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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: a water flea

Taxonomy: available through www.itis.gov

Identification: Daphnia curvirostris is a species of freshwater Cladocera (small planktonic crustacean). Daphnias are characterized by rounded heads and bodies enclosed by a carapace (an uncalcified shell), a large compound eye, and phylopods (flattened leaf-like legs) that move water through a filtering apparatus (Ebert 2005).
Daphnia curvirostris possesses a long postabdominal (lower belly) claw with pronounced pectens (groups of teeth; proximal pecten has 8–10 short, thin teeth, the second pecten has 10–14 large teeth (Ishida et al. 2006). Its ephippia (eggs case) can be identified by the presence of short spines along the dorsal (top) margin and the ephippia being as wide as it is long, whereas the ephippia dorsal margin of the similar species Daphnia galeata mendotae is smooth and the ephippia tapers toward the tail spine (Duffy et al. 2000).
A more detailed diagnostic morphological characterization can be found in Nandini et al. (2009) and Ishida et al. (2006).

Size: Adult body length ranges from 1 mm to 5 mm (Ebert 2005).

Native Range: Temperate Eurasia in Spain, Italy, Czech Republic, Romania, Germany, Sweden, southern Norway, British Isles and Corfu, Turkey, and Russia from the St. Petersburg to the far east (Ishida et al. 2006).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Daphnias are found in waterbodies ranging from large freshwater lakes and rivers, saline lakes, wetlands, and vernal pools (Ebert 2005, Nandini et al. 2009). They are filter feeders and consume suspended particles in the water column, such as bacteria and planktonic algae (Ebert 2005). Food particles are captured in a current produced by phyopods (leaf-like legs) and then transferred by specialized setae into the mouth groove (Ebert 2005). Their common name waterflea originates from the jump-like movement they make while swimming (Ebert 2005). A characteristic behavior of Daphnias is vertical migration, a strategy where they hide from predators in the depths during the daylight and then migrate towards the surface to feed during nighttime (Ebert 2005).
Daphnias usually reproduce sexually and asexually.  Asexual reproduction occurs through parthenogenetic (amictic) eggs produced by mature females that are transferred to an internal brood chamber where they hatch before being released by the mother (Ebert 2005). Juveniles go through a series of instars (molts) before they can produce primipara (eggs), and thereafter eggs are produced after each adult molt (Ebert 2005). In sexual reproduction, diploid resting eggs are produced and encapsulated in an ephippium (protective structure) that generally contains two eggs and is cast off after a molt (Ebert 2005). Ephippia can remain dormant for years until environmental conditions are favorable (Duffy et al. 2000).
The average lifespan of Daphnia curvirostris is roughly 13-18 days and the generation time ranges from 11-17 days (Nandini et al. 2009). Nandini et al. (2009) found that, in captivity, females produce anywhere from 4-10 offspring.

Means of Introduction: Daphnia curvirostris was likely introduced by chemical industry activities occurring on the lakeshores of Onondaga Lake in New York and first occurred in sediment ephippial data in 1952 (Duffy et al. 2000). It is thought that increased pollution from industry and the subsequent reduction in fish predation pressure is what allowed this population to thrive (Duffy et al. 2000).

Status: Failed. Extirpated in Onondaga Lake in New York likely due to reduction in pollution levels and return of predatory fishes (Duffy et al. 2000). It disappeared from sediment ephippial records after 1983 (Duffy et al. 2000).

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

References: (click for full references)

Duffy, M.A., L.J. Perry, and C.M. Kearns. 2000. Paleogenetic evidence for a past invasion of Onondaga Lake, New York, by exotic Daphnia curvirostris using mtDNA from dormant eggs. Limnology and Oceanography 45(6):1409-1414. https://doi.org/10.4319/lo.2000.45.6.1409

Ebert D. 2005. Ecology, Epidemiology, and Evolution of Parasitism in Daphnia, Chapter 2, Introduction to Daphnia Biology. Bethesda, Maryland.

Ishida, S., A.A. Kotov, and D J. Taylor. 2006. A new divergent lineage of Daphnia (Cladocera: Anomopoda) and its morphological and genetical differentiation from Daphnia curvirostris Eylmann, 1887. Zoological Journal of the Linnean Society 146(3):385-405

Nandini, S., M. Silva-Briano, G.G. García, S.S.S. Sarma, A. Adabache-Ortiz, and R.G. de la Rosa. 2009. First record of the temperate species Daphnia curvirostris Eylmann, 1887 emend. Johnson, 1952 (Cladocera: Daphniidae) in Mexico and its demographic characteristics in relation to algal food density. Limnology 10: 87-94.
 

Author: Reaver, K.M.

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.