General Life Style Categories a.pelagic cruisers 1.occurring in water column far away from the bottom (benthic) environment 2.often referred to as "blue water" 3.includes tuna, billfish, blue sharks, mackerel sharks (great whites and mako sharks) Fish Adaptations and Life Styles
b.demersal 1.bottom-associated fishes, but not usually sitting on the bottom 2.rely on the benthic environment as a source of food, place to reproduce, and/or place of refuge, etc. 3.includes most reef fishes (e.g., butterfly fishes, surgeon fishes, wrasses, parrot fishes, etc.)
c.benthic 1.bottom-dwelling fishes that spend the majority of time sitting on the bottom 2.includes flatfishes, lizard fishes, many scorpion fishes, many hawkfishes, gobies, etc.
tuna 1 ) fusiform a) = torpedo-shaped b) allows minimal drag while swimming c) best shape for a pelagic cruise Body shape
2)compressed a)laterally flattened (e.g., butterflyfishes & surgeonfishes) b)allows for maneuverability in surge environments c)useful for demersal fishes that hover above the reef d)exception seen in flatfishes that lie on one side of the body as benthic fishes
3)elongated or attenuated a)long body (e.g., trumpetfish, cornetfish, eels) b)seen in demersal fish that either hover motionless in the water) c)seen also in benthic fishes (e.g., eels) that hide in holes in the reef
4)depressed a)dorso-ventrally flattened (e.g., frogfishes, scorpionfishes & gobies) b)broad ventral surface facilitates resting on the bottom c)seen in many benthic fishes
Body Coloration 1)source of color a)pigment color - chromatophores for yellows, reds, oranges, browns, & blacks b)structural color - iridophores (reflection) & light refraction for blues, silvers, & rainbows
2)patterns a)countershading 1)dark blue or black dorsally, white or silvery ventrally 2)results in blue water "camouflage“ 3)observed most frequently in pelagic cruisers
b)camouflage 1)matching the background coloration 2)usually involves having irregular dark blotches and spots 3)typically seen in benthic fishes, especially benthic ambush predators (e.g., frogfishes, gobies, & many scorpionfishes) 4)some fishes (e.g., flatfishes) may exhibit rapid color changes in response to different backgrounds
b)camouflage 5) matching downwelling light Cookie cutter shark Hatchet fish
c)disruptive coloration 1)color pattern breaks up the silhouette of the fish 2)may involve dark bars across the eye and tail region 3)seen in many demersal fishes such as butterfly fishes
d)bars and stripes 1)bars are vertical (e.g., manini) 2)stripes are horizontal (e.g., ta'ape) 3)seen frequently in schooling demersal fishes 4)may confuse potential predators by making it difficult to select individual prey from the school
e)misdirection 1)false eye spots, etc. 2)observed in many demersal butterfly fishes
f)advertising coloration 1)bright, obvious color patterns 2)possible functions a)advertising a cleaning station (e.g., cleaner wrasses) b)advertising a warning (e.g., nohu) c)advertising for mates (e.g., male parrotfishes) Hawaiian cleaner wrasse Nohu
g)mimicry 1)imitating other creatures 2)seen in a few demersal and benthic fishes 3)examples a)blenny (Aspidontus taeniatus) mimics cleaner wrasses b)shortnose wrasse mimics Potter's angel which sports a defensive spine
g)mimicry 4)leafy sea dragon (Australia)
h)uniform red coloration 1)most often observed in deep-dwelling or night active demersal fishes 2)examples include opakapaka, oweoweo, menpachi, & squirrelfishes
i)noctural versus diurnal color changes j)male versus female color differences k)juvenile versus adult color differences Bluehead wrasse Dragon wrasse Stoplight parrotfish