Life history of the Critically Endangered largetooth sawfish: a compilation of data for population assessment and demographic modelling

© The authors 2021. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are un - restricted. Authors and original publication must be credited. The largetooth sawfish Pristis pristis is a Critically Endangered, once widespread shark-like ray. The species is now extinct or severely depleted in many former parts of its range and is protected in some other range states where populations persist. The likelihood of collecting substantial new biological information is now low. Here, we review all available life history information on size, age and growth, reproductive biology, and demography as a resource for population assessment and demographic modelling. We also revisit a subset of historical data from the 1970s to examine the maternal size−litter size relationship. All available information on life history is derived from the Indo-West Pacific (i.e. northern Australia) and the Western Atlantic (i.e. Lake Nicaragua-Río San Juan system in Central America) subpopulations. P. pristis reaches a maximum size of at least 705 cm total length (TL), size-at-birth is 72−90 cm TL, female size-at-maturity is reached by 300 cm TL, male size-at-maturity is 280−300 cm TL, age-at-maturity is 8−10 yr, longevity is 30−36 yr, litter size range is 1−20 (mean of 7.3 in Lake Nicaragua), and reproductive periodicity is suspected to be biennial in Lake Nicaragua (Western Atlantic) but annual in Australia (Indo-West Pacific). There was a weak relationship between litter size and maternal size in Lake Nicaragua, and lifetime reproductive output for an individual female from Lake Nicaragua was estimated as 73 pups. Future demographic models should aim to capture the variability and uncertainty in life history parameters for P. pristis and we encourage a conservative approach to any application for conservation and management

Image analysis to calibrate French Bean (Phaseolus vulgaris L.) pods

In order to control the characteristics of a variety, bean breeders have to calibrate pods. This calibration is manually realized, workers have to pass pods through a sieve with holes of different diameter in it, each hole corresponding to a caliber. Pods are weighted, and a repartition in the different calibers in weight is given. This calibration is very tedious, moreover, there is an inter and intra-variability between workers, and the number of characteristics measured is limited.  A new automatic method based on image analysis has been performed, it permits in a limited time, to extract and calculate different pods’ characteristics such as the length, the diameter and the curvature, it offers the possibility to conserve images that is helpful for the traceability of products, and it requires less labor than the actual system (manual ones). Moreover, a relation between surface of pods and weight has been found, allowing the program to give directly the repartition in the different caliber in weight.  An acquisition chain as been installed, composed of a mono CCD sensor camera, manually configured, with a backlight fluorescent system of 5000°K, a tripod and a computer. Images are taken in RAW format, which contrarily to the JPEG is not compressed and avoid edges effects.  Images are pre-processed in order to eliminate the noise and converted in binary images. Then algorithms principally based on morphological mathematics, are applied in order to calculate the different characteristics.  The validation of the program has been performed on more than 150 batches of different varieties of French and butter bean pods along 2008 and 2009.  In this presentation, the image analysis system is described, results obtained with the image analysis system are explained and compared to the manual system

Image analysis to calibrate French Bean (Phaseolus vulgaris L.) pods

Bean pod caliber is an important breeding criterion in the development of new French bean cultivars. Grading is manually performed with workers passing pods through a sieve with holes of different diameters. Each hole corresponds to a grade. Then, pods are weighed and a grade is given based on weight. This size grading is very tedious. Moreover, there is an inter- and intra-variability between workers, and the number of characteristics measured is limited. A new automatic method based on image analysis has been performed. It permits in a limited time, to extract and calculate different pod characteristics such as length, diameter and curvature. It offers the possibility to store images that could be helpful for traceability, and requires less labour than the current manual system. A correlation between the surface of pods and weight has been found, allowing the program to directly separate into grades based on weight. An acquisition chain has been installed and an image analysis program has been developed to calculate the different characteristics. The validation of the program has been performed on more than 150 batches of different cultivars of French and butter bean pods during 2008 and 2009. In this paper, the image analysis system is described. Results obtained with the new system are explained and compared to the manual system

Whole mitogenome sequencing refines population structure of the Critically Endangered sawfish Pristis pristis

The largetooth sawfish Pristis pristis (Linnaeus, 1758) is a highly threatened euryhaline elasmobranch that in recent times has undergone a significant range contraction. It now only remains in a few areas, with northern Australia being the main stronghold. Previous work using a single mitochondrial gene approach suggested the existence of regional barriers to gene flow in northern Australia. In this study, whole mitochondrial sequences of 92 P. pristis from 7 river drainages across northern Australia were used to refine the population structure. This approach revealed barriers to gene flow at a scale as fine as between adjacent river drainages. Except for those flowing into the Gulf of Carpentaria, all river drainages appeared to host a genetically distinct population. The apparent genetic homogeneity in the Gulf is probably due to freshwater connectivity between river drainages, either during the last glaciation event when the Gulf was a freshwater lake or through contemporary wet season flooding. These results suggest that each river drainage across the species' range should be considered a discrete management unit unless there is evidence of freshwater connectivity. More broadly, the improved resolution of population structure obtained with whole mitogenome analysis compared to single mitochondrial gene approaches suggests that female reproductive philopatry may have been overlooked in previous studies of some elasmobranch species

Diadromous life cycle and behavioural plasticity in freshwater and estuarine Kuhliidae species (Teleostei) revealed by otolith microchemistry

cited By 10International audienceOtolith microchemistry and microstructure were examined in juveniles of 3 Kuhlia species (Teleostei) from fresh and brackish environments in order to examine their migratory histories. All species presented with strontium:calcium (Sr:Ca) and barium:calcium (Ba:Ca) profiles in the inner region of the otoliths that suggested an obligatory marine larval phase. At approximately 0.3 to 0.6 mm from the otolith core, all individuals showed a sharp increase in Ba:Ca ratios that were generally associated with variation in the Sr:Ca ratio, indicating recruitment into rivers. Microchemical profiles in the outer region of the otoliths indicated a freshwater habitat for most K. rupestris and K. sauvagii and an estuarine habitat for most K. munda. Microstructure analyses validated the presence of an otolith check mark deposited during the habitat shift in K. rupestris and K. sauvagii, but not in K. munda. We hypothesise that this difference was due to lower osmotic stress for the fish moving from the sea to estuaries than from the sea to freshwater. This study demonstrated the ability of otolith multi-elemental microchemistry and microstructure to provide important insights on life history traits of species that lack basic biological information, such as those in the genus Kuhlia. The information provided in this study is critical for the conservation and management of these species. © Inter-Research 2012

Image analysis to calibrate French Bean (Phaseolus vulgaris L.) pods

International audienceBean pod caliber is an important breeding criterion in the development of new French bean cultivars. Grading is manually performed with workers passing pods through a sieve with holes of different diameters. Each hole corresponds to a grade. Then, pods are weighed and a grade is given based on weight. This size grading is very tedious. Moreover, there is an inter- and intra-variability between workers, and the number of characteristics measured is limited. A new automatic method based on image analysis has been performed. It permits in a limited time, to extract and calculate different pod characteristics such as length, diameter and curvature. It offers the possibility to store images that could be helpful for traceability, and requires less labour than the current manual system. A correlation between the surface of pods and weight has been found, allowing the program to directly separate into grades based on weight. An acquisition chain has been installed and an image analysis program has been developed to calculate the different characteristics. The validation of the program has been performed on more than 150 batches of different cultivars of French and butter bean pods during 2008 and 2009. In this paper, the image analysis system is described. Results obtained with the new system are explained and compared to the manual system.</p

Stretched to the limit; can a short pelagic larval duration connect adult populations of an Indo-Pacific diadromous fish (Kuhlia rupestris)?

Freshwater species on tropical islands face localized extinction and the loss of genetic diversity. Their habitats can be ephemeral due to variability in freshwater run-off and erosion. Even worse, anthropogenic effects on these ecosystems are intense. Most of these species are amphidromous or catadromous (i.e. their life cycle includes a marine larval phase), which buffers them against many of these effects. A long pelagic larval duration (PLD) was thought to be critical to ensure the colonization and persistence in tropical islands, but recent findings indicated that several species with short PLDs are successful in those ecosystems. To test the potential of a short PLD in maintaining genetic connectivity and forestalling extirpation, we studied Kuhlia rupestris, a catadromous fish species with an extensive distribution in the western Pacific and Indian Oceans. Using a combination of molecular genetic markers (13 microsatellite loci and two gene regions from mtDNA) and modelling of larval dispersal, we show that a short PLD constrains genetic connectivity over a wide geographical range. Molecular markers showed that the short PLD did not prevent genetic divergence through evolutionary time and speciation has occurred or is occurring. Modelling of larvae dispersal suggested limited recent connectivity between genetically homogeneous populations across the Coral Sea. However, a short PLD can maintain connectivity on a subocean basin scale. Conservation and management of tropical diadromous species needs to take into account that population connectivity may be more limited than previously suspected in those species

Image analysis to calibrate French Bean (Phaseolus vulgaris L.) pods

Date du colloque&nbsp;: 08/2010International audienceIn order to control the characteristics of a variety, bean breeders have to calibrate pods. This calibration is manually realized, workers have to pass pods through a sieve with holes of different diameter in it, each hole corresponding to a caliber. Pods are weighted, and a repartition in the different calibers in weight is given. This calibration is very tedious, moreover, there is an inter and intra-variability between workers, and the number of characteristics measured is limited.&nbsp;A new automatic method based on image analysis has been performed, it permits in a limited time, to extract and calculate different pods’ characteristics such as the length, the diameter and the curvature, it offers the possibility to conserve images that is helpful for the traceability of products, and it requires less labor than the actual system (manual ones). Moreover, a relation between surface of pods and weight has been found, allowing the program to give directly the repartition in the different caliber in weight.&nbsp;An acquisition chain as been installed, composed of a mono CCD sensor camera, manually configured, with a backlight fluorescent system of 5000°K, a tripod and a computer. Images are taken in RAW format, which contrarily to the JPEG is not compressed and avoid edges effects.&nbsp;Images are pre-processed in order to eliminate the noise and converted in binary images. Then algorithms principally based on morphological mathematics, are applied in order to calculate the different characteristics.&nbsp;The validation of the program has been performed on more than 150 batches of different varieties of French and butter bean pods along 2008 and 2009.&nbsp;In this presentation, the image analysis system is described, results obtained with the image analysis system are explained and compared to the manual system.</p