A Few Finds From Around Coffin Bay

Herewith a few finds, most made recently near (the) home (of Brian and Bernadette Saunders of Coffin Bay) :

Eggs sacs like balloons on strings, their sandy stalks attached below the sand’s surface.

We had previously found larval sea snails in similar egg sacs but these were a little smaller (about 20 mm in length) so we opened one and extracted a larva. The microscope showed a little creature (less than 1 mm long) with red eyes and several pairs of legs. It was the larva of a marine (polychaete) worm. Just how the worm contrives to produce and tether the egg sacs is a mystery to us.

 Turning a rock revealed a Shore Eel, Alabes dorsalis. Usually they promptly wriggle away when their cover is disturbed but this one stayed put: it was tending a crop of golden eggs.

A Yellow-nosed Albatross, Thalassarche chlororhynchos; a juvenile, so lacking a yellow nose. I noticed the bird while fishing from the Coffin Bay jetty. It was perched on the edge of the jetty, looking decidedly ill and was being threatened by a dog. I chased the dog away as the bird watched and it stayed next to me. Next day I visited the jetty again and saw the bird in the distance, flying close to the water surface. It approached, landed on the water directly below me and looked up, perhaps hoping for food, perhaps just being friendly, but at the least making a nice photo.

A large female Tongue-biter (Ceratothoa sp.) clinging to the tongue with a small male grasping a gill arch. It is thought that when the female dies the male changes sex and moves to the ‘tongue’ position. This was one of several recently collected from Smoky Bay trevally (at the request of Kate, my daughter-in-law, who is a fish parasitologist) as other specimens I had given her were examined at her fish parasitologists’ congress on Heron Island in 2016 and thought likely to be an undescribed species.

Rowedota sp., a supposedly rare sea cucumber at present common in shallow subtidal seagrass around Crinoline Point. Length fully extended 45 mm.

 This little male Smooth-handed Crab, Pilumnopeus serratifrons, from Crinoline Point is a species that I have not seen previously at Coffin Bay although they are common in the Port River and other protected places. It is distinctive among ‘hairy crabs’ in having hairless ‘hands’ and rather slender legs; and when the claws are closed the movable finger is seen to be distinctly shorter than the immovable finger. It also behaves in a peculiar way: it rarely threatens when disturbed, preferring to fold its legs and arms tightly against the body as in the photo on the right.

Kate, when visiting recently, spotted a hole under a rock that her husband, Richard, said was the home of an octopus. He was asked to prove this: on raising the rock, a catfish hurried away and a shower of eggs floated around. The embryos were attached to the yolk sac by a cord of vessels.

(Brian and Bernadette Saunders of Coffin Bay sent the above details to David Muirhead. David said that he was amazed to learn from the first image that subject are worm egg masses. “I’d almost certainly have thought I was looking at ‘just’ another species of marine algae if I had seen the things in the photo before receiving this revelation! And who knows? Perhaps we’ve all seen such things in shallow pools or as fresh beach wash, but never considered anything other than algae as the basic identification in the field. I’ll be looking more closely at such things on future beach strolls and shallow snorkelling outings, be assured!”)

Our thanks go to Bernadette and Brian Saunders for giving us their generous permission to post the above images and captions.