the hitchhiker

What at first resembles an X-ray, upon closer inspection reveals a small shrimp which has taken up residence inside one of several inter-connected pelagic Salps.

Salps are a type of Tunicate -- one of the closest marine invertebrates to man, on the evolutionary scale.  They  possess a brain, a skeletal rod which supports a nerve chord (much like our backbone) and all of the organ systems of higher vertebrates except specialized sensory organs (such as eyes).  Free-swimming filter-feeders, salps have siphons for both intaking nutrient-laden water, and discharging the used water with body wastes.

The salps pictured -- each about 6" in length -- had formed a colonial chain and were found drifting with the current about 10 miles off the coast of San Diego in the open ocean, at a depth of about 50 feet.  They are a favorite food of the Mola mola.

Lens: 60 mm
Film: Kodak E-100 VS
Location: Nine Mile Bank, San Diego, CA
©1999 Garry McCarthy