Introduction of non-native freshwater fish can certainly be bad

In this paper, we respond to Gozlan's views of the introduction of freshwater fish, as we strongly disagree with his view and approach. We demonstrate that many real-world examples of freshwater fish introductions have catastrophic ecological consequences. We detail a few noteworthy examples, such as those of the Nile perch, carp, tilapias, catfishes, and the zebra mussel. We discuss within-nation introductions, and we explore several related problems, such as hybridization and spread of pathogens and parasites. We propose that Gozlan's analysis is biased, as more reliable data on impacts that are already widespread are urgently needed, mainly in the biologically richest areas of the world. Thus, we continue to advocate the precautionary principle, because species introductions, once established, are largely irreversible.     

Effects of fish hydrolysate (CPSP®) on growth and digestive gland lipid composition of Octopus vulgaris (Cuvier, 1797) juveniles

Effects of artificial diets were tested on growth and digestive gland (DG) lipid composition of juvenile Octopus vulgaris. For Experiment I, three diets were used: (i) SQUID (Loligo gahi) as a control diet; (ii) Squid paste and fish hydrolysate CPSP^®, agglutinated with gelatine (GEL20); and (iii) Squid paste, fish hydrolysate CPSP^® and gelatine (GEL40). For Experiment II, three diets were used: (i) SQUID, control diet; (ii) Squid paste, CPSP^® and alginate (ALG10); and (iii) Squid paste, CPSP^® and alginate (ALG20). For both experiments, growth rates for octopuses fed control were higher (P < 0.05), while artificial diets were not different (P > 0.05) between them. All diets promoted similar growth, regardless of the different CPSP^® concentrations and binders. Growth rates obtained were among the highest obtained for O. vulgaris with artificial diets until now. The lower growth obtained with the artificial diets was greatly reflected in the DG fatty acid composition. The most important fatty acid groups, such as n‐3 highly unsaturated fatty acids, decreased in the DG of animals fed artificial diets. Lipid content, particularly neutral lipids, was higher in the DG of octopuses fed squid, indicating higher nutritional condition of these animals compared to those fed the artificial diets.     

Spectrofluorimetric study of the interaction of methyl-parathion with fish serum albumin

The interaction of methyl-parathion with the albumin of Piaractus mesopotamicus (Holmberg 1887) (= pacu), a fish species typical of Brazilian rivers, was studied and the results compared with known values for human and bovine albumin obtained in an earlier investigation. Methyl-parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous pesticide still used in agriculture and fish farming in many countries. The fluorescence quenching technique with tryptophan as a natural probe was used to detect for the presence of methyl-parathion. Fluorescence can be mathematically expressed by the Stern–Volmer equation to calculate quenching constants, and changes in the behavior of Stern–Volmer curves at different temperatures indicate the nature of the mechanism causing the quenching. Our results indicate that methyl-parathion forms a complex with fish albumin. The estimated association constant is 9.73 × 103 (± 4.9 × 102) M⁻¹ at 25°C.     

Variation in reproductive potential and influence on Icelandic herring recruitment

Explaining recruitment variation in fish is essential for successful fishery management and is consequently under constant review, with an increasing focus on how maternal factors, relative to environmental influences, operate at the level of individual female spawners and extend from the spawning stock through to recruitment. We estimate total egg production (E) in Icelandic summer‐spawning herring (Clupea harengus) from 1963 through 1999 by using sequential population analyses (SPA) and their estimates of stock biomass and recruitment, various size and maturity metrics, and individual fecundity estimates that rely on total length and the condition of the spawners. Generalized linear models indicate that maternal effects are of significance in explaining SPA‐based recruitment‐at‐age‐3 (R). The best model explained 64% of the variation in R and incorporates E constrained to the repeat spawners (40%), the NAO winter index (18%) and ocean temperature (6%). The latter two represent the winter and spring periods subsequent to year‐class formation. Recruit spawner contributions to E were of no significance in explaining variation in R despite the fact that they could contribute as much as 55% of E when their contribution to E was consistently underestimated by a factor of ～ 2, based only on their contribution to spawning stock biomass. We conclude that the spawning potential of the repeat spawners should replace total spawning stock biomass for determining recruitment potential in stock assessment. In addition to the incorporation of oceanographic factors, this would provided a more cautious and risk‐adverse approach.     

Optimum Level of Nitrogen and Phosphorus to Achieve Better Papaya (Carica papaya var. Solo) Seedlings Growth and Mycorrhizal Colonization

An experiment under greenhouse conditions was carried out to evaluate the best level of nitrogen (N) and phosphorus (P), which promote the growth of papaya (Carica papaya L. var. Solo) seedlings without affecting the arbuscular mycorrhizal fungi (AMF) activity. Seedlings of papaya were transplanted to pots inoculated or not with Gigaspora margarita spores at four levels of N (0, 50, 100, and 200 ppm) and P (0, 25, 50, and 100 ppm). P was amended at the same time of pot filling up with substrate but N was applied weekly. The experiment was harvested after 100 days and plant dry weight together with AMF colonization was measured. The major response on the plant dry weight and height was from the fertilizers (N and P) where it proportionally increased. For the dry weight, at low amounts of nutrients the effects of AMF were greater, but as much as the fertilizer level in soil increased this response decreased. The colonization decreased as the nutrient levels increased, especially the P. The best combination of N and P for plant growth and AMF colonization could be at 50 and 25 ppm, equivalent to 5 and 2.5 kg/10a, respectively.     

Biosynthesis of Polyunsaturated Fatty Acids in Marine Invertebrates: Recent Advances in Molecular Mechanisms

Virtually all polyunsaturated fatty acids (PUFA) originate from primary producers but can be modified by bioconversions as they pass up the food chain in a process termed trophic upgrading. Therefore, although the main primary producers of PUFA in the marine environment are microalgae, higher trophic levels have metabolic pathways that can produce novel and unique PUFA. However, little is known about the pathways of PUFA biosynthesis and metabolism in the levels between primary producers and fish that are largely filled by invertebrates. It has become increasingly apparent that, in addition to trophic upgrading, de novo synthesis of PUFA is possible in some lower animals. The unequivocal identification of PUFA biosynthetic pathways in many invertebrates is complicated by the presence of other organisms within them. These organisms include bacteria and algae with PUFA biosynthesis pathways, and range from intestinal flora to symbiotic relationships that can involve PUFA translocation to host organisms. This emphasizes the importance of studying biosynthetic pathways at a molecular level, and the continual expansion of genomic resources and advances in molecular analysis is facilitating this. The present paper highlights recent research into the molecular and biochemical mechanisms of PUFA biosynthesis in marine invertebrates, particularly focusing on cephalopod molluscs.     

Agronomic evaluation of seedlings from crosses between the main Spanish olive cultivar ‘Picual’ and two wild olive trees

Summary

Until recently, olive breeding programmes have been based exclusively on cultivated olive germplasm (Olea europaea subsp. europaea var. europaea), in contrast to breeding in other fruit crops where the use of wild relatives has been widely reported. In this study, ten agronomic traits were evaluated in two progenies derived from controlled crosses between the Spanish olive cultivar ‘Picual’ (female) and two wild (O. europaea subsp. europaea var. sylvestris) genotypes (males). The results of this evaluation were compared with the progenies of crosses between ‘Picual’ (female) and the three cultivars, ‘Sikitita’, ‘Meski’, and ‘Zaity’ (male). The two ‘Picual’ × wild genotype progenies had the highest mean values for vigour traits (i.e., tree height and trunk diameter). Progenies from both ‘Picual’ × wild genotype crossess also showed the highest percentages of trees (53.8% and 37.5%) with a short juvenile period, compared to the progenies from crosses between ‘Picual’ and each of the three cultivars ‘Sikitita’, ‘Meski’, and ‘Zaity’ (0%, 5%, and 3.6%, respectively). Significant differences were also observed between progenies in fruit traits as well as in oil contents and fruit weights. Progenies from both crosses with wild olive showed lower values for the fruit traits evaluated than the cultivated olive progenies. However, significant improvements were achieved compared to fruit traits in the wild parents. The implications of these results for the future use of wild germplasm in olive breeding programmes are discussed.     

Nutritional Properties of Quality Protein Maize and Chickpea Extruded Based Weaning Food

Malnutrition is one of the major causes of morbidity and mortality among young children in most of the developing countries. To minimize the adversities of malnutrition, low-cost infant supplementary foods have been developed and are being supplied to the needy through state-sponsored nutrition intervention programmers. The present study had two objectives: to determine the best combination of nixtamalized extruded quality protein maize (NEMF) and extruded chickpea (ECF) flours for producing a weaning food, and to evaluate the nutritional properties of the optimized NEMF/ECF mixture and the weaning food. The NEMF and ECF were produced applying combinations of extrusion temperature/screw speed of 79.4°C/73.5 rpm, and 150.5°C/190.5 rpm, respectively. Response surface methodology was applied to determine the optimum combination NEMF/ECF; the experimental design generated 11 assays. Mixtures from each assay were evaluated for true protein (TP) and available lysine (AL). Each one of 11 mixtures were used for preparing 11 weaning foods which were sensory evaluated for acceptability (A). The best combination of NEMF/ECF for producing a weaning food was NEMF = 21.2%/ ECF = 78.8 %. This mixture had a global desirability (D) of 0.93; it contained 20.07% proteins (DM), 5.70% lipids (DM), and 71.14% carbohydrates (DM); its essential amino acids (EAA) profile satisfactorily covered the EAA requirements for children 2–5 years old, except for Trp. The weaning food prepared with the optimized mixture had high protein quality and digestibility and could be used to support the growth of infants.     

The shadow of the Balbina dam: A synthesis of over 35 years of downstream impacts on floodplain forests in Central Amazonia

1. The Balbina hydropower dam in the Central Amazon basin, established in the Uatumã River in the 1980s, is emblematic for its socio-environmental disaster. Its environmental impacts go far beyond the reservoir and dam, however, affecting the floodplain forests (igapó) in the downstream area (dam shadow), which have been assessed using a transdisciplinary research approach, synthesized in this review.
2. Floodplain tree species are adapted to a regular and predictable flood pulse, with high- and low-water periods occurring during the year. This was severely affected by the operation of the Balbina dam, which caused the suppression of both the aquatic phase at higher floodplain elevations and the terrestrial phase at lower floodplain elevations (termed the ‘sandwich effect’).
3. During the period of construction and reservoir fill, large-scale mortality already occurred in the floodplains of the dam shadow as a result of reduced stream flow, in synergy with severe drought conditions induced by El Niño events, causing hydraulic failure and making floodplains vulnerable to wildfires.
4. During the operational period of the dam, permanent flooding conditions at low topographical elevations resulted in massive tree mortality. So far, 12% of the igapó forests have died along a downstream river stretch of more than 125 km. As a result of flood suppression at the highest elevations, an encroachment of secondary tree species from upland (terra firme) forests occurred.
5. More than 35 years after the implementation of the Balbina dam, the downstream impacts caused massive losses of macrohabitats, ecosystem services, and diversity of flood-adapted tree species, probably cascading down to the entire food web, which must be considered in conservation management.
6. These findings are discussed critically, emphasizing the urgent need for the Brazilian environmental regulatory agencies to incorporate downstream impacts in the environmental assessments of several dam projects planned for the Amazon region.