(My apologies for going WAY off topic and not posting a personal political
rant, or a defense of why it's okay to shoot varmints or collect
hellbenders.) :-)
Jeremy sent me a copy of his paper, and it's fascinating. Jeremy
hypothesizes that the jugular position of the anus relates to the nocturnal
fish's preference for seeking refuge in thick aquatic vegetation during
daylight hours. Jeremy observed captive pirate perch poking their heads out
of plastic containers and woody debris piles just far enough to expose the
anus, defecating, then retreating back into the vegetative mass. At no other
time was defecation observed. "Because A. sayanus is a relatively inactive
fish that inhabits sluggish waters," Jeremy wrote, "the jugular position of
its anus might allow the fish to partially leaves its refuge to defecate to
avoid altering water quality and without fully exposing itself to
predators." A similar behavior has been noted among marine pearlfishes,
another nocturnal fish with an anterior anus, which live inside the bodies
of sea cucumbers.
(Jan -- I love the "poop on pirate perch" header! I may use it in the AC
summary.)
Chris Scharpf
Baltimore
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