Redbanded rockfish In 1995, 280 tons were caught by longline off British Columbia. Often, though, this fish is taken as bycatch during trawling operations targeting other species, such as the yelloweye rockfish ("S. ruberrimus") and halibut ("Hippoglossus stenolepis"). Bycatch of this species in trawls off the coast of British Columbia well exceeded 1,000 tons in 1992. It has dropped below 300 tons per year since then due to better monitoring. This fish is host to a number of parasitic copepods, including "Chondracanthus pinguis", "C. triventricosus", "Clavella parva", "Colobomatus kyphosus", "Naobranchia occidentalis", "Peniculus asinus", and "Neobrachiella robusta". Redbanded rockfish Sebastes babcocki is a
Fish anatomy Their retinas generally have both rod cells and cone cells (for scotopic and photopic vision), and most species have colour vision. Some fish can see ultraviolet and some can see polarized light. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. The ancestors of modern hagfish, thought to be the protovertebrate were evidently pushed to very deep, dark waters, where they were less vulnerable to sighted predators, and where it is advantageous to have a convex eye-spot, which gathers more light than a flat or concave one. Unlike humans, fish normally adjust focus by