Gulf of Tehuantepec is an important reproductive area for two shark and 10 ray species.

Female Silky Sharks with near-term embryos and neonates with umbilical scars have been reported in this area, mostly during the rainy season (May–September), suggesting that this is a pupping site for this species. In addition, the high proportion of neonates and young-of-the-year in landings from artisanal fisheries over multiple years, reported by several studies, supports the presence of a nursery area (Ruiz Alvarado 2000; Castillo-Géniz et al. 2002; Galván-Tirado et al. 2015; Alejo-Plata et al. 2016; Alatorre-Alba et al. 2021).

Neonate and juvenile Scalloped Hammerhead reported in catches across several years near the Mexico-Guatemala border, suggest the presence of a nursery area. Catches of Scalloped Hammerhead measuring <60 cm total length (TL), close to the reported size-at-birth (31–57 cm TL; Ebert et al. 2021), are regularly observed in this area, mostly from July to September (Ruiz Alvarado 2000; Campuzano-Caballero 2002; Hinojosa-Álvarez 2007; Bejarano-Álvarez et al. 2010; Morales-Pacheco et al. 2016).

Pregnant females and neonates (based on size) of seven ray species were reported in independent-fisheries surveys using bottom trawls in this area between 2009–2010, mostly during the autumn, suggesting the presence of pupping and nursery areas as well as areas important for gestation (Torrest-Huerta 2012).

Neonate California Butterfly Rays (n = 11) measured between 13–29 cm disc width (DW) (Torrest-Huerta 2012), similar to the reported size-at-birth of 21–26 cm DW (Last et al. 2016).

Neonate Longtail Stingrays (n = 42) measured between 33–48 cm DW (Torrest-Huerta 2012), similar to the reported size-at-birth of ~40 cm DW (Last et al. 2016).

Neonate Vermiculate Numbfish (n = 31) measured between 8–9 cm TL (Torrest-Huerta 2012), similar to the reported size-at-birth of ~6 cm TL (Last et al. 2016). In addition, juveniles between 11–27 cm TL (n = 135) were reported from the area.

Neonate Pacific Cownose Rays (n = 18) measured between 12–40 cm DW (Torrest-Huerta 2012), similar to the reported size-at-birth of 39–43 cm DW (Last et al. 2016).  Juveniles (n = 32) between 41–64 cm DW were also reported.

Pregnant Cimar Round Rays, and males with semen in the claspers, are recorded year-round (Torrest-Huerta 2012).

Pregnant Rogers’ Round Rays with embryos as large as 8.9 cm DW were reported. Although the size-at-birth for this species is unknown, individuals measuring 7–11 cm DW (n = 12) were determined to be neonates as this is a similar size to the largest embryo.

Neonate Whitesnout Guitarfish (n = 27) measured between 12–18 cm TL (Torrest-Huerta 2012), similar to the reported size-at-birth of ~19 cm TL (Last et al. 2016), supporting the presence of a nursery area. In addition, juveniles between 20–38 cm TL (n = 125) were reported. Recent data show that these species still occur regularly in this area, suggesting the persistent use of this nursery area (Montes-Sánchez 2019).

Pregnant Blotched Round Rays with embryos at different stages of development were reported year-round within this area as bycatch in shrimp trawlers between 2011–2012. This suggests that this area is important for Blotched Round Ray gestation. The presence of terminal embryos (12–14 cm TL) were also found, suggesting that this area could also serve for parturition from December–March and July–August. In addition, the presence of neonates between 2009–2012 ranging in size 10–14.5 cm TL suggests that this area could function as a nursery (Guzmán-Castellanos 2015; Vázquez-Robles 2015).

Pregnant Dwarf Round Rays were reported as bycatch in shrimp trawlers during 2009–2010. The presence of near-term embryos and neonates between 8.3–9.4 cm TL (reported size-at-birth is ~6 cm TL; Last et al. 2016), suggests that this is a pupping area from May to August (Guzmán-Castellanos 2006). Between 2017–2019, 2,100 individuals were reported as bycatch in the same fishery, suggesting that this area still functions as a pupping area (Montes-Sánchez 2019).

A mating area for Southern Banded Guitarfish, between February and April, has been reported in this area, with adult females and males found at 28–33 m depth. The highest abundance of adults was recorded during those months as well as the maximum size of oocytes in non-pregnant females. In addition, a parturition season has been reported between April and May, due to the presence of pregnant females with near-term embryos and neonates in depths between 21–27 m (Torres-Huerta et al. 2019a). Neonates sampled measured between 15.2–17.5 cm TL, which is similar to the reported size-at-birth (~18 cm TL; Last et al. 2016).