摘要:

During 1963 and 1964, studies were conducted aboard the research vesselG.B.Reedto test schemes for sampling individual trawl catches of groundfish, principally Pacific ocean perch (Sebastodes alutus), for size composition, weight and numbers caught, and sex ratio. A species sort into tub lots preceded sampling. Empirical tests were used to evaluate sampling methods for all parameters except sex ratio. Size composition and sex ratio samples were evaluated with chi-square tests. Estimates of weight and numbers caught were arbitrarily evaluated on the basis of their percentage deviations from actual values.For ocean perch the size composition, weight caught, numbers caught, and sex ratio were best estimated from a stratified sample consisting of the first 2, middle 2, and last 2 full tubs weighed. For 21 test hauls, the error range for weight estimates was −6 to +5%; for estimated numbers caught, −5 to +4%. Sex ratio was homogeneous among tubs within hauls.For six other groundfish species, weight caught was satisfactorily estimated from a serial sample consisting of the first 6 full tubs weighed, providing the tubs within hauls were filled uniformly. For 13 tests, the error range was −3 to +1%.

ISSN:0706-652X    

DOI:10.1139/f67-101

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Sockeye salmon were canned after various periods of cold storage. The volume of oil separated from the drained liquor of the can ("drained free oil") was essentially the same whether the determinations were made 1–4 weeks after canning or 10 months later. It amounted to 2.1–2.5 ml/100 g canned product in fish stored for 1–3 days on ice and decreased to 1.0–1.3 ml/100 g in fish stored for 10 days on ice or 3–10 days in refrigerated, salt-fortified seawater at 25 F. The oil separated by centrifugation (600 g, 60 min) of an aqueous suspension of canned salmon amounted to 65–70% of the total lipid and under these conditions of measurement no differences related to storage history could be detected. After centrifugation (approx 600 g, 60 min) of intact cans (i.e. cans containing salmon), the drained free oil content of cans having a low content when measured without prior centrifugation was equal to that of cans of high drained free oil content without centrifugation. It is suggested that oil binding in canned salmon is physical rather than chemical and might be related to protein denaturation during cold storage, resulting in formation of a more fibrous texture, which may be less favorable for the release of oil from the tissue during canning.

ISSN:0706-652X    

DOI:10.1139/f67-102

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Length measurements of a migrant ommastrephid squidIllex illecebrosus illecebrosus(Le-Sueur), in Newfoundland east coast waters indicated that only one modal class was present except in November of some years. Average lengths and weights of random samples taken monthly from May to November indicated also that growth was very rapid during this period. The majority of the population, averaging 140 mm in mantle length (54 g whole weight) in both sexes in May, reached maximum mantle lengths of 260 mm in males and 300 mm in females by October (weights of 360 and 550 g in males and females respectively). By fitting growth curves to these data, and by observations on sexual maturity, the approximate times of birth and mortality were extrapolated. Spawning and probable subsequent mortality of this squid was estimated to be at not more than 2 years and most probably at only 1 year of age.

ISSN:0706-652X    

DOI:10.1139/f67-103

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Oils were produced from four species of freshwater fish (sheepshead,Aplodinotus grunniens; tullibee,Coregonus artedii; maria,Lota lota; alewife,Alosa pseudoharengus) in a commercial reduction plant. The oil iodine values were, respectively, 123, 143, 158, and 165. Fatty acids were determined by gas–liquid chromatography. All four oils showed higher levels of C16and C18fatty acids than corresponding marine oils, but only sheepshead and tullibee had distinctly low levels of C22acids. The four freshwater oils differed from most marine oils in having higher proportions of linoleic, linolenic, and arachidonic acids. In most respects fatty acid compositions of freshwater fish oils were not dissimilar from marine oils.

ISSN:0706-652X    

DOI:10.1139/f67-104

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Euphausia pacifica,Thysanoëssa spinifera,T.raschii,T.longipes(unspined form), andTessarabrachion oculatusmolted at 4- to 6-day intervals at 11 to 15 C. The average dry weight of the molts of the first three species was 5.92–9.39% of the animal's final dry weight, and the organic fraction ranged from 73 to 83% of the dry weight of the molts. The oxygen consumption ofE.pacificaat 5, 10, 15, and 20 C was directly proportional to the body weight. The slopes of the regression lines were near unity at all temperatures and the difference between the regression coefficients was not significant statistically. The respiration–temperature relation ofE.pacificasuggested its eurythermic character. The Q10value was 2.21 between 5 and 10 C and increased to 2.55 between 10 and 15 C. The Q10value apparently did not increase with increase in body size. The upper limit of temperature tolerance for the observed population ofE.pacificawas close to 20 C. On the day of molting, oxygen consumption ofE.pacificaincreased by an average of 34.2%. Feeding decreased on the day before and on the day of molting and increased after molting. At 15 C, a daily food intake of 0.022 mg carbon per milligram dry body weight would be required to match the respiratory loss and the loss of integument during the molt.

ISSN:0706-652X    

DOI:10.1139/f67-105

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

An apparatus and method were developed to obtain comparative measurements of maximum swimming speeds of small fish. The present method is considered useful in bioassays for measuring sublethal effects of pollutants. The fish swim in an open-topped oval channel with a circumference of 1.48 m. A variable speedmotor turns two paddle wheels and creates measured currents up to 30 m per minute. Fish are not required to swim at the same velocity as the water in the chamber. Rather, they swim in a current which is greater than their maximum swimming speed and which moves them backwards in the channel. The average maximum swimming speed for a group of four to six fish is calculated from the current velocity, circumference of the channel, and the number of laps lost during a specific time period.Tests with fathead minnows,Pimephales promelas, showed that different current velocities gave the same swimming speed as long as the current was greater than the swimming speed of the fish. A swimming period of 3 min gave consistent results.Largemouth bass fingerlings,Micropterus salmoides, which were conditioned by exposing them once daily to the standard test in the chamber, showed a marked increase in swimming ability after 3 days. Fed and unfed fish showed equal increases in performance and the conditioned fish developed a slightly higher active metabolism.

ISSN:0706-652X    

DOI:10.1139/f67-106

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The routine rate of oxygen uptake, of 12 groups of zebrafish aged 0 to 100 days, was measured in well-aerated water free of zinc. The relationship between the rate of oxygen uptake (X) and survival time (T) in four toxic solutions of zinc wasthroughout the life cycle, where Ts, Xs, and K were constants. T was also related to the dry weight of the fish (W) in fish aged 5 days or over.

ISSN:0706-652X    

DOI:10.1139/f67-107

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Polyacrylamide disc electrophoresis of plasma proteins and starch-gel electrophoresis of hemoglobins and muscle myogens of adult and ammocoete forms of three species of Great Lakes lamprey were carried out. Blood proteins were shown to undergo marked changes upon transformation of the ammocoete into the adult form. Muscle myogen did not undergo any change during transformation. The muscle myogen electropherograms ofIchthyomyzon unicuspisandLampetra lamotteiwere found to be the same.

ISSN:0706-652X    

DOI:10.1139/f67-108

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Fifteen adult redfish were taken on floating longlines set at 180–460 m, July 16–19, 1965 and two on March 21 and 24, 1966 on floating longlines set at 180–550 m at the mid-mouth of the Labrador Sea over depths of 3060–3660 m. Additionally two were taken from a porbeagle's stomach in the same area on August 23, 1965. The redfish were matureSebastes mentella, 33–41 cm long, and relatively heavily infested withSphyrion lumpi.These redfish were probably part of an oceanic population of pelagicS.mentellawhich has previously been shown to exist in the eastern portion of the large eddy system extending from south of Iceland and Greenland, east of Labrador and Northeast Newfoundland shelves, and north of the Grand Bank and Flemish Cap slopes.The biology and distribution of the pelagic oceanic redfish of this area are reviewed.

ISSN:0706-652X    

DOI:10.1139/f67-109

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The composition and nutritive value of meals manufactured from four species of freshwater fish, alewife (Alosa pseudoharengus), sheepshead (Aplodinotus grunniens), maria (Lota lota), and tullibee (Coregonus artedii), were determined and compared with meals of marine origin (herring and white fish). The meals from freshwater fish contained 62–68% protein, 7–13% fat, and 14–20% ash. Sodium, potassium, and magnesium levels were lower than in the marine fish meals but iron and copper were higher. Riboflavin, pantothenic acid, niacin, and cobalamin were present in lesser amounts in freshwater fish meals than in herring meal but at similar or higher levels than in white fish meal. There were no consistent differences between the amino acid compositions of the freshwater fish and the marine fish meals. Biological tests with chicks indicated that the freshwater fish meals were similar in supplementary protein value to marine fish meals. The pepsin digestibility values for proteins were 95.5–97.7% which compare favourably with the values for marine fish meals. Metabolizable energy values ranged from 2630 to 3680 Kcal/kg dry weight.

ISSN:0706-652X    

DOI:10.1139/f67-110

出版商:NRC Research Press    

年代:1967

数据来源: NRC