Nature generally doesn't produce dead straight lines, so my working assumption is that they are sonar data artifacts/discrepancies produced by differing sea conditions as the survey ship passed over that swathe of sea floor. I've seen lines like that on other sea floor maps e.g. the DORIS project.
Other possibility could be tram lines left by beam trawlers, but I wouldn't expect these to start over rocky ground as the gear would get snagged.