A Review of the South Pacific Tuna Baitfisheries: Small Pelagic Fisheries Associated with Coral-Reefs

A review is given of current information concerning small pelagic fishes exploited for tuna bait in the South Pacific. These fishes are usually caught over or near coral reefs using light attraction and lift nets. The most common and widespread species are anchovies (Engraulidae), sprats (Clupeidae), silversides (Atherinidae), and herrings (Clupeidae). Recorded yields ranged from 0.5 to 2.6t/km2, and methods are described to estimate potential yields empirically in the absence of catch data. Environmental effects on small pelagic fish production are discussed, and evidence is presented to suggest that rainfall markedly affects stolephorid anchovy production. Some species of small pelagic fish, such as Selar spp., Decapterus spp., and Herklotsichthys sp., have been fished traditionally by artisanal fishermen, but anchovy and sprat stocks were probably unexploited prior to pole-and-line tuna fishing in the South Pacific

Electrochemical and mass spectrometry methods for identification of gunshot residues (GSR) in forensic investigations

Gun violence continues to be one of most significant challenges straining the USA society causing thousands of human lives lost every year. In 2020 alone, firearm-related incidents including homicide, accidents, and suicides, reached a staggering number of over 43,000.1,2 With the increase in these types of incidents, several service areas in crime laboratories are heavily impacted by the number of cases run on a yearly basis. These include firearm examinations, gunshot residue (GSR) analysis, bullet hole identification, and shooting distance determination, which are crucial to support a criminal investigation and, overall, the justice system in our country. These areas are very resourceful for reconstructing firearm-related inquiries and evaluating the evidence under source (GSR present or absent) or activity (fired a gun or in the vicinity of the firing) propositions. GSR particles are evaluated based on single-particle morphological and elemental analysis (e.g., lead, barium, and antimony) by Scanning Electron Microscopy Energy Dispersive Spectroscopy (SEM-EDS) following the ASTM 1588-20 method.3–6 In addition to SEM-EDS, color tests are currently used to evaluate distance determination as per the recommendations given by the Scientific Working Group for Firearms and Toolmarks (SWGGUN) for nitrites, lead, barium, and copper.7, 8,9 Our research group has focused its attention on the development of emerging analytical tools that facilitate the detection of both inorganic (IGSR) and organic gunshot residues (OGSR) using electrochemistry (EC) along with data mining tools to support more objective data interpretation. This research aims to fill some of the gaps observed in existing technologies like color tests by offering faster and complementary methods to decrease subjectivity, cost, analysis time, to aid with triage and more cost-effective workflows at the crime scene and laboratory. The complementary OGSR information is anticipated to cause a breakthrough in the GSR analysis paradigm and respond to the current OSAC recommendations for this specialized area of work. 10–14 To this end, the development of innovative sampling methods for distance determination and bullet hole identification were investigated to simultaneously gain spatial and chemical information via electrochemical detection. In the case of distance determination, a set of 30 calibrations and 45 unknown distance clothing samples on various light, dark, patterned, and bloodstained fabrics were assessed to compare the electrochemical performance against current techniques. Discriminant analysis statistical classification method was applied for the classification of the 45 unknowns resulting in an electrochemical method accuracy of 74% compared to color tests at 58%. Bullet hole identification were investigated on 59 fabrics and other alternative substrates commonly found at crime scenes, such as wood, and drywall to assess potential interference and electrochemical performance from unknown shooting distance. Electrochemical methods successfully provided simultaneous detection of IGSR and OGSR with overall 98% accuracy using calibration thresholds for positive identification. OGSR results were confirmed using our research group\u27s previously validated OGSR solvent extraction and LC-MS/MS method. Transitions toward using portable technology probed investigation to compare the performance of portable and benchtop instrumentation for GSR analysis. A comparison of figures of merit and performance metrics found comparable results on the limits of detection, precision, linear dynamic range, and error rates, with 95.7% and 96.5% accuracies for identifying GSR using critical threshold analysis for benchtop and portable potentiostats, respectively. Quick sample collection and screening allowed for fast electrochemical detection in 15 minutes for bullet hole and distance application. The advantage of this methodology is the developed analytical scheme can be easily incorporated within the current workflow to enhance reliability (i.e., physical measurements, color tests, or SEM-EDS) due to its non-destructive nature and highly selective and sensitive characteristics. The conclusions of this work demonstrate the fit-for-purpose of electrochemical detection expanding from GSR analysis to distance determination and bullet hole identification with fast detection using a low-cost platform for simultaneous IGSR and OGSR detection

Genotypic Effects on Condensed Tannins in the Leucaena Genus

One hundred and eighteen accessions of the Leucaena genus were assayed for extractable and bound condensed tannins (CT). Leucaena taxa varied from low or no CT (0-1%) to extremely high levels (\u3e15%). There was considerable intraspecific variation in CT within key taxa. The proportion of bound tannin decreased with increasing total CT content

A Revised Method of Condensed Tannin Analysis in Leucaena spp.

The proanthocyanidin (butanol-HCl) assay was used to measure condensed tannin (CT) in extracts from Leucaena spp. at the University of Queensland. Inconsistent results were found to be caused by the iron catalyst in the butanol/HCl reagent and the presence of ascorbic acid in the sample matrix which enhanced anthocyanidin development. In addition, preparation of sample extracts by back extraction with organic solvents reduced CT recoveries. An accurate and rapid technique was developed that measures CT directly in 70% aqueous acetone 0.1% (w/v) sodium metabisulphite plant extracts

Leucaena in Northern Australia: A Forage Tree Legume Success Story

Leucaena leucocephala (leucaena) is a long-lived, perennial forage tree legume of very high nutritive value for ruminant production. In northern Australia, leucaena is direct seeded into hedgerows 5-10m apart, with grass species such as buffel grass (Cenchrus ciliaris) planted in the inter-row to form a highly productive and sustainable grass-legume pasture that cattle graze directly. It generally is grown on deep, fertile soils in sub-humid environments with average rainfall of 600-800mm/year. Steer gains of 275-300kg/head per year are achieved, with short-term daily gains over the main growing season \u3e 1kg/head. Being very deep-rooted, leucaena exploits moisture beyond the reach of grasses and remains productive well into the dry season. Once established, leucaena-grass pastures remain productive for \u3e 40 years

Breeding a Psyllid-Resistant Interspecific Hybrid \u3cem\u3eLeucaena\u3c/em\u3e for Beef Cattle Production in Northern Australia

Production of the valuable fodder tree legume Leucaena leucocephala (leucaena) is limited to the subhumid (600-800 mm annual rainfall) areas of northern Australia by the psyllid insect pest Heteropsylla cubana. Defoliation caused by severe psyllid infestations can suppress forage yields of commercial leucaena varieties by 50-80%. Susceptibility to psyllid damage is a major impediment to grazier adoption of leucaena pastures in the more humid tropical areas of Australia. A comprehensive international agronomic evaluation of the entire Leucaena genus (Mullen et al., 2003) revealed that the artificial interspecific F1 hybrid of L. pallida x L. leucocephala ssp. glabrata (called KX2) had a high degree of psyllid resistance, excellent vigour and broad environmental adaptation. The KX2 F1 hybrid also had superior forage quality compared to other psylli-resistant taxa, such as L. pallida, L. trichandra and L. diversifolia. Commercial utilization of the KX2 F1 hybrid by Australian graziers has been prevented by a lack of planting material. To date, seed production of the F1 hybrid has only been possible by laborious hand pollination. The KX2 F1 hybrid has been successfully vegetatively propagated for smallholders in SE Asia, however cloned cuttings are expensive to produce and are not suited to broad acre leucaena planting in Australia. A recurrent selection breeding program was initiated to produce a genetically stable, advanced generation KX2 hybrid that breeds true-to-type and is suitable for commercial release. We anticipate that 4 cycles of selection will be required to achieve this objective. This paper reports the agronomic evaluation of the KX2 F2 generation

Detection of Toxicity in Ruminants Consuming Leucaena (\u3cem\u3eLeucaena leucocephala\u3c/em\u3e) Using a Urine Colorimetric Test

Leucaena (Leucaena leucocephala), a productive leguminous shrub for feeding ruminant livestock, contains the toxic amino acid, mimosine which post- ingestion is converted to 3,4-DHP and 2,3-DHP, isomers of dihydroxy-pyridone. While DHP generally does not exhibit acute toxic symptoms, it has been suggested that it is an appetite suppressant that reduces animal live weight gain (Jones 1994). With no observable symptoms, subclinical toxicity is difficult to detect (Phaikaew et al. 2012). In 1982 the DHP-degrading rumen bacterium named Synergistes jonesii was introduced into Australia as a potential solution to DHP toxicity as it spreads easily throughout cattle herds grazing leucaena (Jones 1994). However, toxicity events reported since the 2003 drought suggest that the toxicity status of herds, previously understood as being protected, may have changed. This may be the result of loss of effective S. jonesii bacteria from the rumen. Widespread subclinical leucaena toxicity has since been confirmed representing a significant economic threat to the beef industry (Dalzell et al. 2012). At present the testing for toxicity requires a sophisticated chemical analysis of urine samples using high performance liquid chromatography (HPLC). Producers, however, require a robust and reliable means to routinely test for toxicity in their herds. A colorimetric urine test protocol is available based on the colour reaction of mimosine and DHP with FeCl3 solution (Jones 1997). When this simpler colorimetric test has been used under a wide range of conditions false negatives have been reported. The aim of this study was to improve the reliability of the FeCL3 urine colour test

Rates of Urinary Toxin Excretion in Unprotected Steers Fed \u3cem\u3eLeucaena leucocephala\u3c/em\u3e

Leucaena (Leucaena leucocephala) is a productive, nutritious, leguminous forage tree with high capacity for ruminant live weight gain. The plant does however contain the non-protein amino acid mimosine which is degraded within the rumen to 3-hydroxy-4(1H)-pyridone (3,4-DHP) with potential to cause adverse effects on animal health and production. Stock can be protected via rumen inoculation with the bacterium Synergistes jonesii, which is capable of degrading the toxin. However surveys have demonstrated sub-clinical toxicity is persisting in Queensland herds (Dalzell et al. 2012). Currently, testing for toxicity involves analysis of urine samples using high performance liquid chromatography (HPLC). A colorimetric urine test protocol has also been developed with the aim of providing a robust and reliable means for routinely testing herds (Graham et al. 2013). A significant problem affecting interpretation of the results from either method is the high variation in the concentrations of toxins excreted among animals on similar diets and by individual animals over time (Dalzell et al. 2012). Factors such as feed intake, water consumption, urine volume, as well as timing of sampling may be the cause of this variation. This research investigated the effect of sample timing by measuring the time taken for mimosine and its breakdown products, to present in the urine following the introduction of leucaena to the ration of cattle naïve to the plant

Diurnal Urinary Excretion of DHP in Steers Fed \u3cem\u3eLeucaena leucocephala\u3c/em\u3e

Leucaena (Leucaena leucocephala) contains the toxin mimosine which is quickly degraded by rumen microorganisms to isomers of dihydroxypyridine (DHP). DHP is detrimental to animal production, causing reduced thyroid hormones, reduced weight gain, goiter and severe deficiencies in essential minerals (Tsai and Ling 1971; Hammond 1995). There are several methods of testing for exposure to DHP toxicity but the simplest is the colorimetric urine spot test (Graham et al. 2013). Several researchers have noted high variability in the excretion of DHP among animals on similar leucaena diets (Dalzell et al. 2012; Phaikaew et al. 2012) and even in the same animal over sequential samplings (O\u27Reagain and Shelton 2013). They noted that it was possible to obtain samples with very low DHP in unprotected animals on high leucaena diets, leading to the false conclusion that the animal was successfully degrading DHP in the rumen. This study examined the extent and possible causes of variation of DHP concentration in spot urine samples taken over a 6-week period, including an intensive sampling over a 24 hour period

Toxicity in Beef Cattle Grazing \u3cem\u3eLeucaena leucocephala\u3c/em\u3e in Queensland, Australia

Improved pastures based on the leguminous shrub Leucaena leucocephala (leucaena) are the most productive, profitable and sustainable for beef cattle production in northern Australia. Leucaena forage contains the toxic, non-protein amino acid mimosine, which is rapidly converted to 3-hydroxy-4(1H)-pyridone (DHP) upon ingestion by grazing cattle. This is a potent goitrogen and appetite suppressant. Animals suffering severe DHP toxicity exhibit distinctive symptoms (e.g. hair loss, excessive salivation, goitre and weight loss), while subclinical DHP toxicity can suppress live weight gain by 30-50% without producing any obvious symptoms. Prior to the discovery and introduction of the DHP-degrading rumen bacteria Synergistes jonesii into Australia in 1982, DHP toxicity severely limited animal performance from leucaena pastures and was a major impediment to adoption. Initial rumen inoculation of cattle in Australia with S. jonesii successfully protected them against DHP toxicity and the bacterium appeared to be easily and rapidly transmitted between grazing animals. Consequently many scientists and graziers believed that a single inoculation of a herd with S. jonesii, combined with simple ongoing herd management, was sufficient to overcome the problem of DHP toxicity. However, during the 2003 drought there were several reports of severe leucaena toxicity (including animal deaths) in cattle grazing leucaena in Queensland. Toxicity was evident even in herds that had followed recommended control measures. Preliminary results are presented of a study, designed to ascertain the prevalence and possible causes of leucaena toxicity in Queensland cattle herds. Meat and Livestock Australia Limited funded this research (NBP.340)