Stimulatory effect of thyroid hormones improves larval development and reproductive performance in alligator gar (Atractosteus spatula) and spotted gar (Lepisosteus oculatus)

Development of alligator gar (Atractosteus spatula) and spotted gar (Lepisosteus oculatus) larvae was evaluated after exposure of embryos to thyroid hormones (TH) by two different methods of administration. For the first method, alligator gar embryos were placed in a water bath with triiodothyronine (T₃; 1 ppm for 2 h), and control treatment embryos were placed in a water bath without T₃. For the second method, spotted gar adult males and females were injected with different TH during induced spawning: a group was injected with T₃ [20 mg kg^?1 body weight (BW)], a second group with thyroxine (T₄; 20 mg kg^?1 BW), a third group with thyroid‐stimulating hormone (TSH; 4 IU kg^?1BW) and a control group with dimethyl sulfoxide. Both methods resulted in increases in the concentrations of T₃ and T₄ in embryos of both species. An increase in the alkaline enzymatic activity of TH‐treated larvae was observed as well as an increase in the RNA:DNA, RNA:Dry weight and DNA:Dry weight ratios at hatching. Some positive effects of TH application were: a significant increase in the hatching rate of spotted gar larvae from TH‐injected parents and a higher percentage of successful spawns. Evenness of larval sizes and a higher survival rate were observed in alligator gar larvae. Snout development was accelerated by TH treatment in both species.     

Data quality and quantity for invasive species: A case study of the lionfishes

Predicting invasion risk involves inherent uncertainty when data on biological and ecological characteristics are lacking. To combat data gaps, assessors are required to use information from secondary sources, further reducing predictive accuracy. Lionfish in the subfamily Pteroinae have invasion history in the Western Atlantic Ocean and Mediterranean Sea, raising concern that other species of globally traded lionfish may pose risks similar to the invasive complex comprised of the red lionfish (Pterois volitans, Scorpaenidae) and devil firefish (Pterois miles, Scorpaenidae). We conducted a standardized literature review of 18 species in the genera Pterois, Dendrochirus, and Parapterois to (a) characterize the volume and composition of literature addressing the invasive complex pre‐establishment and pre‐spread, and compare it to the body of literature that has been generated post‐spread and impact, (b) compare the volume and composition of literature addressing other members of Pteroinae to the invasive complex, and (c) evaluate data quality addressing the Pteroinae by characterizing literature used to generate biological profile reports during a risk screening protocol. Little data were available for the invasive complex prior to introduction and focused primarily on the composition or effects of venom. Following introduction, there was a considerable time lag in research effort. Post‐spread, research effort increased rapidly. We identify similar data deficiencies for other species of lionfish that have not been reported outside of their native ranges. While proactive management is gaining support as an effective framework, it is important to understand data limitations and their resulting uncertainties, which leads to more informed proactive management.     

Early Growth and Survival of Larval Alligator Gar,Atractosteus spatula,Reared on Artificial Floating Feed with or without a Live Artemia spp. Supplement

Alligator gar, Atractosteus spatula, are a new aquaculture species with many aspects about rearing unknown. Alligator gar are cannibalistic during their larval stage and methods to minimize cannibalism should be developed to increase overall survival. Growth and survival were determined for larvae fed pelleted floating food only or fed pelleted floating food supplemented with live Artemia spp. nauplii for the first 7 d of exogenous feeding (5 d after hatching [d.a.h.] to 12 d.a.h.). Total length, weight, condition, and specific growth rate (SGR) was determined at 12 and 20 d.a.h. Fish supplemented with Artemia were larger by 12 d.a.h. and continued to be at 20 d.a.h. than fish fed only floating food. SGR was higher at both 12 and 20 d.a.h. for fish that received the Artemia supplement. Survival was higher for fish supplemented with Artemia (71%) than for the floating food only treatment (43%). Cannibalism was the primary cause of mortalities and was higher in fish fed floating food only (44%) compared to Artemia supplemented fish (19%). Artemia may elicit a stronger feeding response and improve acceptance of pelleted floating foods. Results suggest an improved feeding regime compared to previous feeding regimes used in rearing larval alligator gar.     

Mycoflora and fumonisin mycotoxins associated with cowpea [Vigna unguiculata (L.) Walp] seeds

Cowpea seed samples from South Africa and Benin were analyzed for seed mycoflora. Fusariumspecies detected were F. equiseti, F. chlamydosporum, F. graminearum, F. proliferatum, F. sambucinum, F. semitectum, and F. subglutinans. Cowpea seed from South Africa and Benin and F. proliferatum isolates from Benin, inoculated onto maize patty medium, were analyzed for fumonisin production. Samples were extracted with methanol/water and cleaned up on strong anion exchange solid phase extraction cartridges. HPLC with precolumn derivatization using o-phthaldialdehyde was used for the detection and quantification of fumonisins. Cowpea cultivars from South Africa showed the presence of fumonisin B(1) at concentrations ranging between 0.12 and 0.61 microg/g, whereas those from Benin showed no fumonisins. This is believed to be the first report of the natural occurrence of FB(1) on cowpea seed. Fumonisin B(1), B(2), and B(3) were produced by all F. proliferatum isolates. Total fumonisin concentrations were between 0.8 and 25.30 microg/g, and the highest level of FB(1) detected was 16.86 microg/g.     

Effect of fumonisin B<Subscript>1</Subscript> on the emergence,growth and ceramide synthase gene expression of cowpea (<Emphasis Type="Italic">Vigna unguiculata</Emphasis> (L.) Walp)

Rice production is currently expanding from the south-eastern regions of Australia into northern Australia where indigenous species of wild rice occur widely. A survey of fungal diseases on wild (Oryza australiensis, Oryza spp.) and cultivated rice (Oryza sativa) in North Queensland, Australia, in May 2014 revealed a diverse range of fungal genera species, including important pathogens of cultivated rice. Whilst a single isolate of Magnaporthe oryzae (causal agent of rice blast) was obtained from wild rice, Bipolaris oryzae (causal agent of brown spot) was the predominant pathogen detected under North Queensland conditions. For the first time for Australia, we report Rhizoctonia oryzae-sativae (causal agent of aggregate sheath spot) occurring on wild rice. Other pathogens detected on wild rice included Curvularia lunata, Cochliobolus intermedius, Cochliobolus geniculatus, and Fusarium equiseti present in the majority of wild rice samples. Nearby cultivated rice fields harboured additional pathogens not found in wild rice including Fusarium graminearum, Leptosphaeria spegazzinii and Cochliobolus lunatus, causing scab disease, glume blight and leaf blight, respectively. We also confirmed that Bipolaris oryzae from wild rice can infect cultivated rice. This study highlights the importance of wild rice species as alternative hosts harbouring pathogens of cultivated rice and the likely disease threats to expansion of cultivated rice into the same region(s) where wild rice is endemic.