. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GAMETE DISPERSION IN A. PLANCI 163. Figure 12. Egg numbers predicted by the numerical model, showing a reduction near the seabed due to substrate trapping at 10 m from the starfish in currents of m • s~'. did not indicate a need for an adjustment to the eddy diffusivity as a function of current speed over the range of speed and space scales considered. The predicted contours of the number of eggs trapped in the seabed for the simulation of Cases 1-3 indicate that, if the starfish spawned in the hollows of the undu- lati
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GAMETE DISPERSION IN A. PLANCI 163. Figure 12. Egg numbers predicted by the numerical model, showing a reduction near the seabed due to substrate trapping at 10 m from the starfish in currents of m • s~'. did not indicate a need for an adjustment to the eddy diffusivity as a function of current speed over the range of speed and space scales considered. The predicted contours of the number of eggs trapped in the seabed for the simulation of Cases 1-3 indicate that, if the starfish spawned in the hollows of the undu- lations, many of the eggs would be trapped nearby (Fig. 14). The model predicts that hundreds of eggs per m: (the size of our settlement dishes) enter the seabed. This is higher than the field measurements, but similar numbers were recorded in one case (Experiment No. 4) when up to 118 eggs were trapped at m down- stream of the starfish. The traps were very shallow (about m) and may not have retained all of the settling eggs. Moreover, the entrances of some bed settlement traps were above mean bed level. At this level, the influence of local hydrodynamics, including wave orbital motion creating currents within the dish, was not known. Discussion Inferred fertilization success A rapid reduction in concentration was measured with increasing distance from spawning crown-of-thorns star- fish. These concentrations do not, however, necessarily indicate the levels of fertilization to be expected for the species, even though their rate of decline was similar to the decline in fertilization success reported for sea urchins (Pennington, 1985; Levitan el ai, 1991) and ascidians (Grosberg, 1991). In those studies, fertilization success dropped dramatically—from 80 to 100% near the spawn- ing male to about 10% or less over 1 m—and the authors inferred gamete dilution to be the significant factor con- tributing to the observed decline. Unlike the present study, none of thes
Size: 1677px × 1490px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
