Eel protection measures within the Manapouri hydro-electric power scheme,South Island,New Zealand |
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Authors: | Jacques Boubée Don Jellyman Colin Sinclair |
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Institution: | (1) Department of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, Illick Hall, 1 Forestry Drive, Syracuse, NY 13210, USA;(2) Present address: Department of Biology, Central Michigan University, 302 Brooks Hall, Mount Pleasant, MI 48859, USA;(3) Department of Chemistry, Jahn Laboratory, State University of New York, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210, USA |
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Abstract: | Variation in developmental rate from fertilization to swim-up, and body size at swim-up, may affect the growth and survival
of young-of-the-year fish. Fish egg size (diameter) is often positively correlated to adult female size, but whether increased
egg size equates to higher egg nutrient content and subsequently improved embryo/larval performance, remains unclear. Artificially
fertilized northern pike eggs from individual females (total length 400–800 mm) were cultured under temperature controlled
laboratory conditions to test the hypothesis that female body size positively influences egg size and the amount of specific
nutrients (carbon, nitrogen, phosphorus, and fatty acids) allocated to eggs. We further hypothesized that greater egg nutrient
content would positively influence egg survival, developmental rate, and the size of swim-up fry. These hypotheses were investigated
in the context of two different northern pike spawning strategies (early season tributary vs. late season deep shoal spawning).
Nutrients were allocated conservatively in northern pike eggs, showing very little variation in nutrient concentrations, but
the total mass of all egg nutrients increased linearly with egg dry mass. Neither egg dry mass nor nutrient content (concentration
or mass), were related to either egg diameter or female body size. The mass of individual egg nutrients was, however, strongly
correlated with egg dry mass (r
2 range 0.62 to 0.99 for individual nutrients) and positively related to the total length of swim-up fry (r
2 = 0.58). The eggs of late spawning pike had significantly greater dry mass (average = 3.02 mg/egg) and developed more rapidly
to swim-up (average = 17.89 days) than did those of early spawners (average = 2.28 mg/egg, 19.05 days). Our results indicate
that egg quality may be best assessed by egg dry mass, which was correlated with greater nutrient mass and increased swim-up
fry body length, as opposed to egg diameter or female body size which showed no correlation to egg nutrient composition and
egg/larval performance.
Guest editors: J. M. Farrell, C. Skov, M. Mingelbier, T. Margenau & J. E. Cooper
International Pike Symposium: Merging Knowledge of Ecology, Biology, and Management for a Circumpolar Species |
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Keywords: | Early life history Development Stoichiometry Fatty acids |
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