摘要:

Ages of adult goldeyesHiodon alosoidescollected in 1987 from the Peace–Athabasca delta, northeastern Alberta, were determined from scales and opercula. Mean ages estimated from scales (N= 114) and opercula (N= 117) were 8.5 and 14.8 years, respectively, and the maximum age discrepancy for a single fish was 10 years. The 1971 year-class, dominant and abundant during the 1970s, was used to assess general accuracy of the two age determination methods. The 1971 year-class represented 25% of the 1987 catch of adult goldeyes by the operculum method, but was not recorded by the scale method. This suggests that opercula provided accurate (correct) estimates of age for many of the adult goldeyes.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1992)121<0792:EOTSAO>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Catch-per-unit-effort (CPUE) data for lake whitefishCoregonus clupeaformisin Michigan waters of Lake Huron were examined with time analysis to test if they can describe the abundance of lake whitefish. Relations between lake whitefish CPUE and environmental and biological data were investigated with cross-correlation analysis. A 4-year time lag, corresponding to the age at maturity, was found for lake whitefish CPUE. Cross-correlation analysis indicated that lake whitefish CPUE was negatively correlated with monthly air temperatures and abundance of sea lampreyPetromyzon marinusin previous years, and CPUE was positively correlated with fishing effort 1 year later. The results indicated that fishermen track lake whitefish abundance and that CPUE can describe fluctuations of the lake whitefish population.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1992)121<0797:VOLWCD>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We formulated four diets that simulated the amino acid profiles of eggs of striped bassMorone saxatilis, carcasses of larval striped bass, eggs of rainbow troutOncorhynchus mykiss, or nauplii ofArtemia salina; a fifth diet contained a high concentration (33.6%) of shrimp meal. These diets were fed to juvenile striped bass for 14 weeks. Striped bass grew best when fed diets with an amino acid pattern that simulated the patterns of rainbow trout eggs orArtemia salina. Fish fed these two diets grew as well as, and had carcass compositions and protein efficiency ratios similar to those of, control fish fed the federally specified ASD2-30 salmon diet. No histological or morphological abnormalities were noted. These two diets, which have potentially lower production costs and contain slightly less protein than ASD2-30, may be used as prototype diets specifically for striped bass. Through further minor refinements, the diets could be used in production hatcheries.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1992)121<0802:DOAPDF>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A study of polymorphic allozyme loci in five samples of rainbow troutOncorhynchus mykissfrom central North Island, New Zealand, showed no significant differences in allele frequencies among samples. These and results from similar studies suggest that no genetic differentiation at allozyme loci has occurred in New Zealand rainbow trout since the species was first introduced from coastal California in 1883. This contrasts with recent studies showing differences in morphometric and developmental characters among New Zealand rainbow trout populations, some of which seem to be heritable.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1992)121<0810:NAVIRT>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

An immature female Atlantic salmonSalmo salar, caught by a commercial salmon troller off southeastern Alaska on 20 July 1990, is the first documented representative of this species in the marine waters of Alaska. Identification was based on morphology, meristic characters, and protein electrophoresis. Scale growth patterns, an eroded or clipped dorsal fin, and a high proportion of regenerated scales indicate that the fish escaped from an aquaculture pen during spring 1990. Five additional Atlantic salmon were subsequently caught by commercial fishermen in southeastern Alaska during August 1991; identification was based on morphology and color patterns, Escaped Atlantic salmon are unlikely to have a genetic impact on native Pacific salmonids, but the possibility exists that they will disseminate nonendemic pathogens or parasites.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1992)121<0814:ASIMWO>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Adult striped bassMorone saxatiliswere captured in 20–40-min gill-net sets in the San Joaquin River, California, and in 24–48-h fyke-trap sets in the Sacramento River as part of a tagging program. They were bled by cardiac puncture for various measurements of stress responses to capture and handling. Fish caught in gill nets were more lethargic, were kept longer out of water, and were significantly more acidotic (lower blood pH and higher lactate concentration) than fyke-trapped fish. Gillnetted fish also had a significantly higher Pco2, hematocrit, and plasma glucose and potassium concentrations than fyke-trapped fish. Both capture methods induced secondary stress responses, but responses were greater in gillnetted fish, probably because gill nets restricted buccal and opercular movements.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1992)121<0819:PEOCSB>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Opaque bands on otoliths were validated as annuli for bluegillsLepomis macrochirusthroughout their lives in Par Pond, a nuclear reactor cooling reservoir in South Carolina. Whole mounts of otoliths were suitable for age determination of young bluegills (less than 5 years old), but both whole mounts and otolith sections were necessary for age determination of older bluegills. Marginal increment analyses indicated that annulus formation began as early as February and was complete by June in bluegills of ages 1–9. Annulus formation began earlier in younger (age 1–2) bluegills than in older individuals. Similarity of observed and back-calculated sizes at age supported identification of opaque bands as annuli. Input of warm water from reactor operation occasionally produced opaque bands (false annuli) on otoliths; however, the faintness and incompleteness of such bands clearly distinguished them from true annuli. Identification of the first annulus of some otoliths was problematic due to the occurrence of two types – opaque and translucent – of otolith center (incremental area around the primordium extending out to the first contrasting band). Use of daily otolith increments established that opaque otolith centers were not annuli, Bluegills with opaque otolith centers hatched during the period of annulus formation and were about 1 month older on average than bluegills with translucent otolith centers, which hatched after the period of annulus formation. Comparison of growth rates in Par Pond and elsewhere, though complicated by other researchers' use of scale information, suggests that errors in age determination were unlikely, This study extends previous research into validating annuli of bluegill otoliths to older fish and confirms the utility of otolith information for age assessment of another centrarchid species.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1992)121<0823:VOOAOB>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor