Colchis IMMA

Criterion A – Species or Population Vulnerability

Three threatened subspecies of small cetaceans (Tursiops truncatus ponticus, Delphinus delphis ponticus and Phocoena phocoena relicta) are found in the area year-round.  The Black Sea harbour porpoise and the Black Sea bottlenose dolphin are both listed as Endangered on the IUCN Red List, and the Black Sea common dolphin population is listed as Vulnerable (Birkun & Frantzis, 2008; Birkun, 2008; Birkun, 2012)

Criterion B: Distribution and Abundance

Sub-criterion B2: Aggregations

The IMMA is a wintering ground for harbour porpoise (Birkun and Frantzis, 2008). Double-platform line transect visual surveys were conducted in this IMMA from 2014 until 2020. Approximately 1,200 (SE=310) animals were recorded in the beginning of autumn 2014, and this increased to around 18,000 (SE=1,329) porpoises present in these waters during the winter 2014.  Around 1,200 (SE=310) animals were recorded in the beginning of autumn 2014, and this increased to around 18,000 (SE=1,329) porpoises present in these waters during the winter 2014. In 2016, 16,715 (SE=4902) porpoises were recorded in winter. By comparison, approximately 9,500 (SE=5,574) porpoises were recorded in the area in spring 2016, and 3,200 (SE=825) in summer 2019. (Kopaliani et al., 2015; Kopaliani et al., 2017) Similarly, the IMMA is important aggregation area for common dolphins in winter.  Approximately 15,000 (SE=2988) common dolphins were observed to use the IMMA during winter 2014, up to 8,000 (SE=5,234) animals during spring 2016, and approximately 3,700 (SE=1196) in summer 2019 (Kopaliani et al., 2015; Kopaliani et al., 2017) (see Tables 1 and 2 for more details of survey data showing seasonal variations in cetacean numbers).

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas Evidence that the area is important for cetacean reproduction include: a) observations of courtship behaviour of Tursiops truncatus and Delphinus delphis in May and June (Kopaliani et al., 2015); b) recordings of the all three species with calves under 3 months of age; it is therefore assumed that the area is used for mating and early stages of calf rearing; and c) the finding of stranded harbour porpoises in the late stages of gestation (Kopaliani et al., 2017).

Sub-criterion C2: Feeding Areas In winter and spring, large aggregations of anchovies (Engraulis encrasicolus) use the IMMA as a wintering and spawning area (Chashchin, 1996) and provide harbour porpoises, common dolphins and bottlenose dolphins with abundant food (Birkun, 2008).  The mouths of the  Enguri, Rioni, Khobistskhali, Supsa and Chorokhi rivers are the main feeding grounds for all three species (Kopaliani et al., 2017).