Compositional forecasting of Chinook Salmon Evolutionarily Significant Units in bycatch for Pacific Hake fisheries

Bycatch impacts on non-target species present significant management problems in diverse fisheries throughout the world. Despite successful efforts to minimize bycatch in US West Coast Pacific Hake fisheries, these impacts remain a concern, particularly for sensitive populations of Chinook Salmon. NOAA Fisheries needed predictive models to estimate proportions of Chinook Salmon Evolutionarily Significant Units (ESUs) expected in bycatch. We used genetic mixture analysis to estimate ESU proportions from at-sea bycatch between 2008 and 2015. Using latitude as a predictor and applying jackknife cross validation, we found Dirichlet regression more accurately estimated abundant ESUs, whereas multinomial logistic regression performed better with rare ESUs. This targeted, ESU-specific approach showed the spatial distribution of sensitive stocks in bycatch and supported NOAA's obligations to forecast impacts on listed ESUs. The overarching goal of this continuing work is to maximize sustainable harvest while protecting threatened and endangered Chinook Salmon ESUs.

Phylogenetic placement of a recently discovered population of the threatened alpine she-oak skink Cyclodomorphus praealtus (Squamata: Scincidae) in Victoria

The alpine she-oak skink Cyclodomorphus praealtus is a threatened alpine endemic lizard from the mainland of Australia. The species is previously known from disjunct populations in Kosciuszko National Park in New South Wales and three isolated localities in the Victorian Alps. The New South Wales and Victorian populations represent separate evolutionarily significant units. In 2011, a fourth Victorian population was discovered. We conducted a phylogenetic analysis and determined that the newly discovered population is discrete and may have been separated from other populations since the end of the last glacial maxima. This population requires separate management.

Genetic diversity and structure of one of the most endangered freshwater fish species in Mexico: Tlaloc hildebrandi (Miller, 1950) and recognition of its evolutionarily significant units

The endangered Chiapas killifish Tlaloc hildebrandi is an endemic freshwater species that lives in four subbasins of the Grijalva and Usumacinta basins, and one of the most geographically restricted species of the Produndulidae family. The species was originally described as endemic to springs in the high limestone plateau in San Cristóbal de Las Casas in the Río Amarillo subbasin (upper Grijalva basin). However, it was recently recorded in the Jataté and Tzaconejá subbasins in the upper Usumacinta basin, thereby expanding its known distribution range. The discovery of these populations is relevant not only for the conservation of the species but also for a better understanding of its evolutionary history. Currently, the scarce populations of T. hildebrandi, found in only a few localities in the Grijalva and Usumacinta basins, are fragmented and living under unfavorable conditions. Here, we analyzed three mitochondrial (mt-atp8&6 and mt-nd2) and one nuclear (nuc-s7) marker in order to assess the genetic diversity and population structure of T. hildebrandi. We found that, in comparison with other endangered freshwater fish species from Mexico, T. hildebrandi showed a lower level of genetic diversity (mt-nd2: h = 0.469, π = 0.0009; mt-atp8&6: h = 0.398, π = 0.001; and nuc-S7: h = 0.433, π = 0.001). Moreover, the analyzed populations exhibited a strong genetic structure in accordance with their geographic distribution, and can be placed into three genetic clusters: (1) Amarillo plus Chenhaló in the upper Grijalva basin, (2) Jataté, and (3) Tzaconejá, both in the upper Usumacinta basin. On the basis of our results, we propose the recognition of at least three evolutionarily significant units (ESUs) for the species and the urgent implementation of ex situ and in situ conservation and management efforts that consider the genetic background of the species.

Cabo Verde giant gecko: how many units for conservation?

Tarentola gigas (Bocage, 1875) is the largest gecko living in the Cabo Verde Archipelago. It is subdivided into two subspecies, one confined to the Branco Islet, Tarentola gigas brancoensis (Schleich, 1984), and another to the Raso Islet, Tarentola gigas gigas (Bocage, 1875). These islets were classified as Integral Natural Reserves and further studies on the species are needed to outline more assertive conservation measures. Thus, this study aims to integrate for the first time genetic, morphometric and meristic data to test if there are significant differences between these two taxonomical groups that would support the subspecific designation. The results indicated that they are two closely related subspecies, with some visible differences in size and shape, possibly related to diet, habitat conditions or drift. Given the conservation status of the species, this should be further investigated, aiming an adequate management of these two evolutionarily significant units.

Taxonomy of Horned Lizards, Genus Phrynosoma (Squamata, Phrynosomatidae)

In this article, I revise the taxonomy of the species and subspecies of the genus Phrynosoma through phylogenetic and species delimitation approaches based on four mtDNA markers (ND1, ND2, ND4, and 12S). The resulting taxonomy recognizes 12 species (P. asio, P. bracconieri, P. cornutum, P. coronatum, P. douglasii, P. hernandesi, P. mcallii, P. modestum, P. orbiculare, P. platyrhinos, P. solare, and P. taurus). Several of these species are divided into subspecies as follows: P. coronatum (P. c. coronatum, P. c. blainvillii, P. c. cerroense, and P. c. frontale), P. cornutum (P. c. cornutum and P. c. bufonium), P. hernandesi (P. h. hernandesi, P. h. ditmarsi, and P. h. ornatum), P. orbiculare (P. o. orbiculare, P. o. bradti, P. o. boucardii, P. o. cortezii, P. o. dugesii, and P. o. durangoensis), P. platyrhinos (P. p. platyrhinos and P. p. goodei), P. taurus (P. t. taurus and P. t. sherbrookei). In this coherent and objective approach, those taxa treated here as subspecies have diverged to a much lesser degree than those that are herein recognized as separate species. Typically, those taxa recognized as subspecies are one another’s closest relatives (i.e., they together form a monophyletic group that represents the species) and are distributed allopatrically. In this approach, all separate evolutionarily significant units are recognized as named taxa—either species or subspecies—thereby reflecting the importance of identifying and naming such units for conservation. I provide a checklist of the recognized species and subspecies of Phrynosoma along with synonymies and distribution maps.

Newly discovered cichlid fish biodiversity threatened by hybridization with non-native species

Invasive freshwater fish systems are known to readily hybridize with indigenous congeneric species, driving loss of unique and irreplaceable genetic resources. Here we reveal that newly discovered (2013-2016) evolutionarily significant populations of Korogwe tilapia (Oreochromis korogwe) from southern Tanzania are threatened by hybridization with the larger invasive Nile tilapia (Oreochromis niloticus). We use a combination of morphology, microsatellite allele frequencies and whole genome sequences to show that O. korogwe from southern lakes (Nambawala, Rutamba and Mitupa) are distinct from geographically-disjunct populations in northern Tanzania (Zigi River and Mlingano Dam). We also provide genetic evidence of O. korogwe x niloticus hybrids in three lakes and demonstrate heterogeneity in the extent of admixture across the genome. Finally, using the least admixed genomic regions we estimate that the northern and southern O. korogwe populations most plausibly diverged approximately 140,000 years ago, suggesting that the geographical separation of the northern and southern groups is not a result of a recent translocation, and instead these populations represent independent evolutionarily significant units. We conclude that these newly-discovered and phenotypically unique cichlid populations are already threatened by hybridization with an invasive species, and propose that these irreplaceable genetic resources would benefit from conservation interventions.

Filling a gap in Andean Cat Leopardus jacobita (Cornalia, 1865) (Mammalia: Carnivora: Felidae) distribution range: new record in La Rioja province, Argentina

A pelt of an Andean Cat specimen was discovered in La Rioja Province, Argentina, a region with no previous data recorded, located in a large distribution gap between the two currently identified evolutionarily significant units (ESU). This new record not only improves our knowledge about the species distribution but can also provide relevant genetic information for a better understanding of the relationship between the two ESU.