Dr. Lisamarie CarrubbaNOAA Fisheries, Caribbean Field

Office, Protected Resources Division

Spread of the Non-Native Seagrass, Halophila stipulacea, in

the Caribbean

Atlantic Cod EFH

Eggs Larvae Juveniles Adults

• Native to western Indian Ocean – Red Sea and Persian Gulf, as well as coastal islands of Eastern Africa and Southeast coast of Indian subcontinent

• In 1800’s began to invade Eastern Mediterranean Sea via Suez Canal

• Reached Malta in 1970, Ionian Sea in 1992, and north coast of Sicily in 1997

• First reported in Caribbean in 2002. Thought to have originally come from pleasure yacht traffic between Mediterranean and Caribbean.

History of Spread

History of Halophila stipulacea in Caribbean1. Observed in Flamingo Bay, Grenada in 2002 (Ruiz and Ballantine 2004)2. Documented in Dominica and St. Lucia in 2009, including competition with

Syringodium filiforme (manatee grass) (Willette and Ambrose 2009)3. Reported from Aruba, Curaçao, Grenadines (Grenada), St. Eustatius, St. John

(USVI), St. Martin (France), and St. Vincent and the Grenadines (Willette et al. 2014)

4. Site of Westin Hotel, Cruz Bay, St. John surveyed in 2005, 2012, and 2013 for dock replacement project – no seagrass in footprint. Site resurveyed in March 2015and approximately 0.4 acre area around dock colonized by Halophila stipulacea.

5. Benthic surveys for projects in Charlotte Amalie and Crown Bay areas, St. Thomas, found it dominates in portions of Long Bay and Crown Bay (2014-2015)

6. Site inspections by NMFS to Flamingo Bay (dominant species) and Honeymoon Bay (patch), Water Island (July 2015)

7. UVI tracking it in Brewers Bay (2010 – not present, now spreading)8. Recently observed in 3 locations around Culebra and associated islands/cays (July 2015)

Characteristics of Halophila stipulacea1. Can tolerate a wide range of salinities2. Can grow in very shallow water as well as depths

greater than 50 m3. Can grow in a range of substrate types4. Speculated survival for extended periods as floating

fragments and in vessel anchor wells5. Rapid vegetative expansion6. Adaptation to high irradiance7. Male and female and have been observed flowering

in Caribbean

Capacity for Spread

• Preliminary experiments off St. John in 2014 showed lateral growth up to > 6 m/day

• Up to 50% increase in biomass in 7 days• Fish and invertebrates preferentially grazed

on native seagrass species• Density up to > 10,000 shoots/m2

Capacity for Spread

Steiner and Willette (2014) observed an increase and replacement of native species over 5 years and extension into reef halos

NOAA CRCP FY16 RFP includes jurisdictional priority from USVI DPNR to “to support the investigation of effects and management of invasive species, such as addressing key gaps for improving the understanding of ecosystem impacts from Halophila stipulacea”

Opportunity

• Partners: UVI, NPS, and Dr. Willette (UCLA)• Education and Outreach:

• updates to UVI webpage for reporting sightings (http://geocas.uvi.edu/citseagrass.php)

• Workshop to discuss potential impact in region (led by Dr. Wyllie-Echeverria who led work on Zostera japonica in Northeast Pacific)

• Questions: • Degree to which Halophila stipulacea provides habitat to marine

organisms (nutritional content, herbivory levels, habitat use)• Whether it co-exists or out-competes native seagrass species • Dispersal predictions based on data on current spread

Collaboration

• CFMC categorizes seagrass as EFH – no species-specific designation

• ESA language about habitat for green sea turtle also discusses broad category of seagrass

• More projects with impacts to Halophila stipulacea affect EFH and ESA consultations and mitigation decisions

Regulatory Context

Questions?

Flamingo Bay, Water Island

Dakity, Culebra Island

M. Padover