Cooperative Fishing: Symbiotic Relationships between People and Dolphins

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

Human-wildlife interactions have occurred since people first inhabited the Earth. However, today, when describing human-wildlife interactions specifically in relation to dolphins, frequently we hear about ‘conflicts’. Interactions between fisheries and dolphins that lead to bycatch or depredation (stealing bait/catching from gear) are particularly common. But, symbiotic relationships with dolphin species and certain human groups can also be mutualistic, with both groups benefitting. These symbiotic relationships have been around for hundreds, if not thousands of years.

A depiction of Aboriginal Australians using nets to catch fish in a small inlet with the assistance of coastal dolphins. (Image source: Our Pacific Ocean)

In eastern Australia, cooperative fishing interactions occur between Aboriginal Australians and dolphins—both bottlenose dolphins and orcas. In Burleigh Heads National Park, Queensland, AUS, the dolphins are thought to help the local indigenous Kombemerri (saltwater) people hunt for fish. Indigenous stories recall men wading into the water with their spears and nets. Then, many of the men would hit the surface waters to make noises with the splashes. Underwater, this sound was amplified and then the dolphins would begin chasing the fish toward the men and their nets (Neil 2002). Aboriginal Australians, especially those in eastern Australia have an emotional and spiritual connection to both dolphins and orcas. There are widespread accounts of cooperation between indigenous people and small cetaceans on the eastern Australian coastline, which create both context and precedent for the economic and emotional objectives to contemporary human-dolphin interactions such as dolphin provisioning (Neil 2002).

Dolphins and fishermen work together in Laguna, Brazil, to catch mullet. (Image Source: Fábio Daura-Jorge)

In the coasts off of Laguna, Brazil, bottlenose dolphins and local fishermen cooperatively fish while tourists gather to watch. Previously, PhD candidate Leila Lemos wrote about these interactions in a blog post. Like many groups of socializing dolphins, these dolphins have a unique whistle to recognize each other. The waters surrounding Laguna, Brazil are murky, turbid and dark green to the point where the fisherman cannot see any of the fish in the water. As the fishermen wade into the murky waters, bottlenose dolphins chase shoals of mullet toward the shore. Then the dolphins tail slap or abruptly dive, “signaling” the fishermen to cast their nets. Research has shown that when the fishermen “work with” the dolphins, both the dolphins and the people catch more, larger fish (Roman 2013). One fisherman claims it is not worth fishing unless the dolphins are around (Roman 2013). Here, the fishermen know the dolphins based on their markings. They know which dolphins participate in the different parts of hunting as well—which dolphin initiates the tail slap, which dolphin usually circles the fish, and which drive the fish towards the coastline. After the dolphins round up and chase the fish for the fishermen and themselves, there is no “reward” from the fishermen for the dolphins—no fish tossed their way. Scientists also found there is a difference in whistle structure between cooperative and non-cooperative dolphin groups (Preston 2017).

A fisherman in Brazil throws a net after dolphins chase mullet into the shore. (Image Source: Leo Francini:Alamy Stock Photo)

Along most coastlines worldwide, humans and dolphins are competitors. Dolphins are seen as thieves who steal fish out of nets, or get caught in their gear and ruin fishing opportunities. Thus, dolphins are often unwelcome near fishing communities. Such negative interactions sometimes lead to human-caused fatalities of dolphin from gunshots or stabbings, thought to be from angry fishermen.  Yet, in this same world, fishermen thank the dolphins for bringing their catch to them. Clearly, both humans and dolphins share high intelligence levels and skills in fishing. If it is a matter of two minds are better than one, then I think indigenous communities figured this equation out first: working with the dolphins, and not against, can better feed their people.

Citations:

Neil, David. (2002). Cooperative fishing interactions between Aboriginal Australians and dolphins in eastern Australia. Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals. 15. 10.2752/089279302786992694.

Preston, Elizabeth. “Dolphins That Work with Humans to Catch Fish Have Unique Accent.” New Scientist, 2 Oct. 2017, www.newscientist.com/article/2149139-dolphins-that-work-with-humans-to-catch-fish-have-unique-accent/.

Roman, Joe. “Fishing with Dolphins: An astonishing cooperative venture in which every species wins but the fish.” Slate Magazine, 31 Jan. 2013, slate.com/technology/2013/01/fishing-with-dolphins-symbiosis-between-humans-and-marine-mammals-to-catch-more-fish.html.

Skype a Scientist – Are you smarter than a middle schooler?

By Florence Sullivan, MSc

What do baby whales eat?

Does the mom whale take care of the baby whale alone?

How do whales communicate?

What are their behaviors?

These are the questions 4th grade students half a world away asked me.  They are studying biodiversity and were very curious to meet a real life scientist.  It was 2:00pm on a Tuesday here in Newport, OR, while in Australia, this classroom full of students was sitting in their 9:00am Wednesday science class.  We had an hour-long conversation about gray whale behaviors, habitat, life cycle, and general biology – all thanks to the wonders of science, technology and the computer program, Skype. The next day, I did it all again, and Skyped in to a classroom in British Columbia, to field questions about gray whales, right whales and science careers from a group of enthusiastic 5th and 6th grade students.

 

A class of Australian 4th graders had many imaginative questions for me through the Skype a Scientist Program.

But how in the world did I end up answering questions over Skype for a classroom full of kids in the first place? Like many good things, it began with a conversation.  During the 2016 USA election cycle, it became apparent that many people in this country distrust scientists. Sarah McAnulty, a PhD student at the University of Connecticut who studies the immune system of bob tail squid, had already been engaging in informal science communication through a profile on tumblr.  But posting things on tumblr is like preaching to the choir – your audience tends to be people who are already interested in your subject. If the problem is trying to change the public perception of scientists from aloof and insular to trustworthy and approachable, you need to start by finding people who have a lot of questions, and few pre-existing prejudices.  Who fits the bill perfectly? Kids!

After conversations with colleagues, she came up with the idea of using Skype to reach classrooms of students outside of the range where scientists usually congregate (large cities and universities).  Sarah started by connecting a handful of UConn colleagues with K-12 teachers through Facebook, but the idea quickly gained steam through mentions at a scientific conference, posts on the ‘March for Science’ Facebook group, media coverage, and word-of-mouth sharing between colleagues on both the teaching and the research side of the story.  Now, there is a full-fledged website (https://www.skypeascientist.com/) where teachers and scientists can sign up to be matched based on availability, topic, and sometimes, demographic.  When pairing classrooms and scientists, Sarah makes an effort for minority students (whether this means race, gender, disability, language, or other) to see themselves represented in the scientists they get to talk to, if possible.  Representation matters –we are beyond the age of old white men in lab coats being the only ‘real scientists’ represented in media, but unfortunately, the stereotype is not dead yet! In less than a year, the program has grown to over 1900 scientists, with new fields of expertise being added frequently as people spread the word and get interested.  The program has been, and promises to continue being, an excellent resource for teachers who want to show the relevance of the subjects being discussed in their classrooms. As evidenced by the fact that I spoke with a classroom in Australia, this is a global program – check out the maps below to see where students and scientists are coming from!

This map shows the locations of all participating classrooms, current on Oct 12, 2017.

This map shows the locations of all participating scientists, current on October 22, 2017.

As for myself, I got involved because my lab mate, Alexa, mentioned how much fun she had Skyping with students.  The sign-up process was incredibly easy, and when I got matched with two classrooms, the organizers even provided a nice mad-libs style ‘fill in the blank’ introduction letter so that I didn’t waste time agonizing over how to introduce myself.

Introductory Mad-libs for scientists. Courtesy of the Skype a Scientist program.

I sent the classrooms the youtube video of my field work, and a couple of these blog posts, and waited to hear back.  I was very impressed with the 5th/6th grade class from British Columbia because the teacher actually let the students take the lead from the get-go.  One of the students replied to my email, told me what they were studying, and started the process of scheduling a meeting time that would work for both of us. When I called in, two other students took the reins, and acted as spokespeople for the rest of their classmates by repeating questions from the back of the room so that I could hear everything clearly. It was so fun to see and hear the enthusiasm of the students as they asked their questions.  Their deep curiosity and obvious excitement about the subject matter was contagious, and I found my own tone, body language, and attitude shifting to match theirs as I helped them discover the building blocks of marine ecology that I have long accepted as normal. This two way street of learning is a good reminder that we all start somewhere.

If you are interested in the program at all, I encourage you to sign up at this link: (https://www.skypeascientist.com/). Who knows, engaging with kids like this just might remind you of the innocent curiosity of childhood that brought you to your scientific career in the first place.

 

Here are some of my favorite question that I was asked, and the responses I gave:

  • How do gray whales communicate?

With songs and underwater sounds! Check out this great website for some great examples, and prepare to be amazed! (I played the Conga and the belch-like call during the skype session, much to the amusement of the students)  https://www.sanignaciograywhales.org/project/acoustics/

  • What do baby whales eat?

Whales are mammals just like us, so believe it or not, baby whales drink their mother’s milk!

  • How long have you been a marine special ecologist for?

My favorite bit here was the mis-spelling, which made me a ‘special’ ecologist instead of a ‘spatial’ ecologist.  So I talked about how spatial ecology is a special type of ecology where we look at how big things move in the ocean!

  • My question is, can a grey whale bite people if people come close to them?
    This was a chance to show off our lab baleen samples!  I also took the time to look this up, and it turns out that bite is defined as “using teeth to cut into something” and a gray whale doesn’t have teeth!  Instead, they have baleen, which they use to sieve stuff out of the water.  So I don’t think you need to worry about getting bitten by a gray whale. That being said, it’s important not to get close to them, because they are so much bigger than us that they could hurt us on accident.

 

  • When you go out to see the whales, why don’t you use slightly bigger boats so you don’t flip over if the whale gets too close to you, or when you get to close to the whale?
    Our research kayak is a never-ending delight. It’s less expensive than a bigger boat, and doesn’t use fossil fuels. We want to be quiet in the water and not disturb the whale, and actively avoid getting within 100 yards so there shouldn’t be any danger. Sometimes the whales surprise us though, and we have to be careful. In this case, everyone has safety training and is able to rescue themselves if the boat should flip.

(This led to an entertaining discussion of field safety, and the appalling idea that I would make my interns jump out of the kayak into cold Pacific water on purpose during safety training)

There were many more questions, but why don’t you give the program a try, and see what kind of questions you get to answer?!

Safety First! 

Exploring the Coral Sea in Search of Humpbacks

By: Solène Derville, Entropie Lab, Institute of Research for Development, Nouméa, New Caledonia (Ph.D. student under the co-supervision of Dr. Leigh Torres)

Once again the austral winter is ending, and with it ends the field season for the scientific team studying humpback whales in New Caledonia. Through my PhD, I have become as migratory as my study species so this is also the time for me to fly back to Oregon for an intense 3 months of data analysis at the GEMM Lab. But before packing, it is time for a sum-up!

In 2014, the government of New Caledonia has declared all waters of the Economic Exclusive Zone to be part of a giant marine protected area: the Natural Park of the Coral Sea. These waters are seasonally visited by a small and endangered population of humpback whales whose habitat use patterns are poorly known. Indeed, the park spans more than 1.3 million km2 and its most remote and pristine areas therefore remained pretty much unexplored in terms of cetacean presence… until recently.

In 2016, the project WHERE “Humpback Whale Habitat Exploration to improve spatial management in the natural park of the CoRal Sea” was launch by my PhD supervisor, Dr. Garrigue, and I, to conduct surveys in remote reefs, seamounts and shallow banks surrounding New Caledonia mainland. The aim of the project is to increase our understanding of habitat use and movements of humpback whales in breeding grounds over a large spatial scale and predict priority conservation areas for the park.

Fig. 1. A humpback whale with our research vessel, the oceanographic vessel Alis, in the background.

This season, three specific areas were targeted for survey during the MARACAS expeditions (Marine Mammals of the Coral Sea):

– Chesterfield and Bellona reefs that surround two huge 30- to 60m-deep plateaus and are located halfway between New Caledonia and Australia (Fig. 4). Considered as part of the most pristine reefs in the Coral Sea, these areas were actually identified as one of the main hotspots targeted by the 19th century commercial whaling of humpback whales in the South Pacific (Oremus and Garrigue 2014). Last year’s surveys revealed that humpback whales still visit the area, but the abundance of the population and its connection to the neighboring breeding grounds of New Caledonia and Australia is yet to establish.

Fig. 2. The tiny islands along the Chesterfield and Bellona reefs also happen to host nesting sites for several species of boobies and terns. Here, a red-footed booby (Sula sula).

– Walpole Island and Orne bank are part of the shallow areas East of the mainland of New Caledonia (Fig. 4), where several previously tagged whales were found to spend a significant amount of time. This area was explored by our survey team for the first time last year, revealing an unexpected density of humpback whales displaying signs of breeding (male songs, competitive groups) and nursing activity (females with their newborn calf).

Fig. 3. The beautiful cliffs of Walpole Island rising from the Pacific Ocean.

Antigonia seamount, an offshore breeding site located South of the mainland (Fig. 4) and known for its amazingly dense congregations of humpback whales.  The seamount rises from the abyssal seabed to a depth of 60 m, with no surfacing island or reef to shelter either the whales or the scientists from rough seas.

Fig. 4. Map of the New Caledonia Economic Exclusive Zone (EEZ) and the project WHERE study areas (MARACAS expeditions).

During our three cruises, we spent 37 days at-sea while a second team continued monitoring the South Lagoon breeding ground. Working with two teams at the same time, one covering the offshore breeding areas and the other monitoring the coastal long-term study site of the South Lagoon, allowed us to assess large scale movements of humpback whales within the breeding season using photo-ID matches. This piece of information is particularly important to managers, in order to efficiently protect whales both within their breeding spots, and the potential corridors between them.

So how would you study whales over such a large scale?

Well first, find a ship. A LARGE ship. It takes more than 48 hours to reach the Chesterfield reefs. The vessel needs to carry enough gas necessary to survey such an extensive region, plus the space for a dinghy big enough to conduct satellite tagging of whales. All of this could not have been possible without the Amborella, the New Caledonian governement’s vessel, and the Alis, a French oceanographic research vessel.

Second, a team needs to be multidisciplinary. Surveying remote waters is logistically challenging and financially costly, so we had to make it worth our time. This season, we combined 1) photo-identification and biopsy samplings to estimate population connectivity, 2) acoustic monitoring using moored hydrophone (one of which recorded in Antigonia for more than two months, Fig. 5), 3) transect lines to record encounter rates of humpback whales, 4) in situ oceanographic measurements, and finally 5) satellite tracking of whales using the recent SPLASH10 tags (Wildlife Computers) capable of recording dive depths in addition to geographic positions (Fig. 6).

Fig. 5. Claire, Romain and Christophe standing next to our moored hydrophone, ready for immersion.

Satellite tracks and photo-identification have already revealed some interesting results in terms of connectivity within the park and with neighboring wintering grounds.

Preliminary matching of the caudal fluke pictures captured this season and in 2016 with existing catalogues showed that the same individuals may be resighted in different regions of the Park. For instance, some of the individuals photographed in Chesterfield – Bellona, had been observed around New Caledonia mainland in previous years! This match strengthens our hypothesis of a connection between Chesterfield reef complex and New Caledonia.

Yet, because the study of whale behavior is never straightforward, one tagged whale also indicated a potential connection between Chesterfield-Bellona and Australia East coast (Fig. 6). This is the first time a humpback whale is tracked moving between New Caledonia and East Australia within a breeding season. Previous matches of fluke catalogues had shown a few exchanges between these two areas but these comparisons did not include Chesterfield. Is it possible that the Chesterfield-Bellona coral reef complex form a connecting platform between Australia and New Caledonia? The matching of our photos with those captured by our Australian colleagues who collected data at the Great Barrier Reef  in 2016 and 2017 should help answer this question…

Fig. 6. “Splash” was tagged in Chesterfield in August and after spending some time in Bellona it initiated a migration south. Seamounts seem to play an important role for humpback whales in the region, as “Splash” stopped on Kelso and Capel seamount during its trip. It reached the Australian coast a couple of days ago and we are looking forward to discover the rest of its route!

While humpback whales often appear like one of the most well documented cetacean species, it seems that there is yet a lot to discover about them!

Acknowledgements:

These expeditions would not have been possible without the financial and technical support of the French Institute of Research for Development, the New Caledonian government, the French  Ministère de la Transition Ecologique et Solidaire, and the World Wide Fund for Nature. And of course, many thanks to the Alis and Amborella crews, and to our great fieldwork teammates: Jennifer Allen, Claire Bonneville, Hugo Bourgogne, Guillaume Chero, Rémi Dodémont, Claire Garrigue, Nicolas Job, Romain Le Gendre, Marc Oremus, Véronique Pérard, Leena Riekkola, and Mike Williamson.

Fig. 7A. The teams of the three 2017 MARACAS expeditions (Marine Mammals of the Coral Sea).

Fig. 7B. The teams of the three 2017 MARACAS expeditions (Marine Mammals of the Coral Sea).

Fig. 7C. The teams of the three 2017 MARACAS expeditions (Marine Mammals of the Coral Sea).