16 replies to this topic

[***Simon***]

where and when do they sleep?

[stan4massey]

Simon,
depends a bit on the difinition of `sleep'. "A period of rest and inactivity allowing the body to re-charge and recover from activity"????? Fish dont have eyelids as such so even when they rest it would be impossible to know if they were actually sleeping as we uderstand the term. Shark have nictating membranes which can cover the eyes but not actual eyelids. Some shark have been filmed in apparent sleep in caves and under rock ledges at which time they are totally inactive and can be approached without them moving. Other fish like the lungfish can bury itself in mud for many months during a dry season. Sleep or hibernation ? no idea. On coral reefs there appear to be day feeders and night feeders. At times when they are not in feeding mode the various species retire into safe areas, holes , ledges etc but again whilst they are difinately resting from activity the term sleeping as we know it may not apply.

Hope I aint confused the issue.
Stan.

[Toerag]

Wrasse wedge themselves under a rock, as does the Black Velvet damselfish in my aquarium.

[stan4massey]

Toerag,
obviously some first hand information from your aquarium. Would be interested to hear more. Are there indications that they are actually sleeping (as we understand it) or just resting? Does this happen at any particular light phases, i.e. night /day/lights on/off?? Some more info on this type of thing could give indications as to why and when certain species feed at certain times. I`ve caught many common skate over the years but never had great success at night. 100-130+mtrs down there is certainly still a little light but often wondered does actual dark, i.e. night affect them or what???? Davy??? genuine question, not a dig, any ideas?????

Stan

Stan

[Davy Holt]

Hiya,

Ok aquarium stuff first, most daylight species of fish certainly do "rest" at night, often taking a few minutes to come to when the light come back on. they also take a short time to settle down when the light's are switched off.

Stan, cant say I've noticed that, on the few times I've done night fishing for them I've still caught fish in the dark ok. I'm of the opinion that skate & rays just rest up for a few hours every now and again in between hunting/ feeding spells.

[Stoaty]

I have often thought that they must rest over slack water. It's the only time they can be inactive and not get moved around by the tide. In hard tides they seek refuge but this is something they have to work at and be alert. So I am going for slack water as rest/sleep period.

It might also explain why some neep tides don't fish too well.

We need a boffin to answer this one.

[noah]

The bass in my tank seems to 'rest/sleep' in a hole away from the strong flow of the filters. These periods of rest can happen at any time but they do seem to coincide with low water. the strange thing is i am at least 20 miles from the coast and the tank is not tidale. the fish takes a while to 'wake up' if it is disturbed during this time. Also the bass will not take any food with in 10 mins of coming out of this 'rest' period.

[Sharkbyte]

I have actually witnessed wild bass 'sleeping' some time ago, this was on a spring tide at low water whilst spearfishing. They seemed to like the rocky ground where there is an abundance of kelp to settle on the bottom and did not stir even when I was very close indeed.

I wont finish the story as I am now a reformed character.

[Slashley]

Noah, I once read something along those lines in some fishing book. It was mussels that were used. They were watched to see at what stage of the tide they opened their shells to feed. They were then taken from the seashore to a local aqaurium. Here they adhered to their timetable. From here they were transferred to a biology lab. in the Arizona desert. As before, the mussels established their own pattern of activity. They continued to feed as if governed by the saltwater tide.
Experiments eventually proved that the mussels were responding to the moon. They could even detect it's presence when sealed in a metal container. Calculations showed that their actual feeding time remained exactly in step with the tide that would have occured had the desert been covered by ocean.

[ 05. August 2005, 10:58 PM: Message edited by: Slashley ]

[sam-cox]

wrasse also cover themselves in mucus when sleeping in creveses, this is to help preditors finding them.