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Benny the Blenny's Blog

Nosy fish – keeping watch. The eyes have it!


I'm keeping watch for predators and intruders. You can see from this video that I have unusual eyes and can look in different directions at the same time.

I've spotted something interesting. I'm off!
 

Explore life beneath the waves around Britain with Benny the Blenny

 

Benny the Blenny's Blog

Benny the Blenny's Blog

Is it a bird or a fish? It's a baby tompot blenny, just like Benny the Blenny's babies, swimming in the plankton.

This video shows tompot blenny larvae like my babies swimming around in the plankton. These ones are around 15mm long and Teresa thinks they look like baby birds because they are flapping their pectoral fins to keep themselves swimming up in the water. They power themselves forwards using their tails too. When my babies first hatched as larvae they had a yolk sac which helped them stay up but that has now all been used up so they flap instead. If you look closely at the video you will see, just under the babies' bellies, that there are two blackish lines. These are their pelvic fins (equivalent to your legs) that have started to develop. My youngsters at this stage are not showing any signs of growing head tentacles, but these will develop by the time they settle on the seabed as little tompot blennies around 20 mm long in a few weeks time.

Thank you to the National Marine Aquarium Plymouth for their help in getting this video; it is an excellent place to see tompot blennies like Benny the Blenny and lots of other marine life in action.

vimeo.com


For wonderful line drawings and descriptions of tompot blenny larvae, see this paper:
Fives, Julie. M. 1986 Blenniidae of the Northern Atlantic (revised) Fich. Ident. Plancton (172:6pp)

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Flying about in the plankton, a baby tompot blenny!

Hey, this shows what my tompot blenny babies look like when they have left home, having hatched from those eggs that I’ve been guarding. Swimming among the plankton in the open sea, they are very sleek with gorgeous big eyes and are between 4 and 20 mm long.
When they first hatch they eat very small plant (phyto-) plankton and animal (zoo-) plankton, the youngsters grow quickly and are then able to eat larger plankton. Bigger fish larvae and jellyfish in the plankton are a real danger and my babies have to make smart evasive moves if they see they are about to be grabbed!
If you would like to find out more about plankton visit:
www.lifeadrift.info
This photo was made possible by the National Marine Aquarium in Plymouth so many thanks to them. Paul, my underwater photographer, would never be able to spot and photograph one of my babies in the wild!

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Off to the plankton!

All my babes have now left my crevice home or ‘flown the nest’ as you like to say! I’m very proud of all my work because I was guarding eggs non-stop for nearly 4 months, keeping away all the ‘egg thieves’ (animals that might want to eat them) and caring for the eggs by wiping them over with my bulbous glands. Each batch of eggs takes about 2 months from being laid to hatching but, as we saw in my last blog, I had several batches! I’m keen to show you how wonderful they are closer up. This photo by Paul at the end of May showed that Belinda had just been laying the dark purple ones to the right of the picture. They were then the last to hatch in mid-July.

Now look at the eggs with obvious silver eyes at the front and left, they were the most developed and were almost ready to hatch. In the middle, the gold coloured eggs were part way through their development and so had the different colouring. Can you see the amazing little cups they are laid in?

When the eggs hatch, the very small tompot blenny larvae swim up into the plankton and have to take their chances along with the young of many other sea creatures. Having batches that hatch at different times is a very good survival strategy for us tompot blennies. If one batch of our larvae get hit by bad weather or run into particularly voracious predators eating lots of plankton, there’s a good chance that the other batches will have an easier time.

I’m now looking forward to seeing as many as possible of my youngsters landing back on the reef after their tough time in the plankton!

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Tompot blenny egg development: it’s not bronze, silver, gold like your Olympics, it’s amethyst, gold, silver!

When I’m guarding all the eggs in my crevice, I have plenty of time to watch them develop. Something I notice is how they change colour. You can see in blog 21/4 that when Brenda laid her eggs they were like perfect amethyst jewels, a lovely deep purple, stuck in a very neat honeycomb pattern on the floor of my crevice. As I cared for them, the viable eggs i.e. the ones that were healthy and that I'd successfully fertilised, developed from purple into beautiful golden globes. Over the few weeks after that, they progressed so the baby fishes’ eyes could be seen shining silver. The eyes are large relative to the eggs, so part of the whole layer looks sparkly silver and it feels as though all the eyes are on me!! Because several different females have laid the eggs at different times (this is called partition laying), I am often looking after the three stages of eggs at the same time. Not at the moment though, it’s now the end of the season and I'm just waiting patiently for the last few sparkling silver-eyed eggs to hatch. Phew, I can then build up my strength again because being a 'stay at home dad' is very exhausting!!

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This photo shows my friend Maisie being a Tompot girl. Thank you Maisie, I’m very proud to be starring in the July 2016 BBC Wildlife magazine. My underwater photographer Paul Naylor has written a fascinating article about me, my tompot blenny neighbours and the other colourful fish that live on my reef. The magazine’s the copy with the mugshot of the whiskery hippo on the front cover.