Pre‐Columbian fisheries catch reconstruction for a subtropical estuary in South America

Small‐scale fisheries provide food and livelihoods for thousands of people along the Brazilian coastline. However, considerable uncertainties still surround the extent to which artisanal and subsistence fisheries contribute to the total of national landings and their historical ecological significance. Fisheries monitoring is deficient in Brazil, and historical records are limited to irregular accounts spanning the last few decades, while this coastline has supported human populations for at least 6,000 years. Here, we estimate pre‐Columbian subsistence catches for a large subtropical estuary in southern Brazil. Our results suggest that prehistoric populations may have extracted volumes of fish biomass higher than or comparable with historical subsistence fisheries in the region, and that the latter is likely underestimated. If a long‐term perspective is required to evaluate the current economic value and status of fisheries in subtropical and tropical South America, this should go beyond the historical time interval and integrate the contribution of pre‐Columbian archaeology.     

Pesticide contamination of the upper Elbe River and an adjacent floodplain area

Journal of Soils and Sediments - Pesticide contamination of river waters is a global problem, and therefore, authorities regularly monitor the water quality status. Especially, flood events might...     

The microbial diversity and structure in peatland forest in Indonesia

The microbial community structure and function under forest in tropical peatlands are poorly understood. In this study, we investigated the microbial community structure and diversity in natural peat swamp forest soil, disturbed peat soil and mineral soil in Central Kalimantan, Indonesia, using 454 pyrosequencing. The results showed that the natural peat soil had the greatest fungal species richness (Chao1), which was significantly (p < .05) larger than that in the other two soils. Community structure of both fungi and bacteria in natural peat soil differed significantly from that in the disturbed peat soil (p = .039 and p = .045, respectively). Ascomycota (40.5%) was the most abundant phylum across the three soils followed by Basidiomycota (18.8%), Zygomycota (<0.1%) and Glomeromycota (<0.1%). The linear discriminant analysis with effect size (LEfSe) showed that Ascomycota (p < .05) and genus Gliocephalotrichum (p < .05) dominated in natural peat soil. Functionally, pathotrophs were more abundant in disturbed peat soil (p < .05). Proteobacteria (43.8%) were the most abundant phylum followed by Acidobacteria (32.6%), Actinobacteria (9.8%), Planctomycetes (1.7%). Methylocystis, Telmatospirillum, Syntrophobacter, Sorangium and Opitutus were the more abundant genera in disturbed peat soil, whereas Nevskia and Schlesneria were more abundant in mineral soil and natural peat soil, respectively. The natural peat forest soil supported a more diverse microbiology; however, the land use of such a soil can change its microbial community structure. The results provide evidence that the disturbance of tropical peat land could lead to the introduction and spread of a large number of fungal diseases     

Effect of plant density in coupled aquaponics on the welfare status of African catfish,Clarias gariepinus

We investigated the effects of plant density on the welfare of African catfish, Clarias gariepinus, in coupled aquaponics over 85 days. The moderate density (mpd) of basil, Ocimum basilicum, was compared with the high density (hpd) and control (n = 0). The behavior was analyzed by visual and video observations, and after the application of induced stressors, skin injuries, blood glucose, lactate, and plasma cortisol responses were considered. The hpd fish showed the least activity (control: visual 77.8%, video 81.6%; mpd: 74.6%, 82.6%; hpd: 63.2% [p < 0.05], 78.8%). High agonistic behavior (control: 5, 131; mpd: 4, 57; hpd: 1, 45) and the highest number of injuries (control: 3.9; mpd: 2.9; hpd: 3.4) were observed in the control. Glucose and lactate levels did not differ significantly (control: 5.5, 2.6 mmol/L; mpd: 5.6, 2.7 mmol/L; hpd: 5.3, 2.6 mmol/L); however, cortisol levels did (control: 18.8 ng/mL, mpd: 19.9 ng/mL, hpd: 25.8 ng/mL). pH adjustment led to additional stress, resulting in temporal cortisol alterations. While in the control and mpd, low cortisol levels were followed by acute responses and downregulation, the hpd fish showed prior elevation and lagged an acute response. However, comparing injuries and behavioral patterns with control, aquaponics with high basil density influenced African catfish positively.     

Cell wall disruption: An effective strategy to improve the nutritive quality of microalgae in African catfish (Clarias gariepinus)

The rigid cell walls of microalgae may hinder their utilization in fish feeds. The current experiment assessed the correlation between the accessibility of microalgae nutrients and their in vivo digestibility in African catfish. Nannochloropsis gaditana biomass was subjected to physical or mechanical treatments to weaken its cell wall; untreated—no disruption treatment (UNT), pasteurization (PAS), freezing (FRO), freeze‐drying (FRD), cold pasteurization (L40) and bead milling (BEM). Six experimental diets formulated from differently treated and untreated microalgae (at 30% diet inclusion level) were tested on growth performance and apparent nutrient digestibility (ADCs) in juvenile African catfish. A basal diet (REF) containing no microalgae was used as reference diet. Results showed that biomass gain and feed conversion ratio of fish fed L40 and BEM diets increased by 13% and 11%, respectively, relative to the UNT diet. Additionally, FRD, FRO, L40 and BEM cell wall disruption treatments improved protein digestibility by 0.5%, 5.9%, 8.4% and 16.3%, respectively, compared to the UNT treatment. There was a positive correlation between accessibility of microalgal nutrients and their digestibility in African catfish. Nutrient digestibility of microalgae was dependent on extent of cell disruption. Also, the impact of cell disruption on nutrient digestibility of microalgae differs between African catfish and Nile tilapia.     

Effects of Water Hardness and Calcium: Magnesium Ratios on Reproductive Performance and Offspring Quality of Macrobrachium rosenbergii

This study evaluated the effect of specific calcium and magnesium ratios at two hardness values on reproductive performance and offspring quality of Macrobrachium rosenbergii brood‐females. Hatchery water containing 110.5 mg/L CaCO3 hardness was considered baseline as it has been used successfully to hatch and rear larvae and was used as the control treatment. At each hardness value of 150 and 190 mg/L CaCO₃, four experimental water treatments were made in triplicate. Each treatment was adjusted using soluble salts (CaCl₂·H₂O, MgSO₄·7H₂O, and MgCl₂·6H₂O) to provide the hardness and calcium to magnesium ratios of 0:20, 20:80, 50:50, and 80:20 needed. Each of the experimental tanks (140 L) were stocked with six females and one male. The results indicated that both hardness and Ca:Mg ratios affect brood‐female reproductive qualitative parameters such as intermolt period, egg hatchability, egg dry weight, and egg‐clutch somatic index (ESI) parameters (P < 0.05) but not fecundity and eggs per spawn. The results revealed that brood‐females at 150 mg/L hardness showed greater reproductive performance than at 190 and 110.5 mg/L hardness. The findings also demonstrated that the treatment 50Ca50Mg at 150 mg/L hardness with 38.8 mg/L calcium and 12.9 mg/L magnesium had optimum reproductive performance and offspring quality for M. rosenbergii brood‐females.     

High‐throughput Cryopreservation of Sperm from Sex‐reversed Southern Flounder,Paralichthys lethostigma

The Southern flounder, Paralichthys lethostigma, is a valuable aquaculture fish with established markets in the USA. All‐female production in this species is an important technology for aquaculture because the females usually have body sizes twice those of males at the same age, and sex‐reversed males (genotypic XX neomales) are used for all‐female production by crossing with genetically normal females. However, sperm volume from the neomales is usually small (<0.5 mL) and limits their application for all‐female fish production. Cryopreservation of sperm from these sex‐reversed neomales will provide access on demand with increased efficiency to extend the application of neomales. The goal of this study was to develop a protocol for cryopreservation of sperm from the Southern flounder by using an automated high‐throughput processing system. The objectives were to: (1) determine the effect of osmolality on activation of sperm motility; (2) evaluate the effect of extender solutions on sperm motility capacity; (3) evaluate the acute toxicity of cryoprotectants (dimethyl sulfoxide [DMSO], propylene glycol, and polyethylene glycol) on sperm motility, and (4) estimate the effect of cooling rate on sperm cryopreservation and post‐thaw fertilization. Sperm motility was activated when osmolality was 400 mOsmol/kg or higher. Of the three extender buffers tested, HEPES4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES) at 300 mOsmol/kg resulted in better protection for sperm motility than did Hanks' balanced salt solution and Mounib solution at 300 mOsmol/kg during 7 d of refrigerated storage. After 30 min equilibration with the cryoprotectant of 15% DMSO, sperm motility was 24 ± 21% (fresh sperm motility without any cryoprotectants was 42%). After cooling at a rate of 20 C/min, post‐thaw sperm motility was 8 ± 5% and fertilization was 63 ± 40% evaluated at the 32–64 cell stage (5 × 10⁵ sperm per egg). Overall, a protocol was developed for sperm cryopreservation in the Southern flounder with high‐throughput processing, which provides a tool to preserve the valuable genetic resources from neomale flounders, and enables germplasm repository development for the Southern flounder.     

Genetic control of irregular striping, a new phenotype in Cucurbita pepo

Longitudinal striping of the fruit exterioris a common trait in Cucurbita pepo(pumpkin, squash, gourd). Striping occursas ten pairs of alternating dark and lightstripes that are regularly situated inaccordance with the ten sub-epidermalcarpellary vein tracts. Usually, the darkstripes occur in the central areas betweenthe vein tracts, with the light stripesoccupying the remainder of the fruitsurface. A new phenotype is described inwhich dark spots or streaks occur in thecentral areas between the vein tracts;these are usually accompanied by darkstreaks or stripes that occur adjacent toand over part or all of the length of someor all of the ten carpellary vein tracts. The inheritance of this irregular stripingpattern was studied by crossing anaccession that bred true for this phenotypewith a near-isogenic line havinglight-colored fruits. The resultsindicated that irregular striping isdominant to light coloration and isconferred by a single gene. Testcrossesfor allelism with regular striping wereprepared by crossing the irregularlystriped accession with near-isogenic lineshaving broad stripes, l-1 ^BSt/l-1 ^BSt, and narrowstripes, l-1 ^St/l-1 ^St. The testcross results revealed thatirregular striping is conferred by anallele at the l-1 locus, designatedl-1 ^iSt. The l-1 ^iStallele is dominant to light-colored (l-1), recessive to dark-colored (L-1), and can be co-dominant or recessiveto broad-striped (l-1 ^BSt) andnarrow-striped (l-1 ^St),depending on whether or not it is fullyexpressed. Dominance relationships at thel-1 locus can, therefore, berepresented as L-1 > (l-1 ^BSt > l-1 ^St) l-1 ^iSt > l-1.     

In vitro regeneration of Pacific silver fir (Abies amabilis) plantlets and histological analysis of shoot formation

A protocol is described for the in vitro propagation of Abies amabilis (Dougl.) Forbes. Over 60% of the cotyledonary explants from 5-day-old cotyledons formed shoots when cultured for 7 days on Schenk and Hildebrandt's (SH) medium containing 10 micro M N(6)-benzyladenine (BA) followed by another 7 days on SH medium containing 10 micro M each of BA and zeatin. Shoot multiplication was unsuccessful. Seventeen percent rooting was obtained after pulsing for 4 h in 1 mM indole-3-butyric acid and planting pulsed shoots in 1/1 (v/v) perlite/vermiculite. Cell clusters (promeristemoids) of five to seven cells were observed on the cotyledonary explants after 7 days of culture in the presence of cytokinin. These cells developed further into meristematic domes and apical meristems. In the absence of cytokinin, stomata and resin canals reached maturity, whereas cells within the cortex became vacuolated and developed into palisade and spongy mesophyll.