Observations on the reproductive biology of the original hydrothermal hairy snail, Alviniconcha hessleri, from the Mariana back-arc

• Published in: Marine biology Vol. 172; no. 4; p. 55
• Main Authors: Hanson, Nova B., Bates, Amanda E., Dufour, Suzanne C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2025; Springer Nature B.V
• Subjects: Alviniconcha; Anthropogenic factors; Biomedical and Life Sciences; chemistry; Deep sea; Deep water; Ecological aggregations; Ecosystem biology; Endangered species; Endemic species; Endosymbionts; Energy; Environmental conditions; fauna; Freshwater & Marine Ecology; Gametes; Gametocytes; Gastropoda; geographical distribution; Growth rate; habitats; Human influences; Hydrothermal springs; Hydrothermal vents; indigenous species; Invertebrates; juveniles; Life history; Life Sciences; Marine & Freshwater Sciences; Marine biology; Marine molluscs; Metabolism; Microbiology; Oceanography; Oocytes; Oogenesis; Original Paper; Population structure; Provisioning; Rare species; Recruitment; Snails; species; Threatened species; Zoology; Hydrothermal vent; Population structure; Gastropod; Gametogenesis
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-025-04619-2

Many life history traits of hydrothermal vent fauna are undescribed, yet this knowledge is crucial for the accurate assessment of the vulnerability of vent endemic species, which are endangered by anthropogenic impacts in the deep-sea. Here we advance the knowledge of life history traits in Hessler’s hairy snail, Alviniconcha hessleri , a dominant gastropod harbouring chemosynthetic endosymbionts endemic to hydrothermal vents along the Mariana back-arc. Snails were collected from five aggregations at four hydrothermal vent fields across most of the known geographic range of the species, and site-specific size-frequency distributions and gamete characteristics were examined to assess reproductive patterns. Results indicate that A. hessleri populations varied in their size structure across the sampled aggregations, and that the species shares some of the same traits as other vent gastropods: continuous oogenesis and consistent provisioning to oocyte size, regardless of local vent fluid chemistry. We further report that even in juvenile specimens (~1 mm), excessive shell degradation was evident. Thus our efforts to support whether this species is planktotrophic by measuring protoconch size were not successful. Even so, the maximum oocyte size we observed was 93 µm which is consistent with planktotrophy. Our results also suggest that despite conserved reproductive patterns under differing environmental conditions, A. hessleri population structure is likely subject to the effects of various factors, from recruitment and post-recruitment processes to differential localized growth rates. As its realized range is limited to seven vent fields, this species may be vulnerable to reductions in habitat quantity and quality, even though it has life history traits adapted to high environmental variability.