It's a great idea, the shapes combine quite nicely, and the marking transition of the animals design is pretty good.
I assume its watercolour paint all the way,
though I think the lower-left part of the background lets the image down.
You can see the head of the orca is faded, where the light hits it, which is great.
But the dark of the water in the left corner isn't evident on the lower half of the body, and there is no shading there on or before the tail. So it looks a bit cut/pasted.

Also, what you could do is, with the light coming from above, pinpoint where you would like the sun to eminate from, get a ruler and draw some guidlines as to the rough angles of the suns rays shining down into the abyss. Just to add a bit of Tropicality and warmth to the water.
Try to get less of the strokes in the darker water, to make it seem thicker and denser, and less choppy. After all only the water near the surface would show the bends of the light.

All in all, a really interesting piece to look at, and great to see something fresh from you.

i like it, i really do, as you show an obvous talant with watercolours.

But what i would say, is that it looks like you've just stuck two animals together?! perhaps if you had the lepordsharks colouring (and its tail if thats what you was going for) and still keep the killer's marking's and some of its shape? and make them an equal of the two, instead of two 'stuck' to one-another

All in all i think you did very well! keep up the hard work. i also like the way you did the ocean, and how it seems to get deeper and darker.