Table 2. Maturation stages.

Males
Stage 1—Immature	Stage 2—Maturing	Stage 3—Mature
Testes are small with a mass <0.2 kg and lengths <29 cm. Claspers are not calcified but soft, and shorter than the extreme tip of pelvic fin and measure <19 cm in length. See S1A and S1B Fig.	Enlarged testes with a mass between 0.2–0.4 kg. Claspers still soft but extend longer than pelvic fins. See S1D Fig.	Enlarged and heavily indented testes with a mass >0.5 kg and lengths >30 cm. Calcified claspers measure >19 cm. Clasper spur may be visible. Specimens with freely flowing sperm can be categorized as ‘active’. See S1c to S1F Fig.
Females
Stage 1—Immature	Stage 2—Developing	Stage 3—Ripening
Oviducts and uteri are small/poorly developed. The uteri can be difficult to identify. Ovaries most often appear white and poorly developed with a mass <1 kg and lengths ≤62 cm. See S2 Fig. Ova were not developed or appeared small and granulated/grain-like. Such ova from a single specimen had a maximum diameter of 0.2 cm.	Ovaries are enlarged with a mass ≥2 kg and typically lengths >65 cm. Ova were differentiated and had a maximum diameter (in individual animals) >1 cm and <5 cm. Uteri and oviducts become more developed compared to previous stage 1. Liver mass may vary hundreds of kg for same sized sharks. For a single specimen with ova size up to 3.5 cm in diameter, the uterus was enlarged but contained no internal villi. See S3 Fig.	Very large ovaries with >400 large yolky ova of almost similar size, ≥5.0 cm in diameter (up to 8.0 cm). Numerous small ova <1.5 cm. Uteri and oviducts presumably similar to previous stage. See Fig 4.
Stage 4—Early gravid (no data)	Stage 5—Midterm gravid (no data)	Stage 6—Late gravid (no data)
Uteri filled with yellow segmented fertilized ova (uteri in this stage is also referred to as candle). Oviducts are enlarged and will be in all following stages.	Underdeveloped embryos in uteri having external yolk sack.	Fully formed near-term embryos in uteri with absorbed external yolk sack.
Stage 7—Post-natal	Stage X (7)–Developing/ripening that has given birth previously
Non-gravid with exhausted brownish and flaccid ovaries. The mass from the only specimen was 4.2 kg. Ovaries are empty with only small ova or single degenerated ripe ova present. Uteri remain enlarged in this and subsequent stages with villi present on the inner epithelium. See S4A and S4B Fig.	Enlarged uteri with villi lining the inner epithelium. Ovaries are either developing (Stage 2) or ripening (Stage 3). See S5A and S5B Fig.

Parameters for the maturation stages among the analyzed Greenland sharks. Note there are no available data for gravid stages (Stage 4–6).