Midwater Fishes
Nearly all mesopelagic fishes are quitesmall, about 2 to 10 cm (1 to 4 in) long,although a very few species get consider-ably larger. Bristlemouths (Fig. 16.8
a
) andlanternfishes (Fig. 16.8
b
) are by far themost abundant fishes in the mesopelagic. These two groups may account for 90% ormore of the fishes collected by midwatertrawls (Fig. 16.9). The bristlemouths arethe most common of all. One species
(Cy-clothone signata)
is the most abundant fishon earth, which is both surprising and im-pressive when you consider the hugeschools of fishes like sardines and herringsthat live in the epipelagic. Bristlemouthsare named for their many sharp teeth. They have rows of photophores on theirunderside, or ventral surface