Mass occurrences of the terebratellid brachiopod Magellania venosa with more than 200 individuals.m(-2) are reported from the fjords Comau and Renihue in the northernmost region of the Chilean fjordland, whereas more southern fords do not show these high numbers of the largest living brachiopod. This is an exception to earlier observations that the abundance of M. venosa on the Chilean shelf is positively correlated with increasing latitude. As the sympatric scleractinian coral Desmophyllum dianthus also occurs in unusually high numbers in the fjords Comau and Renihue the hydrographical regime and its associated environmental conditions in these fiords may be responsible for these mass occurrences.