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Communication Dans Un Congrès Année : 2019

Can reproductive strategy be used as surrogates of dispersal potential ? the test case of three sympatric Mediterranean brooders

Résumé

Larval transport which enables connectivity between populations of marine species with a sedentary adult stage results from the coupling between flow and species larval traits. In particular larval transport is expected to differ among species living in a same habitat according to their biological potential for dispersal. The present study aims at testing if reproductive strategy can be used as a surrogate of any larval traits defining the biological potential for dispersal, namely release timing, larval size, larval survival expectancy and competency period (defining pelagic larval duration - PLD), buoyancy, and larval vertical motility behavior, among sympatric gorgonian species, all three with lecitotrophic larvae. Paramuricea clavata is a surface brooder, Corallium rubrum and Eunicella singularis are both internal brooders, the latter having symbionts. Release timing for P. clavata and E. singularis overlapped while C. rubrum releases a month later, but P. clavata displayed shorter spawning event than E. singularis and C. rubrum. Larvae length is 1 mm for P. clavata and C. rubrum and 2.5 mm for E. singularis. Survival expectancy of P. clavata and C. rubrum larvae mantained in the dark and E. singularis larvae maintained in light condition were similar (50% of survival after about 30 days). Morevoer, metamorphosis into polyp peaked around 20 and 40 days age of larvae for both P. clavata and E. singularis, suggesting similarly large potential PLD for both species. Larvae of the three species exhibited negative buoyancy in sea water at 20°C. While free fall velocity was constant until 30 days age for P. clavata and E. singularis larvae, it decreased with larval age for C. rubrum. Upon release, free fall speed for P. clavata larvae (0.056 ± 0.021 cm s-1) was 1.5 times (4 times, respectively) smaller than for C. rubrum larvae (0.09 ± 0.026 cm s-1) (E. singularis larvae, 0.23 ± 0.08 cm s-1, respectively). However, after 15 days, free fall speed for C. rubrum larvae yielded the same free fall speed as for P. clavata larvae. Finally, while C. rubrum larvae had the most frequent swimming activity (82 ± 14.5 %, without difference with light conditions), E. singularis larvae has a slightly less frequent swimming activity (68 ± 18 %, varying with light conditions), while P. clavata larvae hardly swim. In summary, reproductive strategy cannot be used as a surrogate of neither of a single larval traits nor of larval dispersal potential.
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Dates et versions

hal-03999748 , version 1 (21-02-2023)

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  • HAL Id : hal-03999748 , version 1

Citer

Katell Guizien, Núria Viladrich, A. Martínez-Quintana, Lorenzo Bramanti. Can reproductive strategy be used as surrogates of dispersal potential ? the test case of three sympatric Mediterranean brooders. iMARCO International Conference, Sep 2019, Aveiro, Portugal. ⟨hal-03999748⟩
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