Feeding Strategies and Partition of Food Resources in Deep-Water Decapod Crustaceans (400–2300 m)

Abstract

Food resource partitioning and trends in feeding strategies were examined in 3882 individual decapod crustaceans collected from 1989 to 1990, using bottom trawls at depths between 380 and 2261 m in the Catalan Sea (western Mediterranean). The vertical distribution of available food resources near the bottom was the most important factor responsible for food resource partitioning among bathyal decapod crustaceans by depth stratum and season. Decapods were assigned to five different trophic groups according to the food resource exploited and feeding strategy employed (macroplankton feeders, macroplankton-epibenthic feeders, epibenthic feeders, epibenthic-endobenthic feeders, and deposit feeders). There was little dietary overlap, indicating that species did partition the available resources. Overall, dietary overlap values among species increased with depth. Although a trend to increase H’ values for diets with depth was observed, this was not significant (P < 0.10), whereas differences in the percentage of empty stomachs and the frequency of foraminiferans and pteropods in the foreguts increased significantly (P < 0.05) with depth. This last result is indicative of a progressive increase in the importance of deposit feeding in decapod crustaceans as depth increases.

Body fish size tendencies within and among species in the deep-sea of the western Mediterranean

“…Thus, the minor availability of trophic resources above and below this depth interval may ultimately determine the lower biomass characterising the upper and lower slope fish assemblages (see also Stefanescu et al, 1993). On the other hand, the biomass of another major group of predators, namely the decapod crustaceans, which also prey on the suprabenthos (Cartes, 1994;1998b) peaks between 400-700 m (Maynou and Cartes, 2000), and Cartes et al (2001) have suggested that this may originate a phenomenon of competitive exclusion in favour of the latter group of megafaunal predators at this depth interval due to the exploitation of similar resources.…”

Size Influence in Zonation Patterns in Fishes and Crustaceans from Deep-water Communities of the Western Mediterranean

“…The zonation might be directly or indirectly related to changes in food webs, particularly in the deep Mediterranean where thermal and saline stability occur below 200 m. The major part of deep-water megafaunal predators has a highly diverse diets and a variety of trophic guilds can be identified within each taxa (Cartes, 1998). It is also well documented that deep-water species prey on different compartments (plankton-benthos) as a function of depth (Cartes, 1993). Trophic aspects have been considered as a determinant in the size structure of decapod crustaceans in a neighbouring area (Sardà and Cartes, 1993).…”

“…Because of their dominance at mid-latitudes most studies have been on fish (Haedrich and Krefft, 1978;Gordon and Duncan, 1985;Haedrich and Merrett, 1990;Koslow, 1993;Fujita et al, 1995;Stefanescu et al, 1992;Moranta et al, 1998). Zonation has also been documented in other megabenthic taxa, such as crustaceans and other benthos (Rowe and Menzies, 1969;Abelló et al, 1988;Fredj and Laubier, 1985;Cartes, 1993;Cartes and Sardà, 1993;Maynou and Cartes, 2000). Comparative zonation studies between different groups are, however, scarce (Gage and Tyler, 1991), although the taxon factor, together with bottom topography, has been one of the most widely argued reasons to explain discrepancies in zonation (the intensity of faunal change with depth) at a regional scale (Gage and Tyler, 1991).…”

“…In the deep Northwest Medi-terranean Sea, there is a boundary between 350 and 550 m, separating upper and middle slope decapod crustacean communities (Abelló et al, 1988;Cartes et al, 1994). The boundary between the middle and lower slope was established at around 1200 m (Cartes and Sardà, 1992;Cartes, 1993). The zonation of fish communities is characterized by the presence of two boundaries, located at 800 and 1400 m depth between upper-middle and middle-lower slope, respectively (Stefanescu et al, 1993;Moranta et al, 1998).…”

“…The zonation of fish communities is characterized by the presence of two boundaries, located at 800 and 1400 m depth between upper-middle and middle-lower slope, respectively (Stefanescu et al, 1993;Moranta et al, 1998). It has been suggested that this pattern of zonation is related to food availability, especially the influence of mesopelagic prey in the diet of bathyal species down to 1 2001 300 m depth in the Catalan Sea (Cartes, 1998; and references cited therein). The different depth patterns shown by each taxon may be attributed to the different fractions of the food resource, or food spectrum, exploited by each taxon (Maynou and Cartes, 2000).…”