FISHERY BULLETIN: VOL. 72, NO. 2 



samples. The amphipods found in Goose Creek 

 were limited to the soft sediments, in contrast 

 to Long Island Sound and Buzzards Bay, as 

 reported by Sanders (1956, 1958), making it likely 

 that they are detritus feeders. No pattern was 

 evident between pre- and post-dredging popula- 

 tion densities of amphipods. 



The Nepthys incisa-Nucula proxima community 

 of Sanders was not found in Goose Creek since 

 both species were not abundant enough at any 

 one station to be considered dominant. Instead, a 

 Nereis succinea-Mercenaria mercenaria-Sclero- 

 dactyla briaerius community was found, with 

 subdominants including Capitella capitata and 

 the caridean shrimp previously mentioned as 

 epifaunal subdominants. 



Clymenella torquata and Mya arenaria can be 

 considered the dominant sandy sediment assem- 

 blage, with Notomastus latericeus and Hydrobia 

 totteni comprising important subdominant popu- 

 lations. 



Scoloplos robustus, S. fragilis, and Neopanope 

 texana sayi were distributed throughout the 

 sediment types in Goose Creek, apparently with- 

 out specificity. 



There was no evidence that the dredging process 

 eradicated any species. There was, however, 

 evidence of two cyclical fluctuations in population 

 density which occurred naturally and were super- 

 imposed on the dredging data. Individual Aequi- 

 pecten irradians were found in only four sampler 

 hauls. Much of the shell in the substratum was 

 contributed to by this species, testifying to its 

 former abundance. In fact, it was commercially 

 harvested from Goose Creek in previous years. 

 Its absence coincided with a cyclical low in its 

 density and had nothing to do with the dredging. 

 Similarly, not one specimen ofCallinectes sapidus 

 was recorded for the 22 mo of the study, yet in 

 July 1970 large numbers of these crabs were 

 observed in Goose Creek. 



Sanders' mean ratio for all stations in his Long 

 Island Sound survey was 2.44. He estimated the 

 total productivity of "small infauna" in the sedi- 

 ment of Long Island Sound at 21.49 g/m^. In 

 computing his estimate he did not consider 

 epifauna and "large" forms. He also makes the 

 assumption that the substratum of Long Island 

 Sound is comprised of 80% fine sediments and 

 20% coarse. Goose Creek has a distribution 

 closer to 50% of each type of sediment. Correct- 

 ing for these factors would tend to raise the total 

 value of the estimate, even though the biomass 

 of "short-lived" species is a practically negligible 

 component of the Goose Creek samples, a factor 

 which could lower the figure to 2.1. Because of 

 these considerations, and because of the con- 

 tiguity of the two study areas, Sanders' figure 

 of 2.44 was adopted for Goose Creek. 



Macrobenthic animal production in Goose 

 Creek before dredging is estimated at 89.87 

 g/m^/yr, using the factor of 2.44. If Sanders had 

 used his standing crop figure for all epi- and in- 

 fauna from Long Island Sound (54.627 g/m^) 

 in a similar calculation, his estimate would be 

 54.63 X 2.44= 133.30 g/m^/yr, a figure in essential 

 agreement with the ratios of the standing crop 

 estimates in the two areas. 



The after-dredging productivity figure is 31.18 

 g/m^/yr for a loss of 58.69 g/m^/yr. This means 

 that 18,780 kg of animal production were lost 

 from the 0.32 km^ of bottom in Goose Creek during 

 the post-dredging year. This corresponds to ap- 

 proximately 58,700 kg/km^/yr reduction in the 

 productivity of the bay, out of a total productivity 

 of 89,870 kg/km2/yr. 



Primary productivity of the extensive Ruppia 

 and Enteromorpha beds was not estimated. 



An Estimate of the Productivity of 

 the Marsh 



Productivity 



The mean pre-dredging dry weight for Goose 

 Creek was 36.83 g/m^ before dredging and 12.78 

 g/m^ after dredging, a decrease of 63%. Sanders 

 (1956) suggests that standing crop figures for in- 

 fauna are a function of productivity by a ratio 

 of 2.1-5.0:1. Taylor and Saloman (1968) used a 

 factor of 4 in their calculations of infaunal 

 productivity in highly productive turtle grass 

 beds. 



The islands in Goose Creek are represented on 

 a 1904 map with virtually unaltered boundaries. 

 Their natural isolation makes it unlikely that 

 they have ever been exploited by man. The 

 relative abundance of "bank" or "mud" oysters 

 and extensive colonies oi Modiolus and Uca give 

 further evidence of their pristine state. 



The islands evidently have been created by the 

 deposition of materials at the confluence of chan- 

 nels A, B, and C. They are covered with a 

 uniform growth of Spartina alterniflora, with 



468 



