Spatio-temporal patterns of sponge strandings in the southern Gulf of Mexico: The role of cold front events

Abstract

Remnants of marine invertebrates are common in the wrack line of the coasts of many regions worldwide. However, little is known about its spatial and temporal variation. This study aimed to investigate the inter-site and intra-annual variability in species composition, abundance, and biomass of sponge strandings on the coast of a southern Gulf of Mexico tropical island. The environmental factors (oceanographic and meteorological) influencing such spatio-temporal variations on abundance and biomass of sponge strandings were also investigated. From a total of 21 demosponge species identified, three species of genus Clathria (with erect growth forms and a small basal area) were dominant in terms of abundance (93%) and biomass (89%). Both, the monthly average abundance and biomass varied significantly throughout the year, with maximum peaks during the cold fronts season. Only in the case of abundance, a combination of four predictor variables (wind speed, wave height, frequency of southeast winds, and frequency of north winds) explained 84.2% of its intra-annual variability. Results also showed that cold fronts (especially the stronger ones), aside from cyclonic events, can act as disruptive events regulating sponge populations in the coastal zone. Regarding the spatial variability, it was attributed to inter-site differences in the degree of exposure to hydrodynamic forces and the type of substrate. This study contributes to the knowledge of the biodiversity of sponge species in this coastal region of the Gulf of Mexico and demonstrates that large-scale seasonal events such as cold fronts can influence their temporal dynamics. • Sponge strandings varied spatio-temporally and erect growth forms were dominant. • Sponge strandings were more abundant during the cold fronts season. • Cold fronts act as disruptive events regulating shallow water sponge populations.