Tunicates and Medusae
Noon Position: 35 28.0 S 150 46.5 E We are making very slow progress with very light winds. During the night I have had the sails up and down several times, trying to work what little wind there is, setting them when there is sufficient wind to fill them and allow the wind vane to hold a course, and dropping them in the calms to prevent undue wear and tear. This morning it has been so calm I have been able to peer down into the depths at the numerous and various jelly fish, or, looking at my book on Marine Life, more accurately tunicates or sea squirts, both at individuals and also colonies, which are individuals joined end to end looking like a fragile translucent tube up to a meter long; plus some larvacea, which are very interesting, as these are actually tadpole like creatures that build a jelly-like 'house' around themselves, which includes an intricate mechanism for catching food, they draw water through a net that excludes large particles, and then through a fine net which catches the food – extremely small planktonic plants. Apparently at the bottom of their 'house' is an escape hatch through which the animal can escape if danger threatens. I cannot see the escape hatch but reckon if I tried to catch one to have a closer look the 'house' is so delicate that it would just disintegrate, and I assume the little orange brown tadpole like creature inside would make a hasty retreat. I shall remain content to watch. And of course there are the more conventional jelly fish, with their umbrella shaped bodies, some trailing tentacles, others not, which, again according to my book, are actually the medusa stage of the coelenterate. The odd blue bottle jelly fish, their painful stingers trailing beneath them, drifts along the surface of the mirror like surface of the sea; a few gulls rest in small groups here and there, like me waiting for some breeze to help them get airborne again; and in the distance I can see a pod of dolphins occasionally breaking surface as they swim lazily past, obviously the becalmed Sylph is of little interest to them. We have managed to drift past Jervis Bay during the night. I expect it will continue calm and light until Wednesday when the wind is forecast to pick up ahead of a frontal system which is due to reach the east coast sometime early Thursday, so I will be looking to make the most of the favourable winds while they last then duck into shelter before the front arrives. All is well. |