This image shows the skin texture of the white marlin. Although most fish only have one type of bony structure in their skin (scales), white marlin have two. The first are larger, teardrop shaped scales with forked ends that are embedded in the dermis – they’re visible as larger impressions above. The second bony structure present on white marline skin are smaller peaks that are attached to the skin surface and look like small grains in the images above. Understanding these structures is an important step to understanding the function of marlin skin and the reasons behind these modifications (for more information on these scales see ‘Comparative morphology of the scales of roundscale spearfish Tetrapturus georgii and white marlin Kajikia albida’ by Loose et al. – http://bit.ly/2Bq5UBM). Images: Dylan Wainwright and public domain image.