Changes in Demersal Wild Fish Aggregations Beneath a Sea-cage Fish Farm after the Cessation of Farming

Demersal, non-cryptic, wild fish were counted in replicate 100 m2 transects beneath a floating sea-cage fish farm and two nearby sandy locations at Gran Canaria (Canary Islands, eastern Atlantic) four times before and after the cessation of farming. Cessation of farming involved the removal of farmed fish and ceasing of the daily feeding, although farm structures (cages and moorings) remained. A “beyond-BACI” sampling design provided the framework to detect the effect of the cessation of farming, which produced qualitative and quantitative changes in the composition and structure of the fish assemblages beneath the sea-cage fish farm compared with two nearby controls. The aggregative effect on wild fish due to the existence of the farm decreased from approximately 50 times compared to nearby controls when the farm was in full operation to \u3c2 times when only the farm structures remained. Abundances of POM feeders\u3e(large-sized mugilids), large benthic chondrichthyid rays and Pagellus spp. declined markedly at the fish farm after the cessation of farming, suggesting that the removal of daily feeding was responsible for their disappearance. In contrast, abundances of herbivores, benthic macro- and meso-carnivores were similar beneath the fish farm both before and after the cessation of farming. Benthic macro-carnivores, however, were more abundant beneath the sea-cages compared to control locations, supporting the hypothesis that the increase in the physical structure beneath farms plays a role in aggregating these species. Sparids occurred beneath the sea-cages only after the cessation of farming, while the two natural control locations did not show differences from before to after the cessation of farming. Overall, the results show that the wild fish assemblage beneath the farm partially changed after the cessation of farming to a more natural state, approaching the assemblages observed at the control sites

Changes in demersal wild fish aggregations beneath a sea-cage fish farm after the cessation of farming

Demersal, non-cryptic, wild fish were counted in replicate 100 m2 transects beneath a floating sea-cage fish farm and two nearby sandy locations at Gran Canaria (Canary Islands, eastern Atlantic) four times before and after the cessation of farming. Cessation of farming involved the removal of farmed fish and ceasing of the daily feeding, although farm structures (cages and moorings) remained. A “beyond-BACI” sampling design provided the framework to detect the effect of the cessation of farming, which produced qualitative and quantitative changes in the composition and structure of the fish assemblages beneath the sea-cage fish farm compared with two nearby controls. The aggregative effect on wild fish due to the existence of the farm decreased from approximately 50 times compared to nearby controls when the farm was in full operation to (large-sized mugilids), large benthic chondrichthyid rays and Pagellus spp. declined markedly at the fish farm after the cessation of farming, suggesting that the removal of daily feeding was responsible for their disappearance. In contrast, abundances of herbivores, benthic macro- and meso-carnivores were similar beneath the fish farm both before and after the cessation of farming. Benthic macro-carnivores, however, were more abundant beneath the sea-cages compared to control locations, supporting the hypothesis that the increase in the physical structure beneath farms plays a role in aggregating these species. Sparids occurred beneath the sea-cages only after the cessation of farming, while the two natural control locations did not show differences from before to after the cessation of farming. Overall, the results show that the wild fish assemblage beneath the farm partially changed after the cessation of farming to a more natural state, approaching the assemblages observed at the control sites

Coastal aquaculture and conservation can work together

Current fishing practices are regarded as unsustainable (Pauly et al. 2002), yet our appetite for seafood grows. To meet the growing gap, there are increasing calls for mankind to tame the oceans through aquaculture (Marra 2005). Close to the coast, rapid expansion of marine aquaculture is underway throughout the world. Sea cages enclose 2.5 million tons of fish, while 12 million tons of mussels, oysters and clams hang from floating ropes or grow on racks or trays (FAO 2004). Aquaculture structures are now ubiquitous to many coastlines. As the expansion continues, how can we best manage the interaction between natural communities and aquaculture

Vertical variability of wild fish assemblages around sea-cage fish farms: implications for management

Wild fish were counted in 4 depth-related strata (bottom, midwater, cage and surface) around 3 floating sea-cage fish farms (Altea, Campello, Guardamar) along the Spanish coastline and 2 farms (Los Cristianos, San Andrés) in the Canary Islands. Almost 200000 wild fish belonging to 53species were seen; representatives of Sparidae (8 species), Carangidae (6 species), Mugilidae (5species) and Chondrichthyid rays (7 species) were commonly observed. At all 5 farms, 1 to 3 taxa accounted for >74% of the abundance and >94% of the biomass of aggregated wild fish. Abundances (5.7 to 162 times) and biomasses (42 to 1728 times) of wild fish were higher in the cage stratum at the 3 Mediterranean farms than at the bottom. In contrast, abundances and biomasses of wild fish at the Canary Island farms were highest at the bottom at San Andrés and highest at the surface at Los Cristianos. Large differences in the sizes of associated fish existed among farms, with low percentages of fish >20 cm total length at Guardamar, Los Cristianos and San Andrés (11 to 25%) compared to Altea and Campello (81 to 95%). However, the greatest proportions of large fish were present in the cage stratum at each of the 5 farms. This variability suggests that assemblage structure and aggregated biomass of wild fish at farms cannot be predicted prior to their installation, causing uncertainty in modelling of nutrient dispersal. Further, the sedimentation ‘footprint’ of temperate sea-cage fish farms may vary depending on (1) the species and biomass of associated wild fish, and (2)where these fish are distributed in the water column. As wild fish consume lost feed and assimilate nutrients, we suggest that coastal managers prohibit fishing of large planktivorous species at farms to fully harness their ability to ameliorate benthic impacts.The study forms part of the ACUFISH project (Marine Science Department, University of Alicante) and was funded by Spanish Ministry of Science grant MYCT-REN2003-00794. Financial support in the Canary Islands was provided by the ‘Canarias, por una Costa Viva’ framework (Ministerio de Medio Ambiente). Travel to Spain for T.D. was funded by the University of Alicante

Portal hypertension increases the risk of hepatic decompensation after 90Yttrium radioembolization in patients with hepatocellular carcinoma: a cohort study

Background: Transarterial radioembolization (TARE) is increasingly used in patients with hepatocellular carcinoma (HCC). This treatment can induce or impair portal hypertension, leading to hepatic decompensation. TARE also promotes changes in liver and spleen volumes that may modify therapeutic decisions and outcomes after therapy. Objectives: We aimed to investigate the impact of TARE on the incidence of decompensation events and its predictive factors. Design: In all, 63 consecutive patients treated with TARE between February 2012 and December 2018 were retrospectively included. Methods: We assessed clinical (including Barcelona Clinic Liver Cancer stage, portal hypertension assessment, and liver decompensation), laboratory parameters, and liver and spleen volumes before and 6 and 12 weeks after treatment. A multivariate analysis was performed. Results: In total, 18 out of 63 (28.6%) patients had liver decompensation (ascites, variceal bleeding, jaundice, or encephalopathy) within the first 3 months after therapy, not associated with tumor progression. Clinically significant portal hypertension (CSPH) and bilobar treatment independently predicted the development of liver decompensation after TARE. A significant volume increase in the non-treated hemi-liver was observed only in patients with unilobar treatment (median volume increase of 20.2% in patients with right lobe TARE; p  = 0.007), especially in those without CSPH. Spleen volume also increased after TARE (median volume increase of 16.1%; p  = 0.0001) and was associated with worsening liver function scores and decreased platelet count. Conclusion: Bilobar TARE and CSPH may be associated with an increased risk of liver decompensation in patients with intermediate or advanced HCC. A careful assessment considering these variables before therapy may optimize candidate selection and improve treatment planning