October 2015 – Geospatial Ecology of Marine Megafauna Laboratory

Fishing with dolphins

By Leila Lemos, Ph.D. Student, Department of Fisheries and Wildlife, OSU

Hello everybody! I am Leila Lemos, a new member of the GEMM Lab. I am from Rio de Janeiro, Brazil, and moved to Corvallis just 2 months ago where I am now taking classes at OSU. Although I have not yet travelled around Oregon to see my surroundings I am loving the fall colors! We don’t have all of this yellow/orange/red in our Brazilian trees; it’s amazing! The green of the pines also enchanted me. What a beautiful place! However, I confess that I do miss being close to the ocean, so I am looking forward to being based in Newport next year. So, since I cannot see the ocean for now, let’s talk a bit about it and the dynamic cetaceans that live there.

My thesis will explore the impact of ocean noise on the physiology of gray whales, but I have not started my fieldwork yet. So for my first blog post I will discuss a unique interaction between bottlenose dolphins (Tursiops truncatus) and fisherman that occurs in the cities of Laguna, in the state of Santa Catarina, and Tramandaí and Imbé, in the state of Rio Grande so Sul, in southern Brazil. Unlike most relationships between fishermen and marine mammals, this interaction is mutually beneficial and both species appear to seek each other out. There are only three other places in the world where a similar interaction occurs: Mauritania, in the west coast of Africa; Myanmar, in the south coast of Asia; and in the east coast of Australia.

In the southern Brazil, dolphins and artisanal mullet fishermen have adapted their hunting strategies to perform a cooperative foraging strategy. Cast net fisherman wait for the dolphins to arrive and then observe their behavior. Only when a specific aggressive behavior pattern is observed do the fishermen enter the water with their nets. The dolphins move closer to the fishermen and begin rolling movements that trap fish close to the margin. The fishermen wait to throw their cast nets into the water until the dolphins perform specific and vigorous behaviors described by Simões-Lopes et al. (1998):

the dolphin shows an arched back;
the dolphin exposes its head and hits the surface with the throat;
the dolphin moves rapidly, showing just the dorsal fin, producing a whirl;
the dolphin slaps its tail against the surface.

Fishermen waiting for a signal to throw the cast net in Laguna, Santa Catarina, Brazil. Source: Diário Catarinense, 2013.

Fishermen waiting for a signal to throw the cast net in Laguna, Santa Catarina, Brazil. Source: Notícias UFSC, 2009. — Another shots of fishermen waiting to throw the cast net in Laguna, Santa Catarina, Brazil. Source: Notícias UFSC, 2009.

This partnership is mutually beneficial. Dolphins use the disturbance caused by the net to separate the mullet school and trap individual prey. This method allows the dolphins to reduce escapees, capture more prey, and ultimately increase their net energy gain.

For fishermen, this cooperative association leads to greatly increased captures of mullet. The water in the southern coast of Brazil is too murky for the fishermen to see the schools and therefore know where to throw their net. By watching the behavior of the dolphins, the fisherman is able to throw his net at the exact time and location of the passing mullet shoal.

While this symbiotic relationship is remarkable, it is also hereditary in both humans and dolphins. The calves follow their mothers during the foraging events and learn the movements used in this cooperative behavior. Likewise, the fishermen learn their techniques from their relatives through observation. This cross-species interaction has created cultural ties of great socioeconomic value for both humans and dolphins. Furthermore, this unique relationship demonstrates how clever and adaptive both taxa are when it comes to capturing prey. Wouldn’t it be great if more teamwork like this were possible?

Here is a video that captures this amazing relationship:

Until next time and thanks for reading!

Bibliographic References:

Diário Catarinense, 2013. Interação entre golfinhos e pescadores em Laguna chama a atenção de produtores da BBC. Retrieved from http://diariocatarinense.clicrbs.com.br/sc/geral/noticia/2013/05/interacao-entre-golfinhos-e-pescadores-em-laguna-chama-a-atencao-de-produtores-da-bbc-4151948.html

Notícias UFSC, 2009. Especial pesquisa: UFSC estuda pesca cooperativa entre golfinhos e pescadores em Laguna. Retrieved from http://noticias.ufsc.br/2009/08/especial-pesquisa-ufsc-estuda-pesca-cooperativa-entre-golfinhos-e-pescadores-em-laguna/

Simões-Lopes, P.C., Fabián, M.E., Menegheti, J.O., 1998. Dolphin Interactions with the mullet artisanal fishing on southern Brazil: a qualitative and quantitative approach. Revta bras. Zool. 15(3), 709-726.

On learning to Code…

By Amanda Holdman, MSc student, Dept. Fisheries and Wildlife, OSU

I’ve never sworn so much in my life. I stared at a computer screen for hours trying to fix a bug in my script. The cause of the error escaped me, pushing me into a cycle of tension, self-loathing, and keyboard smashing.

The cause of the error? A typo in the filename.

When I finally fixed the error in my filename and my code ran perfectly – my mood quickly changed. I felt invincible; like I had just won the World Cup. I did a quick victory dance in my kitchen and high-fived my roommate, and then sat down and moved on the next task that needed to be conquered with code. Just like that, programming has quickly become a drug that makes me come back for more despite the initial pain I endure.

I had never opened a computer programming software until my first year of graduate school. Before then Matlab was just the subject of a muttered complaint by my college engineering roommate. As a biology major, I blew it off as something (thank goodness!) I would never need to use. Needless to say, that set me up for a rude awakening just one year later.

The time has finally come for me to, *gulp*, learn how to code. I honestly think I went through all 5 stages of grief before I realized I was at the point where I could no longer put it off.

By now you are familiar with the GEMM Lab updating you with photos of our charismatic study species in our beautiful study areas. However, summer is over. My field work is complete, and I’m enrolled in my last course of my master’s career. So what does this mean? Winter. And with winter comes data analysis. So, instead of spending my days out on a boat in calm seas, watching humpbacks breach, or tagging along with Florence to watch gray whales forage along the Oregon coast, I’ve reached the point of my graduate career that we don’t often tell you about: Figuring out what story our data is telling us. This stage requires lots of coffee and patience.

However, in just two short weeks of learning how to code, I feel like I’ve climbed mountains. I tackle task after task, each allowing me to learn new things, revise old knowledge, and make it just a little bit closer to my goals. One of the most striking things about learning how to code is that it teaches you how to problem solve. It forces you to think in a strategic and conceptual way, and to be honest, I think I like it.

For example, this week I mapped the percent of my harbor porpoise detections over tidal cycles. One of the most important factors explaining the distribution and behavior of coastal marine mammals are tides. Tidal forces drive a number of preliminary and secondary oceanographic processes like changes in water depth, salinity, temperature, and the speed and direction of currents. It’s often difficult to unravel which part of the tidal process is most influential to a species due to the several covariates related to the change in tides , how inter-related those covariates are, and the elusive nature of the species (like the cryptic harbor porpoise). However, while the analysis is preliminary, if we map the acoustic detections of harbor porpoise over the tidal cycle, we can already start to see some interesting trends between the number of porpoise detections and the phases of the tide. Check it out!

Now, I won’t promise that I’ll be an excellent coder by the end of the winter, but I think I might have a good chance at being able to mark the “proficient” box next to Matlab and R on my first job application. Yet, whatever your reason for learning code – whether you are an undergraduate hoping to get ahead for graduate school, a graduate student hoping to escape the inevitable (like me), or just someone who thinks getting a code to work properly is a fun game – my advice to you is this:

Google first. If that fails, take mental breaks. Revisit the problem later. Think through all possible sources of error. Ask around for help. Then, when you finally fix the bug or get the code to work the way you would like it to, throw a mini-party. After it’s all over, take a deep breath and go again. Remember, you are not alone!

Happy coding this winter GEMM Lab readers – and I wish you lots of celebratory dancing!

New Zealand’s mega-fauna come to Newport, Oregon.

By Olivia Hamilton, PhD Candidate, University of Auckland, New Zealand.

The week leading up to my departure from New Zealand was an emotional rollercoaster. Excited, nervous, eager, reluctant… I did not feel like the fearless adventurer that I thought I was. D-day arrived and I said my final goodbyes to my boyfriend and mother at the departure gate. Off I went on my three-month research stint at the Hatfield Marine Science Center.

Some thirty hours later I touched down in Portland. I collected my bags and headed towards the public transport area at the airport. A young man greeted me, “Would you like to catch a taxi or a shuttle, ma’am?” “A taxi please! I have no idea where I am”, I responded. He nodded and smiled. I could see the confusion all over his face… My thick kiwi accent was going to make for some challenging conversations.

After a few days in Portland acclimatizing to the different way of life in Oregon, it was time to push on to Newport. I hit a stroke of luck and was able take the scenic route with one of the girls in the GEMM lab, Rachael Orben. With only one wrong turn we made it to the Oregon coast. I was instantly hit with a sense of familiarity. The rugged coastline and temperate coastal forest resembled that of the west coast of New Zealand. However, America was not shy in reminding me of where I was with its big cars, drive-through everything, and RVs larger than some small kiwi houses.

The Oregon Coast. Photo by Olivia Hamilton.

We arrived at Hatfield Marine Science Center: the place I was to call home for the next quarter of a year.

So, what am I doing here?

In short, I have come to do computer work on the other side of the world.

Dr. Leigh Torres is on my PhD committee and I am lucky enough to have been given the opportunity to come to Newport and analyze my data under her guidance.

My PhD has a broad interest in the spatial ecology of mega-fauna in the Hauraki Gulf, New Zealand. For my study, megafauna includes whales, dolphins, sharks, rays, and seabirds. The Hauraki Gulf is adjacent to Auckland, New Zealand’s most populated city and home to one of our largest commercial ports. The Hauraki Gulf is a highly productive area, providing an ideal habitat for a number of fish species, thus supporting a number of top marine predators. As with many coastal areas, anthropogenic activities have degraded the health of the Gulf’s ecosystem. Commercial and recreational fishing, run-off from surrounding urban and rural land, boat traffic, pollution, dredging, and aquaculture are some of the main activities that threaten the Gulf and the species that inhabit it. For instance, the Nationally Endangered Bryde’s whale is a year-round resident in the Hauraki Gulf and these whales spend much of their time close to the surface, making them highly vulnerable to injury or death from ship-strikes. In spite of these threats, the Gulf supports a number of top marine predators. Therefore it is important that we uncover how these top predators are using the Gulf, in both space and time, to identify ecologically important parts of their habitat. Moreover, this study presents a unique opportunity to look at the relationships between top marine predators and their prey inhabiting a common area.

The Hauraki Gulf, New Zealand. The purple lines represent the track lines that aerial surveys were conducted along.

Common dolphins in the Hauraki Gulf. Photo by Olivia Hamilton

A Bryde’s whale, common dolphins, and some opportunistic seabirds foraging in the Hauraki Gulf. Photo by Isabella Tortora Brayda di Belvedere.

Australisian Gannets and shearwaters foraging on a bait ball in the Hauraki Gulf. Photo by Olivia Hamilton.

To collect the data needed to understand the spatial ecology of these megafauna, we conducted 22 aerial surveys over a year-long period along pre-determined track lines within the Hauraki Gulf. On each flight we had four observers that collected sightings data for cetaceans, sharks, predatory fish, prey balls, plankton, and other rare species such as manta ray. An experienced seabird observer joined us approximately once a month to identify seabirds. We collected environmental data for each sighting including Beaufort Sea State, glare, and water color.

The summary of our sightings show that common dolphins were indeed common, being the most frequent species we observed. The most frequently encountered sharks were bronze whalers, smooth hammerhead sharks, and blue sharks. Sightings of Bryde’s whales were lower than we had hoped, most likely an artifact of our survey design relative to their distribution patterns. In addition, we counted a cumulative total of 11,172 individual seabirds representing 16 species.

Summary of sightings of megafauna in the Hauraki Gulf.

My goal while here at OSU is to develop habitat models for the megafauna species to compare the drivers of their distribution patterns. But, at the moment I am in the less glamorous, but highly important, data processing and decision-making stage. I am grappling with questions like: What environmental variables affected our ability to detect which species on surveys? How do we account for this? Can we clump species that are functionally similar to increase our sample size? These questions are important to address in order to produce reliable results that reflect the megafauna species true distribution patterns.

Once these questions are addressed, we can get on to the fun stuff – the habitat modeling and interpretation of the results. I will hopefully be able to start addressing these questions soon: What environmental and biological variables are important predictors of habitat use for different taxa? Are there interactions (attraction or repulsion) between these top predators? What is driving these patterns? Predator avoidance? Competition? So many questions to ask! I am looking forward to answering these questions and reporting back.

Gray whale field work wrap-up; sea you later

Hello everyone,

Florence here with an update about the final numbers from this summer’s gray whale field season.

For folks just hearing about the project, my team of interns and I spent the summer alternating between study sites at Depoe Bay and Port Orford to conduct fine-scale focal follows of gray whales foraging in near-shore Oregon waters using a theodolite. That is to say, we gathered 10,186 ‘marks’ or ‘locations’ where whales came to the surface, and by connecting the dots, we are able to create tracklines and analyze their movement patterns. The idea is to document and describe gray whale foraging behavior in order to answer the questions: Are there patterns in how the whales use the space? Is there a relationship between foraging success and proximity to kelp beds? Do behaviors vary between individuals, location, or over time during the season?

All these tracklines are from one whale, Keyboard, visiting the same area multiple times over the course of a month. I'll break this figure down a little later in the post. Notice how the whale consistently returns to the bay just west of the port jetty — All these tracklines are from one whale, Keyboard, visiting the same area multiple times over the course of a month. I’ll break this figure down a little later in the post. Notice how the whale consistently returns to the bay just west of the port jetty

While at our study sites, we often received questions about vessel disturbance on the whale’s behavior. Over the course of the summer, we saw whales completely ignore boats, approach boats, and actively avoid boats. Therefore, we documented these vessel interactions in order to ask questions such as: Does vessel disturbance alter behavior? How close is too close? Does the potential for vessel disturbance vary depending on (1) size of motor, (2) speed of approach, (3) type of vessel, i.e. kayak, fishing boat, tour boat, (4) the number of vessels already in the area, (5) amount of time a vessel has been following a whale, (6) time of season, (7) the presence of a calf or other whales? The end goal, once the data have been analyzed, is to bring our results to local vessel operators (commercial and recreational) and work together to write reasonable, effective, and scientifically informed guidelines for vessel operations in the presence of gray whales.

And now, the numbers you’ve all been waiting for, here is the tally of our data collection this summer:

	Boiler Bay	Graveyard Point	Humbug Mountain
Whales total	80	73	28
Boats total	307	105	7
Total survey time (HH:MM:SS)	122:22:41	72:49:17	50:22:35
Total survey time with whales (HH:MM:SS)	64:47:54	80:39:57	22:59:00
Total Marks	4744	4334	1108

Table 1. Summary of survey effort for gray whale foraging ecology field season summer 2015

Whale named "Keyboard" visits graveyard head multiple times. Green track: 7.21.15, Pink track: 7.21.15, Teal track: 7.30.15. The orange polygons are approximate locations of kelp patches. — Whale named “Keyboard” visits graveyard head multiple times. Green track: 7.21.15, Pink track: 7.21.15, Teal track: 7.30.15. The orange polygons are approximate locations of kelp patches.

"Keyboard" continues to visit. Red trackline: 8.27.15, white trackline: 8.28.15, purple trackline: 8.28.15 — “Keyboard” continues to visit. Red trackline: 8.27.15, white trackline: 8.28.15, purple trackline: 8.28.15

Whale 130 foraged near Boiler Bay for 5.5 hours on Aug 12. Trying to look at the whole trackline in one go is a little complicated, so let’s break it down by hour.

This panel shows hours 4-6 of the track. Things get more complex as various vessels use the same area. Whale 130 is always in red.

So, what does this all mean? Well, the unsatisfying answer is of course: we don’t know yet. However, it is my job to find out! I will spend the fall and winter processing data, writing and running behavioral models, communicating my successes and frustrations, and finally presenting my results to the community.

The human eye is well adapted to pick out patterns. Test yourself – what trends can you see in these images? Are there areas that the whales seem to prefer over other areas? In the Port Orford images with Keyboard & our kelp patches, does our theory of a relationship between whale presence and kelp patches seem valid?

This field season would not have been possible without the help of some truly excellent people. Thank you Cricket and Justin and Sarah for making up the core of Team Ro”buff”stus. It was a pleasure working with you this summer. Thank you to guest observers and photographers Era, Steven, Diana, Cory, Kelly, Shea and Brittany for filling in when we needed extra help! Thank you to our support network down in Port Orford: Tom, Tyson and the team at the Port Orford Field Station – we appreciate the housing and warm welcome, and to Jim and Karen Auborn and the Port of Port Orford for allowing us access to such a fantastic viewing location. Thank you to Oregon State Parks for allowing us access to the field sites at Boiler Bay and Humbug. Finally, thank you to Depoe Bay Pirate Coffee Company for keeping us warm and caffeinated on many foggy, cold early mornings. This work was funded by the William and Francis McNeil Fellowship Award, the Wild Rivers Coast Alliance, and the American Cetacean Society: Oregon Chapter.

Fair winds,

Florence

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