[Coral-List] Respiration of Parrotfish through their mucus cocoon ?

[Michaël Rard]

Dear all,

Sorry for all coral-listers and others who will be not concerned by this message.

Some species of parrotfishes build a cocoon in mucus during the night. Different roles have been explained for this cocoon :
1- protection against predators where the mucus represents a barrier against pheromons or other chemical components
2- protection against parasits, even some small molluscs eat the blood of them through the cocoon during the night

But I have a lot of problems to find more informations about this cocoon. My principal questions are :

1) Do you know other roles which were attributed for this cocoon ?

2) If this cocoon is a barrier really against chemical transferts between water and fish, how can breath Scarids fishes ?
Can the oxygen go through the mucus of the cocoon ?

If anyone can help me to find some other informations (papers references or something else) and perhaps answers, I would very appreciate any help of your.

Many thanks for this.
Best regards.
Michaël
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                          Michaël RARD
Laboratoire d'Ecologie Marine, Université de La Réunion
   97715 Saint Denis messag CEDEX 9, France
Tel : (262) 262-93-81-57, Fax : (262) 262-93-86-85
http://perso.wanadoo.fr/mika.dit.kl/html/ContactsMika.htm