Editing Squalius cephalus (section)

== Threats ==

Recent work has shown that chub ingest microplastic particles. Whereas many as 25% of sampled fish contained particles, these particles were not found in muscles.<ref>{{Cite journal|last1=Collard|first1=France|last2=Gasperi|first2=Johnny|last3=Gilbert|first3=Bernard|last4=Eppe|first4=Gauthier|last5=Azimi|first5=Sam|last6=Rocher|first6=Vincent|last7=Tassin|first7=Bruno|date=2018-12-01|title=Anthropogenic particles in the stomach contents and liver of the freshwater fish Squalius cephalus|journal=Science of the Total Environment|volume=643|pages=1257–1264|doi=10.1016/j.scitotenv.2018.06.313|pmid=30189542|issn=0048-9697|bibcode=2018ScTEn.643.1257C|s2cid=52171531 |url=https://hal-enpc.archives-ouvertes.fr/hal-01830268/file/Collard%2C%20APs%20in%20stomach%20contents%20and%20liver%20of%20a%20freshwater%20fish%2C%20last%20version.pdf |archive-url=https://web.archive.org/web/20200306222345/https://hal-enpc.archives-ouvertes.fr/hal-01830268/file/Collard%2C%20APs%20in%20stomach%20contents%20and%20liver%20of%20a%20freshwater%20fish%2C%20last%20version.pdf |archive-date=2020-03-06 |url-status=live}}</ref> Many of the particles found were fibres that are released from clothes during washing, these are also ingested by macroinvertebrates such as ''Daphnia''<ref>{{Cite journal|last1=Jemec|first1=Anita|last2=Horvat|first2=Petra|last3=Kunej|first3=Urban|last4=Bele|first4=Marjan|last5=Kržan|first5=Andrej|date=2016-12-01|title=Uptake and effects of microplastic textile fibers on freshwater crustacean Daphnia magna|journal=Environmental Pollution|volume=219|pages=201–209|doi=10.1016/j.envpol.2016.10.037|pmid=27814536|issn=0269-7491}}</ref>''.'' Chub can also be contaminated by metal pollution such as copper, magnesium and sodium which can accumulate in tissues like the muscle, gills and liver.<ref name=":1">{{Cite journal|last1=Nyeste|first1=Krisztián|last2=Dobrocsi|first2=Patrik|last3=Czeglédi|first3=István|last4=Czédli|first4=Herta|last5=Harangi|first5=Sándor|last6=Baranyai|first6=Edina|last7=Simon|first7=Edina|last8=Nagy|first8=Sándor Alex|last9=Antal|first9=László|date=2019-06-01|title=Age and diet-specific trace element accumulation patterns in different tissues of chub (Squalius cephalus): Juveniles are useful bioindicators of recent pollution|journal=Ecological Indicators|volume=101|pages=1–10|doi=10.1016/j.ecolind.2019.01.001|s2cid=92413883 |issn=1470-160X|url=http://real.mtak.hu/102756/2/Nyeste_etal_Czegledi_EcolInd_ms.pdf |archive-url=https://web.archive.org/web/20200305123837/http://real.mtak.hu/102756/2/Nyeste_etal_Czegledi_EcolInd_ms.pdf |archive-date=2020-03-05 |url-status=live}}</ref> Young of the year fish contained particularly high levels of metal contaminants.<ref name=":1" />