摘要:

Channel catfish, Ictalurus punctatus (Rafinesque) exhibited changes in levels of muscle and blood electrolytes during recovery from short-term hypoxia. Ten minutes of confinement in water having zero mg/liter oxygen resulted in an acidosis characterized after 1 hr of recovery by elevated blood lactate, decreased blood pH, and an increase in plasma osmolarity and hematocrit. Muscle water content was increased at this time. Later changes in these parameters appeared to be influenced by season or temperature. Plasma osmolarity dropped below control levels in June and remained depressed after 36 hr of recovery. In August plasma osmolarity fluctuated at levels above control values and had not returned to normal after 48 hr. These data indicate that electrolyte imbalance persists for many hours after blood lactate has declined to control levels and this imbalance may limit the fish's ability to tolerate further stress.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<593:TEOHOC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Development and use of DAM, a computer-implemented learning exercise designed to illustrate management of a large multiple-use reservoir system, is described. Five management roles are available to students using DAM: (1) a regional planning commissioner; (2) a fisheries manager; (3) a power company executive; (4) a recreation specialist; and (5) a city mayor. We found that allowing students to switch roles emphasized inherent management conflicts and increased total system appreciation. There is no “best” management scheme for DAM. In practice, students manage until they can agree on and defend a particular strategy. The specific goal of DAM is to provide students with an understanding of the principles and problems of managing a multiple-use resource. Response from students indicates this goal was achieved. DAM is currently played by students' keypunching decisions on computer cards and submitting these to the computer center. An improvement would be to place DAM on a permanent file for access by remote typewriter terminal.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<601:D>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Two caryophyllaeid cestodes are described, Monobothrium fossae sp. n. from the blacktail redhorse Moxostoma poecilurum (Jordan) and Monobothrium mackiewiczi sp. n., from the Alabama hog sucker, Hypentelium etowanum (Jordan) from Alabama. M. ulmeri Calentine and Mackiewicz collected from the silver redhorse Moxostoma anisurum Robin and Raney in Lincoln County, Georgia constitutes a new locality record for the cestode, previously unknown south of Tennessee or east of Oklahoma. A table comparing the five North American species of Monobothrium is presented.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<610:TNSOMC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The reciprocal of the slope of the regression of force of total mortality on force of reported fishing mortality provides an estimate of the percent of tags returned from tagged fish which are caught. Necessary conditions for the validity of this procedure are presented. An example of the technique is given.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<616:EOTFOA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The parasiticidal activity of Antimycin A was tested against Cleidodiscus pricei Mueller, 1936 on fingerling and adult channel catfish, Ictalurus punctatus (Raf.). C. pricei was eliminated from two groups of fingerlings after 24 hr and 48 hr at Antimycin A concentrations of 0.5 μg, 1.0 μg, and 5.0 μg/liter. In two field tests, C. pricei was eliminated from adults after 48 hr of Antimycin A concentrations at 1.0 μg and 3.5 μg/liter.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<618:AEOAAA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Effects of a plunging water flow on the behavior of green sunfish (Lepomis cyanellus) 7.1 to 9.7 cm in total length were studied at the outflow of a 1.6-ha pond. Jumping ability and behavior were measured at 12-hr intervals using a fish's position in a 0.9 m2-vertical grid or in the discharge pipe. Activity was influenced by flow rate, time of day, and time of year. Fish jumped up to 10 times their body length and traversed a horizontal distance of 0.6 m. Fish with the greatest mean length jumped the highest. The majority of the fish were captured during the 0600-hr tending period: 79.9% pipe only study and 82.4% pipe and grid combined study.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<620:TJAABO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Channel catfish embryos and resulting larvae were exposed to several reduced dissolved oxygen concentrations and control concentrations near air saturation at 25 and 28 C (7.8 and 7.3 mg/liter, respectively). At 25 C survival was similar but slightly reduced at 60% and 70% saturation (5.0 and 5.8 mg/liter) and was statistically less (P=0.01) at 30% and 50% saturation (2.4 and 4.2 mg/liter). No embryos hatched at 20% (1.7 mg/liter) and 25 C. Survival to the end of the test at 28 C was slightly reduced at 50%, 60%, and 70% saturation (3.8, 4.6, and 5.4 mg/liter) and was statistically less (P = 0.01) at 30% saturation (2.3 mg/liter). At all reduced oxygen concentrations at 25 and 28 C embryo pigmentation was lighter, duration of hatch was extended, feeding was delayed, and growth was reduced.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<623:EOLDOC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Pinfish (Lagodon rhomboides) were fed cerium-144 labeled food to determine if movement of the label could be used to estimate food evacuation time. Radioactivity was retained by the fish until their gastrointestinal tracts were empty. Replicate measurements showed that individual fish may have significantly different evacuation rates. Cerium evacuation and serial slaughter methods provided similar estimates of evacuation time; for the same precision fewer fish are needed for the cerium method. From these experiments, it appears that144Ce can be used as a tag to measure food evacuation time.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<626:ARMOMF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Four-hundred-and-forty-six electrophoretic patterns of bluegill (Lepomis macrochirus) serum proteins were analyzed to determine the condition of fish when sampled from ponds with different population densities. It was extremely difficult to rank ponds according to population density by using electrophoresis because of intraspecific variation. This variation was attributed to sex, maturity, season, and ponds, but not all the variation was accounted for in these variables.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<630:SPVIBL>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

From 1,760 freshwater threespine stickleback examined, plerocercoids of Schistocephalus solidus and parasitic copepods, Thersitina gasterostei, were found on 22% and 21%, respectively. The former was more common in pond fish (29%) than stream fish (4%), and conversely the latter was more common in stream fish (56%) than pond fish (7%). Fish infested with S. solidus were hindered in speed and agility; those with T. gasterostei had hypertrophied gill filaments.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<632:TPOTSF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor