a. Richness. The data from base-line and control samples indicate that 

 species richness followed an irregular seasonal pattern. Generally, numbers 

 of species were lowest in a period between late fall and spring, and showed 

 one or more peaks sometime between midsummer and late fall. 



For base-line collections (Table 4), the number of species per sample 

 averaged 49 and ranged between 15 (November) and 120 (July) . The average for 

 control samples was 74 and ranged between 53 (February) and 112 (July). Inter- 

 mediate values were recorded for experimental samples. In these collections, 

 average number of species per sample was 60; the low, which was only 20, 

 occurred in the first collection after dredging; the high was 114, recorded in 

 July 1 year later. 



On a date-to-date comparison at station 1 and stations 1 to 6, richness 

 data for control and experimental samples (Tables 5 and 6) gave somewhat 

 conflicting results. For time-sequence samples at station 1, richness data 

 showed incomplete borrow pit recovery as numbers of species prove to be 

 consistently higher for controls on every occasion except 1 June 1977. This 

 was reflected in the average of 70 and the range between 53 and 89 for control 

 samples, as opposed to an average of 51 and a range of 20 to 85 for experimental 

 samples. Even so, a degree of recovery was evident at station 1 a few weeks 

 after dredging, and richness data for control and experimental samples first 

 approximated one another by October 1976. Species recorded in the early stages 

 of recovery at station 1 are of special interest because they include survivors, 

 migrators, and perhaps the first recruits (Table 7). 



Contrary to indications of the incomplete recovery discussed above, results 

 for richness in the one-time sampling at stations 1 to 6 showed that borrow pits 

 generally supported more species than undredged bottom at 1 year. This was true 

 for stations 2, 4, 5, and 6. Findings at station 1 were contradictory, and at 

 station 3, species in experimental collections were outnumbered by those in 

 control collections. The number of species in control samples averaged 86 and 

 ranged between 57 and 112; the number for experimental samples was higher with 

 an average of 92 and a range between 80 and 114. 



Even though richness data are somewhat inconsistent, overall they indicate 

 that faunal recovery began rapidly and was virtually complete throughout the 

 study area in about 1 year. Data from the one-time sampling at six stations 

 support this statement to a greater degree than those from regular time-sequence 

 samples at station 1. 



b. Abundance . Except for a few anomalies, seasonal cycles of faunal 

 abundance coincided with periods of low and high species diversity, i.e., fewer 

 animals were recorded in winter collections, and peak numbers generally occurred 

 at various times between March and December. In base-line samples, numbers of 

 individuals per square meter of bottom averaged 3,883 and ranged from 1,506 

 (April) to 7,178 (July). The average for control samples was 3,119, with a 

 range betwen 1,408 (July) and 5,576 (August). Experimental samples had an 



22 



