摘要:

Underwater biotelemetry includes studies of movements, behavior, and physiological functions of underwater animals, as well as environmental conditions surrounding them. In such studies data are received via signals from a transmitter on or in an animal. Ultrasonic signals were used in early work. More recently both ultrasonic and radio signals have been used.In the two decades since the first underwater biotelemetry studies in the mid-1950s there have been considerable technical advances. Transmitters have become smaller, more powerful, and have longer operating life. Coding of individual transmitters has become more reliable and decoding more automated. Transmitters capable of sensing environmental, behavioral, and physiological factors from free-swimming animals have been built. Receiving systems ranging from small ones for tracking from canoes to large ones for oceangoing vessels have been developed.With this equipment about 60 species of underwater animals have been studied. Various techniques of transmitter attachment have been developed and different methods of tracking explored.Underwater biotelemetry has been applied to studies of fish migration, orientation mechanisms, movement patterns at obstructions, ecology, behavior, and physiology of animals.Key words: telemetry, underwater biotelemetry, tracking, sonic tags, transmitters, receivers, hydrophones

ISSN:0706-652X    

DOI:10.1139/f77-189

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Lengths at 50% maturity of spiny dogfish (Squalus acanthias) in the Strait of Georgia, B.C., are 78.5 and 93.5 cm, corresponding to ages 19 and 29 yr, for males and females, respectively. Modal lengths of mature males and females are 85 and 100 cm, respectively.Mating occurs from October to January, with a peak in December. Males are capable of mating every year, with smaller dogfish mating earlier in the year than larger ones. Females mate every 2nd yr. Ovulation of 4 cm diam eggs closely follows mating. The fertilized eggs are enclosed in gelatinous capsules for 4 mo after which the embryos are released into the uterine cavity. The external yolk supply of the embryos is totally absorbed by parturition, although the internal yolk is not fully utilized until 2 mo later. Parturition occurs from September to January, with a peak in November. Gestation is roughly 23 mo. Breeding females produce a mean of 7.14 progeny.These population characteristics indicate that regulation of a future fishery should be by total catch limit rather than net mesh size selection.Key words: spiny dogfish, reproduction, length distribution, survivorship, fecundity, fishery regulation

ISSN:0706-652X    

DOI:10.1139/f77-190

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Antibody synthesis, in response to vaccination with a 0.1-ml (1.8 × 108 cells/ml) intraperitoneally injected, heat-killed strain ofFlexibacter columnaris, was employed to investigate the effect of tritium irradiation (0, 0.04, 0.4, 4.0, 40 rads total dose for 20 days during embryogenesis) on development of the primary immune response in 5-mo rainbow trout,Salmo gairdneri, reared under essentially pathogen-free conditions. Specific agglutinins toF.columnaris, determined 1-wk pre vaccination, and 3, 5, 7, 9, and 11 wk postvaccination increased rapidly in both control and irradiated fish following vaccination. Agglutinin levels in irradiated fish were suppressed to 50% of control levels at 40 rads during the 9th wk, and 50% of control levels at 4.0 rads during the 11th wk. Electrophoretic separation of serum proteins of both control and irradiated–vaccinated fish demonstrated four major protein fractions. Densitometry analyses demonstrated that fraction IV increased significantly in percent of total protein following antigenic stimulation, suggesting that fraction IV represents the specific humoral antibody toF.columnaris. The relative percent of total protein contained in fraction IV was significantly reduced in irradiated–vaccinated fish.Key words: antibody synthesis, agglutination assay, vaccination,Flexibacter columnaris, tritium,Salmo gairdneri, electrophoresis, serum protein, densitometry, primary immune response

ISSN:0706-652X    

DOI:10.1139/f77-191

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Cross sections of the 4th–8th fin rays from the second dorsal fin provided reliable ages of lingcod (Ophiodon elongatus), although there was some difficulty interpreting the ages of 1- and 2-yr-old fish. Length was an acceptable indicator of age 1- and 2-yr-old fish. After a scale age of 5 or 6 yr, the scale annulus became difficult to identify. After age 7 or about 75–85 cm, fin-ray ages were older than scale ages. Some of the oldest fish averaged 8 yr older by the fin-ray method.Mature females attained much larger mean sizes than males of similar age, and there was considerable variation in size of similar-aged older fish.Key words: Age determination, fin rays, scales,Ophiodon elongatus, ageing errors.

ISSN:0706-652X    

DOI:10.1139/f77-192

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Laboratory and field crosses show that the absence of the pelvic skeleton in a brook stickleback population is under partial genetic control. Some offspring of parents lacking the pelvis possess a complete pelvic skeleton, while some offspring of parents with a complete pelvic skeleton lack the pelvis. Although a wide range of morphologically intermediate states exists, intermediates do not predominate in the crosses.Loss of the pelvic skeleton occurs in Ontario, Saskatchewan, and Alberta. Within Alberta, 23 localities are known where 20% or more of the sticklebacks lack a complete pelvic skeleton. In some localities 95% or more of the individuals lack all trace of the pelvis. Variation in predation is inferred to be the environmental variable causally associated with the presence or absence of the pelvic skeleton. The absence is postulated to have arisen independently in the various localities.Key words:Culaea inconstans, brook stickleback, pelvic skeleton absence, genetic control.

ISSN:0706-652X    

DOI:10.1139/f77-193

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

New descriptions, redescriptions, taxonomical and ecological comments, and distribution records are given for known stages of 14 species ofParacladopelmaHarnisch and 3 species ofSaetherian.gen. Seven species are described in all stages.Saetheria reissin.sp.,Paracladopelma winnellin.sp., the immature stages ofSaetheria tylus(Townes),Paracladopelma galaptera(Townes),Paracladopelma nereis(Townes), a larval-pupal association placed inSaetheria, and two larvae placed inParacladopelmaare new to the literature. The immature stages ofParacladopelma nais(Townes),Paracladopelma loganaeBeck and Beck andParacladopelma undine(Townes) are redescribed.Keys are provided for the known Nearctic larvae and pupae and for both Nearctic and Palaearctic adult males ofSaetheriaandParacladopelma.Key words: Chironomidae,Paracladopelma,Saetheria. Great Lakes

ISSN:0706-652X    

DOI:10.1139/f77-194

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Dehydration of infectious hematopoietic necrosis virus (IHNV) from water at 4 and 10 °C resulted in only partial inactivation, but dehydration from Hanks' balanced salt solution (HBSS) and homogenized fish tissue resulted in total loss of virus infectivity within 7 days. Survival was not affected by pH between 6 and 8, but virus infectivity was significantly reduced at pH 5 and 9. Water hardness from 20 to 250 mg/ℓ (as CaCO3) did not significantly reduce virus infectivity. Salinity distinctly affected IHNV survival: storage in artificial seawater, filtered ocean water, HBSS. and Earle's balanced salt solution (EBSS) equally reduced virus titers. The addition of protein to deionized water and EBSS and HBSE resulted in increased survival. Survival of IHNV was inversely proportional to HBSS concentration and was highest when it was frozen in media supplemented with 10% calf serum. Virus survival was good at −70 and −20 °C, but virus infectivity decreased sharply with an increase of temperature above 4 °C; increasingly poor survival occurred at 15. 21, 28, and 32 °C. Freezing and thawing of IHNV had no effect if the media contained 10% protein; however, freezing in deionized water resulted in a significant loss of virus infectivity.Key words: virology, virus survival, laboratory storage, environmental effec

ISSN:0706-652X    

DOI:10.1139/f77-195

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The spotted bass (Micropterus punctulatus) and rosyface shiner (Notropis rubellus), when exposed to successively doubling doses of total residual chlorine (TRC) from 0.025 to 0.80 mg/ℓ, generally avoided higher concentrations when acclimated and tested at five temperatures from 6 to 30 °C. Both species avoided 0.05 mg/ℓ TRC when acclimated and tested at 6 °C and avoided 0.20 mg/ℓ TRC at 24 and 30 °C. Variations in avoidance of the free residual chlorine (FRC) ranged from 0.017 to 0.091 mg/ℓ (0.05 to 0.20 mg/ℓ TRC) between 6 and 30 °C. After the initial avoidance response, the rosyface shiner continued to avoid the remaining higher residual levels, while spotted bass showed less avoidance or none at all. The same behavioral responses occurred when each species was exposed to a single concentration (0.05 or 0.10 mg/ℓ TRC) for three successive 10-min observations.The avoidance response was most closely associated with the calculated hypochlorous acid (HOCl) fraction of the TRC, which declined (relative to the percent of TRC) as the pH and acclimation temperature increased. Avoidance to HOCl occurred between 0.012 mg/ℓ (6 °C) and 0.031 mg/ℓ (30 °C) when TRC was between 0.05 and 0.20 mg/ℓ, respectively. Avoidances did not occur at the 12 and 18 °C acclimation temperatures until the HOCl content comprising the 0.10 and 0.20 mg/ℓ TRC doses surpassed the initial HOCl threshold level (0.012–0.014 mg/ℓ) calculated for 0.05 mg/ℓ TRC at 6 °C. The HOCl content may be the most important constituent within the TRC to influence the avoidance response of fish in unpolluted aquatic systems.Key words: avoidance response, hypochlorous acid, free residual chlorine,Micropterus punct

ISSN:0706-652X    

DOI:10.1139/f77-196

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Groups of sea lampreys (Petromyzon marinus) of 10–90 g initial weight were held at temperatures of 1–20 °C for 30 days and allowed to feed ad lib. on white suckers (Catostomus commersoni). Increases in water temperature and in lamprey size caused the rate of host mortality to increase in agreement with observations that mortality in the Great Lakes is seasonal. Instantaneous growth rates were maximal at 20 °C for lampreys of 10–30 g, the optimal temperature for growth shifting to 15 °C for larger lampreys of 30–90 g. Growth rates were intermediate at 10 °C and lowest at 4 °C for lampreys of all size. Accordingly, host mortality increased with temperature over the 4–20 °C range. At all experimental temperatures, increases in lamprey weight were accompanied by an exponential decline in instantaneous growth rates, a phenomenon also observed for teleosts. Laboratory growth rates at temperatures of 5–15 °C were comparable to rates observed for lampreys in Lake Huron between April and November and agree with the observation that lampreys feed in deeper waters between April and June before moving to warmer, shallower waters during the summer when growth rate increases.Key words: sea lamprey, white sucker, host, temperature, growth, Great Lakes, mortality

ISSN:0706-652X    

DOI:10.1139/f77-197

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The movement of underyearling sockeye salmon (Oncorhynchus nerka) in Babine Lake was computer simulated using a grid array with reflection principles applied for the complex shoreline boundaries. Dispersal was in accord with bivariate density functions summed appropriately to give 25 discrete components, with the standard deviations related to observed swimming speeds. Directionally biased dispersal was simulated using the lognormal density function. Natural movement of sockeye underyearlings in Babine Lake suggests three seasonal periods: (1) May 25–June 12; (2) July 13–August 28; (3) August 29–October 12. For (1), natural movement is best simulated by assuming that 90% of the fish move with a 10:90 bias toward southward movement, while 10% of the fish move at random; for (2), the best assumptions are that 50% of the fish move with a 90:10 bias for northward movement and 50% move at random; for (3), the best simulation assumed that 100% of the fry move at random. Considering the simplicity of the model assumptions, the fit to the data for natural movements is good. To construct a better predictive model the directional bias mimicked by the lognormal density function should be divided into components related to physical circulation in the lake basin and components related to fry behavior. The architecture of the computer program is briefly described and could be applied to other salmon dispersal studies.Key words: sockeye salmon, simulation, natural movements, fry distribution

ISSN:0706-652X    

DOI:10.1139/f77-198

出版商:NRC Research Press    

年代:1977

数据来源: NRC