Who is Japanese Fishing Fleet from The Log from the Sea of Cortez and what is their importance?

South of Guaymas, the Western Flyer, encounters a Japanese mother ship, as well as a number of dredging vessels fishing for shrimp. Steinbeck and Ricketts go on board one of the vessels to observe its operations. When the hauls dredge the bottom clean, all the local species are brought up, but only the shrimp are kept. Steinbeck notes that the crew operates in a highly precise rhythm, and that they seem to be very nice, in spite of the ecological damage they are doing. Once their mission is known, the crew begins bringing Steinbeck and Ricketts interesting species they have found.