Editing Mummichog (section)

==Physiology==
This fish is well known for its ability to withstand a variety of environmental conditions.<ref>{{cite journal | last1 = Burnett | first1 = K.G. | last2 = Bain | first2 = L.J. | last3 = Baldwin | first3 = D.S. | display-authors = etal   | year = 2007 | title = ''Fundulus'' as the premier teleost model in environmental biology: Opportunities for new insights using genomics | journal = Comparative Biochemistry and Physiology D | volume = 2 | issue = 4| pages = 257–266 | doi=10.1016/j.cbd.2007.09.001| pmid = 18071578 | pmc = 2128618 }}</ref> They can survive temperatures between {{convert|6|and(-)|35|C|F}}; even within the same [[tidal cycle]] they can tolerate rapid temperature changes from {{convert|15|to(-)|30|C|F}}.<ref name="Abraham">Abraham, B.J. 1985. Species Profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic)--mummichog and striped killifish. U.S. Fish and Wildlife Service Biological Reports 82 (11.40): 23 p. http://www.nwrc.usgs.gov/wdb/pub/species_profiles/82_11-040.pdf</ref> They are able to survive this vast temperature range by altering their metabolic rates at high and low temperatures. This is partly achieved by varying the isoenzyme of the lactate dehydrogenase ([[Lactate dehydrogenase b|Ldh-B]]) enzyme expressed in warm or cold waters. These two versions of the enzyme allow for faster catalytic function and metabolism depending on if the fish is in northern, colder waters or southern, warmer waters.<ref>{{Cite journal|last1=Mitton|first1=Jeffry B|last2=Koehn|first2=Richard K|title=Genetic Organization and Adaptive Response of Allozymes to Ecological Variables in Fundulus Heteroclitus |date=1975-01-01|url=http://dx.doi.org/10.1093/genetics/79.1.97|journal=Genetics|volume=79|issue=1|pages=97–111|doi=10.1093/genetics/79.1.97|pmid=1126624 |pmc=1213263 |issn=1943-2631}}</ref> Based on genetic studies, the enzymes serum [[esterase]] (SERE) and malate dehydrogenase [[Malate dehydrogenase|(MDH]]) also appear to play an important role in mummichog temperature control.<ref>{{Cite journal|last1=Powers|first1=Dennis A.|last2=Schulte|first2=Patricia M.|date=September 1998|title=Evolutionary adaptations of gene structure and expression in natural populations in relation to a changing environment: A multidisciplinary approach to address the million-year saga of a small fish|url=http://dx.doi.org/10.1002/(sici)1097-010x(199809/10)282:1/2<71::aid-jez11>3.0.co;2-j|journal=The Journal of Experimental Zoology|volume=282|issue=1–2|pages=71–94|doi=10.1002/(sici)1097-010x(199809/10)282:1/2<71::aid-jez11>3.0.co;2-j|pmid=9723168 |issn=0022-104X|url-access=subscription}}</ref>

They are also among fish species most tolerant of salinity changes ([[euryhaline]]).<ref>{{cite journal | last1 = Whitehead | first1 = A | year = 2010 | title = The evolutionary radiation of diverse osmotolerant physiologies in killifish (''Fundulus'' sp.) | journal = Evolution | volume = 64 | issue = 7| pages = 2070–2085 | doi=10.1111/j.1558-5646.2010.00957.x | pmid=20100216| s2cid = 23354536 | doi-access =  }}</ref> Mummichog larvae can grow in salinities ranging from 0.4 to 100 parts per thousand, the latter being about three times the normal salinity of seawater. Adult mummichogs tolerate low oxygen levels down to 1&nbsp;mg/L, at which they resort to [[hypoxia in fish|aquatic surface respiration]] (breathing in the surface layer of water, richer in oxygen because of contact with air) to survive.<ref>{{cite journal | last1 = Wannamaker | first1 = C.M. | last2 = Rice | first2 = J.A. | year = 2000 | title = Effects of hypoxia on movements and behavior of selected estuarine organisms from the southeastern United States | journal = Journal of Experimental Marine Biology and Ecology | volume = 249 | issue = 2| pages = 145–163 | doi=10.1016/s0022-0981(00)00160-x| pmid = 10841932 | bibcode = 2000JEMBE.249..145W }}</ref><ref>{{cite journal | last1 = Stierhoff | first1 = K.L. | last2 = Targett | first2 = T.E. | last3 = Grecay | first3 = P.A. | year = 2003 | title = Hypoxia tolerance of the mummichog: the role of access to the water surface | journal = Journal of Fish Biology | volume = 63 | issue = 3| pages = 580–592 | doi=10.1046/j.1095-8649.2003.00172.x| bibcode = 2003JFBio..63..580S }}</ref> They can even survive for a few hours in moist air outside of water, breathing air directly.<ref>{{cite journal | last1 = Halpin | first1 = P.M. | last2 = Martin | first2 = K.L.M. | year = 1999 | title = Aerial respiration in the salt marsh fish ''Fundulus heteroclitus'' (Fundulidae) | journal = Copeia | volume = 1999 | issue = 3| pages = 743–748 | doi=10.2307/1447607| jstor = 1447607 }}</ref>

Populations have developed resistance to [[methylmercury]], [[kepone]], [[dioxins and dioxin-like compounds|dioxins]], [[polychlorinated biphenyl]], and [[polyaromatic hydrocarbons]].<ref>{{cite journal | last1 = Weis | first1 = J | year = 2002 | title = Tolerance to environmental contaminants in the mummichog, ''Fundulus heteroclitus'' | journal = Human and Ecological Risk Assessment | volume = 8 | issue = 5| pages = 933–953 | doi=10.1080/1080-700291905756| bibcode = 2002HERA....8..933W | s2cid = 85361429 }}</ref> One study<ref>{{cite journal | last1 = Whitehead | first1 = A. | last2 = Galvez | first2 = F. | last3 = Zhang | first3 = S. | last4 = Williams | first4 = L.M. | last5 = Oleksiak | first5 = M.F. | year = 2011 | title = Functional genomics of physiological plasticity and local adaptation in killifish | journal = Journal of Heredity | volume = 102 | issue = 5| pages = 499–511 | doi = 10.1093/jhered/esq077 | pmid=20581107 | pmc=3156563}}</ref> has looked at the genomic variation exhibited by mummichogs populations living in [[Newark Bay]], [[Acushnet River|New Bedford Harbor]], and the [[Elizabeth River (Virginia)]] (in some areas heavily polluted with polychlorinated biphenyls and [[creosote]], a complex mixture containing dioxin-like chemicals) and has found that about 20% of their genes were modified as compared to populations living in clean sites.