On the Occurrence and Food Habits of Ctenophores in New Jersey Inland Coastal Waters

The occurrence and distribution of the three ctenophores, Mnemiopsis leidyi, Pleurobrachia brunnea, and Beroë ovata in New Jersey inland coastal waters are considered as affected by factors of the environment. Pleurobrachia was observed twice, Beroë during a few days for three seasons, Mnemiopsis was seen daily for months at a time. Evidence is presented which indicates that all three of these forms are casual visitors to the inland coastal waterways of New Jersey. Beroë and Pleurobrachia are found here only after the heat of summer is past, whereas Mnemiopsis appears in late spring or early summer and flourishes until late autumn or winter. The remarkable power of temperature adaptation of Mnemiopsis is shown by the fact that in individuals taken in the winter the swimming plates continue to beat until frozen fast in the ice. The three ctenophores are shown to be able to withstand salinities in the bays which are considerably below those of the ocean lanes from which the animals came. The conclusions of Mayer and of Bigelow in this connection are discussed. A study of the food habits of Mnemiopsis reveals the fact that large numbers of bivalve larvæ may be destroyed by them. A distinct correlation is shown between the abundance of Mnemi opsis and the intensity of "sets" of oysters and of marine borers.