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Dynamics of Endrin Uptake and Release by Resistant and Susceptible Strains of Mosquitofish
Author(s) -
Ferguson Denzel E.,
Ludke J. Larry,
Murphy George G.
Publication year - 1966
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1966)95[335:doeuar]2.0.co;2
Subject(s) - endrin , mosquitofish , gambusia , fish <actinopterygii> , zoology , toxicology , bioassay , chemistry , biology , fishery , pesticide , ecology , dieldrin
Abstract Results of bioassays and gas chromatographic analyses show that mosquitofish, Gambusia affinis, from near heavily‐treated cotton fields near Belzoni, Mississippi (36‐hr TL m = 1,000 ppb) and from an uncontaminated site near State College, Mississippi (36‐hr TL m = 1 ppb) remove endrin from static test solutions at the same rate. A 500 ppb endrin solution produced 32% mortality in 50 susceptible fish in 25 min but required 144 hr in resistant fish. Relative mortality of fed and starved fish in endrin solutions and the rate of endrin uptake discount swallowing as the primary pathway of endrin entry into mosquitofish. About six times as much endrin is taken up via the exposed head region as is taken up by the general body surfaces. Oxygen requirements of the two populations are similar, but increase for susceptible fish at low endrin concentrations and for resistant fish at high concentrations coincident with the appearance of symptoms of endrin poisoning. Both bioassays and residue analyses revealed endrin uptake in dead mosquitofish (less than in living fish). A single resistant female, exposed to 1,000 ppb endrin, released sufficient endrin in 10 liters of tap water to kill five susceptible fish in 38.5 hr and survived the experience. Field‐collected resistant fish contained 6.8 to 11.95 ppm endrin in late August but only 0.73 to 0.88 ppm in late February. We conclude that the mechanism of resistance is physiological toleration of massive endrin accumulations (e.g., a pooled sample of resistant fish contained 214.28 ppm after a 2‐week exposure in 500‐ppb endrin); however, it is not known how the toxic effects of endrin are avoided.