Stable isotope ratios in archived striped bass scales suggest changes in trophic structure

Abstract

Stable carbon isotope ratios were measured in archived striped bass, Morone saxatilis (Walbaum), scales to identify changes in the feeding behaviour of this species over time. Striped bass tissue and scale samples were collected from Rhode Island coastal waters during 1996 and archived scale samples (1982–1997) were obtained from Chesapeake Bay. Known striped bass prey items were also collected from Chesapeake Bay and analysed for δ13C. A significant correlation was observed between carbon isotope ratios in striped bass scales and muscle tissue (r2 = 0.52; P < 0.05). Carbon isotope ratios were enriched (less negative) in scales relative to muscle tissue by about 3‰. Carbon isotope ratios in archived striped bass scales from Chesapeake Bay increased significantly from −16.7 ± 0.2‰ in 1982 to −15.1 ± 0.3‰ in 1997. Benthic species, especially invertebrates, were isotopically enriched relative to pelagic fish species collected from the main‐stem of Chesapeake Bay. Prey samples collected from riverine locations within Chesapeake Bay were isotopically depleted relative to those collected in the open portion of the Bay. The changes in the carbon isotope ratios of the striped bass scales could be related to changes in the relative proportions of pelagic and benthic food items in the diet of striped bass or to changes in the feeding locations of this species. In either case, there have been changes in the feeding behaviour and/or relationships of the striped bass between 1982 and 1997. Such changes may be related to changing ecological conditions within the estuary, which could influence the health of Chesapeake Bay striped bass.

Bioaccumulation of polybrominated diphenyl ethers and decabromodiphenyl ethane in fish from a river system in a highly industrialized area, South China

“…To validate this hypothesis, we analyzed the relationship between the stable carbon isotope (δ 13 C), which is directly linked with food source of fish, and the percentage of BDE209 in fish. The results showed that the plecostomus had a higher δ 13 C (mean of −21.4‰) than the mud carp (− 23.3‰) and the nile tilapia (−23.2‰), which was in line with previous reports that benthic consumers have high δ 13 C values when compared to phytoplankton-based consumers (Nadon and Himmelman, 2006;Pruell et al, 2003). A simple linear regression analysis revealed that there was no correlation between δ 13 C and the percentage of BDE209 for mud carp and nile tilapia but a significant positive correlation existed for plecostomus (p b 0.05, Fig.…”

Preservation effects on stable isotope ratios and consequences for the reconstruction of energetic pathways

“…The reported isotopic shift is typically small (within 2%) and comparable with the isotopic shifts observed in ecosystem reconstruction using the isotopic signatures of archived sample material (Pruell et al 2003;Solomon et al 2008;Wainright et al 1993). Previous studies have shown that the effects of preservation on stable isotopes depend on organisms and preservatives and are often inconsistent and variable (Barrow et al 2008;Kelly et al 2006;Schmidt et al 2009;Syvaranta et al 2008Syvaranta et al , 2010.…”

Influence of nutritional state on the progression and severity of mycobacteriosis in striped bass Morone saxatilis

“…Dietary changes have been documented in striped bass, suggesting a shift from historically preferred pelagic sources to benthic sources (Hartman & Brandt 1995, Griffin & Margraf 2003, Pruell et al 2003, Walter et al 2003. Concurrently, populations of principal prey items for age 2+ striped bass Atlantic menhaden Brevoortia tyrannus, bay anchovy Anchoa mitchilli, and spot Leiostomas xanthurus have declined (Uphoff 2003, MDNR unpubl.…”