Sepia hierredda is very similar to the common cuttlefish but there are a number of consistent morphological differences which can be used to identify S. hieredda from S. officinalis, the two species being sympatric off northwestern Africa.

The morphological features that distinguishing this species from the common cuttlefish are that in S.hierraedda the number of transverse rows of suckers is higher, for specimens of similar mantle lengths, the striated zone on the cuttlebone of common cuttlefish from the northeastern Atlantic is shorter than the same feature in S. hierredda, however, in common cuttlefish from the Canary Islands this character is not useful because the striated zone is the same length as it is in this species, the mantle of S. hierredda is narrower and the arms are shorter.

[3] As its vernacular name suggests the giant African cuttlefish is a very large species which can grow to a mantle length of up to 500mm and a weight which can reach 7.5 kg.

[1] Sepia hierredda occurs along the west coast of Africa from Cape Blanc in Mauritania south to Baia dos Tigres in Angola.

In waters off Western Sahara and Mauritania, S. hierredda is the main species caught by Spanish trawlers.