SBC LTER: Reef: Long-term experiment: Kelp removal: Urchin size frequency distribution

These data describe the size frequency distribution of red and
purple sea urchins at SBC LTER long-term kelp removal experiment
sites. The diameter of the test (shell without spines) is recorded
in centimeters to the nearest 0.5 cm for 50 red and 50 purple sea
urchins located in 40 m x 2 m transects in each sampling plot. These
data can be combined with size-mass relationships established in the
laboratory to provide a non-destructive estimate of red and urchin
dry mass.

The kelp removal experiment was initiated in 2008 at selected reef
sites along the mainland coast of the Santa Barbara Channel. The
following three giant kelp manipulations are maintained in sampling
plots at each site:

- Control: Macrocystis pyriferais left intact
during the experiment.

- Annual removal: Macrocystis pyriferais
removed from an adjacent plot once each winter and allowed to
re-colonize over the course of the year.

- Continuous removal: Macrocystis pyriferais
removed from the plot on each sampling date.

See protocol for more information.