摘要:

Serum of furunculosis-resistant rainbow trout Salmo gairdneri, when injected into brook trout Salvelinus fontinalis, increased resistance of the brook trout to virulent challenges of Aeromonas salmonicida, the furunculosis pathogen. Serum from susceptible Atlantic salmon Salmo salar did not confer passive resistance on brook trout although natural agglutinin titers in Atlantic salmon serum were equal to those in rainbow trout. Further analyses indicated that rainbow trout serum neutralized toxic components produced by A. salmonicida, but that Atlantic salmon serum did not. When 11 strains of rainbow trout were challenged with 109virulent cells of A. salmonicida, a range of mortality from 0 to 83% resulted. Although no correlation was observed between the natural serum agglutinin level of a particular strain and its relative resistance to experimental pathogen challenge, an inverse relation was apparent between cytotoxic serum-neutralization activity and resistance to furunculosis.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1983)112<95:ROSTAS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

This study was designed to mimic conditions that could exist during an accidental spill of hydrazine, a fuel for missiles and jet engines. Twelve-day-old eggs of rainbow trout Salmo gairdneri were exposed to nominal hydrazine concentrations of 0.01, 0.1, 1.0, and 5.0 mg/liter. The eggs were exposed for 48 hours and subsequently maintained in a recirculating-flow system. Exposure to the various concentrations of hydrazine did not result in significant mortality or reduction in hatching. Aberrations in morphogenesis of larvae included loss of muscular control, reduced growth rates, and loss of tactile sensitivity at concentrations of 1.0 and 5.0 mg/liter.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1983)112<100:EOHOFM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Movements and distribution of eight immature American eels Anguilla rostrata were monitored periodically with location-only ultrasonic transmitters for 5 days in Fridaycap Creek, a Georgia estuarine stream. Fish were concentrated within 25 m of the mouths of feeder creeks. Movements were usually with tidal currents and were restricted to 400 m of the 1,000-m study section. Moves greater than 50 m usually involved round trips from and to a point of origin. Limited movements and regions of concentrated activity may be evidence of home ranges within the creek. Daytime movements were restricted to the main creek channel, shorelines being preferred during high tides and the midchannel during low tides. At night, fish were generally near mouths of feeder creeks during low tides; they often moved up feeder creeks and even onto the marsh with a flood tide, returning to the feeder mouth as the tide ebbed. Tendency to move with tidal currents, activity region sizes, and types of habitats frequented were all more variable at night. Our results suggest a basic pattern of nocturnal activity and diurnal inactivity that is modified by tidal flow.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1983)112<105:UTOAEM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Local movements of 16 radio-tagged American eels Anguilla rostrata were monitored in Lake Champlain, Vermont. Within water depths to 10 m, total displacement distances (sum of straight-line distance between successive position fixes) ranged from 0.6 to 4.9 km per fish; these distances were not well correlated with tracking times (4 to 67 days). Displacement polygons defined by individual tracks had areas of 2.4 to 65.4 hectares. Some American eels showed substantial movement in the first few days after release, whereas others did not; most remained in shallow water, but some moved into deeper water. Fish were displaced up to 0.9 km between capture and release; only two returned to within 500 m from their capture site, indicating that little precise homing occurred. Inshore population-size estimates from multiple mark-and-recapture methods varied from 232 to 636 fish/hectare (161–421 kg/hectare). Seven tagged individuals have been recaptured outside the study area: five at St. Jean, Quebec, one in Quebec City, Quebec, and one in St. Andres, Quebec.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1983)112<111:LMAIPS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Mean values for percent methemoglobin were obtained for 13 groups of channel catfish Ictalurus punctatus from commercial production ponds in west-central Mississippi. Mean percent methemoglobin was correlated with ambient nitrite concentrations (r2= 0.51; P > 0.05). The correlation was improved when mean percent methemoglobin was regressed on the molar ratio of nitrite: chloride concentrations (r2= 0.96; P > 0.01). These data indicate that percent methemoglobin can be predicted more accurately by nitrite-to-chloride ratios than by nitrite concentrations alone.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1983)112<117:ERBPMI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Correction factors for the oxygen-transfer coefficient (α) and correction factors for the concentration of oxygen at saturation (β) were determined for waters from 43 fish-culture systems. Values for α ranged from 0.66 to 1.07 (mean = 0.94), and β factors ranged from 0.92 to 1.00 (mean = 0.98). The magnitudes of α and β factors were not correlated with turbidity, specific conductance, chemical oxygen demand, or chlorophyll-α concentration. A table of factors for estimating aerator performance under pond conditions was developed.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1983)112<120:CFFCOR>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1983.10493222

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor