Morphometric analysis of Chilean blue whales and implications for their taxonomy

In the Southern Hemisphere, blue whales are currently divided into two subspecies, Antarctic blue whales (Balaenoptera musculus intermedia) and pygmy blue whales (B. m. brevicauda), but there is some debate about whether Chilean blue whales should also be considered as a separate subspecies. Here, we provide novel morphometric data to directly address this taxonomic question from a biological survey of 60 blue whales taken during the 1965/1966 Chilean whaling season. The data show that maximum body length and mean body length of both sexually mature females and males for Chilean blue whales are intermediate between pygmy and Antarctic blue whales; and that fluke-anus lengths of Chilean blue whales are significantly different from pygmy blue whales, but not necessarily from Antarctic blue whales. There is also some support from the data that snout-eye measurements are different among all three groups. These data provide further confirmation that Chilean blue whales are a distinct population requiring separate management from other blue whale populations, and are also consistent with suggestions that Chilean blue whales are not the same subspecies as pygmy blue whales.     

A hitherto unknown hybridization between Chilean and South Polar skua

 Three skua specimens with a colouration pattern of the Chilean skua were observed at Potter Peninsula, King George Island, Antarctica. Two of these were breeding birds. However, they showed a pattern of mitochondrial DNA typical for South Polar skua. These birds thus represent hybrids originating from male Chilean skua. The third bird could not be caught. It appeared to be indistinguishable from Chilean skua. Received: 9 October 1995/Accepted: 17 March 1996     

Evaluating the genetic structure of wild and commercial red cusk-eel (Genypterus chilensis) populations through the development of novel microsatellite markers from a reference transcriptome

Molecular Biology Reports - The red cusk-eel (Genypterus chilensis) is a native Chilean species with a high-value market, with the potential to diversify Chilean aquaculture. The objective of this...     

Biogeographical patterns and Rapoport's rule in southeastern Pacific benthic polychaetes of the Chilean coast

Recently three biogeographical units were identified along the Chilean coast (the Magellanic Province, an Intermediate Area, and the Peruvian Province), however few studies have focused on the factors and dynamic processes that formed these spatial units (e.g. Rapoport's rule and its causal mechanisms). In this study we used benthic polychaetes of the Chilean coast to evaluate patterns of latitudinal distribution and species richness, and the existence of the three main biogeographical provinces described for the Chilean coast. Additionally, we evaluated the latitudinal Rapoport effects and geometric constraint as a null hypothesis explaining the species richness distribution.
We found that benthic polychaete diversity increased towards southern latitudes. The cluster and ordination (non-metric MultiDimensional Scaling, nMDS) analyses of the distribution data, presented only two statistically significant (bootstrapping techniques) biogeographic provinces along the Chilean coast, with a break occurring between 41° and 42°S. While, our results did not support a latitudinal Rapoport effect, they did support the view that latitudinal Rapoport effects are a local phenomenon, occurring only for the Northeastern Pacific marine taxa. The relationship between latitudinal range extent and mean latitude indicated the existence of two hard boundaries at either extreme of the Chilean coast, limiting the geographical ranges of the species. However, geometric constraints tested using a Monte Carlo simulation approach showed a weak level of mid-domain effect on species richness. Finally, we propose that geometric constraint together with the geomorphology and historical characteristics of the Chilean coast explain the biogeographical patterns of benthic polychaete taxa in Chile.     

Is the Chilean diet a Mediterranean-type diet?

Food intake in Chile has changed markedly in the last decades, showing an increase in fat consumption and presently a small fruit and vegetables intake. A parallel is made between the Chilean and Mediterranean diet (mainly the one from Spain, Italy, and Greece), both currently and from 50 years ago. The main differences and similarities are based on food availability. Although Chilean diet seems to be approaching the traditional Mediterranean diet of the 60's, there is concern about changes that are moving away from Chilean traditional diet and towards a western one. A new food pyramid for Chile is proposed based on the traditional Mediterranean-type diet.     

A epistemometric view of some biological disciplines in Chile

During the last decade the articles published by Chilean Research Centers grew 1,73 which compares to the 2.34 fold increase of mainstream research articles registered as a whole in Latin America. However, the relative impact of the Chilean publications surpassed that of Latin America. In Biological Sciences, traditionally the strongest research area within Chile, Latin America also shows a steeper slope of growth. Qualitatively, biological disciplines in Chile are comparable to those published in Latin America although in Chile there are specialties as Physiology that surpass the average world's impact. The scientometric data is consistent with the fall in individual grants that the Chilean Research Fund (FONDECYT) has been allocating during the last decade.     

On sociogenetic clines

Both in England and Chile the A blood group is found more frequently in the higher socioeconomic strata. The O group behaves inversely. This seems to be true, at least, for blood donors in England and for the general population in Chile. This sociogenetic cline interacts with sex, being less evident in women. In Chile the Rh system shows a cline with a higher frequency of the Rh(-) or d allele in higher socioeconomic strata. The Chilean population originated from the admixture of Europeans (mostly Spaniards) and Chilean aborigines (since 1541). Spaniards had high frequencies of the A and d alleles and an appreciable frequency of the B alleles. Chilean aborigines had very low frequencies or totally lacked these alleles. Spaniards maintained the higher socioeconomic strata and manual labor was performed by mestizos or aborigines. Thus the Chilean sociogenetic cline was explained by ethnic admixture, socioeconomic discrimination, and socioeconomic assortative mating. The present results show that the exclusive historical and cultural explanation of the cline is not sufficient and a genetic factor should be added to the former ones. The distribution of the ABO groups in England and Chile were found to be similar only in stratum I, the other strata being strikingly different. The AB and B groups did not reflect the cline in either population. The Chilean stratum I showed higher d and lower O gene frequencies than present Spaniards populations, a result that cannot be explained by cultural factors. The distribution of ABO groups in a sample of Chilean medical students and in children from public schools showed a strong interaction with sex. No genetic mechanism can be proposed to fit these results, however psychological heterosis seems a good approximation.     

Gender determination by body weight and linear measurements in American and Chilean flamingos,previously surgically sexed: Within-sex comparison to greater flamingo measurements

Gender was determined by laparoscopic visualization of the gonads for 38 adult American flamingos (Phoenicopterus ruber ruber L.) and 36 adult Chilean flamingos (P. chilensis L.). Concomitant body weight (kg) and linear measurements (mm) of the culmen (bill), tarsus (tarsometatarsus), middle toe, and wing were taken. Statistical comparisons of body weight and linear measurements for male vs. female were made for each species. Also, the same-sex statistical comparisons were made between these two species, and between each of these two species and with data for greater flamingos (P. r. roseas L.) from a previous publication. As previously published for greater flamingos, an overlap between sexes existed in all measurements with males on average larger than females for both American and Chilean flamingos. However, Students' t-test indicated a significant sexual difference for all measurements between males and females of each species except for culmen length in Chilean flamingos. Students' t-test also indicated a significant difference when species were compared (Chilean vs. greater, and American vs. Chilean) and subspecies (American vs. greater) were compared for most of the 5 measurements. Thus, despite limitations imposed by between-sex overlap, weights and linear measurements, especially tarsus, middle toe, and wing length, appear to be useful in determining an individual's gender when species or subspecies identification is considered.     

Waist circumference percentiles in children and adolescents between 6 and 14 years from Santiago,Chile

ObjectiveTo describe the percentile distribution of waist circumference (WC) by sex and age in a representative sample of children and adolescents of lower-middle and low socioeconomic status in Santiago, Chile.MethodsA cross-section of 3022 primary-school students between the ages of 6 and 14 from middle-low and low-class schools of Santiago. Ten schools from the Primary Education Society (SIP) in Santiago, Chile, were selected at random. WC was measured under standardized procedures as instructed by the WHO (midpoint between lower costal margin and iliac crest). The population was categorized between percentiles 10 and 90 and divided by sex and age.ResultsWC tends to increase with age in both males and females, but no significant differences were found in the percentiles by age for boys and girls at any age range (p > 0.05). In our sample, comparing Chilean children with other populations (British, Australian, European-American, African-American, Mexican – American and Colombian), Chilean children have shown a significantly greater WC (p < 0.05).ConclusionsWe present new WC reference values for Chilean children according to sex and age from a representative sample of Chilean population. These can be considered as a new anthropometric assessment tool for estimating cardiometabolic risk in Chilean children.     

An improved technique for sampling lotic invertebrates

The electrophoretic characterization of an Artemia population from a saline lake of the Chilean Andes with unusual ecological features (Salar de Atacama, 23° 30′ S; 68° 10′ W) was carried out with the aim of comparing its genetic variation with, and genetic similarity to, representative populations of A. persimilis (Buenos Aires, Argentina) and A. franciscana (San Francisco Bay, USA). Based on the analysis of 22 loci it is concluded that the Chilean population and that from San Francisco are conspecific (D = 0.144), while the Chilean strain and A. persimilis are congeneric species (D = 1.171), differing in more than 40% of the loci. Parameters measuring genetic variation (e.g., percentage of loci polymorphic, mean number of alleles per locus, mean heterozygosity per locus) demonstrate that values for the Chilean Artemia (50.0, 1.68, 0.126, respectively) are within the range for bisexual Artemia in general and A. franciscana in particular.     

Nuclear and chloroplast DNA reassessment of the origin of Indian potato varieties and its implications for the origin of the early European potato

The modern cultivated potato was first recorded in Europe in 1562, but its area(s) of exportation has long been in dispute. Two competing hypotheses have proposed an Andean area (somewhere from upland Venezuela to northern Argentina) or a lowland south central Chilean area. Potato landraces from these two areas can be distinguished, although sometimes with difficulty, by (1) cytoplasmic sterility factors, (2) morphological traits, (3) daylength adaptation, (4) microsatellite markers, and (5) co-evolved chloroplast (cp) and mitochondria (mt) DNA. The Chilean introduction hypothesis originally was proposed because of similarities among Chilean landraces and modern European cultivars with respect to traits 2 and 3. Alternatively, the Andean introduction hypothesis suggests that (1) traits 2 and 3 of European potato evolved rapidly, in parallel, from Andean landraces to a Chilean type through selection following import to Europe, and (2) the worldwide late blight epidemics beginning in 1845 in the United Kingdom displaced most existing European cultivars and the potato was subsequently improved by importations of Chilean landraces. We reassess these two competing hypotheses with nuclear microsatellite and cpDNA analyses of (1) 32 Indian cultivars, some of which are thought to preserve putatively remnant populations of Andean landraces, (2) 12 Andean landraces, and (3) five Chilean landraces. Our microsatellite results cluster all Indian cultivars, including putatively remnant Andean landrace populations, with the Chilean landraces, and none with the old Andigenum landraces. Some of these Indian landraces, however, lack the cpDNA typical of Chilean landraces and advanced cultivars, indicating they likely are hybrids of Andean landraces with Chilean clones or more advanced cultivars. These results lead us to reexamine the hypothesis that early introductions of potato to Europe were solely from the Andes.     

Invaders Without Frontiers: Cross-border Invasions of Exotic Mammals

We address cross-border mammal invasions between Chilean and Argentine Patagonia, providing a detailed history of the introductions, subsequent spread (and spread rate when documented), and current limits of mammal invasions. The eight species involved are the following: European hare (Lepus europaeus), European rabbit (Oryctolagus cuniculus), wild boar (Sus scrofa), and red deer (Cervus elaphus) were all introduced from Europe (Austria, France, Germany, and Spain) to either or both Chilean and Argentine Patagonia. American beaver (Castor canadensis) and muskrat (Ondatra zibethicus) were introduced from Canada to Argentine Tierra del Fuego Island (shared with Chile). The American mink (Mustela vison) apparently was brought from the United States of America to both Chilean and Argentine Patagonia, independently. The native grey fox (Pseudalopex griseus) was introduced from Chilean to Argentine Tierra del Fuego. Few spread rates are available: the lowest are 10 km/yr and correspond to American beaver and American mink; intermediate rates are observed in muskrat and rather questionably, in grey fox; the highest rates (10–20 km/yr) are found among European hare and European rabbit. Because of their frequent migration, it is difficult to estimate the natural spread rate for wild boar and red deer. Not all mammal invasions in Chilean and Argentine Patagonia have been methodical advances of species; some involve an overlap of invasion fronts, with advances and retreats, and perhaps with re-invasions to different areas of either country. Because national policies with regard to introduced species may differ between countries sharing porous borders, it seems advisable to coordinate such policies in order to prevent the entry of unwelcome invaders.     

Shrub clumps of the Chilean matorral vegetation: structure and possible maintenance mechanisms

Summary Previous studies have claimed that the Chilean matorral is more open than the Califonia chaparral, and have attributed this dissimilarity largely to the role of man in Chile. In this paper we show that in general the Chilean matorral has a structure better described as shrub clumps that merge to form a continuous vegetation matrix only in very mesic habitats, where it is comparable to the Califonia chaparral. We also present evidence that these clumps have been present for at least the last 26 years and that even without human disturbance they are likely to maintain themselves. Evidence for the latter pertains to seed dispersal, seed germination and establishment, seedling survival, and the diameter size structure of shrub clumps. Finally, we propose that differences between the California chaparral and Chilean matorral are more profound than previously thought and are due not only to different degrees of human disturbance, but also to the presence of periodical natural fires in California and not in Chile, and to different shrub recruitment patterns and mammalian herbivore activity in the two areas.     

The effect of temperature and irradiance on the growth and carotenogenic capacity of seven strains of Dunaliella salina (Chlorophyta) cultivated under laboratory conditions

The carotenogenic microalga Dunaliella salina is cultivated as a natural source of beta-carotene. The 9-cis isomer of beta-carotene is found only in natural sources having commercial advantages over the all-trans isomer due to its high liposolubility and antioxidant power. High irradiance appears to stimulate specifically all-trans beta-carotene accumulation in D. salina, whereas low temperature apparently elicits a-carotene and 9-cis betacarotene production. We studied the effect of temperature and irradiance on the growth and the carotenogenesis of three Chilean (CONC-001, CONC-006 and CONC-007) and four non-Chilean (from Mexico, China, Australia and Israel) strains of D. salina cultivated under two photon flux densities (40 and 110 micromol photons x m(-2) x s(-1)) and two temperatures (15 and 26 degrees C). The Chilean strain CONC-001 and all of the non-Chilean strains exhibited the highest growth rates and the maximum cell densities, whereas the Chilean strains CONC-006 and CONC-007 showed the lowest values in both parameters. The Australian strain showed the highest accumulation of total carotenoids per unit volume (40.7 mg x L(-1)), whereas the Chilean strains CONC-006 and CONC-007, the only ones isolated from Andean environments, yielded the highest amounts of carotenoids per cell (61.1 and 92.4 pg x cell(-1), respectively). Temperature was found to be more effective than irradiance in changing the qualitative and quantitative carotenoids composition. The Chilean strains accumulated 3.5-fold more alpha-carotene than the non-Chilean strains when exposed to 15 degrees C and, unlike the non-Chilean strains, also accumulated this pigment at 26 degrees C. The 9-cis/all-trans beta-carotene ratio was > 1.0 in all treatments for all strains, and the values were not greatly influenced by either temperature or photon flux density. Physiological and biotechnological implications of these results are discussed.     

Intraregional variation among Alexandrium catenella (Dinophyceae) strains from southern Chile: Morphological,toxicological and genetic diversity

Morphological, toxicological and phylogenetic analyses, using the partial LSU gene and internal spacer (ITS) regions of the rDNA gene, were combined to evaluate the intraregional diversity of Alexandrium catenella occurring along the southern coast of Chile. Twenty-two strains isolated from different localities along the wide area of distribution of the species (from 42°S to 55°S) were examined by these three approaches. Morphologically, although the strains showed diagnostic characters according to the species definition, variations in these traits within and between strains were also observed. The absence of an apical or posterior attachment pore, for instance, was observed mainly in old isolates. Indirect connection between the apical and 1′ plates, traits normally seen in other species of the same genus, was also noted in some strains. However, the lack of a ventral pore on the 1′ plate was one of the most distinctive characteristics present in all the Chilean strains. Toxicologically, the Chilean strains were characterized by the dominance of N-sulfocarbamate (C1,2) and gonyautoxins (GTX1–4), but also by the scarcity or absence of saxitoxin. Considering the dominance of these toxins in each strain, at least two distinctive toxin patterns were distinguished. Through rDNA sequence analysis, the Chilean strains were segregated as part of Clade I (North American) of the Alexandrium tamarense species complex. Nevertheless, significant genetic diversity was also observed among the Chilean strains, especially using ITS sequences. Through these three approaches, Chilean strains of A. catenella showed significant intraregional variability, which is appropriate for a native species. However, the distribution of its genetic diversity seems to be inconsistent with the apparent northward expansion observed along the west coast of South America.     

Allozyme variability in brown trout Salmo trutta in Chile

1. Brown trout ova were imported during the last century from different locations in Europe to establish populations in Chilean rivers (South America). The rivers are currently occupied by naturalized populations that have adapted to very different environmental conditions, such as areas of semi-desert in the north, or rainy and cold areas in the south.
2. In this first study in this geographical area, electrophoretic variability of proteins encoded by twenty-five loci was screened in seven populations from northern to southern Chile.
3. The results show significant heterogeneity of allelic frequencies between populations in seven of eleven polymorphic loci detected. The estimated value of genetic diversity 0.1274 ( H _T) is higher than that observed in populations from areas of natural distribution of this species. However, only 12.64% of this genetic diversity was found between samples ( G _ST), indicating a low genetic divergence among Chilean populations. The observed associations among the Chilean and 'modern' group of European populations suggests the probable origin of the new populations.     

HLA antigens in cardiomyopathic Chilean chagasics.

The distribution of HLA antigens in a sample of 124 Chagas serologically positive Chilean individuals was studied. The sample was subdivided according to the presence or absence of chagasic cardiomyopathy, in order to search for genetic differences associated with this pathological condition. The frequency of antigen B40 in the presence of antigen Cw3 was found to be significantly lower in subjects with cardiomyopathy. We tentatively suggest that the presence of these antigens among noncardiomyopathics is associated with a decreased susceptibility to develop chagasic cardiomyopathy in the Chilean population.     

Trophic interactions and community structure in the upwelling system off Central Chile (33-39°S)

Trophic interactions and community structure in the upwelling system off Central Chile (USCCh) (33-39°S) are analyzed using biological and ecological data concerning the main trophic groups and the Ecopath with Ecosim software version 5.0 (EwE). The model encompasses the fisheries, cetaceans, sea lion, marine birds, cephalopods, large-sized pelagic fish (sword fish), medium-sized pelagic fish (horse mackerel, hoki), small-sized pelagic fish (anchovy, common sardine), demersal fish (e.g. Chilean hake, black conger-eel), benthic invertebrates (red squat lobster, yellow squat lobster) and other groups such as zooplankton, phytoplankton and detritus. Input data was gathered from published and unpublished reports and our own estimates. Trophic interactions, system indicators and food web attributes are calculated using network analysis routines included in EwE. Results indicate that trophic groups are aligned around four trophic levels (TL) with phytoplankton and detritus at the TL=1, while large-sized pelagic fish and cetaceans are top predators (TL>4.0). The fishery is located at an intermediate to low trophic level (TL=2.97), removing about 15% of the calculated system primary production. The pelagic realm dominates the system, with medium-sized pelagic fish as the main fish component in biomass, while small-sized pelagic fish dominate total landings. Chilean hake is by far the main demersal fish component in both, biomass and yield. Predators consume the greater part of the production of the most important fishery resources, particularly juvenile stages of Chilean hake. Consequently, mortality by predation is an important component of total mortality. However, fishery also removes a large fraction of common sardine, anchovy, horse mackerel, and Chilean hake. The analysis of direct and indirect trophic impacts reveals that Chilean hake is a highly cannibalistic species. Chilean hake is also an important predator on anchovy, common sardine, benthic invertebrates, and demersal fish. The fisheries heavily impact on Chilean hake, common sardine, anchovy, and horse mackerel. Total system biomass (B=476 t km⁻² year⁻¹) and throughput (T=89454 t km⁻² year⁻¹) estimated in the USCCh model are in accordance with models of comparable systems. Considering system attributes derived from network analysis, the USCCh can be characterized as an immature system, with short trophic chains and low trophic transfer efficiency. Finally, we suggest that trophic interactions should be considered in stock assessment and management programs in USCCh. In addition, future research programs should be carried out in order to understand the ecosystem effects of fishing and trophic control in this highly productive food web.     

Pubertal origin of the larger sex dimorphism for adult stature of a Chilean population

Students aged 6 to 20 years attending the public schools in the Northern Area of Santiago, Chile, were examined to search for the developmental origin of the large sex dimorphism in adult stature found in this population. Stature, biacromial diameter, and signs of sexual maturation were studied and comparisons were made with European samples. All of the variables showed that Chilean females reach puberty earlier than, and cease growth before Europeans, while males mature at the same pace as Europeans. It is concluded that the large sex dimorphism in adult stature found in this sample is mainly due to this earlier cessation of growth in Chilean females.