High reproductive potential of the commercially exploited shark Squalus suckleyi in the major fishing grounds of the western North Pacific.

The present study examined body length (precaudal length, PCL) and age at sexual maturity, as well as fecundity and maternal investment in the Pacific spiny dogfish Squalus suckleyi, a long-term commercially exploited shark in the western North Pacific, using samples caught in several fisheries and across seasons. The PCL and age at 50% sexual maturity of males were 60.6 cm and 9.4 years, respectively, and those of females were 73.1 cm and 17.8 years, respectively. The PCL and age at 50% maternity were 77.4 cm and 19.7 years, respectively. General or generalized linear models revealed that capture by different fishing method did not significantly correlate with sexual maturity and maternity rates or litter size. Other general linear models revealed an increase in offspring size with maternal size, but litter size was not affected by embryonic development. These findings indicate that the reproductive potential of Pacific spiny dogfish is relatively high throughout the whole North Pacific region because of a smaller size and earlier age at sexual maturation in both sexes. In addition, pregnant females displayed no resting phase and produced 0.45 more embryos per centimetre of PCL in their lifetime after the onset of maturity, which is higher than in the eastern North Pacific. We suggest that these qualities are not a consequence of stock decline associated with the long-term exploitation of the species, but that its high reproductive potential has likely contributed to the long-term stability of the landings in Japan. SIGNIFICANCE STATEMENT: While reproductive potential has been determined for many fish species, such information is scarce for Pacific spiny dogfish. We evaluated the reproductive characteristics of this species in the major fishing grounds of the western North Pacific. The productivity and rebound potential of sharks is extremely low compared with those of bony fishes. However, our results indicate that even if the reproductive potential has a small effect on the population dynamics, it should not be ignored for sustainable stock utilisation.

First record of Gorgona guitarfish (Pseudobatos prahli) off the Baja California peninsula with updated key to the guitarfishes of the North Eastern Pacific.

The Gorgona guitarfish is a poorly documented ray found in the Eastern Pacific. It can be distinguished from its congeners due to its distinctive coloration and rostral cartilages. Here I document an extensive northern range expansion of almost 2000 km based on a juvenile specimen caught off the Baja California Peninsula. This specimen also represents the smallest documented individual of this species, along with the first quantitative morphometric data reported since the 1995 description. Additionally, an updated key to the guitarfishes of the North Eastern Pacific is included.

Using cumulative human-impact models to reveal global threat patterns for seahorses.

Understanding threats acting on marine organisms and their conservation status is vital but challenging given a paucity of data. We studied the cumulative human impact (CHI) on and conservation status of seahorses (Hippocampus spp.)-a genus of rare and data-poor marine fishes. With expert knowledge and relevant spatial data sets, we built linear-additive models to assess and map the CHI of 12 anthropogenic stressors on 42 seahorse species. We examined the utility of indices of estimated impact (impact of each stressor and CHI) in predicting conservation status for species with random forest (RF) models. The CHI values for threatened species were significantly higher than those for nonthreatened species (category based on International Union for Conservation of Nature Red List). We derived high-accuracy RF models (87% and 96%) that predicted that 5 of the 17 data-deficient species were threatened. Demersal fishing practices with high bycatch and pollution were the best predictors of threat category. Major threat epicenters were in China, Southeast Asia, and Europe. Our results and maps of CHI may help guide global seahorse conservation and indicate that modeling and mapping human impacts can reveal threat patterns and conservation status for data-poor species. We found that for exploring threat patterns of focal species, species-level CHI models are better than existing ecosystem-level CHI models.

Uso de Modelos de Impacto Humano Acumulativo para Revelar los Patrones de Amenaza Mundial para Hipocampos Resumen El entendimiento de las amenazas que actúan sobre los organismos marinos y su estado de conservación es de suma importancia pero a la vez un gran reto debido a la insuficiencia de datos. Estudiamos el estado de conservación y el impacto humano acumulativo (CHI, en inglés) que existe sobre los hipocampos (Hippocampus spp.)- un género de peces marinos raro y escaso de datos. Construimos modelos lineales aditivos con el conocimiento de expertos y conjuntos de datos espaciales relevantes para evaluar y mapear el CHI de los doce estresantes antropogénicos que afectan a las 42 especies de hipocampos. Examinamos la utilidad que tienen los índices de impacto estimado (el impacto de cada estresante y cada CHI) para la predicción del estado de conservación de las especies usando modelos de bosque azaroso (RF, en inglés). Los valores del CHI para las especies amenazadas fueron considerablemente más altos que aquellos obtenidos para las especies no amenazadas (categoría basada en la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza). De esto derivamos modelos RF de alta certeza (87% y 96%), los cuales pronosticaron que cinco de las 17 especies deficientes de datos estaban amenazadas. Las prácticas de pesca demersal con una captura accesoria elevada y la contaminación fueron los mejores pronosticadores de la categoría de amenaza. Los principales epicentros de amenaza se ubicaron en China, el sureste asiático y en Europa. Nuestros resultados y mapas de CHI pueden ayudar a guiar la conservación mundial de hipocampos y también indican que el modelado y el mapeo de de los impactos humanos pueden revelar los patrones de amenaza y el estado de conservación de las especies deficientes de datos. Descubrimos que para explorar los patrones de amenaza de especies focales, son mejores los modelos de CHI a nivel de especie que los ya existentes modelos de CHI a nivel de ecosistema.

Applying habitat and population-density models to land-cover time series to inform IUCN Red List assessments.

The IUCN (International Union for Conservation of Nature) Red List categories and criteria are the most widely used framework for assessing the relative extinction risk of species. The criteria are based on quantitative thresholds relating to the size, trends, and structure of species' distributions and populations. However, data on these parameters are sparse and uncertain for many species and unavailable for others, potentially leading to their misclassification or classification as data deficient. We devised an approach that combines data on land-cover change, species-specific habitat preferences, population abundance, and dispersal distance to estimate key parameters (extent of occurrence, maximum area of occupancy, population size and trend, and degree of fragmentation) and hence predict IUCN Red List categories for species. We applied our approach to nonpelagic birds and terrestrial mammals globally (∼15,000 species). The predicted categories were fairly consistent with published IUCN Red List assessments, but more optimistic overall. We predicted 4.2% of species (467 birds and 143 mammals) to be more threatened than currently assessed and 20.2% of data deficient species (10 birds and 114 mammals) to be at risk of extinction. Incorporating the habitat fragmentation subcriterion reduced these predictions 1.5-2.3% and 6.4-14.9% (depending on the quantitative definition of fragmentation) for threatened and data deficient species, respectively, highlighting the need for improved guidance for IUCN Red List assessors on the application of this aspect of the IUCN Red List criteria. Our approach complements traditional methods of estimating parameters for IUCN Red List assessments. Furthermore, it readily provides an early-warning system to identify species potentially warranting changes in their extinction-risk category based on periodic updates of land-cover information. Given our method relies on optimistic assumptions about species distribution and abundance, all species predicted to be more at risk than currently evaluated should be prioritized for reassessment.

Aplicación de Modelos de Hábitat y de Densidad Poblacional a Series de Tiempo de la Cobertura del Suelo para Informar las Valoraciones de la Lista Roja de la UICN Resumen Las categorías y los criterios de la Lista Roja de la UICN (Unión Internacional para la Conservación de la Naturaleza) son el marco de referencia utilizado con mayor frecuencia para valorar el riesgo de extinción relativo de las especies. Los criterios se basan en umbrales cuantitativos relacionados con el tamaño, las tendencias y la estructura de la distribución y las poblaciones de las especies. Sin embargo, los datos sobre estos parámetros son escasos e inciertos para muchas especies y para otras no se encuentran disponibles, lo puede resultar en una clasificación errónea o en que se las clasifique como una especie con deficiencia de datos. Hemos diseñado una estrategia que combina datos sobre el cambio en la cobertura del suelo, las preferencias de hábitat específicas por especie, la abundancia poblacional, y la distancia de dispersión para estimar los parámetros más importantes (extensión de la presencia, área máxima de ocupación, tamaño poblacional, y grado y tendencia de la fragmentación) y así predecir las categorías de la Lista Roja de la UICN para cada especie. Hemos aplicado nuestra estrategia a las aves no pelágicas y a los mamíferos terrestres de todo el mundo (∼15,000 especies). Las categorías pronosticadas fueron bastante consecuentes con las valoraciones publicadas por la Lista Roja de la UICN, aunque en general fueron más optimistas. Pronosticamos que el 4.2% de las especies (467 aves y 143 mamíferos) se encuentran más amenazadas que su valoración actual y el 20.2% de las especies con deficiencia de datos (10 aves y 114 mamíferos) se encuentran en riesgo de extinción. La incorporación del sub-criterio de fragmentación del hábitat redujo estas predicciones en un 1.5 - 2.3% y 6.4 - 14.9% (dependiendo de la definición cuantitativa de la fragmentación) para las especies amenazadas y las que tienen deficiencia de datos, respectivamente, lo que resalta la necesidad de mejorar la aplicación de este sub-criterio por parte de los asesores de la Lista Roja de la UICN. Nuestra estrategia complementa los métodos tradicionales de estimación de parámetros para las valoraciones de la Lista Roja. Además, proporciona un sistema inmediato de alerta temprana basado en actualizaciones periódicas de la información sobre la cobertura del suelo que permite identificar a las especies que, potencialmente, merezcan un cambio en su categoría de riesgo de extinción. Nuestro método está basado en suposiciones optimistas sobre la distribución y la abundancia de las especies, por lo tanto todas las especies que predecimos que tienen una mayor categoría de riesgo que la que reconoce la evaluación actual deberían ser priorizadas para su revaloración.

Evaluating the predicted extinction risk of living amphibian species with the fossil record.

Bridging the gap between the fossil record and conservation biology has recently become of great interest. The enormous number of documented extinctions across different taxa can provide insights into the extinction risk of living species. However, few studies have explored this connection. We used generalised boosted modelling to analyse the impact of several traits that are assumed to influence extinction risk on the stratigraphic duration of amphibian species in the fossil record. We used this fossil-calibrated model to predict the extinction risk for living species. We observed a high consensus between our predicted species durations and the current IUCN Red List status of living amphibian species. We also found that today's Data Deficient species are mainly predicted to experience short durations, hinting at their likely high threat status. Our study suggests that the fossil record can be a suitable tool for the evaluation of current taxa-specific Red Listing status.

Identifying conservation priorities for threatened Eastern Himalayan mammals.

To augment mammal conservation in the Eastern Himalayan region, we assessed the resident 255 terrestrial mammal species and identified the 50 most threatened species based on conservation status, endemism, range size, and evolutionary distinctiveness. By using the spatial analysis package letsR and the complementarity core-area method in the conservation planning software Zonation, we assessed the current efficacy of their protection and identified priority conservation areas by comparing protected areas (PAs), land cover, and global ecoregion 2017 maps at a 100 × 100 m spatial scale. The 50 species that were most threatened, geographically restricted, and evolutionarily distinct faced a greater extinction risk than globally nonthreatened and wide-ranging species and species with several close relatives. Small, medium-sized, and data-deficient species faced extinction from inadequate protection in PAs relative to wide-ranging charismatic species. There was a mismatch between current PA distribution and priority areas for conservation of the 50 most endangered species. To protect these species, the skewed regional PA distribution would require expansion. Where possible, new PAs and transboundary reserves in the 35 priority areas we identified should be established. There are adequate remaining natural areas in which to expand current Eastern Himalayan PAs. Consolidation and expansion of PAs in the EH requires strengthening national and regional transboundary collaboration, formulating comprehensive regional land-use plans, diversifying conservation funding, and enhancing information sharing through a consolidated regional database.

Lab protocol for investigating impacts of climate change on frogs.

We developed a method to investigate impacts of temperature (elevated) on breeding, growth and development in endemic frogs under laboratory conditions. The method provides details on housing and rearing of larvae, taking various important measurements and observing developmental deformities. The method could also be applied to rescue approach or head-start program for amphibian species experiencing climate change elsewhere in the world. • Rearing of larvae to investigate effects of temperature on larvae • Measurement of data on growth and development • Rescue/ head-start program.

Parameter regionalization based on machine learning optimizes the estimation of reference evapotranspiration in data deficient area.

Reference evapotranspiration (ET0), as one important variable in climatology, hydrology, and agricultural science, plays an important role in the terrestrial hydrological cycle and agricultural irrigation. However, the ET0 estimation process is inaccurate due to the lack of weather stations and historical data. In this study, a new method of ET0 estimation was proposed to improve the ET0 estimation performance in regions with limited data. Four empirical models with different data requirements, Albrecht, Hargreaves-Samani, Priestley-Taylor, and Penman, were applied and optimized the parameters by the Shuffled Complex Evolution-University of Arizona algorithm with the ET0 calculated by the Penman-Monteith model as the reference value at 600 meteorological stations in China. Two machine learning models, Random Forest (RF) and Multiple Linear Regression (MLR) were used to establish the regionalization of the parameter of the empirical model. The result showed that parameter optimization could significantly improve ET0 estimation in different climate regions of China. The Penman model has the strongest physical foundation and the highest estimation accuracy, followed by the Hargeaves-Samani and Priestley-Taylor model. The mass-transfer-based model, Albrecht, could only estimate regional ET0 efficiently after parameter optimization. Based on the more advanced RF machine learning regionalization method that considers complex linear relationships of variables, ET0 estimation in regions lacking data could be improved efficiently. Machine learning could be used to describe the ET0 model parameters in different regions because of the similarity. The combination of machine learning and empirical model could provide a new method for ET0 estimation in data deficient regions.

Amphibian fauna of Pakistan with notes on future prospects of research and conservation.

Research on amphibians and their conservation have gained worldwide attention, as the group includes the highest number of threatened and Data Deficient species when compared to other vertebrates. However, amphibians have long been neglected in wildlife conservation, management decisions, policy making, and research agendas in Pakistan. In this paper, an annotated checklist of the 21 amphibian species of Pakistan, a key to their identification, and detailed discussions on variation in species, including the genera Minervarya and Sphaerotheca, are provided. We found a statistically significant difference in the morphometric measurements of males but non-significant difference in the females of the two forms (rusty dorsum and dotted dorsum) of S.maskeyi. Some genera, such as Microhyla, Uperodon, Minervarya, Allopaa, Chrysopaa, Euphlyctis, Nanorana, and Sphaerotheca, in Pakistan are in need of additional data for molecular and morphological comparisons with taxa in other South Asian countries. The predicaments of amphibian research in Pakistan are discussed, gaps identified, and suggestions are made. Although the occurrence of chytrid fungus in Pakistan is predicted of low likelihood, a lack of data merits studying the prevalence of the fungus, particularly in the northern regions of the country which exhibit complex and dynamic ecosystems. It is recommended that systematic and coordinated surveys are conducted throughout the country to build a database of species occurrences and distributions. Additionally, the monitoring of wild populations and threat mitigation, as well as appropriate legislation, are suggested as long-term measures. By adopting an inclusive wildlife conservation approach in Pakistan, amphibians could be integrated into wildlife conservation and management efforts.

Selva Zoque, Mexico: an important Mesoamerican tropical region for reptile species diversity and conservation.

The Selva Zoque region is characterized by a great variety of ecosystems for which there is little information about reptile species diversity and their conservation status. This study is the first assessment of the species richness, composition, and conservation status of reptiles of this region. Additionally, this information is compared with that of seven other tropical regions in northern Mesoamerica. In total, 141 native reptile species belonging to 81 genera and 29 families are recorded for the Selva Zoque region. Sixty species (42% of the total) recorded in Selva Zoque are in high-risk categories according to the Mexican Ministry of the Environment, the highest number for the Mexican regions of Mesoamerica. According to the IUCN, six species are in high-risk categories, seven species are in Data Deficient, and 23 (16%) have not been evaluated yet. According to the Environmental Vulnerability Scores approach, 28 species (20%) are in the high vulnerability category. The Selva Zoque species composition is most similar to Los Tuxtlas and Lacandona regions, and most dissimilar to Sian Ka´an Biosphere Reserve. The reptilian fauna of Selva Zoque has a distinctive composition, with the highest number (11 species) of endemic reptiles in the northern Mesoamerican, and species from two biogeographic provinces: the Gulf of Mexico and the Mexican Pacific Coast. These results indicate that the Selva Zoque is the most diverse region in native reptile species in northern Mesoamerica, highlighting it as extremely important for the conservation of the reptile fauna at local (southern Mexico) and regional levels (northern Mesoamerica).

Understanding Nutrition and Metabolism of Threatened, Data-Poor Rheophilic Fishes in Context of Riverine Stocking Success- Barbel as a Model for Major European Drainages?

Large-bodied, river-migrating, rheophilic fishes (cyprinids) such as barbel Barbus barbus, nase Chondrostoma nasus, asp Leuciscus aspius, and vimba bream Vimba vimba are threatened in major European drainages. This represents the subject of our present study. Their hatchery nutrition prior to river-release is mostly on a hit-and-trial or carp-based diet basis. The study demonstrates an alternative approach to decide optimum nutrition for these conservation-priority and nutritionally data-poor fishes. The study revealed barbel as a central representative species in terms of wild body composition among other native rheophilic cyprinids considered (asp, nase, vimba bream). Taking barbel as a model, the study shows that barbel or rheophilic cyprinids may have carnivorous-like metabolism and higher requirements of S-containing, aromatic, branched-chain amino acids (AAs) than carps. Besides, there are important interactions of AAs and fatty acids (FAs) biosynthesis to consider. Only proper feeding of nutritionally well-selected diets may contribute to river stocking mandates such as steepest growth trajectory (≈less time in captivity), ideal size-at-release, body fitness (≈blend-in with wild conspecifics, predator refuge), better gastrointestinal condition, maximized body reserves of functional nutrients, and retention efficiencies (≈uncompromised physiology). Considering important physiological functions and how AA-FA interactions shape them, hatchery-raised fishes on casually chosen diets may have high chances of physiological, morphological, and behavioral deficits (≈low post-stocking survivability). Based on the observations, optimum nutrient requirements of juvenile (0+ to 1+ age) barbels are suggested. Future efforts may consider barbels as a nutrition model for conservation aquaculture of threatened and data poor rheophilic cyprinids of the region.

Phylogenetic and Trait-Based Prediction of Extinction Risk for Data-Deficient Amphibians.

Amphibians are among the most highly threatened lineages, with at least 2,000 species estimated to be in danger of extinction [1, 2]. Alarmingly, another ∼2,200 species (∼25% of all ∼7,900 known species) are data deficient or not evaluated (hereinafter termed data deficient) by the International Union for Conservation of Nature (IUCN) [1]. Without an estimate of their status, data-deficient species are usually overlooked in conservation planning and resource allocation [3]. Amphibians have the highest proportion of data-deficient species of any vertebrate group [1, 4], which highlights the need to estimate their threat status considering potentially imminent extinctions. We apply a trait-based spatio-phylogenetic statistical framework [5] to predict threat status for data-deficient species. Because ecological, geographical, and evolutionary attributes increase extinction risk [6, 7], we used geographic distribution data [1, 8], phylogenetically imputed ecological traits, and an amphibian phylogeny [9] to provide initial baseline predictions. We estimate that half of the ∼2,200 data-deficient species are threatened with extinction (vulnerable, endangered, or critically endangered), primarily in the Neotropics and Southeast Asia. This increases the number of amphibian species estimated to be threatened with extinction by ∼50%. Of these, we predict that ∼500 species are endangered or critically endangered, and three may be extinct already. We highlight families that are most at risk and suggest where urgent conservation is needed to avert their loss. We show that some of the most vulnerable species may also be the most poorly known and offer an analytical framework for preliminary analysis of their threat status in the face of deficient empirical data.

Science responses to IUCN Red Listing.

The IUCN Red List of Threatened Species is often advocated as a tool to assist decision-making in conservation investment and research focus. It is frequently suggested that research efforts should prioritize species in higher threat categories and those that are Data Deficient (DD). We assessed the linkage between IUCN listing and research effort in DD and Critically Endangered (CR) species, two groups generally advocated as research priorities. The analysis of the change in the research output following species classification indicated a listing effect in DD species, while such effect was observed in only a minority of CR species groups. DD species, while chronically understudied, seem to be recognized as research priorities, while research effort for endangered species appears to be driven by various factors other than the IUCN listing. Optimized conservation research focus would require international science planning efforts, harmonized through international mechanisms and promoted by financial and other incentives.

Factors driving the global decline of cycad diversity.

Mounting evidence indicates that we are witnessing the sixth mass extinction period. Given the important goods and services biodiversity delivers to humans, there is a need for a continued commitment to investigate what pre-disposes some taxa to greater risk of extinction. Here, we investigate this question using a phylogenetic comparative method and fitting a cumulative link mixed effect model on biological, ecological and evolutionary data of cycads, the most threatened lineage in the plant kingdom. We identified nine groups of threats to cycads, with habitat loss, over-collection, fire and reproduction failure being the most prominent, but only four of these threats (habitat loss, over-collection, medicinal uses and reproduction failure) clustered on the cycad tree of life. This clustering suggests that closely related species may be exposed to similar threats, perhaps because of geographic regionalization of cycad genera. Nonetheless, the diversity of threats and several variables linked to the biology and ecology of cycads correlate with extinction risk (e.g. altitude, height, diameter, geographic range), and different variables seem to be linked to different IUCN status of cycads. Although their predictive power is generally < 50 %, geographic range and maximum diameter stood out as the best predictors particularly for the Vulnerable (VU) category, with a predictive power of 87 % and 69 %, respectively. Using our best model for VU, we predicted all five Data Deficient (DD) species of cycads to be in the VU category. Collectively, our results elucidate the pattern of extinction risk in cycads and, since most threats that we identified as drivers of extinction risk of cycads are anthropogenically mediated, we recommend stronger legislation to regulate human-cycad interactions and the commitment of all governments globally to implement this regulation.