Family: Alariaceae; Genus: Ecklonia; Species: maxima(https://en.wikipedia.org/wiki/Ecklonia_maxima)

https://www.sciencedirec...le/pii/S0176161711803755
[I don't have access to the article it would be nice to see the data with-in]

This article claims that a commercial extract known as 'Kelpak'(http://www.kelpak.com/) contained DMT. Further analysis by J. Gartz according to erowid(which lacks a correct reference...) says it does not.https://www.erowid.org/psychoactives/faqs/faqs_tryptamine.shtml#20

Here is the reference to the J. Gartz article:
Gartz, J. 1991.
Influence of phosphate on fruiting and secondary metabolism of mycelia of Psilocybe cubensis, Psilocybe semilanceata and Gymnopilus purpuratus. Zeitschrift fuer Mykologie 57(1), 149-154.

So it may be a long shot, however, this brings some new ideas to my mind. Maybe Kelp does have DMT in it at certain stages of growth or seasons. Perhaps there was a mistake and another sea species was added to this concentrate(if it is wild harvested). It's unlikely the HPLC analysis in my opinion had a DMT contamination, but it is a possibility.