The Iberian wolf (Canis lupus signatus) is a top predator that inhabits the Iberian Peninsula. In Portugal, its numbers and distribution declined throughout the 20^th century, due to human persecution, habitat degradation and prey decline, which have led to higher predation rates of livestock in the remaining packs. In Montesinho Natural Park (northeast Portugal), wild ungulate populations have been increasing in the last years, which may have led wolf to predate upon them. In order to assess Iberian wolf diet in this area, 85 wolf scats were collected from transects distributed throughout the study area in two periods between November 2017 and August 2019. Scat analysis indicated a high predation on wild ungulates, where the frequency of occurrence showed that roe deer was the most consumed prey (44%), followed by red deer (26%) and wild boar (24%). Domestic/wild cat (6%), domestic goat and stone marten (5%) were consumed in lower quantities. It was found a higher selection towards roe deer (D = 0.71) and this was the only prey item which was significantly dependent of the season of the year (χ² = 16.95, df = 3, p < 0.001). This is the first study in Portugal where was recorded that wolves feed mainly on wild ungulates. We conclude that lower livestock predation may be correlated with higher wild ungulates densities in our study area, as well as suitable husbandry practices, leading to a shift on Iberian wolf diet from mainly livestock on previous studies to wild ungulates.

Live feed enrichments are often used in fish larvicultures as an optimized source of essential nutrients to improve larval growth and survival. In addition to this, they may also play an important role in structuring larval-associated microbial communities and may help improve their resistance to diseases. However, there is limited information available on how larval microbial communities and larviculture water are influenced by different live feed enrichments. In the present study, we investigated the effects of two commercial rotifer enrichments (ER) on turbot (Scophthalmus maximus) larval and post-larval gut-associated bacterial communities during larviculture production. We evaluated their effects on bacterial populations related to known pathogens and beneficial bacteria and their potential influence on the composition of bacterioplankton communities during larval rearing. High-throughput 16S rRNA gene sequencing was used to assess the effects of different rotifer enrichments (ER1 and ER2) on the structural diversity of bacterial communities of the whole turbot larvae 10 days after hatching (DAH), the post-larval gut 30 DAH, and the larviculture water. Our results showed that different rotifer feed enrichments were associated with significant differences in bacterial composition of turbot larvae 10 DAH, but not with the composition of larval gut communities 30 DAH or bacterioplankton communities 10 and 30 DAH. However, a more in-depth taxonomic analysis showed that there were significant differences in the abundance of Vibrionales in both 10 DAH larvae and in the 30 DAH post-larval gut fed different RE diets. Interestingly, the ER1 diet had a higher relative abundance of specific amplicon sequence variants (ASVs) related to potential Vibrio-antagonists belonging to the Roseobacter clade (e.g., Phaeobacter and Ruegeria at 10 DAH and Sulfitobacter at 30 DAH). In line with this, the diet was also associated with a lower relative abundance of Vibrio and a lower mortality. These results suggest that rotifer diets can affect colonization by Vibrio members in the guts of post-larval turbot. Overall, this study indicates that live feed enrichments can have modulatory effects on fish bacterial communities during the early stages of development, which includes the relative abundances of pathogenic and antagonist taxa in larviculture systems.

Aims: In the present study, we tested whether terrestrially derived humic substances (HS) could mitigate the adverse effects of elevated temperature and ultraviolet B (UVB) radiation on the bacterial communities of two hard corals (Montipora digitata and M. capricornis), one soft coral (Sarcophyton glaucum), sediment and water. We also examined the impact of temperature, UVB radiation, and HS supplementation on coral photosynthetic activity, a proxy for coral bleaching. Methods and results: We performed a multifactorial experiment using a randomized-controlled microcosm setup. Coral photosynthetic efficiency was measured in vivo using a pulse amplitude modulation fluorometer. Bacterial communities were analyzed using 16S rRNA gene sequencing. Corals in HS-supplemented microcosms had significantly higher photosynthetic activities than those in microcosms subjected to elevated temperature and UVB radiation. Additionally, HS supplementation significantly influenced the composition of sediment, water, and host-associated bacterial communities. Reef organisms in HS supplemented microcosms contained distinct bacterial communities enriched with groups of potentially beneficial bacteria. In the hard coral M. digitata, we observed an interactive effect of HS supplementation, UVB radiation, and temperature. Conclusion: Our findings indicate that HS significantly modulates coral reef bacterial communities and support the hypothesis that these substances contribute to improved reef resistance to the adverse effects of elevated temperature and UVB radiation.