Nutritional and Organoleptic Characteristics of Sausage Based on an Autochthonous Ecuatorian Fish, Old Blue (Andinoacara rivulatus)

The consumption of fisheries and aquaculture products has been increasing in recent decades, and it is necessary to strike a balance between production and sustainability in aquaculture; this is essential homework to support the demand for human food. This study aimed to investigate the sensory and nutritional characteristics of a sausage made from the fillet of the native fish Old Blue (Andinoacara rivulatus) to stimulate the local economy. A multifactorial A*B*C design was used, with Factor A being rearing systems (wild and farmed), Factor B being types of protein (quinoa meal and soybean meal), and Factor C being lipids of animal (pork fat) and vegetable (sunflower oil) origin. Highly significant differences were observed in all formulas, according to Tukey (p < 0.05). The highest protein percentage was with soybean flour at 11.24%, while quinoa flour had 10.80% of the product. In sensory characteristics, the best attributes were for texture in the mouth with a hedonic scale from 0 to 5, with 4.2 firmness being mostly acceptable, odor at 4.5, the aromatic attribute with the highest and best value, and color was the clearest at 4.3 acceptability. The flavor was 4.3, mostly more pleasant according to the tasters. The yield of farmed fillets was 23.16% compared to wild 13.89%, and the balance of sausage yield was 393 g with a yield of 76.33% of the total weight. Microbiological analysis of the sausage with the native species showed the absence of pathogenic microorganisms. A commercial shelf life of 30 days was also established for the sausage, demonstrating an added value through this processing, allowing its exploitation in areas further away from the fishing sites and, thus, a greater possibility of social development in the area.

A comparison of passage efficiency for native and exotic fish species over an artificial baffled ramp

This study used an experimental approach to compare the passage success of native and exotic fish species from the temperate Southern Hemisphere over an artificial baffled fish ramp designed for overcoming low-head (≤1.0 m) fish migration barriers. Passage efficiency was, on average, lower for the exotic species [koi carp (Cyprinus carpio), rudd (Scardinius erythrophthalmus) and rainbow trout (Oncorhynchus mykiss)] compared to the native species [inanga (Galaxias maculatus), redfin bully (Gobiomorphus huttoni) and common bully (Gobiomorphus cotidianus)]. Nonetheless, there was considerable variation between individual species, with rainbow trout outperforming common bully and juvenile inanga, but koi carp and rudd failing to pass any of the ramps. The differences in predicted probability of passage success between the native and exotic fish species in this study were sufficient in some cases to indicate the potential for the baffled fish ramps to operate as a selective migration barrier. Nonetheless, further testing is required to validate these results across a broader range of conditions before deployment.

Susceptibility of Caligus rogercresseyi collected from the native fish species Eleginops maclovinus (Cuvier) to antiparasitics applied by immersion

A major challenge for Chilean salmon farming is infestation by the ectoparasite Caligus rogercresseyi. In addition, there is evidence that a loss of chemotherapeutic treatment efficacy against important fish pathogens is occurring in salmon farming, including antiparasitic efficacy. Currently, there are known techniques that allow the determination of the susceptibility profile of parasites to antiparasitic treatment. However, there is scarce information about both threshold values and categorization of antiparasitic susceptibility for C. rogercresseyi. Bioassay technique allowed the determination of both mean values and the natural variation of EC50%, which were contrasted with available susceptibility thresholds. Results allowed to determine that parasites from the native fish host, Eleginops maclovinus, are susceptible to azamethiphos, deltamethrin and cypermethrin treatments, showing a high susceptibility profile to antiparasitics.

Identifying correlates of success and failure of native freshwater fish reintroductions

Reintroduction of imperiled native freshwater fish is becoming an increasingly important conservation tool amidst persistent anthropogenic pressures and new threats related to climate change. We summarized trends in native fish reintroductions in the current literature, identified predictors of reintroduction outcome, and devised recommendations for managers attempting future native fish reintroductions. We constructed random forest classifications using data from 260 published case studies of native fish reintroductions to estimate the effectiveness of variables in predicting reintroduction outcome. The outcome of each case was assigned as a success or failure on the basis of the author's perception of the outcome and on whether or not survival, spawning, or recruitment were documented during post-reintroduction monitoring. Inadequately addressing the initial cause of decline was the best predictor of reintroduction failure. Variables associated with habitat (e.g., water quality, prey availability) were also good predictors of reintroduction outcomes, followed by variables associated with stocking (e.g., genetic diversity of stock source, duration of stocking event). Consideration of these variables by managers during the planning process may increase the likelihood for successful outcomes in future reintroduction attempts of native freshwater fish.