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Unique Research Opportunity

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    Jesse Purdy, Morgan Mingle and Stephanie Henderson in Southwestern's aquatic animal research lab. (photo by Carlos Barron)
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    Jesse Purdy doing research with mulloway at the National Marine Science Centre in Australia.
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    The research Purdy and Mingle did focused on whether hatchery-raised mulloway could learn to respond to predators such as pelicans.
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    Jesse Purdy works with a dolphin at the Pet Porpoise Pool in Coffs Harbour, Australia.
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    Morgan Mingle took this photo of a dolphin at the Pet Porpoise Pool.

Southwestern student, professor conduct research in Australia

It’s not uncommon for Southwestern students to conduct research with their professors. But few get the opportunity Morgan Mingle did.

Mingle, a junior animal behavior major, spent three months last summer doing research in Australia with Jesse Purdy, a psychology professor who specializes in aquatic animal behavior.

Mingle spent three months working with Purdy on a project at the National Marine Science Centre, which is located in Coffs Harbour, on the east coast of Australia, four hundred miles north of Sydney. The centre is affiliated with Southern Cross University.

Purdy and Mingle worked with mulloway (Argysomus hololepidotus), a fish species with high commercial potential because it reproduces easily and adapts well in captivity, grows up to 2 meters, and can weigh more than 200 lbs. Mulloway are also highly prized in the sports fisheries industry. One of the questions concerning fish farmers is the ability of a hatchery-raised mulloway to recognize and avoid predators. The main concern is for those mulloway that are released back into the ocean.

“If those fish are ill-prepared for a world full of predators, a release may simply be a way of feeding the other animals in the sea,” Purdy said.

Purdy and Mingle determined whether hatchery-raised mulloway could learn about different predators, whether an attack was imminent, and if their response was appropriate to the predator. In addition, they planned to compare their anti-predatory behaviors with those of wild caught mulloway.

The mulloway project stemmed from work in Purdy’s aquatic animal research lab with mummichogs, a small baitfish found along the Gulf coast. Wild caught mummichogs received trials in which a neutral stimulus was paired with a simulated attack from either an avian or marine predator. Mummichogs responded to a stimulus predicting an attack by an avian predator by descending in the water column, but responded to a stimulus predicting a marine predator by schooling more tightly. Both conditioned responses were appropriate to the anticipated predator and would have increased their chances of survival. Mingle, who started working in Purdy’s aquatic animal lab in her first year, was instrumental in collecting and analyzing the data.

Preparations for the work in Australia began during Purdy’s sabbatical last fall and spring. In addition to preparing an application to Southern Cross University’s visiting research scientist program, Purdy had to get together nearly 500 pounds of scientific equipment that would be required to conduct the proposed research. This was no easy task given the differences between the United States and Australia in terms of electrical power. In March 2009, Purdy received word that his proposal with Southern Cross Psychology Professors Anna Brooks and Rick Van der Zwan was the only one funded for the 2008-2009 academic year.

Once he arrived in Coffs Harbour and started working with mulloway, Purdy said it was easy to see why they have been depleted by overfishing.

“They are very easy to catch,” he said. “A mulloway’s conditioned response to any predator appears to be simply to swim to the bottom, in as tight a group as possible, and freeze. A trawler with a net can easily pick them up by the thousands.”

Purdy and Mingle were not able to complete their research before they had to return home, but a student at Southern Cross University completed the second experiment for them. The second study tested whether their predator avoidance strategy changed during the night. Interestingly, preliminary data analyses appears to show that mulloway were more active at night and that their anti-predatory behavior may differ from their daytime responses.

“If these preliminary data hold up, this might be an important finding,” Purdy said.

Mingle also spent the last month of the summer doing a research project on her own at the Pet Porpoise Pool, which is a marine animal park in Coffs Harbour.

Because one of the dolphins at the facility was pregnant, Mingle helped develop a study that would examine how vocalizations in a group of dolphins change before and after a baby is born. She hopes the study will help researchers learn more about how dolphins learn to vocalize.

“Dolphins, seals, whales, songbirds and humans are the only animals that show clear vocal learning,” she explained.

Mingle used a hydrophone (an underwater microphone) and digital audio recorder to collect sounds the dolphins produce in various situations, such as when they are playing and eating. She brought back more than 30 hours of recordings that she is analyzing this fall.

Mingle received a Mundy Collaborative Research Grant from Southwestern to fund her trip to Australia, and lived with a family while she was there. “It was a great experience,” she said. “I got to meet a lot of people and make some good connections.”

Mingle is trying to find funding to return to Australia over winter break, when the baby dolphin will have been born. Stephanie Henderson, who has been working with Purdy and Mingle in the aquatic animal research lab, hopes to accompany Mingle on this trip.

Mingle said she enjoyed the dolphin research so much that she wants to continue her research on dolphins after she graduates from Southwestern and is trying to find a graduate school with a strong program in dolphin research.

Purdy said the contacts he made on the trip to Australia should allow him to set up future research opportunities for Southestern students who want to work with marine mammals.