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Maternal characteristics versus egg size and energy density: do stocked lake trout in Lake Ontario experience premature reproductive senescence?

Journal of Great Lakes Research

By:
, ,
DOI: 10.3394/0380-1330-34.4.661

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Abstract

Observations from September 1994 and 1997 collections of hatchery-origin, mature female lake trout (Salvelinus namaycush) from Lake Ontario indicated that egg mass decreased with age, fueling the notion that stocked fish experienced premature reproductive senescence. Supplemental collections during September 2002 and November 2002-2004 were combined with the 1994 and 1997 samples to examine whether sample date or maternal age, body mass, condition (K), egg count, or strain were related to egg mass or energy content (percentage dry mass [%DM]). Body mass was correlated with egg mass for age ≥ 8 lake trout sampled in September, and egg count was correlated with egg mass for September age-6 lake trout only. Within each month, egg mass was not related to K or egg %DM, however, egg %DM was 1.52% greater (P ≤ 0.0247) in November than in September which is equivalent to a 110 cal/g difference. Samples were grouped for the three most abundant strains (Seneca, Superior, and Ontario) after finding no strain or year effects from our 1994 and 1997 samples and based on life history data from the literature and our assessment sampling. Further analysis indicated that September egg masses were greater for fish ages ≤ 6 than for fish ages ≥ 8. The age effect disappeared in November when mean egg mass across all ages (0.078 g) was greater than September means (P < 0.0005) for ages -5 (0.054 g), -6 (0.057 g) and ≥ 8 (0.041 g). Our results indicate that the decrease in egg mass with female age in September was not due to senescence, but to oogenesis being closer to completion in young age-5 and -6 fish than in older individuals.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Maternal characteristics versus egg size and energy density: do stocked lake trout in Lake Ontario experience premature reproductive senescence?
Series title:
Journal of Great Lakes Research
DOI:
10.3394/0380-1330-34.4.661
Volume
34
Issue:
4
Year Published:
2008
Language:
English
Publisher:
Elsevier
Publisher location:
Amsterdam, Netherlands
Contributing office(s):
Lake Ontario Biological Station
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
661
Last page:
674
Number of Pages:
14