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An Investigation of Temporal and Spatial Variability of Egg Production in the Gulf of Mexico: A Study of Six Calanoid Copepods

A study was conducted in the Gulf of Mexico to investigate the spatial and temporal variability in secondary production of western Florida waters. The area of interest was divided into four regions representing shelf and oceanic environments of the northern and southern Gulf waters. Physical parameters measured at the same locations in each region were examined in the spring (March 1992) and fall (October 1992). Secondary production of copepods was estimated indirectly from preserved plankton samples. Six copepod species chosen for this study were: Centropages velifurcatus, Eucalanus monachus, Rhincalanus cornutus, Temora stylifera, Temora turbinata and Undinula vulgaris. Adult (C6) female copepods were stained with celestine blue to examine their gonads to determine their level of oocyte maturation. A potential egg production index (PEPI) was determined for each female using the number of mature eggs multiplied by the state of gonad maturity, as determined by Runge (1985). The average PEPI was calculated for each species in both spring and fall in each of the four shelf regions. Centropages velifurcatus, Temora stylifera, and Undinula vulgaris appeared to be in an advanced state of reproductive readiness at all locations at which they were sampled. The remaining three species, Eucalanus monachus, Rhincalanus cornutus, and Temora turbinata, were immature. A regression analysis of physical parameters showed a significant correlation (P<0.05) with fluorescence as an indicator of potential food. The results of a MANOVA for season, species, and location against PEPI showed U. vulgaris as the most productive and R. cornutus as the least. Mean PEPI differed significantly between spring and fall for all species. Southern oceanic location C was the least productive of the four regions sampled (P<0.05). The remaining three regions exhibited no significant differences in their average potential egg production indexes.

Identiferoai:union.ndltd.org:nova.edu/oai:nsuworks.nova.edu:occ_stuetd-1079
Date01 November 2000
CreatorsHouchin, Lee A
PublisherNSUWorks
Source SetsNova Southeastern University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceTheses and Dissertations

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