Ph.D. Hinojosa-Toledo, Ivan

2025, Zenteno-Devaud, Lisette, Aguirre-Martínez, Gabriela, Aguirre, Isabel, Ph.D. Hinojosa-Toledo, Ivan, Vargas, Fernanda, Górski, Konrad, Rebolledo, Melissa, Ramírez, Daniel, Garrido, Ignacio, Brüning, Paulina, Acevedo, Jorge

Concentrations of five metals together with hematological and morphological parameters were measured in three coastal fish species collected in two sites of the Antarctic Peninsula. Furthermore, we assessed isotopic niche widths among fish populations to better understand their trophic ecology. Nothotenia coriiceps from Fildes Bay displayed high concentrations of Fe and Cu, while those from South Bay had higher concentrations of Cd. All fish from South Bay had higher Zn levels than specimens from Fildes Bay. Effects such as biomagnification of Fe, increased fish metal levels and niche width expansion of Nothotenia coriiceps and Harpagifer antarcticus could be attributed to suboptimal environmental conditions in Fildes Bay. Our findings suggest that early warning signals in coastal Antarctic fish may be linked to increased metal bioavailability as a result of climate change and increased human pressure.

2021, Ph.D. Hinojosa-Toledo, Ivan, Colin-Muñoz, Nicole, Górski, Konrad, Vásquez-Castillo, Sara, Poblete, Aldo

Kelp forests are associated with high biodiversity as they provide habitat and food source for many species. Redspotted catshark Schroederichthys chilensis is a coastal shark species associated with kelp forests of southern South America dominated by Lessonia trabeculata. Despite its common occurrence redspotted catshark the knowledge on its trophic ecology is rudimentary. This study aimed to assess the effects of presence/absence of kelp L. trabeculata on the isotopic niche of redspotted catshark through comparison of δ13C and δ15N in its blood and fin tissues (non-lethal samples). We found that males were characterized by higher trophic position and enriched carbon sources compared to females in locations where kelp was present. In contrast, males and females were characterized by similar isotopic niche in absence of kelp. These differences are most probably an effect of higher prey diversity associated with microhabitats generated by kelp forests that allow sexual segregation of isotopic niche. Therefore, extensive kelp harvest may cause significant effects in isotopic niche and nutritional status of adult redspotted catshark and may negatively affect its populations.