Congratulations to reader Suzi for being the first to answer our April puzzler. As Suzi noted, the image shows South Korea’s Sisan Island. While Suzi (and several other readers) thought the offshore grid pattern was evidence of oyster or fish farming, our research suggests it is mainly seaweed farming. Several sources cited the western part of South Korea’s south coast as the main area of seaweed production, and aerial imagery of seaweed farms match the general appearance of our satellite image.
However, Suzi’s comment did prompt me to look more closely at the distribution of oyster farms and other types of aquaculture in South Korea, and it does seem possible that some of the patterns in the puzzler could be evidence of oyster aquaculture. Are there aquaculture experts or South Koreans reading this who are willing to share their opinion? Is this all seaweed or a mixture of seaweed and other types of aquaculture?
I suspect it may not be possible distinguish between seaweed farming and other types of aquaculture at Landsat’s resolution, but I would love to see somebody with more expertise prove me wrong. In the meantime, you can read what we published about this area as our Image of the Day on April 25, 2015.