through fall off New Jersey and Costello et al. (1957) reported 

 spawning in the Woods Hole region to occur between March and 

 August. 



Ruddell (1977) reported that sexual maturity is attained when 

 individuals reach a size of 27 mm or larger off Delaware, while 

 Cocanour ( 1969) reported gonad development at a size of about 40 

 mm in Maine, when the organisms are about 3 yrold. 



Juveniles are reported to grow very slowly during the winter 

 (Gordon 1929). Males and females occur in equal abundance with- 

 out any size differential. Cocanour (1969) reported that maximum 

 growth in Maine occurs during seasons of warmest water tempera- 

 ture, March through September. She also reports that during the 

 winter there is some "negative" growth or shrinkage. The sand dol- 

 lar may have alternating years of growth or gamete production, 

 which may not occur simultaneously. Average growth rates were 

 estimated at 2.0-6.4 mm/yr over a 24-30 mo period for mid-sized 

 (30-50 mm) specimens. Durham (1955) estimated the age of a 48 

 mm Woods Hole specimen to be 7 yr, based on growth ring analy- 

 sis, indicating a growth rate of almost 7 mm/yr. Graef (footnote 19) 

 reported the maximum size E. parma found in New York Bight 

 apex samples was 53 mm, at an age of about 6 yr. and Brykov 

 (1975) reported a maximum age of 21 yr in specimens from the Sea 

 of Japan, both estimates again based on growth ring analysis. This 

 implies a growth of <9 mm/yr in the Bight apex. Younger individ- 

 uals have a faster growth rate than mature individuals and Ebert 

 ( 1975) suggested that, for many echinoids, growth is variable from 

 season to season and from year to year. 



Swan (1966) reported that E. parma is fully capable of regenerat- 

 ing nipped edges. 



ADDITIONAL INFORMATION: E. parma has been reported 

 to occur in numbers up to 1 80 individuals/m 2 off Nova Scotia (Stan- 

 ley and James 1971) and over 200/ nv in the North Pacific 

 (Zenkevitch 1963). In the New York Bight apex, the maximum 

 concentration found was 110/m : . Steimle and Stone (1973) col- 

 lected 195 individuals ( > 10 mm in diameter) in a 0.0625 m 2 sam- 

 ple (or 3, 120/m : ) northeast of the apex boundaries. Graef (footnote 

 19) noted a tendency of size classes to be segregated in the New 

 York Bight apex. Cocanour (1969) noted the tendency of larvae to 

 aggregate together, but she believed that as animals get larger they 

 become more evenly distributed. However, the collections reported 

 upon above would indicate nonrandom aggregations of adults as 

 well as larvae. 



An interesting phenomenon which has been discovered is the 

 presence of dark, heavy mineral grains in the intestinal diverticula 

 of juvenile E. parma. Gregory (1905) noticed them first and Graef 

 (footnote 19) also noticed them in New York Bight specimens. One 

 hypothesis for this phenomenon is that these heavy grains are used 

 as weights by juveniles to increase stability on the bottom. 



Stanley and James (1971) reported that this species moves ran- 

 domly over the sediment. In areas of high concentration, these 

 movements are responsible for modifying ripple microridge and 

 swale topography. Parker (1927) studied the locomotion of E. 

 parma and found that it was a combination of rotation and progres- 

 sion. The maximum rate of progress was 18 mm/min. with the 

 average about 14 mm/min. They can completely bury themselves 

 in about 10 min and are capable of righting themselves if turned 

 upside down. Hyman (1955) reported that locomotion is chief!) or 

 wholly accomplished by the motion of the spines, however, Parker 

 and Van Alstyne (1932) indicated that the peripheral tube feet are 

 also of assistance in locomotion. 



DISCUSSION 



Faunal Composition of the Apex 



Among the species in the apex reviewed in this atlas, the Poly- 

 chaeta were dominant, representing over 64% of total individuals, 

 followed by the Bivalvia representing over 30%. This relative 

 abundance also holds true for the overall species composition (Fig. 

 69; Table 1). These species contain elements of major benthic fau- 

 nal types, correlated with sediment composition, reported or 

 defined elsewhere in the Middle Atlantic Bight. The selected spe- 

 cies exhibited four general patterns of abundance concentrations: 

 1) Species which appeared most often in the fine sediments of the 

 Christiaensen Basin and upper Hudson Shelf Valley; 2) species 

 which appeared to be ubiquitous or generally widespread; 3) spe- 

 cies which usually inhabited the shallower sandy areas near the 

 New Jersey-Long Island shore and Cholera Bank; and 4) a few spe- 

 cies whose distributions were irregular. 



The first abundance distribution pattern included 20 species which 

 were generally most abundant in the relatively deep, cool, silty-fme 

 sand habitat offered by the Christiaensen Basin and upper Hudson 

 Shelf Valley (Table 2). This habitat included the sewage sludge 

 dump site and, peripherally, the dredge spoil dump site. Most of the 

 species in this silty-sand apex assemblage show affinities to the fol- 

 lowing generalized faunal types defined by Pratt (1973): an estua- 

 rine silt-clay fauna (Nephtys incisa, Nucula proximo, Ninoe 

 nigripes, Lumbrineris tenuis, Pitar morrhuanus, and Cerasto- 

 derma pimudatum); a marine silty-sand fauna (Pherusa affinis, 

 Ceriamheopsis americanus, and Arctica islandica); and an estua- 

 rine silty-sand fauna (Leptocheirus pinguis and Prionospio steen- 

 strupi). The Nephtys incisa-NucuIa proximo fauna is common in 

 Long Island (Sanders 1956) and other southern New England 

 sounds (Sanders 1968; Pratt 1973; Steimle et al. 1976 !0 ), Chesa- 

 peake and Delaware Bays (Kinnerand Maurer 1978). The marine 

 silty-sand fauna is a major faunal type on the mid-continental shelf 

 and in southern New England sounds. The estuarine silty-sand 

 fauna is usually dominated by Ampelisca spp. and also occurs in 

 New England sounds and in mid-Atlantic estuaries. Thus, the spe- 



:0 Steimle. R, C. Byrne. R. Reid. and T. Azarovitz. 1976. Hydrology, sediments. 

 macrofauna, and demersal finfish of an alternate disposal site (East Hole in Block 

 Island Sound) for the Thames River (Conn.) dredging project. Final Report to the 

 U.S. Navy. New London. Conn. U.S. Dep. Commer., NOAA, Natl. Mar. Fish. 

 Sen.. Middle Atlantic Coast. Fish. Cent. Informal Rep. 1 10, 63 p. 



CRUSTACEA 

 3.12% 



ANTHOZOA 

 1.48% 



ECHINOIDEA 

 0.37% 



Figure 69.— Percentages of Ne« Vurk Bight ape\ benthic invertebrates in each 

 phylum represented. 



48 



