GULF MENHADEN Brevoortia patronus: A POTENTIAL VECTOR OF DOMOIC ACID (DA) IN
COASTAL LOUISIANA FOOD WEBS
Ross Del Rio1, Sibel Bargu1, Donald Baltz1, Gary Peterson1
1
Louisiana State University, Baton Rouge, LA, USA
Harmful algal blooms are an increasing problem for coastal waters world-wide. The diatom genus,
Pseudo-nitzschia, is of particular concern in Louisiana, due to the potential for several species to produce
the neurotoxin domoic acid (DA). While trophic transfer of DA to consumers has repeatedly occurred
along the California coast, little is known about trophic transfer of recently detected DA in the Gulf of
Mexico. In this study, the presence of DA in gulf menhaden (Brevoortia patronus) and the potential for
trophic transfer to higher order consumers was investigated. Species identification was conducted with
transmission electron microscopy (TEM). DA quantification in corresponding water and tissue samples
was determined by Enzyme-Linked Immunosorbent Assay (ELISA). Examination of the phytoplankton
revealed four species of Pseudo-nitzschia: P. calliantha, P. pseudodelicatissima, P. pungens, and P.
americana, with P. calliantha as the dominant species. The results of the toxin assay illustrated that lowlevels of DA existed in both water and tissue samples, with a significant correlation between the two (n =
25, p = 0.025, α = 0.05). The discovery of P. calliantha is the first identification of this toxic species in
Louisiana waters. The present study is also the first documentation of a DA vector in the entire Gulf of
Mexico and indicates possible DA contamination in food webs of coastal Louisiana.