Biofouling communities on idle petroleum transfer hoses and their potential dispersal role at a platform in the Brazilian Campos Basin

Idle petroleum transfer hoses provide surfaces for attached marine organisms and may subsequently be relocated. This study describes biofouling and visible surface condition at one platform in the Campos Basin, Brazil, after a reported approximately six-month idle period. The dataset comprises 14 reconstructed section records, with approximate total cover estimated visually by one observer from one or two selected monocular ROV stills per record. Recorded cover ranged from 35% to 93%; the unweighted mean was 71.9% (SD 20.0 percentage points). Mean scores were 89.4%, 44.0% and 71.3% in the waterline, near-surface and intermediate categories, respectively. Image-to-section and depth assignments could not be independently verified, and ecological appearance contributed to section assignment. These contrasts are therefore descriptive. Seven broad visual categories were listed in the records. One record included an orange-yellow colonial morphotype originally interpreted as Tubastraea-like; its identity and invasion status remain unresolved. The corresponding 7.1% is the proportion of records containing that report, not coral cover. Eight records were assigned light external surface damage. The observations illustrate biofouling on idle hoses at one platform, but do not demonstrate transport, establishment after relocation, or the frequency of this potential pathway across the Campos Basin. Traceable image sampling and specimen-based identification are needed to evaluate its biosecurity significance.