Distribution, population dynamics, and life history of a mass-occurring jellyfish (Lychnorhiza lucerna) in a large temperate estuary (Río de la Plata): ecological and economic implications

PUENTE TAPIA, F.A.; CHIAVERANO, L.; SOBRERO, L.; ALLEGA, L.; BURLA, J.; DUTTO, M. S.; SCHIARITI, A.

MARINE BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2023

0025-3162

Scyphozoan medusaeare critical components of marine ecosystems; however, our knowledge on theirpopulation dynamics and life history needed to understand their role onecosystem functioning is relatively scarce. We used data from fish-stockassessment cruises (1993-2013), artisanal fisheries and stranding events(2006-2007), to assess spatio-temporal variation in biomass, growth andreproduction, of a large and abundant scyphomedusae (Lychnorhiza lucerna)in a productive estuarine ecosystem (Río de la Plata Estuary, RLPE) (35°S-57°W) from the Southwestern Atlantic Ocean. Medusae consisted of sexually mature individuals only, occurringconsistently during austral summer. Medusae biomass displayed a patchydistribution, concentrating mainly in two geographically different hot-spotsassociated to a frontal feature (turbidity front) of the RLPE. Individual size,relative fecundity, and degree of gonad development varied significantlybetween hot-spots. Biomass varied greatly among years. Bell diameter, wetweight, and percentage of fully-developed oocytes increased during the firsthalf of the summer but decreased during the second half of it. Our resultssuggest high predictability of the period of occurrence and the distribution ofL. lucerna in the RLPE. Physical mechanisms of medusa aggregation,potential effects of medusae on zooplankton dynamics, fisheries production, andconservation of sea turtles, as well as their potential for the development ofa local jellyfish fishery, are here discussed. This work provides novelinformation on patterns of distribution, growth and development of L.lucerna medusae, which can help to enhance our understanding of the role oflarge medusae on ecosystem functioning of marine ecosystems worldwide.