Photoperiod and feeding behavior of the Antarctic fish Notothenia rossii (Perciformes: Nototheniidae) and functional morphology of chemical and visual sensory structures used in foraging

Abstract

The influence of photoperiod on the ability of Notothenia rossii Richardson, 1844 to detect prey was studied experimentally. In 12L/12D there was the highest number of individuals stimulated visually and chemically while in 24D chemical perception was the same as that observed in 12L/12D, the latter being lower than in 24L. The ultrastructure of chemo- and photo-sensory structures, involved in the detection of food, was studied. The photoreceptor cells of the retina are single and double cones, and rods. Taste buds were concentrated in the central part of upper and lower lips. Their shape is even, but the size is variable. The olfactory rosette has a sensory and a non-sensory epithelium, being rich in different mucosubstances. The conclusion was that in different photoperiods there is a difference in the response to visual and chemical stimulation for prey detection and that all sensory systems are more stimulated in periods of more luminosity, mainly when there is an alternation between light and dark periods. Sensory organs are complex when compared to some other Antarctic fish such as Gobionotothen gibberifrons Lönnberg, 1905 and Ophthalmolycus amberensis Tomo, Marshoff & Torno, 1977 but similar to those of N. coriiceps Rchardson, 1844.

The influence of selection for vulnerability to angling on foraging ecology in largemouth bass Micropterus salmoides

“…Micropterus salmoides are visually feeding predators (Shoup & Wahl, 2009) and as such, it seems likely that one or more sensory systems could be affected by selection for vulnerability to angling. The ability of a fish to strike at a prey item is dependent on detecting the prey, accurately assessing position, being motivated and making a strike based on that information (Stoner, 2003; Donatti et al , 2008; Rapo et al , 2009). If selection for vulnerability to angling affected any of the systems used to make these assessments, differences in foraging would be expected as well.…”

Heavy Metals in Antarctic Notothenioid Fish from South Bay, Livingston Island, South Shetlands (Antarctica)

“…Fish with opportunistic feeding habits may leave their usual trophic niche to feed on krill when they are available [8,18,19]. In this connection, the heavy metal analysis was conducted on the krill component of the food as the most important component in the fish diet in Antarctica [17,20,21].…”

Changes in the body chemical composition and the excretion of nitrogen and phosphorus during long-term starvation of Antarctic fish Notothenia coriiceps and Notothenia rossii

“…Conversely, the experiment with N. rossii was carried out at the end of the Antarctic winter, during which body growth had slowed down (Linkowski & Żukowski 1980). This means that N. rossii (caught in September -the end of the Antarctic winter) were in a period of natural starvation because the feeding intensity in many Antarctic fish species depends strongly on the photoperiod and the intensity of exposure to sunlight (Donatti & Fanta 2002;Donatti et al 2008).…”

“…In the final stage of farming, fish farmers often, for a better culture effect, stop feeding the fish for a while, subjecting them to socalled depuration (Zajic et al 2013;Varju-Katona et al 2019). As the temperature of the Southern Ocean waters is relatively stable, the feeding activity of Antarctic fish is mainly dependent on the seasonality of the ice cover and also the day and night duration (Johnston 1993;Donatti & Fanta 2002;Donatti et al 2008). The metabolism of Antarctic fish is also influenced by coastal tides, the amount of sunlight that penetrates the water column (Wróblewski 1984), and water productivity (DeVries & Eastman 1981).…”