Locomotor activity in the painted goby,Pomatoschistus pictus(Malm) (Pisces), in relation to light intensity

Publisher Website
Google Scholar
Abstract
Four painted gobies (two of each sex) were collected in 20 m depth in the inner Oslofjord, Norway, in late fall. The fish were kept in a closed aquarium system under varying artificial light intensities with no access to daylight. The locomotor activity of the whole group of fish was recorded both on the bottom and in the water column by an IR-photocell technique During day the goby was active only close to the sediment, but a nocturnal activity occurred off the bottom. A bimodality in the bottom activity is connected with a crepuscular feeding behaviour whereas the night activity is suggested to be associated with moving under conditions when the fish is less vulnerable to predators The activity reached its maximum level at 4.5 lux and remained so even at 180 lux, simulating a winter and summer situation respectively. The relatively low light intensity for maximum activity is also connected with crepuscular feeding Under the present experimental conditions no evidence of a lasting endogenous circadian activity rhythm was found