Effects of No. 2 fuel oil water-soluble-fractions on growth and reproduction in Neanthes arenaceodentata (Polychaeta: annelida)

Abstract

Effects of water-soluble-fractions (WSFs) from No. 2 Fuel Oil on growth and reproduction in a laboratory strain of Neanthes arenaceodentata were studied in experiments simulating conditions of acute and chronic sublethal exposure. Effects were defined relative to concentrations of diaromatic hydrocarbons (naphthalenes) and total dissolved hydrocarbons. Hatching of metatrochophore larvae was inversely related to WSF concentration and to the length of time larvae were exposed prior to hatching. Growth of larvae into juveniles was unaffected by low concentrations. Inhibition of larval growth by higher WSF concentrations was reversible upon return of larvae to hydrocarbon-free sea water. Growth of juveniles into adult polychaetes was inversely related to concentration. Rate of development to the feeding juvenile stage was not affected by WSF in three successive generations of continuously exposed polychaetes. Oocyte maturation rates in the four WSF concentrations (2.5, 5, 10, 2507o) increased with each successive generation. All concentrations suppressed fecundity in each generation. Survival to the 32-segment juvenile stage (brood mortality) was inversely related to concentration in first generation animals. Brood mortality in all WSF concentrations decreased with successive generations thereafter. Levels of naphthalenes in worms declined with each generation. Naphthalenes concentrations in third generation animals was very similar to those of exposure media.