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On niche partitioning and the Ohio State Buckeyes

By: Erin Pickett, MS student, Biotelemetry and Behavioral Ecology Laboratory & GEMM Lab, MMI

Buckeye anecdote

I recently found myself sitting at a Sunday brunch at the Westin in Washington, D.C., talking to my uncle about my research on the foraging ecology of penguins. Our entire extended family had gathered for a cousin’s wedding, and it was the first family gathering in a long time that I had been able to attend due to always being “out on some island”, as my cousin puts it. In fact, I got a shout-out during one of the dinner reception speeches for coming all the way from Antarctica for the wedding.

My uncle asked me about my research while our surrounding family members sipped their coffee and OJ and recounted the highlights of the previous night’s wedding reception. This conversation with my uncle was the first I’d had with a family member all weekend that had progressed past my ‘elevator speech’ of what I was studying in school. After I described my research questions about resource partitioning between Adelie and gentoo penguins, my uncle glanced around the room full of family members and said to me, “You know what….”? And then he went on to describe his thoughts about how our aunts, uncles, cousins and in-laws all occupied distinct niches within our family.

The definition of the word niche is broad, and for this reason it can be used to describe the roles of younger siblings, matriarchs, sisters, and Ohio State Buckeye fans within their families or communities. Take for example my entire family on the dance floor chanting O-H-I-O during the bands requisite rendition of “Hang on Sloopy” at the wedding reception. As Buckeyes, we were occupying a role distinct from that of the bride’s family, who are Notre Dame Fans. Within our immediate families, the roles of every sibling and parent are further differentiated. My uncle and I looked around the room and saw a family who despite a wide range of personalities and football allegiances, was managing to enjoy a pretty good time together!

Ecological niche theory and sympatric penguins

In ecology, the term niche is used to describe the ecological role that a species occupies within an ecosystem (Hutchinson 1957). The concept of an ecological niche is typically used in ecology to describe how similar species coexist within the same space. This coexistence is made possible through segregation mechanisms that facilitate resource partitioning, such as spatial or temporal differences in foraging location, or dietary segregation (Pianka 1974). With this in mind, the main objective of my master’s research is to quantify the ecological niches of Adelie and gentoo penguins in terms of space, time and diet, in order to investigate whether foraging competition is occurring between these two species. You’ll find more background on this project here.

The first step in my investigation of resource partitioning was to assess the extent and consistency of dietary overlap between these two species. The diets of Adelie and gentoo penguins vary regionally, but along the Antarctic Peninsula the prey of both species is typically dominated by Antarctic krill. This was the case when I studied the diets of these two species at Palmer Station in Antarctica. I also found that both species consume the same size classes of krill and that this was consistent across both low and high prey availability years (Figure 1).

Size class frequency distribution of Antarctic krill found in penguin diet samples (2010-2015). Krill size class bins shown on x-axis and proportions depicted on y-axis
Figure 1. Length-frequency distribution of Antarctic krill found in penguin diet samples (2010-2015). Krill size class bins shown on x-axis with the proportion of those size classes depicted on the y-axis. Palmer LTER unpublished data.

The next step of my project is to assess the foraging habits and space-use patterns of these two species. They share food, but do they forage in the same areas? I am in the process of analyzing spatial data obtained from satellite and TDR (time depth recording) tags temporarily attached to Adelie and gentoo penguins during the breeding season to determine the core foraging areas. I am using kernel density estimate (KDE) techniques to visually and quantitatively determine the size and extent of spatial overlap between both species foraging areas (Figure 2).

Figure 2.
Figure 2. An example plot of 3D kernel density estimates outlining 95% and 50% volume contours of foraging penguins during the 2010 breeding season. Orange and green depict the core foraging areas of gentoo and Adelies, respectively. Horizontal axes show northing and easting values and depth is shown in meters on the vertical axis.

The KDE method allows me to turn hundreds of satellite tag derived location points into a probability density surface which depicts where an animal is most likely to be found (Kie et al. 2010).  2D KDEs are sufficient to describe the ranges of many terrestrial animals, however, 3D KDEs are a more appropriate description of the space-use patterns of diving seabirds. By failing to incorporate the depth at which these two species are foraging, 2D KDEs might overestimate the extent of spatial overlap between two species who are foraging in the same location but at different depths. Similar to other studies (Cimino et al. 2016 & Wilson 2010), I am finding that Adelie and gentoo penguins may be partitioning resources by foraging at different depths, with gentoo penguins diving deeper than Adelies. By foraging at different depths, these two species are limiting foraging competition.

While I am working on these analyses, I am also thinking about my next step, which will be to determine whether foraging niche overlap between Adelie and gentoo penguins is a function of prey availability. Resource availability is a critical component of niche segregation. When resources are abundant, there is typically a higher tolerance for niche overlap (Pianka 1974, Torres 2009). Conversely, niches may become more distinct as resources decrease and successfully partitioning these resources will become more important to minimize competition. In order to address the effect of resource availability on niche partitioning between Adelie and gentoo penguins, I will be comparing their foraging niches during years of both low and high prey availability. This will allow me to truly evaluate the potential occurrence of foraging competition between these two species.

Conclusion

I’ll keep you updated on my progress with data analysis in future blogs, but before I go I’ll share one last piece of wisdom about niche theory that I’ve learned from my family. There is a niche for everyone unless you are a Michigan fan, then no amount of spatial or dietary partitioning in a room full of Ohio State Buckeyes will save you.

References 

Cimino, Megan A., et al. “Climate-driven sympatry may not lead to foraging competition between congeneric top-predators.” Scientific reports 6 (2016).

Hutchinson, G.E. “Concluding remarks. Population Studies: Animal Ecology and Demography.” Cold Spring Harbor Symposia on Quantitative Biology 22 (1957): 415-427.

Kie, John G., et al. “The home-range concept: are traditional estimators still relevant with modern telemetry technology?” Philosophical Transactions of the Royal Society of London B: Biological Sciences 365.1550 (2010): 2221-2231.

Pianka, Eric R. “Niche overlap and diffuse competition.” Proceedings of the National Academy of Sciences 71.5 (1974): 2141-2145.

Torres, Leigh G. “A kaleidoscope of mammal, bird and fish: habitat use patterns of top predators and their prey in Florida Bay.” Marine Ecology Progress Series 375 (2009): 289-304.

Are Oregon gulls trash birds?

By Stephanie Loredo, MSc student

“Violent” and “greedy” are words often used to describe gulls in populous areas where food or trash are readily available.  Humans are used to seeing gulls in parking lots, parks, and plazas eating left over crumbs. Many people have even experienced menacing gulls ripping food away from their hands. Anecdotes like these have caused people to have negative perceptions of gulls. But could the repulsive attitude towards these birds be changed with evidence that not all gulls are the same? Well, Oregon may be home to an odd bunch.

Last year, the Seabird Oceanography Lab in conjunction with the GEMM Lab began putting GPS trackers on western gulls (Laurus occidentalis) off the Oregon Coast. One of the goals was to determine where gulls scavenge for food while raising chicks: at sea or on land in association with humans. We were particularly interested to see if western gulls in Oregon would behave similarly to western gulls in California, some of which make trips to the nearest landfill during the breeding season to bring not only food but also potentially harmful pathogens back to the colony.

During the 2015 breeding season, 10 commercially brand ‘i-gotU’ GPS data loggers were placed on gulls from ‘Cleft-in-the-Rock’ colony in Yachats, Oregon. The tags provided GPS locations at intervals of two minutes that determined the general habitat use areas (marine vs. terrestrial). After a two-week period, we were able to recapture six birds, remove tags, and download the data.   We found that these western gulls stayed close to the colony and foraged in nearby intertidal and marine zones (Figure 1). Birds showed high site faithfulness by visiting the same foraging spots away from colony. It was interesting to see that inland habitat use did not extend past 1.3 miles from shore and the only waste facility within such boundaries did not attract any birds (Figure 1). Tagged birds never crossed the 101 Highway, but rather occurred at beaches in state parks such as Neptune and Yachats Ocean Road.

Figure 1. Tracks from 6 western gulls, each color representing a unique bird, from the Cleft-in-the-Rock colony carrying micro-GPS units.
Figure 1. Tracks from 6 western gulls, each color representing a unique bird, from the Cleft-in-the-Rock colony carrying micro-GPS units.

While it is hard to determine whether gulls avoided anthropogenic sources of food at the beach, preliminary analysis shows a high percentage of time spent in marine and intertidal habitat zones by half of the individuals (Figure 2). At a first glance, this is not as much as it seemed on the tracking map (Figure 1), but it nonetheless confirms that these gulls seek food in natural areas. Moreover, time spent at the colony is represented as time spent on coastal habitat on the graph, and thus “coastal” foraging values are over represented. To get a more exact estimate of coastal habitat use, future analysis will have to exclude colony locations and distinguish foraging versus resting behaviors.

Figure 2. Bar plot of the percentage of time spent in three distinct habitats for each gull carrying a GPS unit. The three-letter code represents the unique Bird ID.
Figure 2. Bar plot of the percentage of time spent in three distinct habitats for each gull carrying a GPS unit. The three-letter code represents the unique Bird ID.

‘Cleft-in-the-Rock’ is unique and its surroundings may explain why there was high foraging in intertidal and marine zones rather than within city limits. (The Cleft colony can also be tricky to get to, with a close eye on the tide at all times – See video below).  The colony site is close to the Cape Perpetua Scenic Area and surrounded by recently established conservation zones: the Cape Perpetua Marine Reserve Area, Marine Protected Area, and Seabird Protected Area (Figure 1).  Each of these areas has different regulatory rules on what is allowed to take, which you can read about here. The implication of these protected areas in place means there is more food for wildlife!  Moreover, the city of Yachats has a small population of 703 inhabitants (based on 2013 U.S Census Bureau). The small population allows the city to be relatively clean, and the waste facility is not spewing rotten odors into the air like in many big cities such as Santa Cruz (population of 62,864) where our collaborative gull study takes place. Thus, in Yachats, there is more limited odor or visual incentive to attract birds to landfills.

Field crew descends headland slope to reach ‘Cleft-in-the-Rock’ gull island in Yachats, OR (colony can be seen in distance across the water). The team must wear wetsuits and carry equipment in dry bags for protection during water crossing.

In order to determine whether gull habitat use in Yachats is a trend for all western gulls in Oregon, we need to track birds at more sites and for a longer time. That is why during the breeding season of 2016, we will be placing 30 new tags on gulls and include a new colony into the study, ‘Hunters Island’. The new colony is situated near the Pistol River, between Gold Beach and Brookings in southern Oregon, and it is part of the Oregon Islands Wildlife Refuge.

We will have 10 ‘i-gotU’ tags (Figure 3) and 20 CATS tags (Figure 4), the latter are solar powered and can collect data for several weeks, months, and hopefully even years! These tags do not need to be retrieved for data download; rather data can be accessed remotely, providing minimal disturbance to the gulls and colony. With long-term data, we can explore further into the important feeding areas for western gulls, examine rates of foraging in different habitats, and determine how extensive intertidal and marine foraging is throughout the year.

Figure 3. Taping an i-gotU tag for temporary attachment on the tail feathers of a gull.
Figure 3. Taping an i-gotU tag for temporary attachment on the tail feathers of a gull.

 

Figure 4. Rehearsing the placement and harness attachment of a CATS tag which must be secured on the bird‘s back, looping around the wings and hips.

We are excited to kick start our field season in the next couple of weeks and see how well the new tags work. We know that some questions will be solved and many new questions will arise; and we cannot wait to start this gull-filled adventure!

References

Osterback, A.M., Frechette, D., Hayes, S., Shaffer, S., & Moore, J. (2015). Long-term shifts in anthropogenic subsidies to gulls and implications for an imperiled fish. Biological Conservation, 191: 606–613.

An update on Oregon’s sound sensitive marine mammal, the harbor porpoise.

By Amanda Holdman, M.S. Student

Marine renewable energy is developing at great speeds all around the world. In 2013, the Northwest Marine Renewable Energy Center (NMREC) chose Newport, Oregon as the future site of first utility-scale, grid-connected wave energy test site in the United States – The Pacific Marine Energy Center (PMEC). The development of marine energy holds great potential to help meet our energy needs – it is renewable, and it is predicted that marine energy sources could fulfill nearly one-third of the United States energy demands.

Wave energy construction in Newport could begin as early as 2017. Therefore, it is important to fully understand the potential risks and benefits of wave energy as the industry moves forward. Currently, there is limited information on wave energy devices and the potential ecological impacts that they may have on marine mammals and their habitats. In order to assess the effects of wave energy, pertinent information needs to be collected prior to the installation of the devices.

This is where I contribute to the wave energy industry in Oregon.

Harbor porpoise are a focal species when it comes to renewable energy management; they are sensitive to a range of anthropogenic sounds at very low levels of exposure and may show behavioral responses before other marine mammals, making them a great indicator species for potential problems with wave energy. Little is known about harbor porpoise in Oregon, necessitating the need to look at the fine scale habitat use patterns of harbor porpoise within the proposed wave energy sites.

I used two methods to study harbor porpoise presence and activity in coastal waters: visual boat surveys, and passive acoustic monitoring. Visual surveys have a high spatial resolution and a low temporal resolution, meaning you can conduct visual boat surveys over a wide area, but only during daylight hours. Whereas acoustic surveys have opposite characteristics; you can conduct surveys during all hours of the day, however, the range of the acoustic device is only a few hundred meters. Therefore, these methods work well together to gain complimentary information about harbor porpoise. These methods are crucial for collecting baseline data on harbor porpoise distribution, and providing valuable information for understanding, managing, and mitigating potential impacts.

Bi-monthly standard visual line-transect surveys were conducted for two full years (October 2013-2015), while acoustic devices were deployed May – October 2014. Field work ended last October, and since then, data analysis efforts have uncovered  seasonal, diel, and tidal patterns in harbor porpoise occurrence and activity.

Harbor porpoises in Oregon are thought to be seasonally migratory. With the onset of spring, coinciding with the start of the upwelling season, porpoise are thought to move inshore and abundance increases into the summer. Most births also occur during the late spring and summer. With the return of winter, porpoise are thought to leave the coastal waters and head out to the deeper waters (Dohl 1983, Barlow 1988, Green et al. 1992).

Results from my data support this seasonal trend. Both visual survey and acoustic recording data document the general pattern of peak porpoise presence occurring in the summer months of June and July, with a gradual decline of detections into the fall (Fig. 1 & 2).

1

Figure 1: Overall, from our acoustic surveys we see a large increase from May to June, suggesting the arrival of harbor porpoise to coastal waters. From July, we see a slow decline into the fall months, suggestive of harbor porpoise moving offshore.

2

Figure 2: Our data from visual surveys mimic those of our acoustic surveys. We see a large increase of porpoises from May to June and then a decline into the fall. We had very low survey effort in July, due to rough seas.  If we were able to survey more, it is likely we would have seen more harbor porpoise during this time.

Using acoustic recorders, we are able to get data on harbor porpoise occurrence throughout all hours of the day, regardless of weather conditions. We deployed hydrophones in two locations – one in a near-shore REEF habitat located 4 km from shore, and the second in the middle of the South Energy Testing Site (SETS) 12 km off-shore. These two sites differ in depth and habitat type. The REEF habitat is 30 m deep and has a rocky bottom as a habitat type, while SETS is 60 m deep and has a sandy bottom. When we compare the two sites (Figure 3), we can see that harbor porpoise have a preference for the REEF site.

Additionally, we are also able to get some indices of behavior from acoustic recordings. Equivalent to sonar or radar, marine mammals use echolocation (high frequency sounds) to communicate and navigate. Marine mammals, specifically odonotocetes, also use echolocation to locate prey at depth when there is very little or no light. Porpoises use a series of clicks during their dives, and as the porpoise approach their prey, the clicks become closer and closer together so they sound like a continuous buzz. When studying echolocation patterns in odontocetes we typically look at the inter-click-intervals (ICIs) or the time between clicks. When ICIs are very close together (less than 10 ms apart) it is considered a foraging behavior or a buzz. Anything greater than 10 ms is classified as other (or clicks in this figure).

Click_Buzz_bargraph.

Figure 3: We see harbor porpoise clicks were detected about 27% of the time at the REEF, but only 18% at SETS. Potential feeding was also higher at the REEF site (14%) compared to (4%) at SETS.

Not only did we find patterns in foraging behavior between the two sites, we also found foraging patterns across diel cycles and tidal cycles:

  1. We found a tendency for harbor porpoise to forage more at night (Figure 4).
  2. The diel pattern of harbor porpoise foraging is stronger at the SETS than the REEF site (Figure 4). This result may be due to the prey at the SETS (sandy bottom) exhibiting vertical migration with the day and night cycles since prey there do not have alternative cover, as they would in the rocky reef habitat.
  3. At the reef site, we see a relationship between increased foraging behavior and low tide (Figure 5).

ratio

Figure 4: When analyzing data for trends in foraging behavior across different sites and diel cycles, we use a ratio of buzzes to clicks, so that we incorporate both echolocation behaviors in one value. This figure shows us that the ratio of buzzes to clicks is pretty similar at the REEF site across diel periods, but there is more variation at the SETS site, with more detections at night and during sunrise.

blog_5

Figure 5: Due to the circular nature of tides rotating between high tide and low tide, circular histograms help to observe patterns. In this figure, we see a large preference for harbor porpoise to feed during low tide. We are unclear why harbor porpoise may prefer low tide, but the relationship may be due to minimal current movement that could enhance feeding opportunities for porpoises.

Overall, the combination of visual surveys and passive acoustic monitoring has provided high quality baseline data on harbor porpoise occurrence patterns. It is results like these that can help with decisions regarding wave energy siting, operation and permitting off of the Oregon Coast.

REFERENCES

Barlow, J. 1987. Abundance estimation for harbor porpoise (Phocoena phocoena) based on ship surveys along the coasts of California, Oregon and Washington. SWFC Administrative Report LJ-87-05. Southwest Fishery Center, La Jolla, CA. 36pp.

Dohl, T.P., Guess, R.C., Dunman, M.L. and Helm, R.C. 1983, Cetaceans of central and northern California, 1980-83: status, abundance, and distribution. Final Report to the Minerals Management Service, Contract 14-12-0001-29090. 285pp.

Green, G.A., Brueggeman, J. J., Grotefendt, R.A., Bowlby, C.E., Bonnel, M. L. and Balcomb, K.C. 1992. Cetacean distribution and abundance off Oregon and Washington, 1989-1990. Chapter 1 In Oregon and Washington Marine Mammal and Seabird Surveys. Ed. By J. J. Brueggeman. Minerals Management Service Contract Report 14-12-0001-30426.

Wildlife of the Western Antarctic Peninsula

Erin Pickett, MS Student, Fisheries and Wildlife Department, OSU

This time last week, I was on a research vessel crossing the Drake Passage. The Drake extends from the tip of the Western Antarctic Peninsula to South America’s Cape Horn, and was part of the route I was taking home from Antarctica. Over the past three months I have been working on a long-term ecological research (LTER) project based out of Palmer Station, a U.S. based research facility located on Anvers Island.

Image: http://www.tetonat.com/2009/11/06/bon-voyage-off-to-antarctica-with-iceaxe-expeditions/
Image: http://www.tetonat.com/2009/11/06/bon-voyage-off-to-antarctica-with-iceaxe-expeditions/

While in Antarctica, I was working on the cetacean component of the Palmer LTER project, which I’ve described in previous blog posts. In lieu of writing more about what it is like to work and live on the Antarctic Peninsula, I thought I’d share some photos with you. Working on the water everyday while searching for whales provided me with many opportunities to photograph the local wildlife. I hope you’ll enjoy a few of my favorite shots.

A porpoise-full lesson on cetacean identification

By Amanda Holdman, M.S. student

The rain is beginning to lighten, the heavy winds are starting  to dissipate, and the sun is beginning to shine. Seabirds are starting to fill the air and marine mammals are starting to fill the coastline, making this week a perfect time to learn about some of the small, cryptic cetaceans that consider the Oregon coast home year round.

While I was walking my dog on South Beach in Newport last week, I heard the mother of a small family point and shout that she had just seen an animal that she referred to as a “porpoise/dolphin/small whale.” Upon a second sighting of it, she ruled against the small whale and decided on a dolphin. In reality, she had just sighted a harbor porpoise.

Throughout the duration of my work with Oregon State studying the patterns of harbor porpoise occurrence, one of the most frequently asked questions I get is “What is the difference between a porpoise and a dolphin?”

Differentiating between a dolphin and porpoise is probably the most common identification mistake when it comes to cetaceans. Understandably, there is significant confusion between the two species. The words dolphin and porpoise were, colloquially, used as synonyms until the 1970’s. Unlike lions and tigers that are not only in the same family, but also the same genus, dolphins and porpoises are in different families, having diverged evolutionarily about 15 million years ago! Therefore, dolphins and porpoises are more distinct than lions and tigers. These differences span from head and fin shape, to behavior, group size and vocals.

Physical Differences

Most people are quite certain they are seeing a dolphin mainly because dolphins are more prevalent than porpoises; over 30 species of dolphins are known to exist, but only 6 porpoise species have been identified worldwide. Unless, you’ve seen dolphins and porpoises side by side, nose to fin, it is quite difficult to tell the difference at first glance. In the natural history of cetacean’s course at Oregon State, we are taught that the three main visual differences are in the shape of the teeth, snout, and dorsal fin. But in reality, the first two characteristics aren’t likely to help you spot them from shore. In addition to fin size, the behavior and group size is more likely to cue you in on what animal you are seeing. The picture below does a pretty good job summarizing their physical characteristics. Porpoise have a small triangle fin, while dolphins have more of a curved, pointy fin.

identificationDrawing by Mike Rock, 2009.

Size Differences

The lengths and widths of dolphins vary anywhere from 4 feet to 30 feet. Killer whales, the largest dolphin species and known predator to the harbor porpoise, can weigh up to ten tons, while the harbor porpoise is about five feet and rarely weighs in over 150 pounds.  Porpoises are one of the smallest cetaceans, and because of their small size, they lose body heat to the water more quickly than other cetaceans. Their blunt snout is likely an adaptation to minimize surface area to conserve heat. The small sizes of porpoise require them to eat frequently, rather than depending on fat reserves, making them more of an opportunistic feeder. The need to constantly forage also keeps harbor porpoise from migrating on a large scale. Harbor porpoise are known to move from onshore to offshore waters with changing water temperatures and prey distributions, but not known to make long migration trips.

Social Differences

Porpoises are also less social and talkative than dolphins. Dolphins are typically found in large groups, can be highly acrobatic, and often seen bow-riding. Porpoise, specifically harbor porpoise, are often found singularly or in groups of two to three, and shy away from vessels, making them difficult to observe at sea. While both species have large melon heads for echolocation purposes, dolphins make whistles through there blow holes to communicate with each other underwater. Evolutionary scientists believe porpoises do not whistle due to structural differences in their blowhole. (This is why acoustics is such a great way to learn about the occurrence patterns of harbor porpoise – their echolocation is very distinct!) Porpoise echolocation signals have evolved into a very narrow frequency range – theoretically to protect themselves from killer whale predation by echolocating at a frequency killer whales cannot hear.  Dolphins have evolved other strategies to avoid predators such as large group size and fast speed.

While differentiating between porpoises and dolphins takes a bit of practice, it is important to differentiate between the two species because we manage them differently due to some of their morphological differences. Their different adaptations between the species make them more sensitive to certain stressors. For example, for harbor porpoise, the sound produced from boat noise or renewable energy devices is more likely to impact them than other cetaceans. The sensitivity of the nerve cells in the ears of animals (including humans) generally corresponds to the frequencies that each animal produces. So animals like the harbor porpoise have more nerves in their ears that are tuned to very high frequencies (since they make high frequency sounds). If the nerve cells in the harbor porpoise ears become damaged, their ability to communicate, navigate and find food is seriously affected. In addition to their small home ranges and moderately high position in the food web, the sensitivity of harbor porpoise to ocean noise levels make harbor porpoise an important indicator species for ecosystem health, and an important species to study on the Oregon Coast.

Smile! You’re on Camera!

By Florence Sullivan, MSc. Student, GEMM Lab

Happy Spring everyone!  You may be wondering where the gray whale updates have been all winter – and while I haven’t migrated south to Baja California with them, I have spent many hours in the GEMM Lab processing data, and categorizing photos.

You may recall that one of my base questions for this project is:

Do individual whales have different foraging strategies?

In order to answer this question, we must be able to tell individual gray whales apart. Scientists have many methods for recognizing individuals of different species using tags and bands, taking biopsy samples for DNA analysis, and more. But the method we’re using for this project is perhaps the simplest: Photo-Identification, which relies on the unique markings on individual animals, like fingerprints.  All you need is a camera and rather a lot of patience.

Bottlenose dolphins were some of the first cetaceans to be documented by photo-identification.  Individuals are identified by knicks and notches in their fins. Humpback whales are comparatively easy to identify – the bold black and white patterns on the underside of their frequently displayed flukes are compared.  Orcas, one of the most beloved species of cetaceans, are recognized thanks to their saddle patches – again, unique to each individual. Did you know that the coloration and shape of those patches is actually indicative of the different ecotypes of Orca around the world? Check out this beautiful poster by Uko Gorter to see!

Gray whale photo identification is a bit more subtle since these whales don’t have dorsal fins and do not show the undersides of their fluke regularly.  Because gray whales can have very different patterns on either side of their body, it is also important to get photos of both their right and left sides, as well as the fluke, to be sure of recognizing an individual if it comes around again.   When taking photos of a gray whale, it’s a good idea to include the dorsal hump, where the knuckles start as it dives, as an easy indicator of which side of the body you are looking at when you’re trying to match photos.  Some clues that I often use when identifying an individual include the placement of barnacles, and patterns of pigmentation and scars.  You can see that patience and a talent for pattern recognition come in handy for this sort of work.

While we were in the field, it was important for my team to quickly find reference features to make sure we were always tracking the same whale. If you stopped by to visit our field station, you may have heard use saying things like “68 has white on both fluke-tips”, “70 has a propeller scar on the left side”,  “the barnacles on 54’s head looks like a polyp”, or “27 has a smiley face in front of the first knuckle left side.” Sometimes, if a trait was particularly obvious, and the whale visited our field station more than once, we would give them a name to help us remember them.  These notes were often (but to my frustration, not always!) recorded in our field notebook, and have come in handy this winter as I have systematically gone through the 8000+ photos we took last summer, identifying each individual, and noting whenever one was a repeat visitor. With these individuals labeled, I can now assess their level of behavioral and distribution consistency within and between study sites, and over the course of the summer.

Why don’t you try your luck?  How many individuals are in this photoset? How many repeats?  If I tell you that my team named some of these whales Mitosis, Smiley, Ninja and Keyboard can you figure out which ones they are?

#1
#2
#2
#3
#4
#4
#5
#5
#6
#6
#7
#7
#8
#8
#9
#9
#10
#10

 

Keep scrolling for the answer key ( I don’t want to spoil it too easily!)

 

 

 

 

 

Answers:

There are 7 whales in this photoset. Smiley and Keyboard both have repeat shots for you to find, and Smiley even shows off both left and right sides.

  1. Whale 18 – Mitosis
  2. Whale 70 -Keyboard
  3. Whale 23 -Smiley
  4. Whale 68 – Keyboard
  5. Whale 27 -Smiley
  6. Whale 67
  7. Whale 36 -Ninja
  8. Whale 60 – “60”
  9. Whale 38 – has no nickname even if we’ve seen it 8 times! Have any suggestions? leave it in the comments!
  10. Whale 55 – Smiley

 

Midway Atoll: Two weeks at the largest albatross colony in the world

By Rachael Orben, Postdoctoral Scholar, Seabird Oceanography Lab & Geospatial Ecology of Marine Megafauna Lab, Oregon State University

In January I was extremely lucky to accompany my former PhD advisor, Scott Shaffer to Midway Atoll National Wildlife Refuge in the Papahānaumokuākea Marine National Monument as part of my job as a postdoc working in Rob Suryan’s Seabird Oceanography Lab. We were there with the dual purpose of GPS tracking Laysan and Black-footed albatrosses as part of Scott’s long-term research and to collect fine-scale data on flight behavior to develop collision risk models for wind energy development (in other areas of the species ranges such as Oregon). Here are my impressions of this amazing island.

So many albatrosses! Our approximately four hour flight from Honolulu to Midway landed at night and as we stood around on the dark tarmac greeting the human island residents I could just make out the ghostly glistening outlines of albatrosses by moonlight. But I had to wait until the following morning to really take stock of where I had suddenly landed: Midway Atoll, the largest albatross colony in the world. This was my first trip to the Northwestern Hawaiian Islands, but I have been to other albatross colonies before and Midway is most definitely different.

First of all, it was hot(ish)!

Secondly, I was amazed to see albatrosses nesting everywhere. Unlike the southern hemisphere colonies I have visited, the albatrosses aren’t restricted to their section of the island or even nesting as close to each other as possible. Instead there are nests literally everywhere there might be enough loose substrate! Birds nest in the middle of the roads, in the bike racks (bikes are an easy quick means of transportation), along the paths, next to the extremely loud generator, near piles of old equipment, and around buildings. Hawaiian albatross nests are not much to look at compared to the mud pedestal nests of the southern hemisphere mollymawks (see the photos below) and are often made of just enough sand and vegetation to keep the egg in place. There are no aerial predators of these birds, beyond the occasional vagrant peregrine, and certainly nothing that might rival the tenacity of the skuas in the southern hemisphere. Perhaps it is this naiveté that has lead to their willingness to nest anywhere.

It may also be this naiveté that has facilitated the following unfortunate turn of events. Just before I arrived, the USFWS and a crew of volunteers had just finished up the annual albatross count. During their counting sweeps they noticed injured adults incubating eggs. After setting out trail cams, suspicions were confirmed. The introduced mice on Midway have discovered that albatrosses are a source of food. House mice are known to prey on albatross chicks on Gough and Marion Islands in the South Atlantic (more information here – warning graphic photos), but to my knowledge this is the first time that they have started eating adult birds. You can read the USFWS announcement here. The plane that I flew out on brought in people, traps, and resources to deal with the situation, but stay tuned as I fear this saga is just beginning.

Finally, and on a further less than positive note, I went to Midway fully aware of the problem that plastics pose to these birds and our marine ecosystem, but there is something to be said for seeing it first hand. The chicks were very small when I was there so I didn’t see any direct impacts on them, but see below for photos of carcasses of last year’s fledglings with plastic filled stomachs. Instead, it was the shear amount of random plastic bits strewn around the island and buried layers deep into the sand that struck me. I learned that sometimes the plastic bits are glow-in-the-dark! Sometimes fishing lures have batteries in them – I am not sure what they are used to catch – do you know? And toothbrushes are very common. All of the plastic that I saw among the birds arrived in the stomach of an adult albatross. All-in-all the experience gave me renewed inspiration for continuing to reduce the amount of plastic that I use (click here for more information on albatrosses and plastic, and here and here for info on marine plastic pollution in general). I collected interesting pieces to bring home with me (see the photos below), but it is a non-random sampling of what caught my eye. I left many many plastic shards where they were.

I have written mostly about the birds, but Midway is full of human history. As I biked along the runway, or past the old officer quarters, I often found myself wondering what all these albatrosses have seen over the years and what they might witness in the future. Two weeks was really just a blink-of-an-eye for an albatross that can live over 40 years (or longer like Wisdom the albatross). I was terribly sad to leave such a beautiful place, but I came home with amazing memories, photos, and gigabytes of data that are already giving me a glimpse into the world of albatrosses at sea.

Racing blues

By Dr. Leigh Torres, Assistant Professor, Oregon State University, Geospatial Ecology of Marine Megafauna Lab

A week ago we observed two racing blue whales.

Please read my blog about this amazing sighting that was recently posted on The National Geographic Explores webpage. You can also watch these videos:

 

Marine Megafauna Ecology Fund

 

Blues Clues

Although blue whales are big, the South Taranaki Bight is bigger. So finding them is not straight forward. In fact, with little prior research in this area, the main focus of our project is to gain a better understanding of blue whale distribution patterns in the region. So, while bouncing around on the sea, we are collecting habitat data that we relate to whale occurrence data to learn what makes preferred whale habitat.

We conduct CTD casts. CTD stands for Conductivity, Temperature and Depth. This is an instrument we lower down to the bottom of the ocean on a line and along the w ay it records temperature and salinity (conductivity) data at all depths. This data describes the water structure at that location, such as the depth of the thermocline. The ocean is often layered with warm, low-salt water on top, and cooler and salty water at the bottom. This thermocline can act as a boundary above which prey aggregate.

Todd and Andrew deploy the CTD off the R/V Ikatere.
Todd and Andrew deploy the CTD off the R/V Ikatere. (Photo by Callum Lilley)
CTD cast
Example data retrieved from a CTD cast showing how temperature (green line) decreases and salinity (red line) increases as it descends through the water column (depth on y-axis).

We also have a transducer on board that we use to record the presence of biological material in the ocean, like krill (blue whale prey). This transducer emits pings of sound through the water column and the echoes bounce back, either off the seafloor, krill or fish. This glorified echosounder records where blue whale prey is, and is not.

Example display image from our echosounder (EK60) showing patches of prey (likely krill) in the upper surface layer.
Example display image from our echosounder (EK60) showing patches of prey (likely krill) in the upper surface layer.

Additionally, the research vessel is always recording surface temperature (SST). I monitor this SST readout somewhat obsessively while at-sea as well as study the latest SST satellite images. Using these two bits of data as my “blues clues”, we search for blue whales.

After a bumpy ride across the Cook Strait we had a good spell of weather last week. We covered a lot of ground, deploying our 5 hydrophones across the Bight and keeping our eyes peeled for blows. Our first day out we found three whales. Fantastic sightings. But, as we continued to survey through warm, low productivity water we found no signs of blue whales. The third day out was a beauty – the type of day I wish for: low swell and low winds – perfect for whale finding. We covered 220 nautical miles this day (deploying 2 hydrophones) and we searched and searched. But no whales. I could see from the SST satellite image that the whole Bight was really warm: about 20 ⁰C. I could also see a strip of cold water down south, toward Farewell Spit. I said “Let’s go there”.

Sea surface temperature (SST) satellite image of the South Taranaki Bight region in New Zealand that shows mostly warm water with a plume of colder water down south.
Sea surface temperature (SST) satellite image of the South Taranaki Bight region in New Zealand that shows mostly warm water with a plume of colder water down south.

After twelve and a half hours of survey effort through clear, blue, warm water, we finally saw the water temperature drop (to about 18 ⁰C) and the water color turn green. We started to see gannets, petrels, shearwaters, and common dolphins feeding. Then I heard the magic words come from Todd’s mouth: “Blow!” So began our sunset sighting. From 7:30 to 10 pm we worked with four blue whales capturing photographs and biopsy samples, and echosounder prey data.

Diving blue whale in the South Taranaki Bight, NZ (photo by Leigh Torres)
Diving blue whale in the South Taranaki Bight, NZ (photo by Leigh Torres)

This is an example of a species-habitat relationship that marine ecologists like me seek to document. We observe and record patterns like this so that we can better understand and predict the distribution of blue whales. Such information is critical for environmental managers to have in order to effectively regulate where and when human activities that may impact blue whales can occur. Over the next two weeks we will continue to document blue whale habitat in the South Taranaki Bight region of New Zealand.

An update from the Antarctic Peninsula

By: Erin Pickett

Yesterday someone said to me, “I don’t know if it was sunrise or sunset, but it was beautiful”. So it goes on the R/V Lawrence M. Gould (LMG), the surrounding scenery is incredible but the work schedule on this research ship makes it difficult to remember what time of day it is.

Here on the Antarctic Peninsula, the sun never really sets and our daily schedules are dependent on things like the diel vertical migration of krill, the current wind speed and the amount of sea ice in between us and our study species, the humpback whale. For these reasons, we sometimes find ourselves starting our workday at odd hours, like 11:45 pm (or 4:00 am). As a reminder, I am currently working on research vessel on a project called the Palmer long term ecological research (LTER) project.  You can read my first blog post about that here. We are about one week into our journey and so far, so good!

Our journey began in Punta Arenas, Chile, where we spent two days loading our research supplies onto the LMG and getting outfitted with cold weather gear. From Punta Arenas we headed south through the straights of Magellan and then across the Drake Passage. Along the way we spotted a variety of cetaceans including minke, fin, sei and humpback whales, and Commerson’s and Peale’s dolphins. I spent as much of our time in transit as I could looking for seabirds, the most numerous being white-chinned and cape petrels, southern giant petrels, and black-browed albatrosses. Spotting either a royal or a wandering albatross was always exciting. An eleven foot wingspan allows these albatross to glide effortlessly above the water and this makes for a beautiful sight!

We have spent the last four days transiting between various sampling stations around Palmer deep, which is an underwater canyon just south of our home base at Palmer station. When conditions allowed, we loaded up our tagging and biopsy gear into a small boat and went to look for humpback whales. We’ve been incredibly successful with the limited amount of time we’ve had on the water and this morning we finished deploying our sixth tag.

We brought a few different types of satellite tags with us to deploy on humpback whales. One type is an implantable satellite tag that transmits location data over a long period of time. These data allow us to gain a better understanding of the large-scale movement and distribution patterns of these animals. The other tag we deploy is a suction cup tag, so called because four small suction cups attach the tag to the whale. These suction cup tags are multi-sensor tags that measure location as well as fine scale underwater movement (e.g. pitch, roll, and heading). They are also equipped with forward and backward facing cameras and most importantly, radio transmitters! This allows us to recover the tags once they fall off the animal and float to the surface (after about 24 hours). The data we get from these tags will allow us to quantify fine-scale foraging behavior in terms of underwater maneuverability, prey type and the frequency, depth and time of day that feeding occurs.

When we deployed each of these tags we also obtained a biopsy sample and fluke photos. Fluke photos and biopsy samples allow us to distinguish between individual animals, and the biopsy samples will also be used to study the demographics of this population through genetic analysis.

Now that we’ve deployed all of our satellite tags and have recovered the suction cup tag just in the nick of time (!), we are starting our first major transect line toward the continental shelf. We will be continuing south along these grid lines for the next week.

My lab mate Logan Pallin and I will be continuing to write about our trip over the next couple of months on another blog we created especially for this project. You can find it here: blogs.oregonstate.edu/LTERcetaceans

I’ll leave you with a few of my favorite photos of the trip so far!