Thermoacclimatory variations in the activities of enzymes implicated in ion transport in the rainbow trout, salmo gairdneri

Two groups of rainbow trout were acclimated to 20 , 100 , and 18 o C. Plasma sodium, potassium, and chloride levels were determined for both. One group was employed in the estimation of branchial and renal (Na+-K+)-stimulated, (HC0 3-)-stimulated, and CMg++)-dependent ATPase activities, while the other was used in the measurement of carbonic anhydrase activity in the blood, gill and kidney. Assays were conducted using two incubation temperature schemes. One provided for incubation of all preparations at a common temperature of 2S oC, a value equivalent to the upper incipient lethal level for this species. In the other procedure the preparations were incubated at the appropriate acclimation temperature of the sampled fish. Trout were able to maintain plasma sodium and chloride levels essentially constant over the temperature range employed. The different incubation temperature protocols produced different levels of activity, and, in some cases, contrary trends with respect to acclimation temperature. This information was discussed in relation to previous work on gill and kidney. The standing-gradient flow hypothesis was discussed with reference to the structure of the chloride cell, known thermallyinduced changes in ion uptake, and the enzyme activities obtained in this study. Modifications of the model of gill lon uptake suggested by Maetz (1971) were proposed; high and low temperature models resulting. In short, ion transport at the gill at low temperatures appears to involve sodium and chloride 2 uptake by heteroionic exchange mechanisms working in association w.lth ca.rbonlc anhydrase. G.l ll ( Na + -K + ) -ATPase and erythrocyte carbonic anhydrase seem to provide the supplemental uptake required at higher temperatures. It appears that the kidney is prominent in ion transport at low temperatures while the gill is more important at high temperatures. 3 Linear regression analyses involving weight, plasma ion levels, and enzyme activities indicated several trends, the most significant being the interrelationship observed between plasma sodium and chloride. This, and other data obtained in the study was considered in light of the theory that a link exists between plasma sodium and chloride regulatory mechanisms.

Water quality and fish populations of the Welland River, Ontario /

The water quality and fish populations of the Welland River were observed to decline with distance downstream. This coincided with increased agricultural , domestic and industrial waste loadings. The river upstream of the City of Welland received considerable loadings from agricultural sources. Centrarchids, sciaenids, ictalurids, cyprinids and esocids characterized this upper section of the river. Most of these species were tolerant of low dissolved oxygen concentrations and the high turbidity which prevailed there . The river near Port Robinson receives many industrial and domestic wastes as evidenced by the water quality data. The fish in this section were less abundant and the observed population was comprised almost solely of cyprinids. Further downstream, near Montrose, the Welland River received shock loads of chemical wastes that exceeded a specific conductance of ISiOOO ;umhos/cm. Few fish were captured at this site and those that were captured were considered to be transients. A review of the literature revealed that none of the common indices of water quality in use today could adequately predict the observed distributions. In addition to the above, the long-term trend (l3 yrs) of water quality of the lower Welland River revealed a gradual improvement. The major factor thought to be responsible for this improvement was the operation of the Welland Sewage Treatment Plant. The construction of the New Welland Ship Canal coincided with large fluctuations of the total solids and other parameters downstream. These conditions prevailed for a maximum of three years (1972- 1975)' Furthermore, spawning times and temperatures, geographic distributions, length-weight regressions and many other descriptive aspects of the ecology of some 26 species/ taxa of fish were obtained. Several of these species are rare or new to southern Ontario.

Letter to S.D. Woodruff from William Leary, steward, endorsing G. Fish to paint the new building

Letter to S.D. Woodruff from William Leary, steward, endorsing G. Fish to paint the new building (1 ½ pages, handwritten), June 7, 1875.