Transfer of Cd, Cr and Zn from zooplankton prey to mudskipper Periophthalmus cantonensis and glassy Ambassis urotaenia fishes

Abstract

Assimilation efficiency (AE) of metals from ingested food is critical for understanding trace metal accumulat~on and trophic transfer in aquatic animals. Most recent measurements of metal AEs have been on aquatic invertebrates, whereas relatively few studes have examined metal assimilation in fishes. In this study we determined the AEs of Cd, Cr and Znin 2 fishes (pelagic glassy Ambassis urotaenia, Ambassidae, and the intertidal mudskipper Penophthalmus cantonensis, Gobiidae) feeding on 2 zooplankton prey (brine shrimp k t e m i a larvae and copepods). Zooplankton were radiolabeled either by feeding on radiolabeled phytoplankton or by direct exposure to radiotracers in the dissolved phase. Fishes were then fed with radiolabeled zooplankton prey for < l h., and the retention of ingested metals in the fishes was followed for 2 d. The measured AEs of Cd, Cr and Zn were 14 to 33, 4 to 12, and 5 to 17% in glassy fish, and 10 to 26, 4 to 19, and 11 to 31 % in mudskipper, respectively. Routes of radiolabeling in copepod prey did not affect metal AEs in either mudskipper or glassy, whereas metal AEs differed by up to 10-fold in glassy fish feeding on Artemia larvae labeled from different routes. There was little difference m the gut passage time of metals for different food types and metals or between fishes. AE was not significantly related to metal gut passage time or metal distribution in the soft tissues of zooplankton prey, for each metal. However, AE in mudskippers was significantly correlated with metal distribution in the prey's soft tissues when all 3 metals were considered. Our study demonstrated that marine fishes can appreciably assimilate trace metals, and trophic transfer should be considered as a source for metal accumulation in fishes.

Trace metal contamination in estuarine fishes from Vitória Bay, ES, Brazil

“…These generally consume their prey whole, and may be contaminated by organs (gills, bones, liver, spleen, etc) that specifically accumulate metals (see for example Wood andVan Vleet, 1996, andParsons, 1999). None of the metals analyzed in the present study has been reported as being commonly bioaccumulated (e.g., Miramand et al, 1998; but see Ni et al, 2000) and, in fishes, metal levels generally diminish from the bottom (i.e., mullet, as primary consumers) to the top of the food chain (i.e., snook, as secondary consumers) (Mance, 1987). Our study showed little evidence for such phenomena (T ables 2 and 4) or its opposite (i.e., bioaccumulation).…”

Bioaccumulation kinetics and exposure pathways of inorganic mercury and methylmercury in a marine fish, the sweetlips Plectorhinchus gibbosus

“…Among the many elements studied so far, the AE of MeHg and radiocesium in fishes are the highest (Ni et al 2000, Zhao et al 2001, Baines et al 2002. For example, the AE of radiocesium range between 78 and 95% in the marine mangrove snappers Lutjanus argentimaculatus (Zhao et al 2001).…”

Significance of subcellular metal distribution in prey in influencing the trophic transfer of metals in a marine fish

“…They suggested that the AEs of elements in fish were directly correlated with the metal distribution in the nonexoskeleton fraction of the copepod prey. The correlation was based on a variety of elements with contrasting physiological and geochemical behaviors, but it was not observed in the two fish Periophthalmus cantonensis and Ambassis urotaenia (Ni et al 2000). Recently, Wallace and Luoma (2003) introduced the concept of trophically available metal (TAM) (combination of organelles, HDP, and HSP) and indicated that about 100% of the TAM could be assimilated by predators.…”

“…It has been shown that different prey resulted in a variation of metal AEs in fish (Ni et al 2000;Xu and Wang 2002), suggesting that different forms of metals in the food may influence the availability of metals. Some previous studies have indicated that the cytosolic distribution of metals in marine phytoplankton is important in dietary assimilation by marine herbivores (Reinfelder and Fisher 1991;Wang and Fisher 1996;Chong and Wang 2000), but assimilation in marine predators appears to be more complicated.…”