. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 176 C R \\IIKl\so\ \\[) V C CTHSHIRI 1 km to the west of the Discover. Ba> Marine Labora- tory (see Goreau and Goreau, 1973, for site description). Care was taken to select only regular-shaped animals (presumably derived from a single larva) which were at- tached to rubble and without obvious signs of predation damage. The sponges were weighed after draining for ap- proximately 20 seconds and the volume measured by displacement in water. Estimations of dry weight were made on 5 individuals of each species after dry ing fo
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 176 C R \\IIKl\so\ \\[) V C CTHSHIRI 1 km to the west of the Discover. Ba> Marine Labora- tory (see Goreau and Goreau, 1973, for site description). Care was taken to select only regular-shaped animals (presumably derived from a single larva) which were at- tached to rubble and without obvious signs of predation damage. The sponges were weighed after draining for ap- proximately 20 seconds and the volume measured by displacement in water. Estimations of dry weight were made on 5 individuals of each species after dry ing for 36 h at 80°C. The size-class structure of the Pseudoceratina crassa population was estimated using the MIX program of Macdonald and Pitcher (1979; Macdonald and Green, 1986). MIX is an interactive program used to fit distribu- tions to grouped data by maximum likelihood estima- tion. The program has been used effectively in the analy- sis of fisheries size-frequency data where the groups rep- resent successive year classes. For P. crassa. it was assumed that there were five size groupings representing the recruitment from five annual spawning events be- tween Hurricane Allen and the date of collection. To test this assumption, all possible combinations of groups from two to ten were tried, but a significant fit was only obtained for five groups. The mean size of sponges in each size-class was determined from the significant fit ob- tained to the size-frequency data with the MIX program. These mean values for each size-class were analyzed us- ing a least squares regression to provide an exponential growth model (W, = aeat) from which the relative growth rate « was estimated. Growth rates for the other four sponge species could not be obtained by the same method due to the limited number of specimens. Growth rate approximations for these species were derived using the growth model from P. crassa. It was assumed that the average size at 50 days after spawning was the same for
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
