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

Abstract

We examined the diet of nearly 7500 orange roughy Hoplostethus atlanticus Collett. 1889 from southeastern Australian waters caught during trawl surveys in 1988 and 1989. Juveniles fed mainly on bentho-and meso-pelagic crustaceans, while mature fish consumed predominantly fish and squid. The con~position of the diet changed significantly ~l t h depth, geographical area, and year. Evidence of die1 feeding periodicity found in adults at a station sampled over 42 h was supported by patterns of stomach fullness and digestion stage in the full data set. Based upon observed rates of stomach evacuation, daily rates of food consumption were estimated as 1.15 % body weight for adults and 0.91 'L, for juveniles. The metabolism of orange roughy, estimated from a mass balance model, is similar to that of active, migratory mesopelagic fishes and substantially higher than that of non-migratory bathypelagic fishes. The bodily composition of orange roughy, which is high in lipid and protein and low in water, is also similar to that of active rnesopelaglc f~shes. Non-migratory bathypelagic fish.es typically have exceptionally low metabolic rates. which, d e s p~t e low food consumption, lead to high growth rates and high growth efficiency. Orange roughy, however, appears to have very high metabolic costs, which lead to an exceptionally low growth rate and growth efficiency, despite relatively high rates of food consumption.

Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling

“…No juveniles of orange roughy or oreosomatid fishes were obtained from the reef habitat, and the dominant benthopelagic fishes feed mostly on prey within the water column (Clark et al 1989, Bulman & Koslow 1992. However, the removal of the reef habitat formed by Solenosmilia variabilis clearly may affect the several fishes and numerous invertebrate species associated with the coral substrate, many of which appear to be endemic to the region.…”

Trophic structure of a bathyal benthopelagic boundary layer community south of the Balearic Islands (southwestern Mediterranean)

“…Information is available on stomach contents of fish species in the deep sea (summarised in Gordon & Mauchline 1990), which are the dominant megafaunal taxa. These studies have often focused on species of commercial interest (Bulman & Koslow 1992, Cartes 1994 or on some well-diversified and characteristic families, such as the Macrouridae (Macpherson 1979). In general, there is still a lack of integral approaches that relate different compartments (trophic levels), and most studies also lack an approach which considers the influence of environmental factors on population structure and abundance.…”

“…Some studies quantitatively describe deep-water food webs and trophic balances both at multispecific and autoecological levels (Bulman & Koslow 1992, Maynou & Cartes 1997, 1998, Pakhomov et al 1997. Also, some general schemes on the carbon cycle have been published for abyssal depths (Pfannkuche 1992, Smith 1992.…”

Feeding guilds of western Mediterranean demersal fish and crustaceans: an analysis based in a spring survey

“…In practice, however, great difficulties exist in developing such models in deepwater systems, because only scarce data have been published on important quantitative aspects such as secondary production (Cartes and Sorbe, 1999;Cartes et al, 2000), and daily rations (Maynou and Cartes, 1997;1998;, with only some preliminary trophic balances constructed for the mid-slope depths . Trophodynamic studies in deep-sea systems have often focused on species of commercial interest (Macpherson, 1985;Bulman and Koslow 1992, Maynou andCartes 1997), whereas by-catches and studies on the lowest trophic levels, i.e. those compartments that sustain the trophic webs and fisheries, have received, in general, little attention (Christensen, 1995;.…”