During the 2014 experimental season extension in CCAMLR sub-Area 48.3 a single line caught 74 white chinned petrels, which is the most significant incidental mortality event in the fishery for over 10 years. The circumstances associated with the event were investigated and a review of seabird mortality in the fishery undertaken. The mortality event occurred on a “Spanish” system longline that was partly set after Nautical Twilight (dawn), so was in breach of CM25-02. Although the line was partly set after Nautical Twilight other factors may have contributed to this event. A review of available data indicates that, while the risk of seabird mortality is slightly higher in April, autoline vessels very rarely catch seabirds. In accordance with CM 41-02, there will not be a season extension in 2014/15. Options for possible future season extensions are discussed.