摘要:

Sodium chloride prevents drip in lightly brined fish muscle by causing the proteins to swell and to bind liquid firmly, and not by a surface sealing action. In whole and in comminuted muscle at its natural pH, free drip is almost completely inhibited, and expressible drip greatly reduced, by incorporation of about 1 per cent NaCl. On either side of an approximate "isoelectric zone" (about pH 4.5 to 6.0) addition of HCl or NaOH causes fish muscle to swell markedly and to withhold liquid against hydraulic pressure, peptization of the proteins occurring above and below about pH 10 and 2 respectively. Between about pH 4.5 and 7.0, from 1 to 3 per cent NaCl enhances swelling and liquid binding power of fish muscle, while below pH 4.5 it has an entirely opposite effect. Addition of NaCl effects an increase in pH of fish muscle below, and a decrease above about pH 4.5. In 1 per cent NaCl fish muscle does not swell appreciably; in 3 to 7 per cent swelling is at a maximum, while higher concentrations cause an apparent decrease in swelling which may be due in part to the peptizing action of the salt. Theoretical and applied aspects of the process of brining fillets are discussed.

ISSN:0706-652X    

DOI:10.1139/f40-042

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

In vitamin A (colorimetric) and vitamin D (biological) assays on representative seasonal samples of commercially produced pilchard and herring oil (from the whole fish), the vitamin D potency was found to vary inversely with the yield of oil, and the potencies of these oils with laboratory samples of tullibee oil were found to be within the range quoted for authentic cod liver oil, whereas the vitamin A potency was considerably lower than for most fish liver oils. The vitamin D of pilchard, herring, and salmon offal oil was found equally effective for rats and chickens. Vitamin D was found occluded with the stearine fraction of herring oil and was separated from it by three recrystallizations from acetone. The vitamin D potency of herring oil was found not to be related to the size of the fish.

ISSN:0706-652X    

DOI:10.1139/f40-043

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Twenty-four samples of seawater, fish slime and intestinal contents, taken off Halifax harbour, yielded two red halophilic sarcina strains from codfish slime.

ISSN:0706-652X    

DOI:10.1139/f40-044

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

On removal of scales in the smolt new scales develop in the scale pockets, attaining normal width in 40 days, but not quite normal length even by 59 days. Initial growth is very rapid and without circulus formation, but with decreasing rate circuli are formed with intervening spaces diminishing in width and there is often a check when normal growth commences. Scales near a large area of regeneration show checks corresponding to time of most rapid regeneration. Pairs of small and large regenerating scales occur, each pair apparently developing from the one pocket.

ISSN:0706-652X    

DOI:10.1139/f40-045

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Stomach contents of 293 rainbow, 160 cutthroat and 113 brown trout were examined and analyzed according to species, size groups (5 cm.) and habitat (river or lake). For rainbows of both river and lake (4 to 50 cm. in length), insects, chiefly Trichoptera and Simuliidae, were predominant in all size groups. Fish constituted a small fraction of the food except in the winter when salmon eggs were available. River cutthroat subsisted chiefly on insects (Trichoptera) up to 15 cm., on insects and fish (Gasterosteus) up to 30 cm., thereafter largely on fish. Lake cutthroat samples did not eat fish in any number until 41 cm. long. Brown trout ate chiefly insects (Trichoptera) up to 45.5 cm., thereafter turning more definitely to a fish (salmonid) diet. The cutthroat were more piscivorous than the brown trout. A definite selection of food by the trout was indicated.

ISSN:0706-652X    

DOI:10.1139/f40-046

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Nymphon glaciale,N.serratum,Pallenopsis longirostrisandAmmothea scabraare recorded for the first time from the Canadian Atlantic coast.

ISSN:0706-652X    

DOI:10.1139/f40-047

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

The distances moved in response to varied stimuli are measured, at constant temperature, by a new method. A sigmoid curve shows the relation between strength of stimulus and distance moved. For any strength of stimulus maximal amount of movement occurs at about 10 °C. Laboratory experiments and field observations reveal response temperatures (more active behaviour of the fish) at 15 and 20°, which may somewhat increase the distance moved at and above these temperatures.

ISSN:0706-652X    

DOI:10.1139/f40-048

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

In the sea, brook trout travel in schools along the sea shore and feed largely upon small fishes of various species and upon Crustacea.

ISSN:0706-652X    

DOI:10.1139/f40-049

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Statistical treatment of vertebral counts of young herring taken along the southeast coast of Vancouver island demonstrates significant differences between localities in the same year and in the same locality in different years. These differences are probably largely due to the effects of environment. The larger fish in a sample tend to have higher vertebral counts. This increase is somewhat greater in the caudal than in the abdominal region, and is accompanied by a disproportionate increase in mean number of tail vertebrae. Between samples, variation in total count is reflected mainly in the abdominal vertebrae, and significant differences in mean tail count may occur where no difference in total count exists.

ISSN:0706-652X    

DOI:10.1139/f40-050

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Deaths in Moser river, N.S., in 1939 were at time of day, on days, and in locality with highest water temperature. Symptoms were loss of sensitivity to light and very rapid breathing with recovery therefrom in cool water; otherwise followed by loss of equilibrium and cessation of breathing with death. Freshly run grilse died at about 29.5 °C. and acclimated grilse at about 30.5°. Large salmon died first and parr survived. In experiment, the latter died between 32.9 and 33.8°, the smallest at the highest point. Death is considered due directly to temperature.Rainfall after long period of drought brought the salmon from the sea into the river to die where water was shallowest and without cascades, therefore warmest. The very high temperatures and deaths occurred in afternoon from sun's heat and at ends of periods of days with moist air from the ocean and mounting water temperatures, dew point temperatures and mimimal air temperatures.Prevention is seen possible by bringing fish in early with artificial freshets, by constructing low dams to create deep pools and cascades, by making a deep channel or by raising level at critical periods with stored water.

ISSN:0706-652X    

DOI:10.1139/f40-051

出版商:NRC Research Press    

年代:1942

数据来源: NRC