摘要:

To study quantitatively and qualitatively the dissolved organic matter in the St. Lawrence maritime estuary, a comparison between the different extracting methods has been undertaken. We propose two of them; one based on liquid–liquid extraction, the second by adsorption on a resin (Amberlite XAD-2). The methods used remove different spectrums of organic compounds from sea water. Hydrocarbons were found to constitute the major part of the extracts varying between 3 and 5 mg/liter. None of the methods used extracts more than 20% of the total organic matter present. The concentration of the organic chloro-compounds in the water column is in the order of 80 ppb.

ISSN:0706-652X    

DOI:10.1139/f74-023

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Nutrient composition studies have been carried out on single samples of meals produced from whole Atlantic argentines (Argentina silus), capelin (Mallotus villosus), American sand lance (Ammodytes americanus) and from filleting scrap from flounders (Pleuronectidae sp.) and redfish (Sebastes marinus).Analyses included protein, fat, ash, moisture, minerals, vitamins, available lysine, amino acids, and protein digestibility. The whole fish meals appeared nutritionally equal to good herring meal. The filleting scrap meals were lower in protein content but the nutritional values of the proteins were equivalent to that of herring.

ISSN:0706-652X    

DOI:10.1139/f74-024

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Light and electron microscopy were used to describe the functional morphology ofBothrimonus sturionisin detail. In particular, the musculature, nervous system, osmoregulatory system, and tegument are dealt with, and the findings compared with those of other workers. The musculature of the scolex consists of several interrelated systems, the structure of each being discussed in relation to its function. Associated with the regular nervous system, considered typical of cestodes, is an extensive system of giant nerve fibers. The osmoregulatory system is unusual in that there are lateral "excretory" pores in many proglottides which open directly to the exterior of the worm. The microtriches of the tegument are long, like those of other primitive cestodes, and are covered by a noncellular sheath while the worm is in its gammarid host. The sheath is lost when the worm becomes established in its fish host; the nature and function of the sheath are discussed.

ISSN:0706-652X    

DOI:10.1139/f74-025

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Studies on four succeeding generations of the snail,Helisoma trivolvis, indicated that nominal concentrations of trisodium nitrilotriacetate up to 100 mg/liter were not acutely toxic. Concentrations above 25 mg/liter appeared to impose a stress on the growth and fecundity of the snails. However, the effects seemed to be lessened with each succeeding generation. At predicted environmental levels Na3NTA is unlikely to have any lasting effect on euryplastic species of aquatic invertebrates, such asH.trivolvis.

ISSN:0706-652X    

DOI:10.1139/f74-026

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

A new species of monogenean,Cleidodiscus baldwini, from the trout-perch (Percopsis omiscomaycus) is described. This is the first report of a monogenean of the genusCleidodiscusfrom North American populations of the trout-perch.

ISSN:0706-652X    

DOI:10.1139/f74-027

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

In a narrow, shallow estuary on the east coast of Canada, the dominant intertidal invertebrates were bivalve and gastropod molluscs. On a sand flatMya arenariaproduced 11.6 g∙m−2∙yr−1flesh dry weight with a production:biomass ratio of 2.54, whereasMacoma balthicaproduced 1.93 g∙m−2∙yr−1with a P:B ratio of 1.53. On aSpartinamarsh,Littorina saxatilisproduced 3.25 g∙m−2∙yr−1with a P:B ratio of 4.11. Approximate P:B ratios were applied to biomass figures for four other species to give the following estimates of productivity:Mytilus edulisonZosterabeds 19.7 g∙m−2∙yr−1flesh dry weight;M.edulisonSpartinabeds 3.5 g∙m−2∙yr−1;Nassarius obsoletus1.15 g∙m−2∙yr−1;Melampus lineatus1.1 g∙m−2∙yr−1;Lacuna vincta0.06 g∙m−2∙yr−1. A total production of the molluscs in the estuary is estimated at 4.7% of the production ofSpartinaandZostera(all measured in kcal). It is postulated that molluscs are the chief

ISSN:0706-652X    

DOI:10.1139/f74-028

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The physiological stress of 200 ppm formalin treatments at 10 C is more severe in the juvenile steelhead trout (Salmo gairdneri) than in the spring chinook salmon (Oncorhynchus tshawytscha). In the steelhead, a marked hypochloremia follows a 1-hr treatment and recovery requires about 24 hr. During longer treatments, hypercholesterolemia together with reduced regulatory precision, hypercortisolemia, alkaline reserve depletion, and hypocapnia unaccompanied by a fall in bloodpH occur — suggestive of compensated respiratory alkalosis. In the spring chinook, hypochloremia and reduced plasma cholesterol regulatory precision are the significant treatment side effects but recovery requires only a few hours.Formalin treatments also cause epithelial separation, hypertrophy, and necrosis in the gills of both fishes but again, consistent with the physiological dysfunctions, these are more severe in the steelhead.

ISSN:0706-652X    

DOI:10.1139/f74-029

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The mean annual volume of seawater pumped by Pacific oysters in Departure Bay, British Columbia is 1488 liters/g per year. The energy requirement for metabolism and pumping is 1.74 cal/liter, while the mean annual caloric content of the seawater is 60.4 cals/liter. Annual biodeposition is 8.9 g/g per year; these data applied to a mean biomass of 190 g/m2for a mature oyster reef show that 22,052 kcal are theoretically available for ingestion, but only 11% are retained, mostly to be biodeposited. The biodeposits have a caloric value of 1545 kcal/m2and furnish an important nutritional substrate. Another important contribution to the food web is the annual release of gametes, equivalent to 502 kcal/m2reef.

ISSN:0706-652X    

DOI:10.1139/f74-030

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Concentrations of DDT residues were higher in lake trout (Salvelinus namaycush) from southern Lake Michigan in 1966–70 (average 18.1 ppm in fish 558–684 mm long) than in lake trout of the same size-class from Lake Superior in 1968–69 (4.4 ppm), and higher in adult coho salmon (Oncorhynchus kisutch) from Lake Michigan in 1968–71 (averages for different year-classes, 9.9–14.0 ppm) than in those from Lake Erie in 1969 (2.2 ppm). Residues were significantly higher in lake trout from southern Lake Michigan than in those from the northern part of the lake. In lakes Michigan and Superior, the levels increased with length of fish and percentage oil. In Lake Michigan coho salmon, the residues remained nearly stable (2–4 ppm) from September of the 1st yr of lake residence through May or early June of the 2nd yr, but increased three to four times in the next 3 mo. Residues in Lake Erie coho salmon did not increase during this period, which preceded the spawning season. Although the concentrations of total residues in whole, maturing Lake Michigan coho salmon remained unchanged from August 1968 until near the end of the spawning season in January 1969, the residues were redistributed in the tissues of the spawning-run fish; concentrations in the loin and brain were markedly higher in January than in August. This relocation of DDT residues accompanied a marked decrease in the percentage of oil in the fish, from 13.2 in August to 2.8 in January. Concentrations of residues were relatively high in eggs of both lake trout (4.6 ppm) and coho salmon (7.4–10.2 ppm) from Lake Michigan. The percentage composition of the residues (p,p′DDE,o,p′/DDT,p,p′DDT, andp,p′DDT) did not differ significantly with life stage, size, age, or locality, or date of collection of lake trout or coho salmon.

ISSN:0706-652X    

DOI:10.1139/f74-031

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Three composite samples of whitefish meals, each representing samples over 4 mo from plants in eastern Canada were analyzed for proximate composition, minerals, vitamins, amino acids, available lysine, and pepsin digestibility. Protein quality was evaluated biologically in feeding trials with chicks. The composite samples were similar in chemical composition with respect to both macro- and micronutrients. In vitro pepsin digestibility was 95–96% and chemically estimated available lysine 6.5–6.9 g/16 g N, or 87–96% of the total lysine present. The growth response to the meals, when they were fed to supply either 4 or 8% of supplementary protein in diets containing a total of 14.5 or 18.5% of protein, respectively, indicated that the supplementary protein value was high.

ISSN:0706-652X    

DOI:10.1139/f74-032

出版商:NRC Research Press    

年代:1974

数据来源: NRC