The seasonal changes in somatic energy content of Gulf of Alaska yellowfin sole, Pleuronectes asper

1993 ◽  
Vol 43 (1) ◽  
pp. 131-138 ◽  
Author(s):  
A. J. Paul ◽  
J. M. Paul ◽  
R. L. Smith
Keyword(s):  
Seasonal Changes ◽  
Energy Content ◽  
Gulf Of Alaska ◽  
Yellowfin Sole ◽  
Somatic Energy

Freshwater Migration as a Determinant Factor in the Somatic Cost of Reproduction of Two Anadromous Coregonines of James Bay

1990 ◽  
Vol 47 (2) ◽  
pp. 318-334 ◽  
Author(s):  
Yvan Lambert ◽  
Julian J. Dodson
Keyword(s):  
Energy Cost ◽  
Reproductive Effort ◽  
Energy Content ◽  
Cost Of Reproduction ◽  
Energy Gain ◽  
Lake Whitefish ◽  
James Bay ◽  
Energy Increase ◽  
Species Specific ◽  
Somatic Energy

We tested the hypothesis that the species-specific costs of migration differentially affect reproductive effort and somatic cost of reproduction in sympatric anadromous populations of cisco (Coregonus artedii) and lake whitefish (C. clupeaformis) of James Bay. Reproductive effort, which includes the energy cost of migration, is higher for cisco. Female cisco allocate more energy to reproduction than its total energy gain. The energy invested by lake whitefish in reproduction is approximately equal to its seasonal energy gain. Reproduction results in large differences in the energy content of gonads, viscera, and carcass between reproductive and nonreproductive fish of the same length. Neither cisco nor lake whitefish are able to spawn two years in succession. The somatic energy increase of reproductive female cisco is 121% lower than the somatic energy increase of nonreproductive females; similar comparisons are 89% (female) and 103% (male) for lake whitefish. The energy cost of migration is largely responsible for the higher somatic cost of reproduction observed for cisco. These different somatic costs of migration are related to resource accumulation prior to migration and to differences in the aerobic cost of swimming between the two species in combination with the difficulty of the freshwater migration.

Ecología trófica de Lacerta lepida en la provincia de León, noroeste de España

1991 ◽  
Vol 12 (3) ◽  
pp. 283-292 ◽  
Author(s):  
Joaquín Alegre ◽  
José María Salgado ◽  
Angel Hernández
Keyword(s):  
Seasonal Changes ◽  
Energy Content ◽  
Average Length ◽  
Occurrence Frequency ◽  
Nw Spain ◽  
Faecal Pellets ◽  
Invertebrate Prey ◽  
Important Prey ◽  
June July

AbstractThe diet of Lacerta lepida in the province of León (NW Spain) was studied through the analysis of 286 faecal pellets collected during May-August. Insecta were the numerically most important prey group, and always represented more than 85 % of prey numbers. Coleoptera and Hymenoptera were the dominant orders. Other important prey groups were Heteroptera and Arachnida. The number of Orthoptera consumed increased gradually from May to August. With respect to the occurrence frequency of prey in the faecal pellets, Coleoptera and Hymenoptera occurred in more than 75% at all times. The lowest trophic diversity was detected in june-july. Seasonal changes in the diet were noteworthy within short-terms and augmented in the long-term. The average length of the invertebrate prey was within the interval 9-14 mm. In terms of energy content, Vertebrata (43.82%), Coleoptera (15.77%), Orthoptera (14.40%) and Hymenoptera (13.95%) were the principal groups. L. lepida is considered to be an opportunistic feeder, although some prey groups are apparently selected.

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