摘要:

In February 1970, a large spill of Bunker C oil occurred in Chedabucto Bay, Nova Scotia. The incident was of particular interest since large spills of this type of oil had not previously been studied. Further interest was added by the unusually cold temperatures and by the nonuse of detergents in cleanup. The effects of the oil on intertidal and lagoonal biota have been followed since the accident. Many rocky shores and lagoons were heavily oiled. On exposed shores, oil has decreased steadily since oil stopped coming ashore in mid-1970 and by August 1971 only small amounts remained. In sheltered areas, particularly lagoons, heavy oil contamination remains. The summer remobilisation and subsequent redeposition of oil added a chronic aspect to the pollution. Initial effects of oil involved minor smothering of fauna and tearing loose of algae. Longer term effects involved extensive mortalities ofFucus spiralison rocky shores andMya arenariaandSpartina alterniflorain lagoons. Other biota were not visually affected. In all three affected species, mortalities took place either continuously or only in the second year of pollution. Causes of death are unknown. It is recommended that in all intertidal areas very heavy oil deposits should be mechanically removed and the remainder of the oil left to natural degradation.

ISSN:0706-652X    

DOI:10.1139/f73-011

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The use of the Nash test, in conjunction with TCA extraction, for measuring formaldehyde in fish muscle was made more quantitative. This was done by means of a "recovery factor" which took into consideration the percent of formaldehyde added to the muscle extracted by the TCA solution. The average recovery from 15 different samples of cod muscle was 51.3% with anSDof 5.6. Because of differences between species in capacity to bind formaldehyde, it would appear that a different "recovery factor" may be required for each species of fish. As heating muscle increases its ability to bind formaldehyde, recovery factors developed for use with raw muscle are not applicable to the same muscle after it has been cooked. The percentage of added formaldehyde that was recovered varied with variations in the procedures used in preparing the muscle, making the extract, and carrying out the Nash test.

ISSN:0706-652X    

DOI:10.1139/f73-012

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

In studies on 11 rainbow trout (Salmo gairdneri), 217.3 ± 6.5 g, 14.0 ± 0.5 C) fitted with rubber membranes for direct measurement of ventilatory water flow, buccal, cleithral, and differential pressure traces increased in amptitude asrose from 40 to 160 ml/min. Ventilation rate remained steady at around 77 breaths/min in therange 40–120 ml/min and rose to 90 breaths/min at aof 175 ml/min. Oxygen uptake more than doubled asrose from 40 to 120 ml/min. Calculated utilization of oxygen from the inspired water declined only slightly over thisrange, indicating that large increases in nonrespiratory spillage of water (anatomical dead space) had not occurred. The calculated oxygen cost of breathing was low. Area mean differential pressure appeared closely related toover therange 40–160 ml/min. Area mean differential pressure increased from two- to four fold over thisrange, depending upon which individual fish was examined. Over therange 40–160 ml/min the calculated resistance of the gill sieve did not appear to decline although some variability was present and a variety of gill sieve resistances could be measured at a givenfor each fish. It is concluded that changes inare largely dependent on changes in mean differential pressures across the gills, with no marked decline in gill sieve resistance over the normal physiological range of.

ISSN:0706-652X    

DOI:10.1139/f73-013

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Oxygen tolerance was determined 0.25, 3, and 24 hr after introducing young American shad (Alosa sapidissima) to washtubs 7, 4, 2, 5, 2, and 2 days after previous disturbance in the holding tank. Dissolved oxygen at equilibrium loss and death varied from 1.1 to 8.0 and 0.9 to 5.7 mg/liter, respectively; and mean oxygen levels at equilibrium loss and death in the 3-hr × 2-day tests were 1.5–3 times higher than in any other handling combination. Present evidence indicates that the effects of handling American shad vary, with the intensity of excitement generated by handling seeming to determine whether the fish lives, dies immediately, or dies later. This phenomenon is probably responsible for difficulty in transporting and marking this species and for conflicting reports on oxygen requirements and salinity and low temperature tolerance. Mean oxygen levels with 99% confidence limits at equilibrium loss and death of unexcited individuals were 1.62 ± 0.13 and 1.28 ± 0.19 mg/liter, respectively. Virtually no individuals lost equilibrium or died until oxygen declined to 2.56 and 1.92 mg/liter, respectively. Nearly all lost equilibrium or died at 0.68 and 0.64 mg/liter, respectively. Field and laboratory evidence suggests that minimum daily oxygen levels of 2.5–3.0 mg/liter permit migration through polluted areas, but 4.0 mg/liter appears necessary in spawning areas.

ISSN:0706-652X    

DOI:10.1139/f73-014

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f73-015

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Odd-chain fatty acid (OCFA) levels in rainbow smelt (Osmerus mordax) from Jeddore Harbour, N.S., showed a pronounced seasonal variation during the period from spring 1969 to fall 1970, reaching a maximum of 20% total fatty acids in the January–March period, and falling to a minimum of approximately 2% total fatty acids in summer and fall. The variation appeared to be general, and occurred in all OCFAs. Analysis of smelt stomach contents suggested that OCFAs originated in the diet. Smelt caught in inlets adjacent to Jeddore Harbour showed no unusual accumulation of OCFAs in January, 1970.

ISSN:0706-652X    

DOI:10.1139/f73-016

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Fingerling channel catfish (Ictalurus punctatus) were injected subcutaneously and intramuscularly with an injectableChondrococcus columnarisantigen to test for the production of agglutinating antibodies. The test fish of both routes of injection had a mean titer of 1:4337. No significant differences in titers between the two routes of injection were determined.

ISSN:0706-652X    

DOI:10.1139/f73-017

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

An inexpensive, do-it-yourself hydrophone for tracking aquatic animals is described. It can be used with or without a preamplifier, on small or large boats. A new mounting arrangement used on the bow of a 25-m tracking vessel is discussed. It was used successfully in coastal waters at cruising speeds up to 9 knots (5 m/sec) and at slow speeds during rough weather in 30-knot (15.3 m/sec) winds.

ISSN:0706-652X    

DOI:10.1139/f73-018

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The winter surface circulation around Cape Breton Island was studied by tracking ice fields. The resulting streamlines compare favorably with prior work.

ISSN:0706-652X    

DOI:10.1139/f73-019

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A harp seal,Pagophilus groenlandicus, tagged in the Gulf of St. Lawrence, was recovered at sea off northern Norway at 14 months of age. From tag recoveries, the degree of transfer eastward of young animals from the morphologically most distinct western population of harp seals can be assessed at about 1%, and from the central to the morphologically rather similar eastern population, about 10%.

ISSN:0706-652X    

DOI:10.1139/f73-020

出版商:NRC Research Press    

年代:1973

数据来源: NRC