Figure 37.— Distribution and abundance of Travisia carnea in the New York 

 Bight apex. 



.00 / /noi; \i.i^j / 



Figure 38.— Distribution and abundance of Spio filicornis in the New York 

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



primarily in fine sand, and only in the lowest organic areas (<3%) 

 (Fig. 37; Table 1). 



FEEDING ECOLOGY: T. carnea is a motile deposit feeder 

 which burrows head downward in the sediment. Its gut has often 

 been observed to be full of sand grains ingested along with the 

 organic matter in the substrate (Day 1967). 



REPRODUCTION AND GROWTH: No information was avail- 

 able for this species. 



Order Spionida 



Spio filicornis (Muller, 1776) 



DESCRIPTION: Usually tubicolous as are other spionids, but 

 can leave tube (Remane 1933); length to 30 mm, 90 segments, usu- 

 ally smaller (Day 1967). 



DISTRIBUTION: Worldwide (Hartman 1969). 



HABITAT: Spio filicornis often forms dense colonies on sand- 

 banks (Day 1967). In the New York Bight apex, we found S. fili- 

 cornis in depths ranging from 9.6 to 45.6 m. It was usually 

 associated with medium to fine sands with low to medium organic 

 content (Fig. 38). 



FEEDING ECOLOGY: S. filicornis is a tentaculate surface 

 deposit feeder (Day 1967). 



REPRODUCTION AND GROWTH: Although mating in Spio 

 spp. has not been observed, on the basis of observations during cul- 

 ture experiments, Greve (1974) has hypothesized that S. filicornis 

 is unusual in that it uses the indirect transfer of pelagic sperma- 

 tophores to fertilize its eggs. Other marine organisms exhibiting a 

 similar behavior are members of the Halacaridae (marine mites). 

 The reproductive activities of S. filicornis have also been studied by 

 Curtis (1977) in Godhavn. Greenland. He reported that spawning 

 occurs during autumn or winter with the release of large (180-300 

 ixm) eggs. Eggs were brooded within the female tubes until late 

 spring, when they developed into larvae with three setigers bearing 

 long swimming setae. As is the case with members of the genus 

 Polydora, these larvae appeared to metamorphose within the 

 parental tubes, some juveniles (1 mm, 10 setigers) being found in 

 an adult tube collected in April 1959. The onset of maturity 

 occurred at a length of about 10 mm (2-3 mg). 



In the Gullmar Fjord, Sweden, Hannerz (1956) observed that S. 

 filicornis laid its eggs in gelatinous masses within or on top of the 

 substratum. Brood protection was lacking, and the pelagic larvae 

 metamorphosed at the 15-setiger stage. 



Simon (1967. 1968) found that Spio setosa. a close relative of S. 

 filicornis, exhibited poecilogony, spawning once in the late spring 

 resulting in benthic larvae, and again in the fall with pelagic larvae. 



27 



