Age Validation for the Mountain Brook Lamprey, <i>Ichthyomyzon greeleyi</i>

Medland, T. E.; Beamish, F. W. H.

doi:10.1139/f87-107

Cited by 15 publications

(13 citation statements)

References 11 publications

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“…however, most downstream movement occurred in the spring The was valid for younger age groups of some when the discharge was the highest, consistent with other stud-populations of some other species of lamprey (Medland and ies (Manion and McLain 197 1 ;Manion and Smith 1978). Beamish 1987). However, the differences in mean size and age Smaller of ocoetes moves out of the river in the estimates between the statolith and length-frequency age detersummer even though flows were reduced, water levels were mination methods indicate that the ages produced by the stalow, and temperatures were high.…”

Section: Migration Of Ammocoetesmentioning

confidence: 98%

Abundance and Freshwater Migrations of the Anadromous Parasitic Lamprey, Lampetra tridentate, in a Tributary of the Fraser River, British Columbia

Beamish¹,

Levings²

1991

Can. J. Fish. Aquat. Sci.

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The migration of young adult Lampetra tridentata out of the Nicola River during 1984–85 through 1987–88 was estimated to be approximately 176 000,19 000,90 000, and 102 000; at the same time, approximately 749 000, 909 000, 920 000, and 605 000 large ammocoetes, age 4 and 5 yr, left the river. Migration of young adults started in September, with the largest number migrating from mid-March to mid-May. Ammocoetes behaved similarly except that movement continued throughout the year. Most young adults metamorphosed at age 4 or 5 and were age 5 or 6 when they migrated to sea. It was not determined when lamprey from the Nicola River reached salt water; however, L. tridentata entered the Strait of Georgia from the Fraser River from March until July. Maturing adults first returned to the Nicola River from the ocean in August when water levels in the river were at their lowest. This is the first estimate of abundance of young adult L. tridentata in any river in the Fraser River drainage. The very large number of young adults and older ammocoetes leaving the Nicola River indicate that parasitic lamprey are abundant in the Fraser River and that they are potentially a common predator of commercially important fishes.

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Section: Migration Of Ammocoetesmentioning

confidence: 98%

Abundance and Freshwater Migrations of the Anadromous Parasitic Lamprey, Lampetra tridentate, in a Tributary of the Fraser River, British Columbia

Beamish¹,

Levings²

1991

Can. J. Fish. Aquat. Sci.

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“…Examinations of statoliths have revealed internal patterns of alternating broad opaque bands and narrow translucent bands (terminology follows Jearld 1983;Jebbink and Beamish 1995). Volk (1986) observed a direct relationship between the number of narrow bands and the known age of larval sea lampreys Petromyzon marinus, and Medland and Beamish (1987) used the fluorochrome oxytetracycline to validate the annular deposition of the narrow bands within statoliths of mountain brook lampreys Ichthyomyzon greeleyi. On the basis of their findings, Medland and Beamish (1987) suggest that the broad opaque bands are the result of rapid growth during the spring and summer, whereas the narrow translucent bands observed in statoliths, which represent the annuli (Jearld 1983), are produced in the winter during periods of slow growth.…”

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confidence: 99%

Morphology and Aging Precision of Statoliths from Larvae of Columbia River Basin Lampreys

Meeuwig

Bayer

2005

N American J Fish Manag

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The general morphology and precision associated with age determination of statoliths from larval Pacific lampreys Lampetra tridentata and western brook lampreys L. richardsoni found within the Columbia River basin were examined. Significant positive correlations were observed between the size of left and right statoliths from individuals. Principal components analysis indicated an allometric relationship between lamprey length and statolith size as well as a potential species grouping based on these measurements. Discriminant analysis was able to correctly classify more than 94% of Pacific lampreys and 92% of western brook lampreys based on lamprey length and statolith size, and Pacific lamprey statoliths tended to be larger than western brook lamprey statoliths for lampreys of a given size. Reader bias in age estimates of statoliths was greater for older lampreys. Multiple independent age readings of both statoliths from individual lampreys indicated that the overall average percent error was 16.7% for Pacific lampreys and 33.0% for western brook lampreys. Within‐individual average percent error ranged from 5.1% to 20.1% among species and readers. Within‐reader average percent error ranged from 6.4% to 17.8% among species and readers. The average percent error observed in this study was greater than that observed in studies of other species of lampreys; however, statoliths that were ambiguous or difficult to read were not excluded from this study. In general, the modal separation of age‐groups observed in length‐frequency distributions for lampreys is poor, as seen in this study; therefore, statolith‐based ages may verify or provide better estimates of population age structure. These data demonstrate that estimates of precision are necessary before management actions founded on statolith‐based age structure determination are implemented.

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“…The ages of ammocoetes from the field however, were indirectly determined using length frequency distributions (Kux 1965(Kux ,1967 and these await validation. The counting of statolith bands, either unstained or stained with oxytetracycline, has so far only been used to validate ages in larvae of Petromyzon marinus (Volk 1986) and Ichthyomyzon greeleyi (Medland & Beamish 1987). This cautionary note is made so that arguments based on age of ammocoetes and presented in this paper are taken in their proper perspective.…”

Section: Resultsmentioning

confidence: 99%