Complex sentence: In April 2001 when the fishing vessel "South Tomi" was detected poaching Patagonian toothfish near Heard and McDonald Islands in the Southern Ocean and following a pursuit the Togo-flagged vessel was subsequently boarded by an SASR troop of the southern tip of Africa.
Split into simpler sentences: In April 2001 the fishing vessel "South Tomi" was detected poaching Patagonian toothfish near Heard and McDonald Islands in the Southern Ocean. Following a pursuit, the Togo-flagged vessel was boarded by an SASR troop off the southern tip of Africa.