New Research Studies Spread and Ecology of Invasive Seaweed

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Date: April 28, 2017
Contact: Yvonne Menard, 805-658-5725

University of California, Santa Barbara (UCSB) PhD candidate Lindsay Marks will discuss new research on the spread and ecology of the invasive seaweed Sargassum horneri in southern California.
Marks has worked with Channel Islands National Park and other institutions to monitor and track the significant spread of S. horneri since its first appearance in southern California in 2003. Her research has revealed several life history characteristics of this seaweed that make it particularly adapted to thriving in southern California waters.
Marks and other researchers at UCSB are assessing the distribution of S. horneri both inside and outside the Marine Protected Areas (MPAs) at Anacapa Island. They have found reduced densities of S. horneri inside the historic MPAs where the density of native kelp and other algae is higher.  
Marks will also discuss experiments that she performed off Catalina Island, in which she removed S. horneri in test plots and compared recruitment and survivorship to untreated control plots. Although Marks was able to reduce recruitment and survivorship relative to the untreated plots, overall densities actually increased, likely due to warm water conditions that favored S. horneri. While these results point towards the possible success of control efforts, they also highlight the challenges associated with controlling established populations of invasive algae.
Marks’ work includes important efforts to educate recreational boaters, divers, and beach-goers on how they can help scientists track and possibly prevent the spread of this and other invasive marine species. She has collaborated with the University of California, Santa Cruz (UCSC) to develop a monitoring website to which citizens across California can contribute. This site can be found at:
Marks earned her degree in Marine Biology from UCSC and has studied kelp forest ecology for the past ten years, as both a research diver and graduate student. She is currently a PhD candidate in the department of Ecology, Evolution, and Marine Biology at UCSB. As a Dr. Nancy Foster Scholar, she is supported by NOAA’s Office of National Marine Sanctuaries to monitor the spread of S. horneri in southern California. Her research was funded by UC Sea Grant and the National Marine Fisheries Service.
The talk will be held on Thursday, May 11, 2017. The From Shore to Sea lecture series is sponsored by Channel Islands National Park to further the understanding of current research on the Channel Islands and surrounding marine waters. The 2017 lecture series will take place at 7:00 pm on the second Thursday of each month, January through December, at the Channel Islands National Park Robert J. Lagomarsino Visitor Center, 1901 Spinnaker Drive in Ventura Harbor. The programs are free and open to the public.
This lecture can also be viewed live online, at: Shore to Sea lecture series.

Lectures are recorded and posted at:

Last updated: April 28, 2017

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