Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site uwmacc.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!uwvax!uwmacc!dubois From: dubois@uwmacc.UUCP (Paul DuBois) Newsgroups: net.origins Subject: Salt Water Taffy Message-ID: <1337@uwmacc.UUCP> Date: Tue, 30-Jul-85 13:44:42 EDT Article-I.D.: uwmacc.1337 Posted: Tue Jul 30 13:44:42 1985 Date-Received: Thu, 1-Aug-85 05:17:11 EDT Distribution: net Organization: Famous Briefcases, Inc. Lines: 53 J Chervinski, "Salinity tolerance of the guppy, _Poecilia reticulata_ Peters", J Fish Biology, 24(4), April 1984, 449-452. Abstract: Experiments were conducted to determine the adaptability of the guppy to various salt concentrations. The guppy, _Poecilia reticulata_, (total length 11-40 mm) were subjected to abrupt and gradual changes from fresh water (salinity=0.1%) to various salinities (%). No mortality occurred when the fish were transferred from fresh water to 50% sea water (19.5%). Through gradual adaptation from 50% sea water to [sic - remove word?] 80% of the fish were able to tolerate 100% (39%) sea water for 7 days. After a 7 day stay in sea water, fish were readapted to fresh water during a 3 h period. Through gradual adaptation fish were also able to tolerate salinities ranging from 39.0% (100% sea water) to 58.5%. After a 30 day stay in 150% sea water (58.5%), fish were readapted to fresh water over a 5 h period. The results indicate that they were well able to tolerate the abrupt change from 100 or 150% sea water to fresh water. Females that stayed in 150% sea water (58.5%) for 30 days had embryos in the gonads. Table 1. Mortality of _Poecilia reticulata_ (%) after direct transfer from fresh water to various saline concentrations Mortality at various concentrations of sea water Time from start of experiment (h) 0% 50% 60% 70% 90% ----------------------------------------------------- 8 0 0 0 20 100 24 0 0 10 100 48 0 0 20 72 0 0 20 96 0 0 20 120 0 0 20 144 0 0 20 168 0 0 20 The practical significance of this work is that brackish water and salt marshes are favorable mosquito breeding habitats. Stocking of guppies, which feed on the mosquito larvae, is thus a pest control measure. The significance may also extend to some of the discussion in this newsgroup...I thought that perhaps some of the readers might be interested. -- | Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois --+-- | "Why are you standing on one leg?" | "I'm trying to see if I'm a stork."