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:
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):
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.
My name is Rachael Orben and I am a postdoctoral scholar affiliated with both the Seabird Oceanography Lab and the GEMM Lab here at Hatfield Marine Science Center. I am writing this from Anchorage, Alaska where Abram (a Master’s student at San Jose State University) and I are just finishing gear gathering and shopping before flying on to St George Island to spend the end of May and June observing, tracking, and sampling red-legged kittiwakes.
This video is taken looking down to the beach from the top of High Bluffs, St George Island. Turn up the volume!
Just a little bit of background
Red-legged kittiwakes are endemic to the Bering Sea and most of their population nests on the cliffs on St George Island. St George is one of the Pribilof Islands located in the southeastern Bering Sea and is home to over a million nesting seabirds including auklets, cormorants, kittiwakes, murres, and puffins. The Pribilofs are also known for the large rookeries of Northern Fur Seals (http://www.afsc.noaa.gov/nmml/education/pinnipeds/northfs.php). St. George has a small Aleut community (http://www.apiai.org/tribes/st-george/) so we will be living in town and commuting by ATV and foot to the bird cliffs.
Click on the link below – Can you spot the red-legged kittiwake?
Photo credits: Caitlin Kroeger
We would like to know how individual foraging behaviour and physiology influence reproductive success and then how these might carry over to wintering behaviour.
Tracking: We will be using GPS dataloggers (10g) and geolocation/wet-dry dataloggers (1g) to track movements and foraging behaviour of red-legged kittiwakes during incubation and overwinter.
Physiology: When we catch birds we will take physiological samples to measure individual stress levels, mercury loads, and body condition that we can link to foraging behaviour.
Observations: We will observe the birds that we track so that we know when eggs are laid, chicks hatch and fledge so that foraging and physiology can be connected to these measures of breeding success. And next year we will return and resight these birds to measure survival.
This study is funded by the North Pacific Research Board (http://www.nprb.org/) with additional support from OceanClassrooms (http://oceanclassrooms.com/) for pre-breeding tracking. I also have been writing short blogs about project with the Seabird Youth Network aimed for middle schoolers that you can check out here: (http://seabirdyouth.org/category/kittiwake-behavior/)
Internet access will be intermittent on St George, but I hope to periodically post updates via Twitter @RachaelOrben (#OCGrants), Instagram @raorben, and the Seabird Youth Network Blog.
