Tusks from hundreds of slain elephants found by Hong Kong in ship containers Dale De La Rey / AFP - Getty Images Ivory tusks seized during an anti-smuggling operation are displayed during a Hong Kong Customs press conference Saturday. Hong Kong Customs announced Saturday that it had found 1,209 elephant tusks smuggled in two shipping containers from Kenya and Tanzania. Seven people were arrested in what customs said was the biggest such bust in Hong Kong history. The tusks, valued at $3.4 million, are used for making ivory ornaments. A single tusk can fetch thousands of dollars on the black market. Most large seizures of illicit ivory from Africa have originated from either Kenyan or Tanzanian ports. Large-scale seizures have gone up in recent years -- 13 in 2011, compared to 6 in 2010. A 1989 ban on the ivory trade helped elephant populations increase, but an analysis of data from 1979 to 2007 found that some of the 37 countries in Africa with elephants continued to lose substantial numbers of them. Related: Religious leaders organize to stop ivory trade About 450,000 elephants roam Africa today. In 1930, the number was estimated to be between 5 million to 10 million African elephants.