Albardão is an important reproductive area for seven shark and three ray species.

Between 2013–2023, these species were regularly recorded by onboard observers on vessels from the commercial coastal gillnet fleet operating along a ~700 km coastline (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025). From October to March, the net was 16±7 km (average net area = 0.05±0.01 km²) and 13–14 cm between opposite knots, and from April to September, 9±4 km (average net area = 0.02±0.01 km²) and 9–11 cm mesh nets (Fogliarini et al. 2024; Saüt et al. 2024). Of 564 gillnet sets monitored off the Rio Grande do Sul coast, 426 were within this area in 2013 (n = 12), 2014 (n = 69), 2015 (n = 40), 2018 (n = 127), 2019 (n = 80), 2020 (n = 47), 2022 (n = 41), and 2023 (n = 32) (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025). Data comprised the number of individuals and total kilograms per species in each gillnet set, and the TL was calculated based on the length-weigh relationship using parameters available on Fishbase (Froese et al. 2014; Froese & Pauly 2024). Neonate/YOY were inferred from sizes estimated from weight measurements.

During the early 1980s, juvenile and neonate Sandbar Shark were frequently recorded in beach fisheries (seine and gillnet) south of Cassino Beach, within this area, leading to its identification as an important nursery ground for the species (ICMBio 2018). Due to the disappearance of juvenile and adult records in nearly all areas where the species formerly occurred in Brazil—especially in the southern region, where it was most frequently observed—a population decline of at least 80% over the past three generations was estimated (ICMBio 2018). Only neonates and YOY Sandbar Sharks were captured by contemporary gillnets within this area (DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025), supporting its continued importance for reproductive purposes. Of 48 neonates/YOY captured off the Rio Grande do Sul coast by gillnets, 46 individuals (47–63 cm TL) were captured in nine hauls in this area in 2018, 2022, and 2023 (DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025). Size-at-birth for Sandbar Shark is 40–76 cm TL (Ebert et al. 2021).

All neonate/YOY Tope (<52 cm TL) captured off the Rio Grande do Sul coast by gillnets were from this area (n = 22) in March 2015 and September 2018 (DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025).  Size-at-birth for Tope is 26–40 cm TL (Ebert et al. 2021). The size of Tope within this area ranged 33.5–100.5 cm TL (n = 74). In southern Brazil, copulation occurs in winter along the upper slope (180–350 m), where mature males and females aggregate. Pregnant females then migrate to the continental shelf (50–350 m) to feed, complete gestation, and give birth in coastal waters (ICMBio 2018). In the 1980s, a resident population of Tope reproduced in coastal waters off Rio Grande do Sul during spring; however, this population was no longer observed during a scientific survey conducted in 2005 (ICMBio 2018). Therefore, even if the number of neonates recorded in this area is not as high as in other species, and other life stages have not been observed (as adults occur in deeper waters), the area is still important for the reproduction of the species.

In November 1989, one beach seine within the area captured 16 Narrownose Smoothhounds, all neonates/YOY based on size measurements (23–29 cm TL) (Vooren & Klippel 2005). Size-at-birth for the species is 24–36 cm TL (Ebert et al. 2021). All 525 neonates/YOY (<47 cm TL) captured in the gillnet fleet off the Rio Grande do Sul and Santa Catarina coast, were captured within this area, in 2018, 2019, 2020, 2022, and 2023 (n = 480 individuals from February to March) (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025).

From gillnet operations monitored between 2013–2023, 2,272 neonates /YOY (<75 cm TL) Scalloped Hammerheads were captured off the Rio Grande do Sul and Santa Catarina coast, of which, 1,953 were within this area. Size-at-birth for the species is 49–63 cm TL (Ebert et al. 2021). Almost all (n = 1,852) were captured between October–March, indicating a seasonal signal in their reproductive cycle. The only year in which neonates/YOY were not captured was 2013, as sampling occurred only in August. The size of Scalloped Hammerheads within this area ranged 27–140 cm TL (n = 1,990) (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025).

Of 1,380 Smooth Hammerheads neonates/YOY (<82 cm TL) captured in the broader Rio Grande do Sul and Santa Catarina coast, 1,241 were within this area from October–March (not captured only in the years 2013 and 2015) (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025). Size-at-birth is 49–63 cm TL (Ebert et al. 2021). The size of Smooth Hammerheads within this area ranged 48.1–185.9 cm TL (n = 1,287) (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025).

Angular Angelsharks neonates/YOY (<39 cm TL) were captured off the Rio Grande do Sul and Santa Catarina coast by gillnets. Of 1,138 neonates/YOY captured in the whole region, 1,133 were within this area in 2014, 2019, 2020, 2022, and 2023 (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025).  Size-at-birth for Angular Angelsharks is 24–30 cm TL (Ebert et al. 2021).

All neonates/YOY Hidden Angelsharks (<39 cm TL) captured off the Rio Grande do Sul coast by gillnets were from this area (n = 135), from February–June, in 2014, 2019, and 2020 (DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025). Size- at- birth for Hidden Angelsharks is 28–30 cm TL (Ebert et al. 2021). Neonates/YOY were captured. Hidden Angelsharks were captured in 62 hauls within this area (n = 309 individuals; 28.6–81.6 cm TL). In Brazil, parturition occurs between January and February, which aligns with the period when neonates/YOY were recorded. From June 1980 to November 1992, a broader area in southern Brazil was surveyed during 13 cruises using otter trawls, and 19 pregnant females were captured and dissected to analyse reproductive organs and embryos (Sunyem & Vooren 1997). The Hidden Angelshark completes its entire life cycle on the southern Brazilian continental shelf, but has a long reproductive cycle, evidenced by the rarity of neonate sightings and low incidence of pregnancy (ICMBio 2018).

Brazilian Guitarfish neonates/YOY (<38 cm TL) were captured by gillnet off the Rio Grande do Sul coast (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025). Of 242 captured in the broader region, 180 were within this area in 2018, 2019, and 2022. Size-at-birth of Brazilian Guitarfish is 22–29 cm TL (Vooren & Klippel 2005). Additionally, in December 2018, one bottom trawl, pulled manually from a motorboat, captured 2,134 Brazilian Guitarfish within the area, totalling ~10,000 kg (Gowert & Oddone 2023). The only two individuals sampled were pregnant females (Gowert & Oddone 2023).

Of 250 neonates/YOY Brazilian Cownose Rays (<56 cm TL) captured in the Rio Grande do Sul and Santa Catarina coast gillnet fleet, 204 were within this area (n = 190 from December–March) (DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025).  Neonates/YOY were captured in 2018, 2019, and 2020. Brazilian Cownose Rays were captured in 41 sets within this area (n = 328 individuals; 20.7–90 cm TL).

Rio Skates were captured in 89 sets from the gillnet fleet (n = 268 individuals) in 2018, 2019, 2020, and 2023 (Saüt et al. 2024; DS Monteiro, LG Cardoso, LG Fischer unpubl. data 2025). Between 2009–2012, from 4,312 egg cases collected on the beach between the tide line and the dunes in a ~1 km range, 3,050 (70.7%) were from Rio Skates (Cordeiro & Oddone 2019). Between 2016–2017, from 3,620 eggs collected on the same beach in a ~6 km range, 1,681 (46.4%) were from Rio Skates (Cordeiro & Oddone 2019). Besides, the slightly higher density within this area, the presence of egg cases indicates that the species uses this area for reproductive purposes.