Fish energy budget under ocean warming and flame retardant exposure

Abstract

Climate change and chemical contamination are global environmental threats of growing concern for the scientific community and regulatory authorities. Yet, the impacts and interactions of both stressors (particularly ocean warming and emerging chemical contaminants) on physiological responses of marine organisms remain unclear and still require further understanding. Within this context, the main goal of this study was to assess, for the first time, the effects of warming (+ 5 °C) and accumulation of a polybrominated diphenyl ether congener (BDE-209, brominated flame retardant) through dietary exposure on energy budget of the juvenile white seabream (Diplodus sargus). Specifically, growth (G), routine metabolism (R), excretion (faecal, F and nitrogenous losses, U) and food consumption (C) were calculated to obtain the energy budget. The results demonstrated that the energy proportion spent for G dominated the mode of the energy allocation of juvenile white seabream (56.0-67.8%), especially under the combined effect of warming plus BDE-209 exposure. Under all treatments, the energy channelled for R varied around 26% and a much smaller percentage was channelled for excretion (F: 4.3-16.0% and U: 2.3-3.3%). An opposite trend to G was observed to F, where the highest percentage (16.0 ± 0.9%) was found under control temperature and BDE-209 exposure via diet. In general, the parameters were significantly affected by increased temperature and flame retardant exposure, where higher levels occurred for: i) wet weight, relative growth rate, protein and ash contents under warming conditions, ii) only for O:N ratio under BDE-209 exposure via diet, and iii) for feed efficiency, ammonia excretion rate, routine metabolic rate and assimilation efficiency under the combination of both stressors. On the other hand, decreased viscerosomatic index was observed under warming and lower fat content was observed under the combined effect of both stressors. Overall, under future warming and chemical contamination conditions, fish energy budget was greatly affected, which may dictate negative cascading impacts at population and community levels. Further research combining other climate change stressors (e.g. acidification and hypoxia) and emerging chemical contaminants are needed to better understand and forecast such biological effects in a changing ocean.

Assessing Knowledge Gaps and Management Needs to Cope With Barriers for Environmental, Economic, and Social Sustainability of Marine Recreational Fisheries: The Case of Spain

“…Global warming exerts considerable effects on the marine ecosystems (Hoegh-Guldberg and Bruno, 2010;Kersting, 2016), which are affecting fish assemblages (e.g., Anacleto et al, 2018;Carozza et al, 2019;McLean et al, 2019), and the global fisheries that exploit them (Phillips and Pérez-Ramírez, 2017;Barange et al, 2018). It is plausible that recreational fisheries will be affected in a similar way to commercial fisheries (especially SSF), so response to global warming may be comparable in some cases (Townhill et al, 2019).…”

Exposure effects of the UV-filter 4-MBC to "Solea senegalensis" metamorphosis

“…The increased energy used by S. senegalensis exposed to lower 4-MBC through increased swimming distance can be associated with effects on energetic budget. In fact, effects of chemical stressors on energetic balances have already been reported (Agbohessi et al, 2014;Rabasa and Dickson, 2016;Anacleto et al, 2018). Such excitatory swimming response after 4-MBC exposure may also have later implications on growth or successful feeding and reproduction.…”

Combined threats of climate change and contaminant exposure through the lens of bioenergetics

“…Examples of negative antagonistic interactions also exist. For instance, a flame retardant's negative effect on AE in white seabream ( Diplodus sargus ) declined at higher temperatures, perhaps reflecting enhanced contaminant metabolism and clearance at higher temperature, or higher growth rates (Anacleto et al, 2018).…”