MEPS 667:25-41 (2021)  -  DOI: https://doi.org/10.3354/meps13712

ABSTRACT: The life history of marine invertebrates is intrinsically related to the environmental conditions of their habitats. However, the effect of environmental factors on life history traits, e.g. reproduction, is poorly understood due to difficulties in cultivating these animals in controlled conditions. Natural experiments, using latitudinal gradients, provide an alternative to better understand this relationship. We investigated the effect of environmental factors on some aspects of the reproduction of Tedania ignis (Porifera, Demospongiae) along a latitudinal gradient in the Western Atlantic Ocean (WAO). We assessed the predicted trade-off between size and fecundity and biogeographical patterns in some of the life history traits of this sponge species. Except for the southernmost population, all populations of T. ignis reproduced aperiodically, but their reproductive dynamics were modulated by different sets of environmental factors. Therefore, this trait seems to be a physiological adaptation to local conditions. Nonetheless, the species reproduced mainly when the temperature was above 21°C, which could be a factor limiting its distribution along the tropical WAO. We did not detect any trade-off between size and quantity of oocytes and larvae in this species. A possible explanation is that the species invests low energy in offspring in a given period, resulting in a low but continuous reproductive effort, independently of the environmental conditions. These findings will be important to support management plans, as this species is a potential target for obtaining biotechnological natural products.

KEY WORDS: Trade-off · Temperature · Western Atlantic Ocean · Thorson’s rule · Demospongiae · Porifera