Enteromorpha compressa var. prolifera, Enteromorpha compressa var. trichodes, Enteromorpha polyclados, Enteromopha prolifera, Enteromorpha salina, Enteromorpha salina var. polyclados, Ulva compressa var. prolifera, Ulva enteromorpha f. prolifera

Ulva prolifera exhibits different reproductive strategies. Some plants are sexual and produce biflagellate anisogametes and quadriflagellate meiospores, while others are asexual and can either produce biflagellate or quadriflagellate negatively phototactic zooids. Plants of different sexuality may not be morphologically distinct, and some populations comprise plants of mixed life histories. Zygotes can remain dormant for a year or more in female filaments of sexual plants. Different populations of U. prolifera frequently exhibit high genetic diversity because plants can reproduce sexually, are highly fecund, are perennials (allowing for the accumulation of diverse traits), and undergo a colonization process involving highly diverse propagules on which various selective forces act (Hirakoka et al. 2003, Huh et al. 2004).

Ulva prolifera is known to host gammarid amphipod species in a brackish lake in Japan (Yamaguchi et al. 2006). In European coastal waters, it is preferred over its congener U. intestinalis as a surface for benthic diatom colonization because it is monosiphonous and not broad or flattened (Holt 1980b).

There is little or no evidence to support that Ulva prolifera has significant environmental impacts in the Great Lakes.
Realized:
While blooms of U. prolifera have had significant negative environmental and socio-economic impacts in Asia (Xu et al. 2012), these impacts have not been realized in the Great Lakes. Moreover, the persistence of a population in the Great Lakes region is still uncertain.

Potential:
Negative effects have not been realized in the Great Lakes because of the small and uncertain nature of the U. prolifera population (Mills et al. 1993).

However, in recent years, large blooms (over 1 million tons) of U. prolifera on the coastline of Asia have lead to declines in seagrass beds due to shading, disruption of feeding by wading birds, and an overall loss of algal biodiversity (Xu et al. 2012). In those “green tides,” Ulva prolifera released allelochemicals that inhibited growth and photosynthesis in native competitors (Xu et al. 2012). The massive blooms covered large extents of the sea bottom (13,000-30,000 km²) and decoupled biogeochemical cycles between the sediments and the water column. These chemical changes exposed native flora and fauna to oxygen deficiency and anoxia (Xu et al. 2012).

Ulva prolifera mats that formed on intertidal sandflats in Scotland were also found to significantly decrease the macrofaunal diversity. These negative impacts were particularly on species that use planktonic larval recruitment (Bloam et al. 2000). In intertidal flats of the Wadden Sea, dense mats of U. prolifera and other Ulva spp. have been associated with fewer occurrences of brown and red algae (Schories et al. 1997).

Domestically, U. prolifera, among other species, has been responsible for green tides in waters off the coast of Washington (Waaland and Hayden 1998).

There is little or no evidence to support that Ulva prolifera has significant socio-economic impacts in the Great Lakes.
Potential:
China has been experiencing an increase in U. prolifera-dominated green tides since 2007, with a notable event just prior to the 2008 Beijing Olympics. There were significant impacts on the tourism industry as well as on aquaculture. The cost for emergency mitigation action in China during the 2008 bloom was estimated to cost around 200 million Euro. According to Nai-hao et al. (2011) green tides are responsible for aquaculture losses of approximately 86 million Euro annually.

In Spanish waters, U. prolifera is one of the species responsible for fouling intertidal oyster culture systems, although this problem can be partly controlled by snail grazing (Cigarria et al. 1998).

There is little or no evidence to support that Ulva prolifera has significant beneficial effects in the Great Lakes.
Potential:
Zhuang et al. (2012) proposed the use of U. prolifera as green feedstock, biofuel substitute, and chemical production. Ulva prolifera is edible and is considered an economically viable food option in Japan and China (Dan et al. 2002).

Regulations (pertaining to the Great Lakes region)
There are no known regulations for this species.

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control
Biological
There are no known biological control methods for this species.

Physical
Ulva prolifera can be physically harvested from the water and beaches. However, depending on the size of the bloom this may not be an economically viable option (Nai-hoa et al. 2011).

Chemical
Ulva prolifera blooms occur in eutrophic marine waters. As a result, the reduction of pollution and nutrient run-off could decrease the viable habitat for U. prolifera.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.