Editing Daphnia (section)

==Invasive species==
[[File:Cercopagidae GLERL 1.jpg|thumb|[[Fishhook waterflea]] (above) and ''[[Bythotrephes longimanus]]'' (spiny water flea) (below)]]

Some species have developed permanent defenses against fish eating them, such as spines and long hooks on the body, which also cause them to become entangled on fishing lines and cloud water with their high numbers. Species such as ''[[Daphnia lumholtzi]]''<ref>USGS: ''[https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=164 Nonindigenous Aquatic Species: Daphnia lumholtzi]''</ref><ref>Center for Freshwater Biology - University of New Hampshire: ''[http://cfb.unh.edu/cfbkey/html/Organisms/CCladocera/FDaphnidae/GDaphnia/Daphnia_lumholtzi/daphnialumholtzi.html Daphnia lumholtzi]''</ref><ref>ISSG: Global Invasive Species Database: ''[http://www.issg.org/database/species/ecology.asp?si=998 Daphnia lumholtzi (crustacean)] {{Webarchive|url=https://web.archive.org/web/20160304195733/http://www.issg.org/database/species/ecology.asp?si=998 |date=2016-03-04 }}''</ref><ref>James A. Stoeckel, Illinois Natural History Survey: ''[http://www.iisgcp.org/catalog/downlds_09/daph.pdf Daphnia lumholtzi: The Next Great Lakes Exotic?] {{Webarchive|url=https://web.archive.org/web/20161220225152/http://www.iisgcp.org/catalog/downlds_09/daph.pdf |date=2016-12-20 }}''</ref> (native to east Africa, the Asian subcontinent of India, and east Australia) have these characteristics and great care should be taken to prevent them from spreading further in North American waters.

Some species of ''Daphnia'' native to North America can develop sharp spines at the end of their bodies and helmet-like structures on their heads when they detect predators,<ref>Elizabeth A. Colburn (2004), ''Vernal Pools: Natural History and Conservation'', page 118 of paperback second edition from 2008</ref><ref>Patrick Lavens and Patrick Sorgeloos, ''Manual on the Production and Use of Live Food for Aquaculture: [http://www.fao.org/docrep/003/w3732e/w3732e0x.htm#6.1.%20Daphnia%20and%20Moina Daphnia and Moina]''</ref> but this is overall temporary for such species and they do not completely overwhelm or discourage native predators from eating them. While ''Daphnia'' spp. are an important base of the food chain in freshwater lakes (and vernal pools), they become a nuisance when they are unable to be eaten by native macroscopic predators, and some concern exists that the original spineless and hookless water fleas and spp. end up outcompeted by the invasive ones. (This may not be the case, however, and the new invaders may mostly be a tangling and clogging nuisance.)

In the water bodies of the world, at least 15 species of ''Daphnia'' and hybrids are non-native species, many of which pose a great threat to aquatic ecosystems.<ref>{{Cite journal |last1=Kotov |first1=Alexey A. |last2=Karabanov |first2=Dmitry P. |last3=Van Damme |first3=Kay |date=2022-09-09 |title=Non-Indigenous Cladocera (Crustacea: Branchiopoda): From a Few Notorious Cases to a Potential Global Faunal Mixing in Aquatic Ecosystems |journal=Water|volume=14 |issue=18 |pages=2806 |doi=10.3390/w14182806 |issn=2073-4441 |doi-access=free}}</ref>

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