Spatial distribution and feeding habits of the shrimp Crangon uritai as a predator on larval and juvenile marbled sole Pleuronectes yokohamae

Abstract

To examine predation on larval and juvenile Pleuronectes yokohamaeby Crangon uritai, the spatial distribution and feeding habits of C. uritai were studied.C. uritai fed on various prey, including P. yokohamae. Density-dependent predation on juvenile Crangon spp., larval and juvenile gobiid fish Chaenogobius heptacanthus, mysids, and gammarids was observed. The abundance of alternative prey might therefore play an important role in reducing the pressure of predation on P.yokohamae. In each year, C. uritai migrated from depths of 10m in March to depths of 3m in May. There was a significant negative correlation between the weighted mean depth (WMD) of C. uritai and the weighted mean bottom water temperature (WMBWT). The migration was therefore delayed in the cold spring, during which C. uritai occupied depths of approximately 10m. In contrast, no significant correlation was found between the WMD of P. yokohamae and WMBWT.Settlement of P. yokohamae began at depths of 15m, mainly during early April.The spatial distributions of these two organisms show greater overlap during the cold spring, resulting in increased opportunities for predation.

Maternal effects and larval survival of marbled sole Pseudopleuronectes yokohamae

“…It is possible that the reproductive strategy of marbled sole of the population studied here is a response to poor larval growth conditions and large eggs in the early spawning period mitigate recruitment failure. In Hakodate Bay, water temperature and densities of copepod nauplii and rotifers (the initial prey items for marbled sole larvae) are low in March and increase in April (Nakagami, 2001;Nakaya et al 2004). It has been shown that smaller larvae may be disadvantaged in terms of food availability and growth under conditions of low prey abundance or inadequate temperature in the wild (Hutchings, 1991;Benoît and Pepin, 1999;Rideout et al, 2005).…”

Comparison of the nutritional transition date distributions of marbled sole larvae and juveniles in Hakodate Bay, Hokkaido

“…Therefore, marbled sole juveniles that were larger than the maximum vulnerable size for sand shrimp predation were assumed to get out of the phase that predation mortality was relatively high. The maximum ratio of body length of predated marbled sole to that of C. uritai is 0.32 [8], and the maximum body length of C. uritai has been reported to be 48. were omitted from the analysis. Data were expressed as the percentage frequency of occurrence (F%, the percentage of larvae that consumed a particular type of prey), percentage in number (N%, the percentage of each prey type consumed to the total number of prey items), feeding intensity (FI, the ratio of the total number of each prey type to the total number of larvae examined), and the feeding rate (the proportion of larvae with prey to the total number of larvae examined).…”

“…The sand shrimp C. uritai is a predator of metamorphosing larvae and juveniles [8][9][10]; other demersal predators of them are rare in Hakodate Bay [20]. Therefore, marbled sole juveniles that were larger than the maximum vulnerable size for sand shrimp predation were assumed to get out of the phase that predation mortality was relatively high.…”

“…Transportation of pelagic larvae and immigration of juveniles [6], the feeding ecology of larvae and juveniles [4,7], and predation by the sand shrimp Crangon uritai on demersal larvae and juveniles [8][9][10] have been studied. The early life history of marbled sole also has been studied in other locations and in the laboratory [11][12].…”

Feeding ecology of the sand shrimpCrangon hakodateiRathbun, 1902 (Decapoda: Crangonidae) in the East Sea of Korea

“…A number of studies have investigated the feeding behavior of crangonid shrimp including C. affinis by Kosaka (1970) and Hong and Oh (1989); C. allmani by Allen (1960); C. crangon by Lloyd and Yonge (1947); Tiews (1970), and Oh et al (2001); C. franciscorum and C. nigricauda by Wahle (1985); C. septemspinosa by Price (1962) and Wilcox and Jeffries (1974); and C. uritai by Nakaya et al (2004). However, despite its ecological and economic importance, there is no information on the diet of C. hakodatei.…”