The shallow water benthic fauna was collected in Kongsfjord, West Spitsbergen. Sampling was conducted along two main environmental gradients: vertical gradient (depth 5–50 m) and horizontal gradient (sedimentation regime) along the fjord axis. A small rectangular dredge was used. Altogether 169 taxa were identified and four macrofaunal associations were distinguished. Bottom type and distance from the tidal glaciers seem to be the main factors responsible for species distribution. The Soft Bottom I Association occupying the fine mud of the Kongsbreen glacial bay consisted mostly of Crustacea with high dominance of scavenging amphipod Onisimus caricus. Bivalves prevailed in the Soft Bottom II Association, located further away from the main glacier outflows. The barren rocky shelf, deprived of vegetation by a sea urchin Strongylocentrotus droebachiensis was inhabited by the Rocky Shelf Association dominated by decapods. The last distinguished association (the Kelp Association) occurred on the hard bottom overgrown with macroalgae. The gastropod Margarites helicinus and amphipods Ischyrocerus spp. made up 60% of the individuals collected there.

Sessile suspension feeders depend primarily on availability of a space to settle and access to the water column. Their sessile nature incapacitates displacement during disturbances, and they must rely on their morphology to overcome selective processes. We classified the assemblage of SSF from Mackellar Inlet (King George Island, Antarctica) according to their growth forms (GF) and epibiotic association type, the latter based on direct observation of the epibiotic behaviour of every individual. Organisms that did not comply with any previously established GF were grouped into ‘other GF’. Sampling stations were distributed across the fjord following a gradient based primarily on the distance to Domeyko Glacier (inner, middle, outer sections). Seven GF were recognised in the glaciomarine fjord: tree, bush, stalk, mound, flat, runner, and sheet. Four types of epibiotic associations were identified: basibiont, both facultative epibiont and basibiont, facultative epibiont, and epibiont. Our results showed that the tree GF were found in the inner and middle sections, mound in middle and outer, and flat across all fjord sections. These GF enhanced GF-diversity since they constituted additional substrate for most of the ‘other GF’ which had primarily an epibiotic strategy. Contrastingly, bush, runner and stalk GF were only found in the outer section of the fjord, thus the most distanced from periglacial disturbances. The GF distribution was consistent with distance to glacier, both in number and strategies. These results highlight the potentialities of the morpho-functional classification applied to Antarctic sessile suspension feeders to help understand their distribution based on adaptive capabilities.