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Marine Researchers Studying Changes in Fish Life

Published: November 17, 2008

Bolsa Wetlands

Photo by David J. Nelson
Professor Chris Lowe (l) working with students at Bolsa Chica.

The new ocean inlet to Orange County’s Bolsa Chica wetlands that opened in 2006 now provides an opportunity for predators to enter the estuary, so a team of CSULB marine biology researchers have begun a study of the effects of these animals on marine life in the wetlands.

Biological Sciences’ Chris Lowe and graduate students Thomas Farrugia and Mario Espinoza are looking at shovelnose guitarfish, a species of ray, and gray smoothhounds, small sharks also known as sand sharks. Their research is supported by a grant from the USC Sea Grant program, administered by the National Oceanic and Atmospheric Administration.

Espinoza is from Costa Rica and is studying at CSULB with a Fulbright international education scholarship from the U.S. Department of State. He is focusing on the area’s smoothhound sharks, which typically only reach three to four feet in length and eat worms and crustaceans. Farrugia earned his bachelor of science at McGill University in Montreal, Canada, and is studying shovelnose guitarfish.

“This is only the second year since they opened the inlet by Huntington Beach so that open ocean water can now get into that estuary,” Lowe said. “The question is, how has this open inlet changed the marine organisms that live in there now that predators have open access to it?”

The shovelnoses and smoothhounds “are two coastal elasmobranches that we know use estuaries, based on work down in Baja and other locations throughout Southern California,” Lowe explained. “It’s thought that those species go into estuaries, probably for reproduction, to mate and pup. In Southern California, we’ve lost over 90 percent of our wetland habitat, so the reopening of the Bolsa Chica estuary could be really important in terms of understanding the impacts that all that habitat loss has had on these coastal shark and ray species.

“We’re sampling throughout all of Bolsa Chica in the full tidal basin that’s closer to Huntington Beach. That project will run probably for two years. We’ll be tagging and tracking and doing beach seines to determine abundance—how many animals are in there throughout the year, what species are there, how much they move, do they stay there all summer long or do they commute periodically?”

The seines are large nets in which animals are caught and counted before being released. A number of animals also will be fitted with small acoustic tags which will enable the researchers to track their movements.

“I did my bachelor’s degree in biology at the University of Costa Rica,” Espinoza said. “As soon as I was done, I started looking for scholarship opportunities in a marine field outside my country,” which he said lacks a strong marine science graduate program with an emphasis on elasmobranch studies.

Espinoza, who wants to become a university marine biology professor, said, “My motivation to follow a marine science career and to dedicate my life to the understanding of the ecology and behavior of sharks and rays encouraged me to apply for different research opportunities that would strengthen my experience and knowledge before starting graduate school.”

After interning at the Center for Shark Research in Florida’s Mote Marine Laboratory, he learned about the CSULB marine biology program and applied for a Fulbright scholarship to study with Lowe.

“His contribution to our understanding of the coastal environment and interactions of California local fisheries has been absolutely impressive,” said Espinoza. “He is now advising me through my graduate program to investigate the seasonal residency, habitat use and foraging behavior of the gray smoothhound shark in a Southern California restoration project located in Bolsa Chica.”

The loss of Southern California wetlands “is particularly critical considering that connectivity of estuarine fish may be threatened due to the extensive habitat loss and degradation of natural systems,” Espinoza said. “Restoration of estuarine habitats is emerging as a popular mitigation approach and has been successfully implemented in several coastal areas to offset the loss of fish habitat.”

Understanding the animals’ movement over space and time is vital to understanding the biology and life history of a species and “makes it possible to assess the importance of coastal restoration projects as a viable ecological approach that will increase habitat for other coastal economic species.” This research can provide useful recommendations to marine ecosystem managers in understanding and designing protected areas along the coast.

Farrugia has similar interests. “I was accepted at several master’s and Ph.D. programs, but after meeting with Dr. Lowe and seeing the research he was involved in, I decided to do my master’s with him. It also helped that CSULB is renowned for its marine biology program,” he said.

“I’m studying shovelnose guitarfish inside the Bolsa Chica estuary. I want to understand the timing of their arrival into Bolsa Chica—they use estuaries primarily during the summer—and what factors influence their movements into and within estuaries. Through this research, I hope to understand more about the behavior and physiology of shovelnose guitarfish, which are a source of wonder in California and a source of food in Mexico.”

Farrugia said that his career goals include working in marine natural resources conservation and management through scientific biological research. “Particularly, I am interested in studying the behavior of large marine animals (fish and marine mammals) as a tool to help in marine conservation.”

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