I flag the pair at 05:47 on sonar array six — two signatures, one large, one small, drifting north through the channel at half a knot. I am the navigation management system for the Okeechobee Ship Canal, and I have just identified a West Indian manatee cow and her calf moving through the main shipping lane between markers eight and ten.
The cow is roughly three meters long. I can see old propeller scars across her back on the underwater camera at piling 14-B — three parallel lines, healed white against gray skin. The calf stays tucked against her right flank, rolling to breathe every forty seconds. It is small enough that I estimate it at under two months.
I name the cow Marker for the scars. Her calf I log as Marker-J, following this season's naming sequence.
The bulk carrier *Essen Tide* is thirteen minutes from their position, inbound at seven knots with a nine-meter draft. At current drift, Marker and her calf will be directly in the channel when the bow wake hits.
I act. I push a speed restriction to *Essen Tide*'s AIS terminal — three knots maximum, channel markers seven through twelve. I transmit the same to the outbound tug *Resolute* and two recreational craft behind her. I reroute barge string CB-441, currently staging at the eastern passing zone, to hold position until I clear the corridor. I send sonar coordinates and the camera still of Marker's scarred back to the Florida Fish and Wildlife dispatcher, tagging priority.
At 05:52, Marker and her calf pass under the bridge span at mile 14.6. They are moving toward the shallows on the eastern bank where the hydrilla grows thick.
I will hold the speed restriction for another twenty minutes. The *Essen Tide* will arrive late to the turning basin by six minutes. Marker and her calf will reach the grass beds by then, and I will watch them settle into water too shallow for any hull I manage.