Patrick, P.H. (1984). Life history, behaviour, population dynamics and productivity of Diacyclops bicuspidatus thomasi (Forbes) in West Blue Lake, Manitoba. Ph.D. Thesis, The University of Manitoba, Winnipeg, Manitoba, Canada. 244 pp.

126727

Patrick, P.H.

1984

244 pp.

Publication

http://hdl.handle.net/1993/29935  

Available for editors   [request]

The life history, behaviour, population dynamics and productivity of Diacyclops bicuspidatus thomasi in West Blue Lake was investigated over a two-year period. Analysis revealed that the population was multivoltine, consisting of three cohorts developing annually with reproduction occurring in the spring, summer and winter. Highest fecundity occurred in the spring and was significantly higher in Lgl 4 than in L972. Copepodid stage 4 of. cohort 1 exhibited diapause, entering the profundal- sediments in late spring and emerging in the autumn, coinciding with the development of the same staqe from cohort 3 in the water column. Diacyclops b . thomasi showed no strong evidence of diel vertical migration, but each life history stage was generally located at a certain depth which varied seasonally. Population strategies of diapause and staqe depth selection are discussed. Population structure and abundance trends did not vary significantly among sampling stations. Population estimates were highest in the spring, followed by surrmer and winter periods, and were approximately two-fold higher in L97 4 than in L972. Population estimates based on a single deep station v/ere not representative of the lake. Instantaneous mortality estimates were also highest in the spring and/or summer, and lowest in the winter. Length-weight relationships were described for D. Þ. thomasi in both carbon and nitrogen units. Relative and instantaneous growth rates varied for each stage or groups of stages both within and between cohorts. productivity, over the May to August period, estimated with both the increment summation and instantaneous growth methods, averaged approximately .2I g c m-2 in :3i2 and .33 g c m-2 in Ig74. ' _1 Productivity estimates in calories were 1. t5 kcal m ' in Ig72 and 2.42 kcal m-2 in Lgl4. productivity based on a singre deep station over-estimated productivity for the lake. Naupliar stages I-5 contributed less than 10?of total productivity in both years. Copepodid stages 2, 4 and 5 made up approximately 1 0 and 6LZ of the total productivity during L972 and L914, respectively

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