**Abstract**

Epibiosis occur frequently on the shells of some marine crustaceans, which often serve as substrate for various species of algae, there is few information on the associations between these. The objective of this study was to determine if the gastropod mollusk *Aliger gigas* (formerly *Lobatus gigas*) in larval had some sort of the association with algal. To the above was carried out collecting egg masses in the environment, the larvae were cultivated in seawater filtered 5 μm. The algal material found was observed in electron microscopy, for its identification and quantification. We analyzed 60 larvae aged 2–44 days for analyzing the structure of the shell and its epibionts. Of the larvae analyzed, 50 larvae presented epizoic. The algae community consisted of 28 taxa, and composed of 25 diatoms (Bacillariophyta) and three cyanophytes (Cyanobacteria). The H′ diversity values fluctuated between 0.2 a 1.2. The dominant and frequent species were formed by diatoms: *Nitzschia panduriformis var. minor*, *Halamphora* sp. and *Cyclophora* sp.

**Keywords:** cyanophyte, diatom, epibiont, *Aliger gigas*
