can still incorporate in the project.

Source: http://binapatel.me/2017/05/25/literature-review-citation-
tracing-concept-saturation-results-mind-mapping/

 

At the end of my PhD, if we are able to answer our proposed questions, we will have contributed to advancing the field of knowledge, and we will be able to apply our results to the conservation and management of baleen whales in nearshore coastal ecosystems.

The more I read the content proposed by my committee members, the more I find connections between my PhD project, its aims, and the title I proposed for myself as being a “Conservation Physiologist”. Being a Conservation Physiologist is exactly what I want to be, during my PhD, and in the future.

 

 

 

Can we talk about how cool sea otters are?

By Dominique Kone, Masters Student in Marine Resource Management

A couple of months ago, I wrote a blog introducing our new project, and my thesis, on the potential to reintroduce sea otters to the Oregon coast. In that blog, I expressed that in order to develop a successful reintroduction plan, scientists and managers need to have a sound understanding of sea otter ecology and the current state of Oregon’s coastal ecosystems. As a graduate student conducting a research-based thesis in a management program, I’m constantly fretting over the applicability of my research to inform decision-making processes. However, in the course of conducting my research, I sometimes forget just how COOL sea otters are. Therefore, in this blog, I wanted to take the opportunity to nerd out and provide you with my top five favorite facts about these otterly adorable creatures.

Photo Credit: Point Lobos Foundation

Without further ado, here are my top five favorite facts about sea otters:

  1. Sea otters eat a lot. Previous studies show that an individual sea otter eats up to 30% of its own body weight in food each day[1][2]. With such high caloric demands, sea otters spend a great deal of their time foraging the seafloor for a variety of prey species, and have been shown to decrease prey densities in their local habitat significantly. Sea otters are famously known for their taste for sea urchins. Yet, these voracious predators also consume clams, sea stars, crabs, and a variety of other small invertebrate species[3][4].

    Photo Credit: Katherine Johns via www.listal.com
  2. Individuals are specialists, but can change their diet. Sea otters typically show individual foraging specialization – which means an individual predominantly eats a select few species of prey. However, this doesn’t mean an otter can’t switch or consume other types of prey as needed. In fact, while individuals tend to be specialists, on a population or species level, sea otters are actually generalist predators[5][6]. Past studies that looked at the foraging habits of expanding sea otter populations show that as populations expand into unoccupied territory, they typically eat a limited number of prey. But as populations grow and become more established, the otters will start to diversify their diet, suggesting intra-specific competition[3][7].
  3. Sea otters exert a strong top-down force. Top-down forcing is one of the most important concepts we must acknowledge when discussing sea otter ecology. With top-down forcing, consumers at the top of the food chain depress the trophic level on which they feed, and this feeding indirectly increases the abundance of the next lower trophic level, resulting in a cascading effect[8]. The archetype example of this phenomenon is the relationship between sea otters, sea urchins, and kelp forests. This relationship goes as follows: sea otters consume sea urchin, and sea urchins graze on kelp. Therefore, sea otters reduce sea urchin densities by direct predation, thereby mediating grazing pressure on kelp. This indirect effect allows kelp to grow more abundantly, which is why we often see relatively productive kelp forests when sea otters are present[9]. This top-down forcing also has important implications for the whole ecosystem, as I’ll explain in my next fact.

    Pictured: sea urchin dominated seascape in habitat without sea otters. Photo Credit: BISHOPAPPS via Ohio State University.
  4. Sea otters help restore ecosystems, and associated ecosystem services. In kelp habitat where sea otters have been removed, we often see high densities of sea urchins and low biomasses of kelp. In this case, sea urchins have no natural predators to keep their populations in check and therefore completely decimate kelp forests. However, what we’ve learned is that when sea otters “reclaim” previously occupied habitats or expand into unoccupied territory, they can have remarkable restorative effects because their predation on sea urchins allows for the regrowth of kelp forest[10]. Additionally, with the restoration of key ecosystems like kelp forests, we can see a variety of other indirect benefits – such as increased biodiversity, refuge for fish nurseries and commercially-important species, and carbon sequestration[11][12][13]. The structure of nearshore ecosystems and communities change drastically with the addition or removal of sea otters, which is why they’re often referred to as keystone species.

    Photo Credit: University of California, Santa Barbara.
  5. Sea otters are most often associated with coastal kelp forests, but they can also exist in other types of habitats and ecosystems. In addition to kelp dominated ecosystems, sea otters are known to use estuaries and bays, seagrass beds, and swim over a range of bottom substrates[14][15]. As evidenced by previous studies, sea otters exert similar top-down forces in non-kelp ecosystems, as they do within kelp forests. One study found that sea otters also had restorative effects on seagrass beds within estuaries, where they consumed different types of prey (i.e., crabs instead of urchins), demonstrating that sea otters play a significant keystone role in seagrass habitats as well [12]. Findings such as these are vitally important to understanding (1) where sea otters are capable of living relative to habitat characteristics, and (2) how recovering or expanding sea otter populations may impact ecosystems and habitats in which they don’t currently exist, such as the Oregon coast.
Pictured: sea otter swimming through eel grass at Elkhorn Slough, California. Photo Credit: Kip Evans Photography.

Well, there you have it – my top five favorite facts about sea otters. This list is by no means exhaustive of all there is to know about sea otter ecology, and isn’t enough information to develop an informative reintroduction plan. However, a successful reintroduction plan will rely heavily on these underlying ecological characteristics of sea otters, in addition to the current state of Oregon’s nearshore ecosystems. As someone who constantly focuses on the relationship between scientific research and management and conservation, it’s nice every now and then to take a step back and just simply appreciate sea otters for being, well, sea otters.

References:

[1] Costa, D. P. 1978. The ecological energetics, water, and electrolyte balance of the California sea otter (Enhydra lutris). Ph.D. dissertation, University of California, Santa Cruz.

[2] Reidman, M. L. and J. A. Estes. 1990. The sea otter (Enhydra lutris): behavior, ecology, and natural history. United States Department of the Interior, Fish and Wildlife Service, Biological Report. 90: 1-126.

[3] Laidre, K.L. and R. J. Jameson. 2006. Foraging patterns and prey selection in an increasing and expanding sea otter population. Journal of Mammology. 87(4): 799-807.

[4] Estes, J. A., Jameson, R.J., and B. R. Rhode. 1982. Activity and prey election in the sea otter: influence of population status on community structure. The American Naturalist. 120(2): 242-258.

[5] Tinker, M. T., Costa, D. P., Estes, J. A., and N. Wieringa. 2007. Individual dietary specialization and dive behavior in the California sea otter: using archival time-depth data to detect alternative foraging strategies. Deep-Sea Research Part II. (54):330-342.

[6] Newsome et al. 2009. Using stable isotopes to investigate individual diet specialization in California sea otters (Enhydra lutris nereis). Ecology. 90(4): 961-974.

[7] Ostfeld, R. S. 1982. Foraging strategies and prey switching in the California sea otter. Oecologia. 53(2): 170-178.

[8] Paine, R. T. 1980. Food webs: linkage, interaction strength and community infrastructure. The Journal of Animal Ecology. 49(3): 666-685.

[9] Estes, J. A. and J.F. Palmisano. 1974. Sea otters: their role in structuring nearshore communities. Science. 185(4156): 1058-1060.

[10] Estes, J. A., and D. O. Duggins. 1995. Sea otters and kelp forests in Alaska: generality and variation in a community ecological paradigm. Ecological Monographs. 65(1): 75-100.

[11] Wilmers, C. C., Estes, J. A., Edwards, M., Laidre, K. L., and B. Konar. 2012. Do trophic cascades affect the storage and flux of atmospheric carbon? An analysis of sea otters and kelp forests. Frontiers in Ecology and the Environment. 10(8): 409-415.

[12] Hughes et al. 2014. Recovery of a top predator mediate negative eutrophic effects on seagrass. Proceedings of the National Academy of Sciences. 110(38): 15313-15318.

[13] Lee, L.C., Watson, J. C., Trebilco, R., and A. K. Salomon. Indirect effects and prey behavior mediate interactions between an endangered prey and recovering predator. Ecosphere. 7(12).

[14] Laidre, K. L., Jameson, R. J., Gurarie, E., Jeffries, S. J., and H. Allen. 2009. Spatial habitat use patterns of sea otters in coastal Washington. Journal of Mammalogy. 90(4): 906-917.

[15] Lafferty, K. D., and M. T. Tinker. 2014. Sea otters are recolonizing southern California in fits and starts. Ecosphere. 5(5).