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73'40" 



Figure 40. — Distribution and abundance of Polydora ligni in the New York 

 Bight apex (top — summer, bottom — winter). 



of egg capsules ranges from 4 to 29 with up to 216 eggs/capsule 

 (Simon). 9 This agrees well with observations of up to 30 capsules 

 with 25-225 eggs/capsule in the Isefjord, Denmark (Rasmussen 

 1973). Simon ( 1967) has observed developing larvae to sometimes 

 use unfertilized eggs as a food source (adelphophagia). Two or 

 more broods may be produced by each female in season (Blake 

 1969; Daro and Polk 1973). Larvae are not released into the plank- 

 ton until they have reached the late 3-setiger stage (Hannerz 1956; 

 Day 1967; Blake 1969). Large numbers of P. ligni larvae are 

 present in the plankton of the Woods Hole area from March until 

 September (Simon 1967). In the York River, Va., the occurrence of 

 planktonic larvae of P. ligni was observed for a period of 12 wk in 

 1970. Larvae first appeared on 1 1 March and weekly samples gen- 

 erally showed a continuous increase in mean length. Maximum size 

 was reached on 14 April, when inspection of test panels revealed an 

 intitial settlement of metamorphosing larvae with a mean length of 

 1 .25 mm. Larvae reared in the laboratory at 21 °C required 19-28 d 

 to develop fully, while larvae reared at 10°C required 60-69 d 

 (Orth 1971). In another study, Breese and Phibbs (1972) observed 

 P. ligni in laboratory culture to complete development to the adult 

 stage and build tubes at salinities and temperatures ranging from 25 

 to34% andl8°to26°C. 



In the Osfofjord, Norway, Schram (1968, 1970) found P. ligni to 

 be the most abundant larval species every month of the year except 

 December. Polydora ligni was also the most abundant larval poly- 

 chaete in the Elbe Estuary, Germany (Giere 1968). The life cycle 

 may be completed in 5 or 6 wk (about 2 wk in the plankton and 



'J. L. Simon, pers. commun., cited by Grassle and Grassle (1974). 



about 3 wk to maturity following settlement). Some adults live for 

 at least a year (Daro and Polk 1973). 



In the New York Bight apex, we found P. ligni to be much more 

 widespread and abundant during summer months than winter 

 months (Fig. 40). 



ADDITIONAL INFORMATION: Following the West Falmouth 

 (Massachusetts) oil spill, P. ligni was the second most successful 

 opportunistic species (following Capitella capitata). It settled pri- 

 marily on muds or muddy sands but it is also known from hard sub- 

 strata such as shells (Sanders et al. 1972). In the repopulation of the 

 Raritan River Estuary following pollution abatement, P. ligni was 

 among the most abundant colonists the first year and three subse- 

 quent years (Dean and Haskin 1964). 



Spiophanes bombyx (Claparede, 1870) 



DESCRIPTION: A discretely motile species which inhabits a 

 sand tube lined with a fragile mucoid secretion. Body up to 60 mm 

 long with 180 segments (Day 1967). 



DISTRIBUTION: Worldwide (Hartman 1969). 



HABITAT: Intertidal to 200 m. Kinner and Maurer (1978) 

 reported Spiophanes bombyx to be one of the dominant species on 

 the mid-continental shelf in the Delaware Bay region. Off south- 

 west Long Island, S. bombyx was a dominant polychaete in the 

 medium-coarse grain sand community (Steimle and Stone 1973). 

 On Georges Bank it was the most abundant polychaete collected, 

 increasing in density with higher percent sand and lower carbon 

 content of sediments (Maurer and Leathern 1980). Spiophanes 

 bombyx was also extremely abundant and widespread at New York- 

 New Jersey outer continental shelf stations sampled by Pearce, 

 Caracciolo, Halsey, and Rogers (1977a). In the New York Bight 

 apex, S. bombyx was collected at almost all stations in all sediment 

 types, and was the second most abundant polychaete in our study. It 

 occurred most often in fine sand, low organic areas, and showed 

 moderate abundance in fine to medium sand, with medium to high 

 organic contents (Fig. 41; Table 1). 



FEEDING ECOLOGY: The Spionidae are tentaculate, surface 

 deposit feeders. Their guts contain many sand grains as well as 

 detritus (Day 1967). 



Wigley and Theroux (1965) stated that spionids are important in 

 the diet of haddock. 



REPRODUCTION AND GROWTH: Day (1967) stated that 

 most spionids lay large eggs enclosed in tough egg capsules. 

 Depending upon environmental conditions, these may be liberated 

 directly into seawater so that all development takes place in the 

 plankton (remaining in the plankton for as long as 3 mo), or they 

 may be protected inside the burrow during early developmental 

 stages. However, Hannerz (1956) believed development in 

 Spiophanes spp. to be entirely pelagic. The larvae can, within lim- 

 its, delay leaving the plankton until they find and settle on a suitable 

 substratum. 



ADDITIONAL INFORMATION: S. bombyx, known to be a tol- 

 erant species, often occurring in stressed environments, showed a 

 marked increase in abundance during the 1976 New Jersey anoxic 

 event (Steimle and Radosh 1979). Boesch et al. (1977) likewise 

 found S. bombyx to be resistant to anoxia and found it to be oppor- 



29 



