Work smarter avoiding complex masks using selective blending. I will show you a really nice trick to make this amazing composition.
Selective blending in Photoshop
Sometimes, being a bit smarter saves you a lot of time in Photoshop. In this case, blending the shark with the wave could seem a bit more difficult than it actually is. I will show you how to blend it using no blend modes.
First I placed the extracted shark over the surfer photo. Then I created a copy of the background layer (the surfer) and I placed it right on top of the shark. I other words I “sandwiched” the shark layer with the background image.
Using the “Blend if” option on the layer style panel you can blend even better the shark and the water’s foam and reflection, it’s what I call selective blending. See the video for more details.
Create a layer mask for the shark layer and use a soft brush with Opacity 50 and Flow 20 and mask the far ends of the shark’s body to create the sense of depth.
Also you can use a Color Overlay on Normal mode and sample the color of the water to add more color and realism to the shark.