Gobius cobitis

Tony Gilbert Yesterday, we found what we think is a juvenile giant goby, Gobius cobitis. This was in North Wales, under Trefor Pier, and was around 8-11cm long, in a depth of around 2m near to the breakwater inner end of the pier. Unfortunately my shots were not good as my strobe batteries were depleted, however my friend got a better shot: http://www.flickr.com/photos/30550682@N04/7189586159/in/photostream If this is Gobius cobitis, on checking MarLIN it seems it could be the first Welsh record, as previous records appear to be from south west England. If we can get confirmation that would be great, thanks.

Erling Svensen I am not the best one in gobies, but my pictures from Ireland of Gobius paganellus looks like this?

Chris Barrett I'd be inclined to go with Gobius paganellus, due to the banding along the dorsal fins

Tony Gilbert We don't think its a rock goby as the markings are different - and we've seen many rock gobies. The markings almost match a giant goby. We checked images on MarLIN. Originally I thought it could be a Couchis goby, but then the markings are different on that. Sadly, my shot isn't the best, but my buddy had a better shot; he only got one off before it disappeared into the under growth.

Chris Barrett Which markings do you believe to be different? The banding on the dorsal fin of paganellus is a distinguishing feature of the species

Tony Gilbert Many gobies have similar banding on the dorsal fins. Its described as "brownish-olive pepper & salt with dark blotches below the lateral midline". Sadly a rock goby looks similar, and id in the field may prove difficult.

Chris Barrett I wouldn't say the more common species have the banding though. As far as I've seen, cobitis doesn't tend to have the banding. I could be wrong, but I've not seen a confirmed cobitis photo which has the bands

Tony Gilbert To me the dorsal bandings look very similar on this fish to that of both rock and giant, but the markings on the body below the lateral lne on this image seem to be less defined than those of the rock goby. But perhaps thats because its a juvenile? The MarLIN record for giant: http://www.marlin.ac.uk/speciesinformation.php?speciesID=3396# I think from what you've said, then we should stick to G. paganellus.

Chris Barrett I might be wrong Tony - your best bet would be to e-mail the photo to either Frances Dipper, Paul Kay or Lin Baldock - it'd be great if it was cobitis! Douglas Herdson, Andy Horton, your thoughts?

Tony Gilbert Yes indeed, a good idea, thanks. I was consulting Paul & Frances' recent excellent book to see if I could narrow it down more. Gobies and blennies are a bit of minefield. Happy to go with the flow, am just disappointed we didn't get more and better shots. Of course, we could always go back and see if we can find it again.

Tony Gilbert Thanks for your thoughts, appreciate it.

Tony Gilbert The habitat of rock goby would certainly be Trefor Pier and we've seen what we think are Rock gobies there. Giants are usually found in rock pools and lower shores, so perhaps the habitats are very similar. The area we found it in was covered in marine weeds, kelp, sea oak, and is usually very shallow to 1-3m. The floor is mixed stones along with pieces of metal, pipes etc., small manmade blocks.

Chris Barrett Sounds like another dive's in order! :) You're welcome - please let me know what anyone who you might e-mail say

Tony Gilbert I'd rather raise a query and be wrong about it, than not show an image - because you never know :-). I'd better make the dive soon, as sadly this wonderful place - Trefor Pier - is collapsing even further now, its such a shame because its a great haven for marine life along this stretch of coast. Every year storms bring down more. Will let you know if I have any feedback outside of this forum.

Andy Horton I would go for Gobius paganellus on the facial appearance. Giant Gobies are fuller in the face.

Douglas Herdson Have just spent half an hour writing a comment only to have facebook wipe it out!!! will see if i get time on Monday.

Tony Gilbert Ok, thanks Andy. Yes, facebook does that occasionally - prob. developer-glitches :-)

David Fenwick Snr Confusing me this one! Found by my partner Carol at Carnsew Pool, Hayle, Cornwall, yesterday It was under a rock with goby eggs. Pretty good camouflage! Thanks.

David Fenwick Snr Was about 4-5mm

Marco Faasse I suggest to check whether it could be Calma gobioophaga, described in 2002: http://www.seaslugforum.net/find/calmgobi

David Fenwick Snr It appears to be similar Marco and closer than Eubranchus or Cuthona which I thought it originally might be. Where to go next with it is the question?

Marco Faasse Might be important to have ethanol material from the British Isles. I don't know whether it has been recorded there before. I believe I saw it in Brittany in 2010.

David Fenwick Snr Sadly I didn't preserve it, oh dear!

Ian Smith Hi David, I agree with Marco. Jakov Prkic is also very keen to get British Calma material for comparison with his Croatian specimens. I'm sure he'd love to see your image if you would email it to him. He sometimes finds 150 C. gobioophaga under a single stone with Goby eggs. He's seen Marco's Brittany image and thinks its the same as his C. gobioophaga, except his are bigger because on eggs of Gobius cobitis, a larger fish sp.

David Fenwick Snr Have three Cornish records for Calma glaucoides, pre. 1959 - 1995, two with a few miles of home. I guess if C. gobioophaga has only recently been split, these records are no help at all, the only good thing being the fact that the species was definately on Goby eggs and looks very much similar.

João Pedro Silva No doubt regarding being Calma. Besides the food source, C. glaucoides has shorter propodial tentacles than C. gobioophaga. Gonçalo Calado is the best person to check these. Photos of both spp. can be found here: http://www.flickr.com/photos/jpsilva1971/tags/calmaglaucoides http://www.flickr.com/photos/jpsilva1971/tags/calmagobioophaga

Gonçalo Calado it is Calma gobioophaga. Perhaps the nothernmost confirmed record of the species although T.E.Thompson already pictured two "forms" of Calma galucoides in his book.

David Fenwick Snr Thank you for looking at it Gonçalo, much appreciated. Will make sure it's recorded.

David Fenwick Snr Gonçalo, from the images you have seen here can I ask what are the main characteristics you've seen that have helped you in determining this species. I'm asking this because I know others will ask the same question on supplying the record.

Gonçalo Calado I start by the propodial tentacles that in this case can be a bit misleading. They use to be shorter in C glaucoides. But the eyes (big in comparison to C glaucoides) are very distinctive and, above all, the fact the animal is in pear-shaped fish eggs, i. e. gobiid eggs, is the best indicator. This apperars to be a small individual and the eyes are already very distinctive underneath the basis of the rhinophores.

David Fenwick Snr Thank you very much indeed.

Marco Faasse This supposed C. gobioophaga from Brittany is somwhat different from the British one: http://www.facebook.com/photo.php?fbid=439222672822248&set=oa.357735087671111&type=1&theater

Gonçalo Calado indeed. A detail of its head is appreciated

David Fenwick Snr Looks a good deal older.

Marco Faasse detail head: http://www.facebook.com/photo.php?fbid=439226156155233&set=oa.357735087671111&type=1&theater

Gonçalo Calado It's an adult, mature, C. gobioophaga. The eyes are big as well. Cerata accumulate undigested material from the fish eggs, with the denser part at the insertion. Very typical when the animal eats developed eggs, rather than pure yolk.

Marco Faasse they were adults indeed : http://www.facebook.com/photo.php?fbid=439231922821323&set=oa.357735087671111&type=1&theater