The health of Hawai'i's tourism industry improved again in April with the number of visitors traveling to the Islands climbing for the fourth straight month.

Increases in visitors from the western U.S., Canada, China and South Korea helped boost overall arrivals to 552,059, a 1.9 percent increase over April 2009, the Hawai'i Tourism Authority reported yesterday. Those who arrived by air spent $760.2 million, $3.8 million more than they did a year earlier.

However, one reason the numbers appeared better in April is that they were compared with April 2009 when the swine flu scare kept a lid on travel to Hawai'i.

Mike McCartney, the HTA's president and chief executive officer, said the impact of the H1N1 epidemic serves as a reminder that Hawai'i's tourism industry is vulnerable to outside forces.

"We remain mindful of current issues in the global market that may adversely affect travel," McCartney said.

In addition, the pattern of visitor arrivals was uneven across the state, with Maui accounting for the the bulk of the increase. Arrivals declined on O'ahu, Kaua'i and the Big Island.

After falling for much of 2008 and 2009, visitor arrivals returned to positive territory in 2010. Through the first four months of the year visitor arrivals totaled 2.2 million, up 3.6 percent from the same period a year earlier. Spending reached $3.5 billion, $133 million more than during the first four months of 2009.

"It is clear that tourism in Hawai'i continues to improve," state tourism liaison Marsha Wienert said in a prepared statement. "This is very encouraging for businesses and residents in our state as our overall economy begins to recover."

The number of tourists from the U.S. West, Hawai'i's single largest visitor market, rose to 245,203, a 5.8 percent increase from April 2009. That more than offset a 4.7 percent decrease in visitors from the U.S. East to 119,768.

More Canadians traveled to Hawai'i, stayed longer and spent more than they did a year go. The 33,259 visitors from Canada was up 2 percent from April 2009.

The number of visitors from Japan fell 1.4 percent to 83,230. However for the first four months of the year arrivals from Japan are up 2 percent to 375,882.