SELECT COUNT("Crowd") FROM table_55831 WHERE "Venue" = 'moorabbin oval'
What was the crowd size at the moorabbin oval venue?
CREATE TABLE table_55831 (
    "Home team" text,
    "Home team score" text,
    "Away team" text,
    "Away team score" text,
    "Venue" text,
    "Crowd" real,
    "Date" text
)