Sargassum Called a Serious Threat to LA's Coastal Waters. But There's an App For That.

Sargassum horneri was brought to LA's waters in 2003 on shipping vessels. Known as devil's weed, it's causing concern for kelp forests, in particular, because local groups did an intensive effort from '97 to 2015 tor restore kelp habitat.

A new research effort by LA Waterkeeper (based in Santa Monica), NOAA and UCSB is tracking the spread of it (using a phone app!) and examining effectiveness of removal strategies. It's launching from recent "vacuum" efforts reducing sargassum around Catalina by 25%.

Dive Team Heads Underwater to Begin its Investigation of Controlling Invasive Species

LOS ANGELES, November 23, 2016- Today, marine watchdog group Los Angeles Waterkeeper alerts all beachgoers and coastal enthusiasts to look out for its team of volunteer scientific divers in the water. LA Waterkeeper's Dive Team is conducting an investigation into the effectiveness of removing invasive algae to restore habitats along the Palos Verdes coastline.

The investigation specifically studies the non-native algae species Sargassum horneri. In 2003, Sargassum horneri was introduced to Long Beach Harbor in the form of biological pollution from commercial shipping vessels. Commonly called the "devil weed," sargassum originates from Japan and Korea, but it has spread as far south as Baja, Mexico and north to Santa Barbara.

The introduction of non-native species is one of the greatest threats to our coastal marine environments. The US Department of Commerce's National Oceanic and Atmospheric Administration (NOAA), a major funder and partner of LA Waterkeeper's study, has designated kelp forests as a habitat area of particular concern, citing their value to fishery management and susceptibility to degradation by human activity. In fact, kelp forests are among the most productive ecosystems in the world, providing food and shelter for over 700 species.

"Since 1911, 76 percent of the region's kelp forests were lost due to a number of factors, such as pollution and overfishing," says LA Waterkeeper Dive Program Manager Ian Jacobson. "Overfishing along the coast led to the reduction of natural sea urchin predators and competitors for resources, enabling sea urchins to overpopulate and overwhelm our kelp forests."

LA Waterkeeper's dedicated team of volunteer divers worked tirelessly from 1997 to 2015 as part of a collaborative kelp restoration effort, but the kelp forests now face the challenge of invasive species.

In response to this growing threat, LA Waterkeeper has reshaped its dive program to focus on tracking the spread of Sargassum and to test various removal strategies. Added Jacobson, "We need all hands on deck to help us better understand how this invasion is impacting our native coastal ecosystems."

LA Waterkeeper's study, which will run from October 2016 through March 2017, draws on the past success of a joint effort from NOAA and University of California, Santa Barbara that used a vacuum device to reduce Sargassum horneri around Catalina Island by 25 percent in experimental plots relative to un-cleared areas. In addition to funding from NOAA, LA Waterkeeper is also receiving support from the Edgerton Foundation and the Paul M. Angell Family Foundation.

For more information on LA Waterkeeper's Dive Program, visit: https://lawaterkeeper.org/diveprogram.