摘要:

The nonvolatile constituents that are acutely toxic to juvenile coho salmon (Oncorhynchus kistuch) have been fully identified in a kraft pulping effluent derived from Douglas fir and western hemlock. Toxicity and material balances were maintained through out a fractionation procedure leading to isolation of the toxic factors.Over 80% of the toxicity was caused by three resin acid soaps: sodium isopimarate (55%), sodium abietate (22%), and sodium dehydroabietate (5%). The remaining toxicity (18%) was contributed by sodium salts of the unsaturated fatty acids: palmitoleic, oleic, linoleic, and linolenic.

ISSN:0706-652X    

DOI:10.1139/f73-085

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Mercury toxicity in rainbow trout fingerlings was related to temperature and chemical formulation of the mercury. At 10 C, the 24-hr TLmconcentration (median tolerance limit) for mercuric chloride (HgCl2) was approximately 30 times that for phenyl mercuric acetate (PMA). The 96-hr TLmvalues for mercuric chloride at 5, 10, and 20 C were 0.40, 0.28, and 0.22 mg Hg/liter. The velocity of mortality, (V = reciprocal of time to death in hours), was linearly related to temperature. For a mercuric chloride concentration of 0.5 mg Hg/liter, V =.002 +.0023t, wheret = temperature in centigrade degrees.Temperature also affected accumulation rate of mercury in the fish muscle. At 5, 10, and 20 C a mercuric chloride concentration of 0.1 mg Hg/liter in the water produced biological magnification factors (conc. in fish ÷ conc. in water) of 4, 10, and 22 ×, respectively,PMAproduced higher magnification factors of 80–100 × at 10 C.Active metabolic rate, though increased by higher temperatures, was depressed by mercuric chloride, and higher temperatures augmented the depressant effect.

ISSN:0706-652X    

DOI:10.1139/f73-086

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The macrobenthos of sawdust-bearing substrates in the Penobscot River estuary (Maine) were sampled bimonthly from January through November 1968. The polychaeteScolecolepides viridisand the bivalvesMacoma balthicaandMya arenariadominated the sandy sediments of the shallow station.Prionospio malmgreniandCorophium volutatorwere dominant in the granular substrate of the deeper station. The population of the shallow station (1-m depth, mean low water) was seasonally more stable and had a higher mean monthly bio-index (number of individuals/number of species) than that of the deeper station (6-m depth, mean low water).

ISSN:0706-652X    

DOI:10.1139/f73-087

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Tests were performed at 15 C, pH 6.8, and dissolved oxygen values of 90–100% air saturation. Growth rate and conversion efficiency were measured by feeding a ration level of 15% body dry weight/day to underyearling sockeye salmon (Oncorhynchus nerka) held at sodium pentachlorophenate (PCP) concentrations of 0, 1.14, 1.99, 3.49, 7.16, 13.60, 27.73, 31.57, and 47.18 ppb. Swimming performance was measured at PCP concentrations of 0, 7.21, 19.00, and 50.00 ppb. The 96-hrLC50 was 63 ppb PCP. Growth rate and conversion efficiency were almost equally affected by PCP, theEC50 values being 1.74 ppb for growth rate and 1.80 ppb for conversion efficiency. This is approximately 2.8% of the 96-hrLC50. Swimming performance was unaffected by PCP at the concentrations used.

ISSN:0706-652X    

DOI:10.1139/f73-088

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The majority of work done in the economics of fisheries uses the assumption of a fixed price of output. This paper describes the effects on the traditional fisheries model of relaxing this assumption, the most important of which, as far as regulation agencies are concerned are the negation of marginal cost of effort equaling marginal revenue of effort as the criterion for a social optimum, and the introduction of the possibility of multiple equilibria and multiple industry profit maxima. Also, some new insights on fishery management with variable price and different assumptions about the number of fisheries and the number of countries involved are pointed out.

ISSN:0706-652X    

DOI:10.1139/f73-089

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

In early September 1969 and late August 1971, the vertical and horizontal distribution of temperature, Secchi disc visibility, some chemical components, and zooplankton abundance in lakes Okanagan, Skaha, and Osoyoos were investigated. In addition, lakes Kalamalka and Wood were sampled only in late August 1971. Four different basins could be distinguished in Lake Okanagan: the Penticton-Summerland basin, the Peachland-Kelowna basin, a basin north of Kelowna, and one formed by the northern end of the lake. Total dissolved solids, calcium, and electrical conductivity within the lake decreased gradually from north to south. Macroelement values within lakes Okanagan, Skaha, and Osoyoos were apparently not substantially different but Kalamalka and Wood lakes were about twice higher in sodium, potassium, magnesium, and about 1.5 higher in total dissolved solids. Four species of copepods and nine species of cladocerans were found withCyclops bicuspidatus thomasiandDiaptomus ashlandidominant in all five lakes.Diaphanosoma leuchtenbergianumandDaphnia longiremiswere the most common cladocerans in all five lakes. Also,Daphnia thoratawas common in all except Wood Lake. Eighty-nine percent of the total plankters in Lake Okanagan were located in the upper 50-m layer. Relatively little horizontal variation was found within the lake but two areas, near Kelowna and in the northern end showed in both years of investigation greater abundance of plankton than the remaining areas. Crustaceans were usually less abundant inshore than offshore. Volume of settled net plankton varied from 8 mm3/cm2in Okanagan Lake to 31 mm3/cm2in Wood Lake. No substantial changes in species composition of zooplankton, Secchi disc visibility, and dissolved oxygen in the hypolimnion were found relative to the data of 1935 reported by Rawson. However, in 1969 and 1971 net plankton volumes were about five and three times larger, respectively, than in 1935. Calculations of total phosphorus load from two independent sources of data provided similar results and indicated that lakes Okanagan and Kalamalka are still in the oligotrophic range but close to mesotrophy. Lake Wood is moderately eutrophic and lakes Skaha and Osoyoos showed a marked degree of eutrophy, higher than in Lake Washington, U.S.A. before sewage diversion, or in Lake Erie. The estimates for lakes Wood, Skaha, and Osoyoos were supported by the values of the hypolimnetic areal deficits characteristic for highly eutrophic lakes. The trend of changes in phosphorus load during the past century is presented and predictions are made about the load in 1990 in situations with and without phosphorus removal from sewage.

ISSN:0706-652X    

DOI:10.1139/f73-090

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Fecundity of resident Dolly Varden (Salvelinus malma) in an isolated population of southeastern Alaska averaged 66 eggs per female in comparison with 1888 eggs for anadromous Dolly Varden from two nearby streams. A relatively large egg size, averaging 3.6 mm in diameter and overlapping the range for the anadromous char, has been retained by the females in the resident population. Curvilinear regressions between egg number and fish length and linear regressions between egg number and body and ovary weights show that resident females have fewer eggs per unit of length, approximately the same number of eggs per gram of body weight, and more eggs per gram of ovary weight than anadromous females. The resident char attain sexual maturity a year earlier in life and at a smaller size than the migratory char. Development of a larger left ovary containing more eggs than the right was a common occurrence for both resident and anadromous Dolly Varden.

ISSN:0706-652X    

DOI:10.1139/f73-091

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A neoplasm in a rainbow trout (Salmo gairdneri) identified as a nephroblastoma is described and its possible pathological implications discussed. The characteristic conditions of abortive renal tubules and glomeruli in a fibrous stroma were observed; however, metastases were absent. The simultaneous presence of inflammatory kidney disease made association of clinical signs with the neoplasm impossible. This is the first case of nephroblastoma in Canadian hatchery stock. The etiological factors are unknown.

ISSN:0706-652X    

DOI:10.1139/f73-092

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The trachymedusaAglantha digitaleundergoes a diel migration in Saanich Inlet, Vancouver Island, British Columbia. The species has a single yearly breeding cycle at a high seas station in the northeastern Pacific.

ISSN:0706-652X    

DOI:10.1139/f73-093

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Five whitefish species are present in the Colville River. Least cisco (Coregonus sardinella) was the most common species in the Colville Delta, while the broad whitefish (C.nasus) was most abundant at test net sites near Umiat.Limited age and growth data indicate slower growth than in interior Alaska waters.

ISSN:0706-652X    

DOI:10.1139/f73-094

出版商:NRC Research Press    

年代:1973

数据来源: NRC