摘要:

Fluorescence spectroscopy is demonstrated to be a valuable technique for estimating petroleum residue concentrations in sea water when large numbers of samples must be analyzed. A recommended procedure is presented, along with some concentrations observed in Bedford Basin, Nova Scotia, and along a section between Halifax and Bermuda.

ISSN:0706-652X    

DOI:10.1139/f73-175

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The lampricide TFM (3-trifluoromethyl-4-nitrophenol) was tested against the following life stages of rainbow trout (Salmo gairdneri): green eggs, eyed eggs, sac fry, swim-up fry, fry, and fingerlings in four water hardnesses (12, 44, 170, and 320 mg/liter as CaCO3). The eyed-egg stage was one of the most resistant stages tested, and the sac-fry stage was one of the least resistant. Increased water hardness decreases toxicity to all stages. The LC50’s range from 0.532 mg/liter to 40.0 mg/liter depending upon life stage, water hardness, and duration of exposure. The margin of safety for coexisting species exposed to TFM ranges from 3.2 to 4.1 in natural waters. The margin of safety for early life stages of rainbow trout and larval lamprey under controlled laboratory conditions ranges from 4.2 to 12.2. Therefore, all six early life stages of rainbow trout are safe in minimum lampricidal concentrations of TFM.

ISSN:0706-652X    

DOI:10.1139/f73-176

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

From 1969 to 1971, 78 harp seals (Pagophilus groenlandicus), ranging in age from newborn to 18 years were obtained from the Gulf of St. Lawrence and the Newfoundland and Labrador coasts (Front). A further 12 seals captured in the Gulf died (in captivity) after being held for various periods of time.Total DDT and metabolites (Σ DDT) in the blubber of wild beaters and bedlamers from the Gulf were > 2 ppm, from the Front < 2 ppm. DDT levels increased to 8.7 ppm as the animals matured, and in females levelled off at 6.5 ppm when the breeding age was reached. Dieldrin levels were only 5% of those for Σ DDT, and did not accumulate appreciably in either wild or captive seals. PCB residues were only slightly less than Σ DDT and showed a similar increase with the age of the seal.Residues in tissues of captive seals were as much as eight times higher than in nature, indicating either that natural diets contain lower residues than the selected, often monospecific diet, or differing rates of assimilation of organochlorines in wild and captive animals. The differences between levels in wild seals from the Gulf and Front may offer evidence for sub-population groups in the harp seals of the North West Atlantic.In seals examined brain lipids contained between 7 and 20% of concentrations of all three chlorinated hydrocarbons found in the extractible fat of blubber, muscle, and liver, indicating a brain barrier.

ISSN:0706-652X    

DOI:10.1139/f73-177

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The number of white whales inhabiting western Hudson Bay is about 10,000. In July and early August the herds are concentrated in river estuaries at 57° to 60° N, but a migration in mid-August through September takes them to between 62° and 66°N. Wintering occurs in the western part of the Bay. In the estuary of the Churchill River feeding, mainly on fish, is not heavy and the herds are believed to enter the river estuaries in this region for reproduction as much as feeding. Further north in late summer feeding is heavier and changes towards a diet of decapod Crustacea. It is believed that two dentinal layers are laid down in the teeth each year, each layer consisting of one opaque and one translucent zone of dentine, with the translucent material laid down during periods of reduced feeding. These may occur either at an autumn and a spring migration or during a summer fast at calving time and during winter deprivation. Females attain sexual maturity at 8–13 (mean 10) growth layers and males at 16–18 layers, i.e. at supposed mean ages of 4–7 (5) and 8–9 years. The skin loses all trace of grey color at 18–22 layers. Maximal duration of life is about 50 layers or a supposed age of 25 years in both sexes. The sexes are probably about equal in numbers. Gestation lasts 14 months and lactation about 20 months. Overlap of pregnancy and the previous lactation is infrequent so that calving occurs about once in 3 years. The annual crude birth rate is estimated at 0.12. Estimation of the maximal number of births from counts of corpora luteal scars is complicated by the frequent presence of accessory corpora lutea and luteinized follicles, estimated at about 32% of the total. The mean maximal number of scars retained in the ovaries during a female’s reproductive lifetime is 14.5. The full reproductive lifetime, on the basis of two growth layers per annum, is 20 years. Thus the mean ovulation rate is about 0.7 per annum. Reducing the number of scars by 32% gives 0.5 true (fertile) ovulations per annum, which would indicate a reproductive rate of one pregnancy in 2 years, and a maximal number of 10 pregnancies in a full reproductive lifetime

ISSN:0706-652X    

DOI:10.1139/f73-178

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The effects of previous exposure top,p′-DDT,o,p′-DDT,p,p′-DDD,p,p′-DDE, and methoxychlor on temperature selection by juvenile Atlantic salmon (Salmo salar) in a horizontal temperature gradient were similar. Exposure to low concentrations resulted in no change or a decrease in selected temperatures as compared to control values of about 16 C. Exposure to higher concentrations raised selected temperatures. The concentrations of the substances required to produce a given effect varied as:p,p′-DDT≥p,p′-DDD> methoxychlor >o,p′-DDT>p,p′-DDE. Exposure levels ofp,p′-DDA≤ 8 ppm did not alter temperature selection nor did exposure to Aroclor®1254, a polychlorinated biphenyl (PCB) preparation at 2 ppm. Aldrin lowered temperature selection at 0.1–0.15 ppm. In a vertical gradient, brook trout (Salvelinus fontinalis) previously exposed top,p′-DDT andp,p′-DDD selected higher temperatures than controls.

ISSN:0706-652X    

DOI:10.1139/f73-179

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The effect of 17 α-methyltestosterone feeding on the weight of juvenile coho salmon (Oncorhynchus kisutch) and on the weight, length, and condition factor of juvenile chinook salmon (O.tshawytscha) was determined. Significant increases in weight and length but not in condition factor were noted at all levels of steroid tested. Coho fed rations containing 10 mg/kg of the steroid for 42 days showed a 29% net weight gain and chinooks fed 1 mg/kg of the hormone for 84 days exhibited a 17% net weight gain over the respective control groups.A marked thickening of the skin was noted in the coho retained on diets containing 10 and 50 mg/kg of the steroid. This alteration was most evident in those fish fed the highest concentrations of hormone for the longest period.In the coho, diets containing 10 or 50 mg/kg of the hormone evoked marked degenerative changes in the testes. Less drastic alterations were noted in the testes of the chinooks retained on the 1 mg/kg test ration for 84 days. No apparent structural changes were noted in the ovary of any of the test fish.

ISSN:0706-652X    

DOI:10.1139/f73-180

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The behavior ofSarsia tubulosa(M. Sars 1835),Phialidium gregarium(L. Agassiz 1862), andPleurobrachia pileus(O. F. Müller 1776) was investigated in chambers where salinity discontinuity layers could be established.Sarsia tubulosaandP.pileusaggregated at the layer for salinity discontinuities of as little as 2‰ althoughP.gregariumshowed more variable behavior. This aggregation was shown to be due to an active response rather than passive flotation in the density barrier set up when low salinity water is placed over high salinity water.Sarsia tubulosaalso showed increased fishing activity in any column containing a discontinuity layer compared with any homogeneous control column.

ISSN:0706-652X    

DOI:10.1139/f73-181

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

This paper comprises sight records for nine species and morphometries, color descriptions, and miscellaneous notes on the food and parasites of seven species of small odontocetes observed from West Greenland to Florida 1967–72. Of interest are the first western Atlantic extralimital record ofMonodon monoceros, first Newfoundland records ofStenella coeruleoalba, and extralimital records ofDelphinapterus leucasfrom Newfoundland. Intraspecific variability is described in the pigmentation patterns ofPhocoena phocoena.

ISSN:0706-652X    

DOI:10.1139/f73-182

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Over 95% of 3,5,3′-triiodo-L-thyronine (T3) or L-thyroxine (T4) up to added hormone levels of at least 5 μg/ml, were precipitated by trichloroacetic acid with plasma proteins of brook trout using a semimicro method. Hormone recovery in the precipitate was higher than with precipitation methods previously used on fish plasma.Equilibrium dialysis showed over 99% of T4or T3bound to plasma proteins of trout up to added hormone levels of at least 5 μg/ml.Acrylamide gel was superior to paper and particularly cellulose polyacetate as a medium for electrophoretic separation of proteins responsible for binding T3or T4. In vitro studies at high hormone levels showed that T3and T4bound mainly to prealbumin-like proteins. In vivo studies at more physiological levels showed T4bound to fast prealbumin-like, albuminlike, and β-globulin-like proteins, while T3bound to slow prealbumin-like and probably the same albumin-like and β-globulin-like proteins as T4.

ISSN:0706-652X    

DOI:10.1139/f73-183

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Accommodation, in response to atropine and pilocarpine, was measured retinoscopically and photographically in seven species of freshwater fishes. These species accommodate in varying magnitudes and directions by means of lenticular movements. The common white sucker (Catostomus commersoni) and the goldfish (Carassius auratus) accommodate mainly in the lateral direction (5–10 diopters), whereas the common bluegill (Lepomis macrochirus), northern rock bass (Ambloplites rupestris), and yellow perch (Perca flavescens), exhibit a larger accommodative ability which occurs primarily along the rostral–caudal axis (up to 40 diopters in the yellow perch). The rainbow trout (Salmo gairdneri) accommodates equally along the lateral and rostral–caudal axes. No accommodative response occurs in the northern black bullhead (Ictalurus melas). Reference to the diets and feeding habits of the above species suggests that the magnitude and principal direction of accommodation is a response to the visual demands of a particular life history.

ISSN:0706-652X    

DOI:10.1139/f73-184

出版商:NRC Research Press    

年代:1973

数据来源: NRC