South Korean fishing boat sinks

A fishing boat with 42 men on board sank in cold Antarctic waters early this morning. Only 20 men were rescued, by another South Korean fishing boat. Five bodies were recovered. Another 17 men are missing.

The boat was fishing for toothfish. This is a popular fish which lives in Antarctic waters. It usually weighs about 10kg but older toothfish can get a lot bigger.

The boat sank about 6.30am this morning but there was no SOS signal. It is possible it hit an iceberg. Two New Zealand fishing boats helped to search at first and three South Korean boats are continuing the search. However anybody in this cold water would not survive more than 10 minutes. The water temperature is about 2 degrees Celsius. New Zealand Search and Rescue did not send an Air Force plane because it would take about 8 hours to reach the area where the boat sank. This is about 2,500km south of New Zealand.

The crew of this fishing boat come from South Korea, China, Vietnam, The Philippines, Indonesia and Russia.

This is the second South Korean fishing boat to sink in the last few months. Listen to Aug 18th 2010.

Questions
There have been problems with over-fishing of toothfish (catching too many). How can countries stop this?
Why was the crew come from so many different countries?