WEBVTT 00:00:04.028 --> 00:00:07.360 So this is a cusk eel in the genus Bassogigas. 00:00:09.177 --> 00:00:16.350 The elongate body that a lot of these fish have is useful in this deep-sea environment for several different reasons. 00:00:16.890 --> 00:00:18.890 It gives them an eel-like swimming motion that uses relatively little energy compared to the standard way 00:00:19.090 --> 00:00:30.480 fish swim by wagging the tail and moving fast, because energy is at a premium in the deep-sea environment. 00:00:31.235 --> 00:00:38.170 It also increases the length of the lateral line, the line of vibration-sensing organs along the body. 00:00:38.804 --> 00:00:46.450 By tilting the body slightly, the eel-like swimming tends to drive the body down and enable the fish to stay closer to the bottom. 00:00:46.650 --> 00:00:56.900 Now you can see, or I can see on my lag, that this fish has elongate fin rays on the bottom, just behind the head, those have a sensory function, too.