Sentence:  On rising, and casting another hasty glance at the big head and huge back fin of my enemy, I saw that he was evidently hungry and excited, and making frantic efforts to get at me; but that, being a big shark, success in his laudable attempts was not within the resources of science -- in fact, morally and physically impossible, for there was scarcely water enough to swim a good-sized salmon. Being convinced of this highly comfortable state of things, I at once became cool and jolly; and, calling out to Frank to run to the United States Hotel, and fetch my rifle and a little bag of ammunition, which I always kept handy for chance occasions of sport, I prepared to have a little “chaff” with the “<WSD>sea lawyer</WSD>". 
Meaning of the word marked with <WSD> tags:  A shark.