Abstract
Doliolids and salps are pelagic tunicates that reproduce both asexually and sexually during their life history, occasionally forming massive blooms (> 1000 ind. m −3 ) that can clear large volumes of water daily. Although blooms of doliolids and salps are often associated with pulses of primary productivity, little is understood about their life history dynamics in response to the full range of oceanographic conditions they encounter. Here, we quantify patterns in the abundance and distribution of doliolid and salp life stages related to oceanographic variables using an in situ imaging vehicle deployed during monthly cruises from April 2021 to March 2022 in the South Atlantic Bight shelf. Doliolid life stages were observed across the mid‐shelf (25, 45 m isobaths) in all months in a variety of conditions, albeit often at low abundances ( −3 ), while salps were infrequently observed during winter months and were more common at the 45 m isobath. Relative to doliolids, salps were associated with a narrower range of shelf habitat conditions. A single parameter quotient analysis revealed doliolids associated with cooler temperatures (16–29°C), higher chlorophyll a (Chl a ) fluorescence (0.25–5 mg m −3 ), and more particles > 0.5 mm ESD (0–150 L −1 ) compared to salps (20–29°C, 0.25–2 mg m −3 Chl a , 0–70 particles L −1 ). For both taxa, sexual life stages were associated with smaller ranges of oceanographic variables compared to asexual stages, implying their population dynamics are influenced by sequences of conditions that may involve different water masses.