water-flea, water flea

Like other Daphnia, D. lumholtzi produces ephippia (resting eggs). All ephippia are resistant to adverse environmental conditions and can lay dormant in sediment for long periods of time delaying hatching until optimal conditions are present. The ephippia of D. lumholtzi have hairs and spines that could grip boats or other objects and thus aid dispersal (Dzialowski et al. 2000).

Dzialowski et al. (2000) found that non-human dispersal mechanisms had little to do with the spread of D. lumholtzi in Kansas. D. lumholtzi was not detected in small ponds inaccessible to boats, even though the ponds were within watersheds where D. lumholtzi was established (Dzialowski et al. 2000). Because of rapid and widespread introductions, D. lumholtzi may become a dominant zooplankter in the southern U.S. (Havel et al. 1995).

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

Environmental	Beneficial

Realized:
Daphnia lumholtzi has been known to invade ecosystems rapidly (Havel and Medley 2006); as a result, much research exists on this daphnid’s invasion success (e.g., Acharya et al. 2006, Frisch and Weider 2010, Lennon et al. 2003). However, studies of its impacts are limited, especially in the Great Lakes.

In situ research comparing native Daphnia spp. to the exotic D. lumholtzi has found that competition between these species is lower than expected. Daphnia lumholtzi is a tropical species and is adapted to warmer temperatures than native North American Daphnia. Thus, D. lumholtzi population sizes tend to increase in late summer when native Daphnia populations have been historically low. As a result, D. lumholtzi may be filling a vacant "temporal niche" in the warmer summer months (Dzialowski et al. 2000, East et al. 1999, Goulden et al. 1995, Johnson and Havel 2001, Work and Gophen 1999).

Potential:
In competitive experiments between D. lumholtzi and Great Lakes native D. pulex, Dobberfuhl and Elser (2002) found that in tanks with mixed populations, D. lumholtzi productivity dropped to 55% of its control value, while D. pulex productivity dropped to just 17% of its control value. Combined productivity of the daphnids dropped by over 50%, indicating that the presence of D. lumholtzi could facilitate competitive exploitation and have adverse impacts on overall productivity of the zooplankton community. In this regard, research by Dzialowski (2010) suggests that some Daphnia species are more vulnerable to competition with D. lumholtzi (e.g., D. parvula and Ceriodaphnia dubia were more affected than D. magna).

By occupying a niche that was previously unexploited by Daphnia spp., D. lumholtzi has been hypothesized to compete with non-daphnid zooplankton (Dzialowski et al. 2000). One such zooplankter is Diaphanasoma, whose population size was significantly lower in Kansas reservoirs following D. lumholtzi invasion (Dzialowski et al. 2000).

If D. lumholtzi outcompetes native zooplankton populations during their normal peak abundance in late summer, this may adversely impact planktivorous fish relying on that critical food source but unable to tolerate D. lumholtzi’s spines. Larval and juvenile stages of fish are more likely to be unable to consume D. lumholtzi due to gape (mouth-size) limitation (Kolar and Wahl 1998).

Soeken-Gittinger et al. (2009) found that the density of D. lumholtzi in some parts of the Illinois River was larger than the density of all other native zooplankton combined. High densities appeared to be correlated with high temperatures and increased inorganic sediment suspension, suggesting that areas in the Great Lakes with these conditions could face the greatest impacts (Soeken-Gittinger et al. 2009).

There is little or no evidence to support that Daphnia lumholtzi has significant socio-economic impacts in the Great Lakes.

Current research on the beneficial effect of Daphnia lumholtzi in the Great Lakes is inadequate to support proper assessment.

Potential:
When juvenile fish attain a size capable of consuming D. lumholtzi, the fish can grow more rapidly and more easily avoid predation. This is particularly advantageous during the summer months, when D. lumholtzi presents itself as a larger prey item than would otherwise occur in the zooplankton. Silverside (Menidia beryllina) may be able to use this new prey item and survive longer during their late summer spawning period (Leinesch and Gophen 2001). The findings of Lemke et al. (2003) support this prediction, observing an increased consumption of D. lumholtzi in four fish species of Lake Chautauqua, Illinois (blue gill Lepomis macrochirus, white bass Morone chrysops, white crappie Pomoxis annularis, and black crappie Pomoxis nigromaculatus), as fish size increased.

This species is a common research subject, as scientists have been able to track its spread since establishment and to evaluate factors of its invasion success (Havel and Herbert 1993, Havel and Medley 2006, Havel et al. 2005, Work and Gophen 1999). Daphnia lumholtzi has also been studied for its unique ability to proliferate during high cyanobacterial growth, a time when few other daphnids are present (Pattinson et al. 2003, Semyalo et al. 2009).

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

Control
Biological
Daphnia lumholtzi is preyed upon by a variety of zooplanktivorous fishes, including inland silversides, Menidia beryllina, in Lake Texoma, OK-TX, and bluegill (Lepomis macrochirus), white bass (Morone chrysops), white crappie (Pomoxis annularis), and black crappie (Pomoxis nigromaculatus) in Lake Chautauqua, IL (Lienesch and Gophen 2001, Lemke et al. 2003).  The degree to which these fishes may be able to control Daphnia lumholtzi populations is not certain. 

Physical
D. lumholtzi is likely transferred through anthropogenic vectors, including on recreational boats (Frisch et al. 2013). Its resting eggs (ephippia) feature a long point and hairs on the margin that serve as hooks, possibly aiding in attachment to boats or macrophytes caught on boats (Dzialowski et al. 2000). Therefore, the same precautions recommended to prevent the spread of more commonly known waterfleas should be taken to help prevent D. lumholtzi distribution, namely cleaning all aquatic/fishing/boating equipment, including downrigger lines and monofilament on reels, using high pressure (>250 psi) or hot (>50°C) water after each use (Ontario’s Invading Species Awareness Program).
While D. lumholtzi is not listed as a target species by the U.S. Army Corps of Engineers Great Lakes and Mississippi River Interbasin Study (USACE GLMRIS), the methods suggested to control spiny and fishhook waterfleas in aquatic pathways would likely control D. lumholtzi as well. Electron beam irradiation has been used to control microorganisms in aquatic pathways by exposing water to low doses of radiation using gamma-sterilizers or electron accelerators, breaking down DNA in living organisms while leaving behind no by-products (GLMRIS 2012). Ultraviolet (UV) light can also effectively control microorganisms, in water treatment facilities and narrow channels, where UV filters can be used to emit UV light into passing water, penetrating cell walls and rearranging DNA of microorganisms (GLMRIS 2012).

Chemical
There are no known chemical control methods for this species

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