Precision of Estimated Ages of Lake Trout from Five Calcified Structures

Sharp, D.E.; Bernard, David R.

doi:10.1577/1548-8675(1988)008<0367:poeaol>2.3.co;2

Cited by 47 publications

(36 citation statements)

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“…While validation by means of the above-described methods is desired, Kocovsky and Carline (2000) recommended comparing results from multiple aging structures when beginning research on unstudied fish stocks, and many other authors have used this comparative approach (e.g., Boxrucker 1984;Sharp and Bernard 1988;Stolkarski and Hartman 2008). Although such an effort does not constitute a true validation study, obtaining similar age estimates for multiple structures can provide additional confidence with aging results (Casselman 1987).…”

Section: Introductionmentioning

confidence: 99%

Validation of scales and otoliths for estimating age of redband trout in high desert streams of Idaho

2010

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Studies validating aging structures for rainbow trout are sparse and none have been conducted for redband trout, a common western U.S. sub-species. Oxytetracycline mark-recapture methods (MR), marginal incremental analysis (MIA), and comparisons across multiple populations were used to evaluate the utility of two structures for aging redband trout in high desert streams. We assessed periodicity of annulus formation on scale and otolith samples from all age classes of trout residing in two streams, identified the location of the first annulus on otoliths, and compared age estimates and between-reader coefficient of variation on nine additional streams. The use of MIA successfully validated opaque zone periodicity for fish transitioning from age-0 to age-1, and from age 1 to age 2 in two streams. For fish at liberty 13 and 28 months in the same two streams, MR-derived age estimates from whole and sectioned otoliths were 94-100% accurate for fish from 2-9 years old. Scales were only 77% and 38% accurate for fish at liberty 13 and 28 months, respectively. Between-reader coefficient of variation (CV) for scales was high (11.5%), while CV for sectioned otoliths using whole otoliths as corroboratory structures averaged 2.3%. Scales were thus, an unacceptable aging structure for desert redband trout. Given the confusion in the literature, we suggest that more rigorous research should be conducted to define and explain otolith zone formation.

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Section: Introductionmentioning

confidence: 99%

Validation of scales and otoliths for estimating age of redband trout in high desert streams of Idaho

2010

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“…Opercular bones were reported to be superior to all other structures in common carp, (C. carpio; McConnell 1952) and in C. catla (Khan and Khan 2009). Sharp and Bernard (1988) reported that opercles provided age estimates nearly identical to those from otoliths and suggested the use of opercles in place of otoliths for many age and growth studies on lake trout (Salvelinus namaycush) from Alaskan lakes. Khemiri et al (2005) found opercular bones unsuitable for age estimation in Boops boops from Tunisian waters.…”

Section: Discussionmentioning

confidence: 99%

Precision of aging structures for Indian major carp,Cirrhinus mrigala, from the River Ganga

Khan

Miyan

2011

Journal of Freshwater Ecology

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Scales, opercular bones, otoliths, vertebrae, and dorsal fin rays were compared to ascertain the best aging structure of Cirrhinus mrigala. All structures showed alternating opaque and translucent bands that were interpreted as annuli; however, structures differed greatly in the clarity of their presumed annual marks. Age estimates were compared by calculating the percentage of agreement (PA), average percentage of error (APE), and coefficient of variation (CV) and by constructing age bias plots. Age estimates were evaluated between readers and between the pairs of aging structures. Among all structures, scales showed the clearest annual rings and had highest (94.6%) PA between readers, followed by opercular bones (88.6%), otoliths (83.9%), vertebrae (79.9%), and dorsal fin rays (62.4%). Due to highest PA and lower minimal aging error, the scales were considered the most reliable bony structure for aging C. mrigala. When scale ages were compared with those of the other structures, the highest PA and lowest APE and CV values were found between scale and opercular bone estimates. Mean values of age estimate from scales were comparable ( p40.05) to the values obtained from opercular bones, otoliths, and vertebrae and were significantly ( p50.05) different with the dorsal fin ray age estimates. Scales were the most suitable structures for age estimation in C. mrigala.

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“…Otolith aged fish were estimated to be older than those estimated by scales. Lake trout (Salvelinus namaycush) otoliths have been reported to be the best out of five different bony structures for aging (Sharp and Bernard 1988). Bull trout are taxonomic cousins of lake trout and are morphologically similar.…”

Section: Discussionmentioning

confidence: 99%

“…The ages determined by otoliths and scales were compared to verify the estimated age of the captured fish. Both aging methods were used to maximize precision and reduce biases (Sharp andBernard 1988, Beamish andMcFarlane 1983). We also back-calculated length at age in order to determine if the growth rates of each species differed between study streams.…”

Section: Age and Growthmentioning

confidence: 99%

“…As a result, the use of bony structures as a media for aging and backcalculated growth rate has become a topic of heated debate (Francis 1990;Carlander 198 1;Campana 1990). The debate has revolved around which bony structures best estimates the age and growth rate of a given species and to what extent is somantic growth coupled with bony structure growth (Hubert et al 1987;Sharp and Bernard 1988;Wright et al 1990). …”

Section: Introductionmentioning

confidence: 99%

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Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams. Final Report 1992.

Underwood¹

1995

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The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Uncorhynchus mykiss) and spring chinook salmon (0. &zwytscha) negatively impacted wild native bull trout (Su2velinu.s confluentus) through competitive interactions. Four streams with varying levels of supplementation activity were sampled in Southeast Washington: Mill Creek, Tucannon River, Wolf Fork and Asotin Creek. Mill Creek was not supplemented with hatchery reared fish. The Tucannon River was intensely supplemented with hatchery reared steelhead smolts, rainbow trout and spring chinook salmon smolts. Wolf Fork was indirectly supplemented with hatchery reared steelhead smolts by releasing smolts at the mouth of the stream. Asotin Creek was supplemented for three years in the mid-1980's with hatchery reared steelhead smolts. Sampling in Asotin Creek was discontinued after the first year of study because too few bull trout were collected for analysis (n = 1). Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. The data were used to identify the extent of geographic overlap among species and resources utilized by each species. This information was compared among stream populations and among species within a stream to identify changes in behavior that resulted from supplementation activities. We found that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and 0. mykiss significantly overlapped in each of the study streams, however, food was abundant and did not appear to be a limited resource. Age at length and backcalculated lengths identified differences in growth among bull trout and steelhead populations. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although, other factors such as stream temperature may have contributed to the difference in growth. Condition factor among stream populations did not differ suggesting that the ability of each fish species to add weight as length increased was the same among stream populations. At current population levels, and current habitat quantity and quality, we detected no impacts to bull trout as a result of supplementation with hatchery reared steelhead...

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Precision of Estimated Ages of Lake Trout from Five Calcified Structures

Cited by 47 publications

References 0 publications

Validation of scales and otoliths for estimating age of redband trout in high desert streams of Idaho

Validation of scales and otoliths for estimating age of redband trout in high desert streams of Idaho

Precision of aging structures for Indian major carp,Cirrhinus mrigala, from the River Ganga

Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams. Final Report 1992.

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