Individual lamellibranchid tube worms, the longer of two taxa found at seeps can reach lengths of 3 m (10 ft) and live hundreds of years (Fisher et al., 1997; Bergquist et al., 2000). Growth rates determined from recovered marked tube worms have been variable, ranging from no growth of 13 individuals measured one year to a maximum growth of 9.6 cm/yr (3.8 in/yr) in a "Lamellibrachia" individual (MacDonald, 2002). Average growth rate was 2.19 cm/yr (0.86 in/yr) for the "Escarpia"-like species and 2.92 cm/yr (1.15 in/yr) for lamellibrachids. These are slower growth rates than those of their hydrothermal vent relatives, but "Lamellibrachia" individuals can reach lengths 2–3 times that of the largest known hydrothermal vent species. Individuals of "Lamellibrachia" sp. in excess of 3 m (10 ft) have been collected on several occasions, representing probable ages in excess of 400 years (Fisher, 1995). Vestimentiferan tube worm spawning is not seasonal and recruitment is episodic.