Table 1.

Observations of Bathyopsurus nybelini in the Puerto Rico Trench and Mid-Cayman Spreading Center on the Alvin Science Verification Expedition (AT50−02). Date and encounter time are reported in GMT. Individuals that were observed carrying Sargassum are indicated with a Y (yes), while individuals that were not carrying Sargassum are shown with an N (no). Observations where it was not possible to determine if the isopod was carrying Sargassum due to distance or focus are blank. Individual 5089–05, denoted by an asterisk, was seen six times over a short period, with the initial encounter time and location reported here. Example videos and paddle stroke frequencies are available in the electronic supplementary material.

Location	Alvin dive ID	Encounter ID	Dive site	Date	Encounter time (GMT)	Latitude (°N)	Longitude (°W)	Depth (m)	Carrying Sargassum
Puerto Rico Trench	5089	5089-01	Central Ridge	7.29.22	16:38:46	19.53967	−65.57386	6103.5	N
Puerto Rico Trench	5089	5089-02	Central Ridge	7.29.22	16:47:22	19.54050	−65.57327	6095.1	Y
Puerto Rico Trench	5089	5089-03	Central Ridge	7.29.22	16:47:40	19.54054	−65.57324	6094.4	N
Puerto Rico Trench	5089	5089-04	Central Ridge	7.29.22	16:59:19	19.54188	−65.57231	6069.3	Y
Puerto Rico Trench	5089	5089-05*	Central Ridge	7.29.22	17:01:12	19.54194	−65.57227	6067.6	N
Puerto Rico Trench	5089	5089-06	Central Ridge	7.29.22	17:27:08	19.54355	−65.57149	6034.8	N
Puerto Rico Trench	5090	5090-01	North Wall	7.30.22	15:40:32	20.29516	−65.70579	6287.6	Y
Puerto Rico Trench	5090	5090-02	North Wall	7.30.22	15:53:31	20.29542	−65.70582	6279.2	N
Puerto Rico Trench	5090	5090-03	North Wall	7.30.22	15:54:56	20.29549	−65.70579	6273.1	Y
Puerto Rico Trench	5090	5090-04	North Wall	7.30.22	15:58:01	20.29576	−65.70579	6259.2	Y
Puerto Rico Trench	5090	5090-05	North Wall	7.30.22	16:01:55	20.29596	−65.70572	6245.3	Y
Puerto Rico Trench	5090	5090-06	North Wall	7.30.22	16:04:55	20.29614	−65.70576	6238.9
Puerto Rico Trench	5090	5090-07	North Wall	7.30.22	16:05:09	20.29617	−65.70576	6236.3	Y
Puerto Rico Trench	5090	5090-08	North Wall	7.30.22	16:20:55	20.29653	−65.70581	6216.8
Puerto Rico Trench	5090	5090-09	North Wall	7.30.22	16:50:23	20.29683	−65.70581	6117.0	Y
Puerto Rico Trench	5090	5090-10	North Wall	7.30.22	16:51:03	20.29678	−65.70593	6114.3	Y
Puerto Rico Trench	5090	5090-11	North Wall	7.30.22	16:56:49	20.29691	−65.70581	6100.2	Y
Puerto Rico Trench	5090	5090-12	North Wall	7.30.22	16:58:15	20.29695	−65.70576	6096.8	Y
Puerto Rico Trench	5090	5090-13	North Wall	7.30.22	16:59:02	20.29699	−65.70571	6093.1	Y
Puerto Rico Trench	5090	5090-14	North Wall	7.30.22	16:59:02	20.29699	−65.70571	6093.1
Puerto Rico Trench	5090	5090-15	North Wall	7.30.22	16:59:02	20.29699	−65.70571	6093.1
Puerto Rico Trench	5090	5090-16	North Wall	7.30.22	17:06:22	20.29735	−65.70536	6055.9	Y
Puerto Rico Trench	5090	5090-17	North Wall	7.30.22	17:10:51	20.29750	−65.70520	5999.8	Y
Puerto Rico Trench	5090	5090-18	North Wall	7.30.22	17:14:25	20.29769	−65.70516	5974.9	Y
Puerto Rico Trench	5091	5091-01	South Wall	7.31.22	17:55:01	20.09438	−66.27648	5868.6	Y
Puerto Rico Trench	5091	5091-02	South Wall	7.31.22	18:38:42	20.09536	−66.27606	5806.2
Puerto Rico Trench	5091	5091-03	South Wall	7.31.22	18:45:27	20.09584	−66.27616	5753.9	Y
Mid-Cayman Spreading Center	5094	5094-01	Axial volcanic Ridge	8.8.22	17:48:23	18.17784	−81.72858	5191.7	Y
Mid-Cayman Spreading Center	5097	5097-01	North Ridge	8.11.22	16:19:13	18.68616	−81.78744	6026.5	N
Mid-Cayman Spreading Center	5097	5097-02	North Ridge	8.11.22	16:25:55	18.68445	−81.78717	6040.5	Y
Mid-Cayman Spreading Center	5101	5101-01	Beebe Woods	8.15.22	18:10:49	18.54712	−81.71882	5001.9	N
Mid-Cayman Spreading Center	5101	5101-02	Beebe Woods	8.15.22	18:10:57	18.54713	−81.71881	5001.9	N