US specialty retailer of action sports related apparel, footwear, equipment and accessories Zumiez Inc., has posted a 42.8% increase in total net sales for the four-week period ended April 29. Sales reached $15 million compared with $10.5 million for the four-week period ended April 30, 2005. The company's comparable store sales increased 19.3% for the four-week period, versus a comparable store sales increase of 11.1% in the year ago period.