. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FERTILIZATION * F(DENSITY) 155 positioned along a transect oriented parallel to the shore. and spaced about 7 m from their nearest neighbor. Egg counts prior to deployment averaged 105 per colony (± 12 SE). All colonies remained in the Held through the beginning of the next asexual generation (hereafter termed takeover) and the full period of egg viability, so that eggs were fertilized by naturally available sperm. Fertilization levels were determined as described above. Throughout most of the season, all embryos within a co
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FERTILIZATION * F(DENSITY) 155 positioned along a transect oriented parallel to the shore. and spaced about 7 m from their nearest neighbor. Egg counts prior to deployment averaged 105 per colony (± 12 SE). All colonies remained in the Held through the beginning of the next asexual generation (hereafter termed takeover) and the full period of egg viability, so that eggs were fertilized by naturally available sperm. Fertilization levels were determined as described above. Throughout most of the season, all embryos within a colony were at the same developmental stage. The presence of a mixture of developmental stages indicated that embryos lagging in development were fertilized later than the others (Meidel and Yund, 2001). Typically, all embryos surgically re- moved from a colony were at about stage four, and pos- sessed a tail that wrapped completely around the embryo (Milkman, 1967). Embryos at a tail-bud stage or earlier (by the criteria of Milkman, 1967) were at least 24 h behind in development and therefore were reported as unlikely to complete development (Stewart-Savage et at. 200la). Throughout the reproductive season, we surveyed the density of B. schlosseri colonies at both sites monthly. Density surveys, made with the aid of scuba, involved counting all of the colonies present in eight randomly de- ployed 0,64-m 2 quadrats. We did not measure the size distribution, reproductive status, or reproductive output of the colonies because past work (Stewart-Savage et u/., 200 Ib; Yund and Stires, 2002) permits reasonable inference about variation in these variables between sites. A subset of the field fertilization data was used to assess the possible relationship with population density. Fertilization values obtained during three week-long intervals (including the weeks immediately before, during, and after the week of a population survey) were paired with the associated popula- tion density
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
