Enteropneust production of spiral fecal trails on the deep-sea floor observed with time-lapse photography

Photographs of the deep-sea floor not infrequently show conspicuous spiral fecal trails, sometimes with an enteropneust hemichordate at the leading end. Here, we report on the dynamics of enteropneust trail production and disappearance at an abyssal station. A time-lapse camera deployed in the abyssal NE Pacific (Station M, 4100 m depth) photographed the same field of view at hourly intervals for 4 months in 2001-2002. Fortuitously, the final 10 days of the time-lapse sequence showed an enteropneust (of an undescribed species) abruptly appear in the field of view and spend 39 h foraging and producing a clockwise, four-whorl spiral fecal trail before ascending off the sea floor. The selection of the foraging site was not obviously influenced by previous biological or sedimentation processes observed in the time-lapse photographs over the 3-month period prior to the enteropneust arrival. After departure of the enteropneust, the fecal trail degraded rapidly over the remaining 8.5 days of the deployment. In an ancillary analysis of 52 camera sled transects over a 15-year period (1989-2004) at Station M, the photographs revealed that the same enteropneust species was present in small numbers through the 1990s but increased four-fold in abundance between 2002 and 2004. Similarly, the number and length of fecal trials increased over the same period. We were unsuccessful in collecting any of these enteropneusts in a semi-balloon trawl routinely towed behind the camera sled, presumably because of their fragility.