The European hare Lepus europaeus is an exotic mammal with a wide distribution potential, suggesting the presence of highly flexible anti-predation mechanisms. Through the use of camera traps, the ...activity pattern of this species was studied for two years at a site of the coastal foothills in southern Chile. During the second year it was observed that the hare maintained a non-random pattern of activity in relation to the light periods of the day. This fact suggests the adoption of anti-predator strategies, considering the variation in the presence of their predators between both years. The effect of predation on the observed temporal patterns is discussed, as well as its population fluctuations in the long term, to describe the role of this lagomorph in this type of ecosystem.
Understanding the scope of local adaptation is critical to the definition of restoration strategies as it may affect individuals used as breeders or transplants. The assessment of such risks is, ...however, challenging for large seaweeds such as kelps, because their experimental manipulation is difficult in marine coastal environments. We investigated the consequences of local adaptation on reproductive traits of gametophytes, and growth and survival of sporophytes of the giant kelp,
Macrocystis pyrifera
. Over a thousand juvenile sporophytes were obtained from controlled crosses using 2 to 3 parental sporophytes from each of 18 populations from 5 different regions (i.e. Magellanes. Southern Chile, Atacama, Peru and California), to assess fertility and fecundity of female gametophytes when exposed to males of different habitats, and to produce juvenile sporophytes that were used to test for local adaptation sensu stricto in common garden experiments. By comparing sympatric and allopatric combinations of source populations and the average temperature of the sampled regions, we detected a significant pattern of local adaptation. We quantified the risks associated with different combinations of population/habitat for the performance of juvenile sporophytes typically used as transplants in kelp restoration actions. We found evidence of reduced reproductive success associated with outbreeding for high latitude populations, while low latitude populations favored hybrid crosses, suggesting a shift between outbreeding depression and hybrid vigor across different habitats (i.e., temperature). We also showed that a heatwave equally increased mortality of sporophytes across all regions except for Peruvian inbred crosses, suggesting these low latitude populations hold key genetic resources for future actions under ocean warming. Altogether, these experiments provide a framework for assessing risks associated with the choice of source populations in any kelp species.
Inbreeding, the mating between genetically related individuals, often results in reduced survival and fecundity of offspring, relative to outcrossing. Yet, high inbreeding rates are commonly observed ...in seaweeds, suggesting compensatory reproductive traits may affect the costs and benefits of the mating system. We experimentally manipulated inbreeding levels in controlled crossing experiments, using gametophytes from 19 populations of Macrocystis pyrifera along its Eastern Pacific coastal distribution (EPC). The objective was to investigate the effects of male–female kinship on female fecundity and fertility, to estimate inbreeding depression in the F1 progeny, and to assess the variability of these effects among different regions and habitats of the EPC. Results revealed that the presence and kinship of males had a significant effect on fecundity and fertility of female gametophytes. Females left alone or in the presence of sibling males express the highest gametophyte size, number, and size of oogonia, suggesting they were able to sense the presence and the identity of their mates before gamete contact. The opposite trend was observed for the production of embryos per female gametes, indicating higher costs of selfing and parthenogenesis than outcrossing on fertility. However, the increased fecundity compensated for the reduced fertility, leading to a stable overall reproductive output. Inbreeding also affected morphological traits of juvenile sporophytes, but not their heatwave tolerance. The male–female kinship effect was stronger in high‐latitude populations, suggesting that females from low‐latitude marginal populations might have evolved to mate with any male gamete to guarantee reproductive success.
Profilicollis rancoensis
n. sp. is the tenth species of
Profilicollis
Meyer, 1931 which includes 9 other species mostly known from marine decapod crabs and shore birds. Cystacanths of
P. rancoensis
...are described from the dominant freshwater crab
Aegla abtao
in Ranco Lake, Chile and are morphologically distinguished from cystacanths of the 9 other species based on a combination of 4 characters. These are body size, number of proboscis hook rows, number of hooks per row, and length of the largest anterior 2–4 hooks. Male and female cystacanths of
P. rancoensis
are 2.10–3.33 mm long having an ovoid proboscis with 14 rows of 6–7 hooks per row, with the largest anterior 2–4 hooks being 105–110 micrometers long; the anterior trunk has many small spines in 70–80 concentric rings, each with 50–60 spines around them; hook roots are simple, directed posteriorly, about as long as the blades anteriorly with unremarkable anterior manubria; the cephalic ganglion are in mid-receptacle just anterior to the level of the anterior trunk; the lemnisci are long and slender; the testes are in the anterior trunk, posterior trunk, or one in each; the primordia of 2 tubular cement glands are evident; strong bundles of fibers link the anterior and posterior trunk; and the posterior trunk has a corrugated surface cuticula. Molecular analysis (COI and 18S) sequences coincided with the morphology and support its taxonomy. The phylogenetic profile revealed that
P. rancoensis
n. sp. fell into the
Profilicollis
clade. Both sequences showed low genetic variation, and three different haplotypes were found. The new species was more closely related to
P. botulus
(Van Cleave, 1916) Witenberg, 1932 than to other
Profilicollis
species.
Profilicollis rancoensis
n. sp. est la dixième espèce de
Profilicollis
Meyer, 1931 qui comprend neuf autres espèces principalement connues de crabes décapodes marins et d’oiseaux de rivage. Les cystacanthes de
P. rancoensis
sont décrits chez le crabe d’eau douce dominant
Aegla abtao
dans le lac Ranco, au Chili et se distinguent morphologiquement des cystacanthes des neuf autres espèces sur la base d’une combinaison de quatre caractères. Il s’agit de la taille du corps, du nombre de rangées de crochets du proboscis, du nombre de crochets par rangée et de la longueur des 2 à 4 crochets antérieurs les plus grands. Les cystacanthes mâles et femelles de
P. rancoensis
mesurent de 2,10 à 3,33 mm de long et ont une trompe ovoïde avec 14 rangées de 6 à 7 crochets par rangée, les 2 à 4 crochets antérieurs les plus grands mesurant 105 à 110 micromètres de long ; le tronc antérieur a de nombreuses petites épines en 70-80 anneaux concentriques chacun avec 50-60 épines ; les racines des crochets sont simples, dirigées vers l’arrière, à peu près aussi longues que les lames vers l’avant avec une manubrie antérieure sans particularité ; les ganglions céphaliques sont au milieu du réceptacle juste en avant du niveau du tronc antérieur ; les lemnisques sont longs et minces ; les testicules sont dans le tronc antérieur, le tronc postérieur ou un dans chacun ; les ébauches des 2 glandes cémentaires tubulaires sont évidentes ; de solides faisceaux de fibres relient le tronc antérieur et postérieur ; le tronc postérieur a une cuticule à surface ondulée. Les séquences d’analyse moléculaire (COI et 18S) coïncidaient avec la morphologie et confirmaient sa taxonomie. Le profil phylogénétique a révélé que
P. rancoensis
n. sp. appartient au clade
Profilicollis
. Les deux séquences ont montré une faible variation génétique et trois haplotypes différents ont été trouvés. La nouvelle espèce était plus proche de
P. botulus
(Van Cleave, 1916) Witenberg, 1932 que des autres espèces de
Profilicollis
.
Predation is one of the most important interactions in biology, playing a fundamental role in the ecology of populations and communities. In southern Chile, the mussel Mytilus chilensis supports a ...large aquaculture industry. This species cohabits with one of its predators, the crab Acanthocyclus albatrossis, both in wild bivalve beds and in suspended culture systems. In this investigation, we assessed the predator-prey interaction between these two species, addressing the following aspects: a) the vulnerability pattern of M. chilensis to predation by A. albatrossis; b) prey sizes that are free of predation (the refuge in size); c) the attack rate and d) the effects of temperature and salinity on predation by different-sized A. albatrossis crabs. The prey sizes most likely to be attacked were 7.5, 12 and 14 mm (valve length) respectively for the three predator size categories evaluated. The sizes of the mussels that are free of predation were > 12, > 18 and > 22 mm respectively for each predator size. The mean attack rate was affected by the size of M. chilensis, with the smallest prey (6–12 mm) exposed the highest predation pressure. Temperature exhibited a positive linear effect on the median attack rate only for crabs in the smallest size category; no pattern was observed for the effect of temperature on the other sizes of crabs. Salinity showed no evident effects on the median attack rate at any size category. Our results indicate that A. albatrossis could be an important predator of M. chilensis recruits in wild bivalve beds, and of seeds in suspended culture systems.
•The vulnerability of mussel seeds depends on the size of the crab and of the prey.•Larger predators reduced the size refuge by consuming larger seeds.•The smallest seed were the most attacked.•The mean attack rate of the smallest crabs increases with increased temperature.•Salinity showed no evident effects on the mean attack rate of crabs of any size.
Patagonian aquatic environments have been invaded since the end of the last century by different species of salmonids. Knowing the natal origin and homing/straying rate of the salmonids in colonised ...environments is essential to understanding the dispersal mechanisms and developing management plans. In the last two decades, Chinook salmon Oncorhynchus tshawytscha showed the greatest natural dispersal capacity in Patagonia. The main goal of this study was to evaluate the environmental strontium isotope ratio (87Sr/86Sr) as a potential natural tag to infer the natal origin and ontogenetic habitat use of salmonids in Patagonia, specifically Chinook salmon. 87Sr/86Sr ratio was determined in water samples from 26 sites distributed in 14 Atlantic and Pacific basins in low and high water seasons. Environmental 87Sr/86Sr showed greater spatial than temporal variation, revealing great potential as a tool to infer the natal origin and life history of several migratory fish species in Patagonia. Otolith core-to-edge 87Sr/86Sr profiles were also analysed in 108 Chinook salmon from six basins. A cluster analysis based on the Unweighted Pair Group method (UPGMA) and Euclidean distances without prior classification grouped the sampled rivers into five main groups with significantly different (p < 0.05) isotopic ratios, sometimes integrated basins with different slopes (Atlantic or Pacific). The cluster analysis based on the natal 87Sr/86Sr period in otolith (∼natal origin) showed clear segregation between the Atlantic and Pacific samples. A mismatch between water and otolith natal 87Sr/86Sr ratio was detected in some Atlantic basins (e.g. De las Vueltas River in Santa Cruz Basin) and Pacific (e.g. Liquiñe Basin) and, which could be explained either by straying behaviours or by large geochemical variability between tributaries, within river systems. Our results showed that 87Sr/86Sr is a useful natural tag to trace the life history of migratory fishes in Patagonia, especially for invasive species such as Chinook salmon.
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•Water 87Sr/86Sr was assessed as a natural tag to infer the natal origin of fishes.•87Sr/86Sr ratio was measured in water and Chinook salmon otolith core-to-edge.•87Sr/86Sr is a useful geomarker to study the life history of an invasive fish.•Chinook salmon presents very contrasting migratory strategies in Patagonia.•Natal origin of the fish revealed high segregation between the Pacific and Atlantic.
The upwelling ecosystem of central southern Chile sustains the pelagic common sardine and anchovy fisheries, which are managed by setting a global quota allocated to small-scale (artisanal) and ...industrial fishers. A prearranged spatial allocation of quotas for small-scale fishers is based on historical landings rather than the current spatial distribution of the target species. Artisanal fishers can only fish in their original Spatial Administrative Units (SAUs) according to fishing rights. Marked environmental variability, such as that caused by ENSO events, trigger changes in the local availability of resources. Thereafter, artisanal and industrial fishers compensate for low yields by transferring their fishing quota to quota holders (artisanal-artisanal, industrial-artisanal, artisanal-industrial) from other SAUs. The legal procedure for transferring quotas among users is efficient to harvest the total allowable catch. This procedure favors the quota holders but is detrimental to the crew of vessels that transfer quotas to other fishers. A mechanism is recommended to distribute the profits obtained by quota transfers between ship owners and crews to avoid this negative effect.
Three management units (MUs) are used for stock assessment and fishery regulations of anchoveta Engraulis ringens in Chilean waters (>65% of E. ringens latitudinal range): MU‐I 18–25)°S, MU‐II ...25–32)°S and MU‐III 32–42)°S. To evaluate whether these three MUs correspond to separate demographic units (DUs), as well as to estimate mixing rates and spatial distribution of these DUs, we combined three types of otolith natural markers: isotopic signatures (δ13C and δ18O), elemental compositions (Na, Mg, Mn, Sr and Ba) and microstructural indexes. All otolith markers were determined in nuclear and marginal regions of juveniles and adults from cohorts 2012 and 2015. Differences in core region markers indicated spatial segregation between three environmentally distinct nursery areas, probably related to Subtropical Water (MU‐I), Subantarctic Water (MU‐III) and the Subtropical Convergence (MU‐II). Comparison of core and marginal regions, from juvenile and/or adult fish, suggested that adult fish remained nearby nursery areas, separated from fish nursed in other MUs. Nonetheless, ontogenetic migrations from warmer (offshore) nursery habitats to cooler (deeper/more coastal) feeding habitats occurred within MUs. In summary, our results support the consideration of the three MUs as three separate DUs. Estimated mixing rates indicated MU‐II received contributions of 31% from MU‐I and 3% from MU‐III, while complete segregation existed between MU‐I and MU‐III. Such mixing rates between MU‐I and MU‐III seem large enough to justify its further consideration by stock assessment models and management procedures.
For aquatic breathers, hypoxia and warming can act synergistically causing a mismatch between oxygen supply (reduced by hypoxia) and oxygen demand (increased by warming). The vulnerability of these ...species to such interactive effects may differ during ontogeny due to differing gas exchange systems. This study examines respiratory responses to temperature and hypoxia across four life-stages of the intertidal porcelain crab
Petrolisthes laevigatus
. Eggs, megalopae, juveniles and adults were exposed to combinations of temperatures from 6 to 18 °C and oxygen tensions from 2 to 21 kPa. Metabolic rates differed strongly across life-stages which could be partly attributed to differences in body mass. However, eggs exhibited significantly lower metabolic rates than predicted for their body mass. For the other three stages, metabolic rates scaled with a mass exponent of 0.89. Mass scaling exponents were similar across all temperatures, but were significantly influenced by oxygen tension (the highest at 9 and 14 kPa, and the lowest at 2 kPa). Respiratory responses across gradients of oxygen tension were used to calculate the response to hypoxia, whereby eggs, megalopae and juveniles responded as oxyconformers and adults as oxyregulators. The thermal sensitivity of the metabolic rates (
Q
10
) were dependent on the oxygen tension in megalopae, and also on the interaction between oxygen tension and temperature intervals in adults. Our results thus provide evidence on how the oxygen tension can modulate the mass dependence of metabolic rates and demonstrate changes in respiratory control from eggs to adults. In light of our results indicating that adults show a good capacity for maintaining metabolism independent of oxygen tension, our study highlights the importance of assessing responses to multiple stressors across different life-stages to determine how vulnerability to warming and hypoxia changes during development.
La anemia de células falciformes es una enfermedad genética frecuente en la que la herencia de dos genes mutantes de la hemoglobina, uno de cada progenitor, produce un trastorno de la hemoglobina. Es ...una enfermedad crónica con exacerbaciones agudas que causan efectos a largo plazo en la educación, la vida familiar, la integración social y la calidad de vida del paciente. La clínica se resume en vaso oclusión e isquemia tisular, anemia hemolítica y la susceptibilidad a infecciones. Se presenta el caso de un hombre de raza negra, de 28 años cursando con crisis dolorosa vaso-oclusiva, trastorno hemolítico y síndrome anémico de volúmenes normales.
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