Cordylophora lacustris Allman, 1844

C. caspia has relatively broad environmental tolerances. They can survive temperatures ranging from 8 to 30 degrees celsius and salinity as high as 40 ppt (Seyer et al., 2017). Colonies of C. caspia grow on hard substrates such as rock surfaces, shells, wood, and submerged infrastructure (Pucherelli et al., 2016).

This species is considered a benthic predator, capturing prey using nematocysts: their diet includes small crustaceans, worms, insect larvae, watermites and other zooplankton and benthic invertebrates (Pucherelli et al., 2016). Their diet puts them in competition with many species of larval, juvenile, and benthivorous fish (Seyer et al., 2017). They also compete with other benthic species for substrate; however, their filamentous structure may also provide substrate for chironomids, caddisflies and Dreissena spp. veligers (Folino-Rorem, 2015).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental	Socioeconomic

Research in the Great Lakes and Europe indicates that C. caspia has complex relationships with dreissenids. Competition for space (i.e. suitable substrate for colonization) may occur between zebra mussels (Dreissena polymorpha) and C. caspia (Berg and Folino-Rorem, 2009; Walton, 1996). However, these species have been known to colonize one another; juvenile zebra mussels may use C. caspia as a substrate (Moreteau and Khalanski, 1994), while C. caspia may settle on dreissenids (Berg and Folino-Rorem 2009; Darling and Folino-Rorem, 2009). An initial survey completed in Chicago harbors found 55% of quagga mussels to be colonized by C. caspia (Berg and Folino-Rorem, 2009). In addition, zebra and quagga mussel larvae appear to constitute a large portion of C. caspia polyp's diet (Berg and Folino-Rorem, 2009).

Smith et al. (2002) described C. caspia as a benthic colonial predator that preys upon chironomids and other larval insects. Where the hydroid is sufficiently dense, this could locally reduce the preferred prey of certain fishes. Following a study in Chicago harbors, researchers concluded that while the current impact of C. caspia on fish food availability is likely limited, it has the possibility of becoming significant in combination with the growth of D. bugensis populations (Berg and Folino-Rorem, 2009).

There is little or no evidence to support that Cordylophora caspia has significant socio-economic impact in the Great Lakes.

C. caspia clogged intake tunnels and blocked filters and condenser tube sheets at a power plant in Morris, IL; however, these colonies were eradicated by exposing them to temperatures > 37.7 C for > 1 hour (Folino-Rorem and Indelicato 2005).

Cordylophora has had degrading effects on cement and mortar at Brazilian power plants (Portella and Joukoski 2009).

There is little or no evidence to support that Cordylophora caspia has significant beneficial effects in the Great Lakes.

C. caspia has been found to consume settling zebra mussel veligers, but this predation is unlikely to control the well-established Dreissena populations found in the Great Lakes (Berg and Folino-Rorem, 2009).

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

Control
Control of Cordylophora caspia primarily focuses on its potential role as a biofouling agent. Cordylophora spp. has been documented colonizing the inner walls of power plants in Europe and the United States (Folino-Rorem and Indelicato 2005; Nakko and Strayer 2014), primarily causing blockages in nozzles and tailpipes of rapid gravity filter beds (RGFs) (Mant et al. 2012).  The menont life-stage of Cordylophora caspia often found in hydroelectric intakes, is both drought and temperature resistant which may prove an obstacle to control (Gutierre 2012).  

Physical

Thermal treatments of >37°C have been proven effective in eradicating colonies of Cordylophora spp. sampled from the walls of power plant intakes (Folino-Rorem and Indelicato 2005), but are not efficient in water treatment facilities where there is no residual heat energy available (Mant et al. 2012). Desiccation may result in the formation of dormant resting stages. Physical removal often fails to remove sub-surface hydrorhizae from which colonies can rapidly recover. Displaced fragments can also reattach and create new colonies (Koetsier and Bryan 1995).

Chemical
Gutierre (2012) found that Cordylophora caspia is completely eradicated at pH levels of below 4.0 or above 10.0, with increasing survival rates in between, and suggested maintaining pH levels at 10.0 for 6 hours or more by injection of NaOH to reduce and eliminate colonies. Furthermore, chlorine use is highly regulated at water treatment facilities where Cordylophora most frequently causes problems on intake screens and in coolant pipes. Chlorine treatments negatively affect Cordylophora growth, but treatments as high as 5 mg/L for periods of 105 minutes have been unsuccessful in completely eradicating colonies (Rajagopal et al. 2002, Folino-Rorem and Indelicato 2005, Mant et al. 2012).

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

Cordylophora caspia is preyed upon by an introduced nudibranch (Tenellia adspersa) (Mills and Sommer 1995).

Cordylophora caspia is thought to be taxonomically synonymous with C. lacustris by many scientific researchers (Folino 2000 and references).