Trophodynamics of the Fish Valenciennellus tripunctulatus. Ill. Energetics, Resources and Feeding Strategy

Abstract

A model was constructed which relates energy in diet to metabolic requirements for the mesopelagic zooplanktivore fish Valenciennellus tripunctulatus. Linear and Von Bertalanffy growth models were used to explore the energetic consequences of a number of feasible age/growth strategies. Maxlmum efficiencies were obtained with linear growth to about 30 mm in 1 y. Efficiencies declined rapidly for slower growth strategies. It was hypothesized that a n 'annual' life history strategy was optimum based on energetic considerations. Copepod prey in the 1-2 mm size class were an order of magnitude more abundant and over 4 tlmes higher in caloric content than larger size classes. V. tripunctulatus, however, is highly efficient in obtaining calories from larger prey size classes ( 2 4 mm) which contain a high caloric content per individual. The resource field places severe constraints on predator growth and at 38 mm no surplus energy is estimated available from daily ration over and above metabolic requirements. V tripunctulatus should be sensitive to 'nearfield' competitors as well a s 'remote' predators grazing zooplankton populations in different space/time.

Diet and food consumption of a deep-sea fish orange roughy Hoplostethus atlanticus (Pisces Trachichthyidae), off southeastern Australia

“…ism to reduce intra-specific competition at depths where prey are not abundant (Baird & Hopkins 1981). Such a mechanism might be effective for a species such as Hoplostethus atlanticus which is the dominant component of the fish biomass at these depths in the region (Bulman et al in press).…”

Deep-Sea Food Chains and the Global Carbon Cycle

“…It is not just particulate matter that is moved. Attention in this area originally focused on relatively few taxa (Baird and Hopkins, 1981) and on depth as the controlling factor for metabolic rates in the deep sea (Siebenaller et al, 1982;Graham et al, 1985). Measurements from a very few stations but over broad areas indicate that this respiratory flux rate could range from 12 to 53% of the measured small particle flux .…”