摘要:

New electrophoretic analyses have provided additional information concerning intraspecific genetic variation among largemouth bass Micropterus salmoides. Genetic differences, previously unknown, were found among four stocks of largemouth bass, two of them domestic and two of which were one generation removed from the wild. The domestic stocks were derived from intergrade populations of northern and Florida subspecies; one nonintergrade stock represented the northern subspecies M. s. salmoides and the other represented the Florida subspecies M. s. floridanus. More than 60 presumptive loci were electrophoretically examined. At least 11 loci were polymorphic. Of the polymorphic loci, two represented previously known fixed subspecific differences and two or perhaps three represented previously known allele frequency differences. Variation among the stocks at the remaining loci was expressed as allele frequency differences. Allelic polymorphisms restricted in our sample to Florida or intergrade populations (or both) were observed at superoxide dismutase-2 and α-glycerophosphate dehydrogenase-A (loci with previously described variability), and at adenosine deaminase, alcohol dehydrogenase, galactose-1-phosphate uridyltransferase, and mannosephosphate isomerase. Variation restricted to northern largemouth bass and intergrade populations was observed for malate dehydrogenase-1 (previously reported), peptidase-3, and triosephosphate isomerase-2.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<460:NBGMFL>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A protocol for experimental challenge with infectious pancreatic necrosis (IPN) virus was defined with brook trout Salvelinus fontinalis as the model species. Fish were exposed by immersion for 5 h in water containing IPN virus at a concentration of 105plaque-forming units per milliliter. We propose the protocol as a standard challenge based on our studies of exposure methods and host response to virulent virus. Immersion challenge induced higher and more consistent mortality than did challenge by hyperosmotic infiltration. Challenge virus should be sequentially transferred no more than five times in cell culture because further transfers reduced the virulence of the virus. At 12°C, mortalities due to primary infection occurred 6–12 d after immersion challenge and were highest (≥70%) in fish 27–56 d old. Susceptibility to lethal infection was enhanced by nutritional stress.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<466:IPNV>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Only claws are harvested from stone crabs trapped in marine waters off Florida, and crabs are released to regenerate them. In practice, stone crabs often are held in shipboard boxes and declawed as vessels return to port. A direct relationship exists between holding time and stone crab mortality, but mortality is reduced significantly when crabs are dampened periodically with seawater. When crabs held 6 h in boxes were wetted with seawater once every hour, mortality declined from 100% (no wetting) to 23% (periodic wetting). Mortality of both wetted and unwetted stone crabs increased when claws were not broken along the natural fracture plane.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<471:EOAEAC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Growth and activities of the digestive enzymes trypsin, chymotrypsin, carboxypeptidase A, α-amylase, and pepsin in striped bass Morone saxatilis were measured from the day before the fish first accepted food (day 4) to near the end of larva development (day 32). Fish were fed either live brine shrimp nauplii Artemia sp. (BSN), heat-killed BSN, or a prepared diet designed to be nutritionally complete with satisfactory physical and palatability properties. The larvae consumed the prepared diet but did not grow and all larvae fed this diet died soon after day 16. Larvae fed live or heat-killed BSN grew satisfactorily but growth of fish fed live BSN was faster (P < 0.05). With the exception of pepsin, which was not found until day 16, all of the measured enzymes were present in the digestive tract at the time of first feeding and activities of these enzymes were 25 to 60% of those at day 32, For the first 12 d, specific activity of the enzymes was not influenced by growth or diet. Near day 16, enzyme activities decreased for all diet groups but after day 16 enzyme activities increased with growth rate. These results suggest that lack of growth by fish fed the prepared diet was caused not by inactivity of digestive enzymes but possibly by deficiency of growth factors supplied in living or heat-killed BSN.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<478:DEAISB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Monthly sensory (taste) analyses of channel catfish Ictalurus punctatus from 11 commercial culture ponds in Alabama during April-October 1983 showed that earthy-musty flavor was the major off-flavor during the summer growing season. Geosmin (1,10-trans-dimethyl-trans-(9)-decalol) was found by gas chromatography in detectable amounts, 3.7 to over 200 μg/kg of fish flesh, in 80% of fish having earthy-musty or detritus (pond mud) flavor. Geosmin was not found in fish without these flavors. The geosmin analysis procedure used in this study recovered 68 to 85% of geosmin added to fish flesh, at concentrations ranging from 8 to 32 μg/kg, with relatively high consistency (SD = 2.5–3.3). Reproducibility in analysis of fish with naturally occurring geosmin (6–15 μg/kg fish) was also favorable (coefficients of variation, 100˙SD/mean, 6.9–16.8%). The compound 2-methylisoborneol, found in muddy-flavored rainbow trout Salmo gairdneri, could not be confirmed as an off-flavor compound in channel catfish. The use of geosmin analysis to partially replace sensory evaluation of channel catfish for off-flavor during summer appears feasible.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<485:GAMFIP>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Observations of a school of adult yellowtail rockfish Sebastes flavidus over an 11-year period in southeastern Alaska revealed negligible recruitment as the school dwindled in numbers and remaining individual fish grew in size.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<490:RYSARL>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Crossbred coho salmon Oncorhynchus kisutch were produced from all possible crosses among three stocks. The relative susceptibility of the progeny to infection by the myxosporean parasite Ceratomyxa shasta was determined by exposure of juvenile fish to Willamette River water that contained the infective stage of the parasite. Susceptibility of coho salmon native to the Columbia River basin to the disease ceratomyxosis was relatively low whereas that of coho salmon from remote locations was relatively high. Susceptibility of crossbred progeny nearly always was intermediate between the susceptibilities of fish from the parental stocks.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<492:SOPFCA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Plasma corticosteroid concentrations were measured in 14 species of fish immediately after they were electrofished from reservoirs on the Alabama River and after they had been transported for 2 h. There was no corticosteroid response in spotted gars Lepisosteus oculatus. Bowfins Amia calva, longnose gars Lepisosteus osseus, and freshwater drums Aplodinotus grunniens had only small corticosteroid increases (14–39 ng/mL) during transportation. Corticosteroids increased by intermediate amounts (59–184 ng/mL) during transportation in blue catfish Ictalurus furcatus, paddlefish Polyodon spathula, largemouth bass Micropterus salmoides, channel catfish Ictalurus punctatus, river carpsuckers Carpiodes carpio, white bass Morone chrysops, striped bass Morone saxatilis, and crappies Pomoxis sp. The greatest increases were 223 ng/mL in gizzard shad Dorosoma cepedianum and 286 ng/mL in common carp Cyprinus carpio. Spotted and longnose gars, largemouth bass, and common carp also were held in tanks for about 2 months at 21°C and then stressed by confinement in a dip net for 30 min. The confinement caused significant increases (P < 0.01) of plasma corticosteroid concentration in all four species. Dip-net confinement appears to be a useful method for comparing corticosteroid responses among species of warmwater fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<495:PCSROF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<499:E>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1984.10492816

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor