A moving average with an unweighted 100 m window served as a low-pass filter for the particle data before they were matched with depths.

The degree of overdispersion (i.e., patchiness) in the system was assessed using two indices. One, the Lloyd index of patchiness (Lloyd, 1967), is domain-dependent (i.e., zero values affect the estimates); the other one, the index of aggregation (Bez, 2000), is domain-independent.

The Lloyd index (Lloyd, 1967) was calculated as:

(equation 1) ,

where *Lp* is the Lloyd index of patchiness, *m* the mean particle abundance (number of particles per frame in 1 m bins), and *s*^{2} the variance of the particle abundance.

The index of aggregation (Bez, 2000) was calculated as:

(equation 2) ,

where *ia* is the index of aggregation, *z*_{i} the particle density, and *S* the sample scale (set to 1 for this analysis).

**BCO-DMO Processing notes:**

- added conventional header with dataset name, PI name, version date

- modified parameter names to conform with BCO-DMO naming conventions

- reduced number of digits to right of decimal due to sampling precision methods