Monday, April 7, 2008

Fishes on the North Cottesloe Reef (3) - Dusky morwong

I have seen a single dusky morwong (Dactylophora nigricans) (also called strongie or strongfish) a few times on the North Cottesloe Reef. It was searching the reef for food I think.

It was interesting to watch it because I could actually hear the short dull sound it made every time it sucked in (or maybe spat out) some food. The strongie feeds on small invertebrates (literally spineless animals).

And today, I saw two coming my way. I have no idea if they are a couple but I wonder why I always saw only one before this. Could there be actually three - the lone ranger and this couple - living on this reef?

The water clarity was not the best today due to too much sand in the water. And the slightly cloudy skies was not helpful. But these are some of the best dusky morwong photos I have taken so far.


The two dusky morwongs or strongies I saw this morning.


This strongie found something eatable.


This strongie went where it's brighter so that I could take a decent photo.


Some features of a dusky morwong are quite clear here:
(1) Small mouth and thick lips
(2) The lips do not reach back to below the eye

(3) The lower few rays of the pectoral fins extend beyond the pectoral membrane (see arrows). (Rays = the stiff bony spines in the fin)


Last week, I saw a western king wrasse hanging around with some tarwhines.
And today I saw one with this dusky morwong. Why?

Was this wrasse a cleaner wrasse?
But if it was, I didn't see it picking away stuff from the strongie's body.
Could it be that the wrasse is simply a sociable fish?

By the way, another reason why the strongies are nice to watch is that they are big! The ones I have seen so far are all at least 60 cm in length, probably near one meter. And they look strong as their name says.

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