Feeding ecology of red snapper Lutjanus campechanus in the northern Gulf of Mexico

Regional variation in mercury and stable isotopes of red snapper (Lutjanus campechanus) in the northern gulf of Mexico, USA

“…The average d 15 N values of phytoplankton, the dominant basal resource for red snapper (S.T. Daigle, 2011, Master's thesis, Louisiana State University, Baton Rouge, LA, USA), can vary among sample regions from 3 to 10% (Table 4) [18,44,45]. However, these ratios were not significantly different in red snapper tissue collected from the three different regions, making interpretation of this result difficult.…”

“…For instance, benthic algae is more enriched in d 13 C compared with marine phytoplankton (-17 and -21%, respectively), whereas benthic plants and microalgae absorb sulfides depleted in d 34 S compared with sulfate of seawater [47]. To examine the benthic contribution to red snapper, Wells et al [18] analyzed benthic microalgae collected off the coast of Alabama and found it had an average d 13 C value of -19.9%. Furthermore, Thomas and Cahoon [46] showed that sulfur was vitally important for separating benthic and pelagic food sources for five different fish species.…”

“…Recent studies showed a decrease of total Hg and MeHg in sediment samples with increasing distance from platforms [11,48]. Dietary studies have revealed that red snapper prefer sand-and mud-associated prey, with only a small percentage of their diet consisting of reef-associated species [17,18], such as those inhabiting platforms. Although red snapper aggregate near platforms, they tend to periodically move away from platforms, possibly for foraging purposes [49; M. McDonough, 2009, Master's thesis, Louisiana State University, Baton Rouge, LA, USA].…”

“…Red snapper (Lutjanus campechanus) is a commercially important reef-associated fish in the Gulf, with an estimated site fidelity range of 25 to 60% per year [14][15][16], and a low-level consumer that feeds mostly in the benthos [17,18]. Typical of reef-associated fish, red snapper tend to aggregate near structured environments on the sea floor, including oil and gas platforms [19,20].…”

Spatial variation in basal resources supporting benthic food webs revealed for the inner continental shelf

“…For example, although they did not analyze MPB directly, Thomas and Cahoon (1993) attributed the differences in tissue d 13 C of fishes on offshore reefs to consumption of benthic algae. Working on the Louisiana shelf, Wells et al (2008) actually measured MPB isotopically and concluded that the indirect dependence of red snapper (Lutjanus campechanus) on MPB increased with age, reaching 50% in year 3+ fish. However, such studies are few, and, despite the potential utility of stable isotopes, most isotope studies of shelf food webs have only distinguished between benthic or pelagic consumers without specifically addressing the trophic roles of MPB and settled phytoplankton (Fry et al 1984;Davenport and Bax 2002;Sherwood and Rose 2005).…”