Movements and spatial distribution of an endangered fish (Sciaena umbra) within a marine protected area.

The brown meagre (Sciaena umbra) is an endangered species, which requires specific protection measures to ensure its conservation. These measures need to be informed by high-quality scientific knowledge on their space use patterns. Here, we used acoustic telemetry to assess its seasonal movement patterns and habitat use within a marine protected area (MPA). Our results suggested that S. umbra is a highly sedentary species (home range < 1.0 km2) and, therefore, the MPA is extensive enough to protect the local population. Their population was discretely distributed in two main areas within the MPA, which was likely a result of habitat segregation and density-dependent movements. The temporal variability of their movements further uncovered when and where spawning occurs (mainly, but probably not only, in the fully protected area in June) and indicated that spillover of this species is limited but still possible. Overall, we highlight the importance of MPAs in the recovery of S. umbra, we advocate the need to perpetuate the current national fishing bans and extend it to other countries in the Mediterranean region, and we emphasize that considering the fine-scale movements of S. umbra in future management actions is key to achieving a successful recovery of their populations.

Intense scuba diving does not alter activity patterns of predatory reef fish: Evidence from a protected tourism hotspot.

The rise of nature-based tourism has provided a new avenue for disturbing animal behaviour, especially in protected areas. One of the most important tourism sectors in aquatic environments is scuba diving, an activity considered sustainable given its non-extractive nature and capability of bringing relevant socio-economic benefits to local communities. However, knowledge about its impact on the activity patterns of aquatic animals is still scarce. Here, we used biotelemetry techniques to assess the importance of scuba diving in modulating the activity patterns of the dusky grouper (Epinephelus marginatus, Lowe, 1834), a marine predatory fish of high interest for fishing and tourism. We implemented Hidden Markov Models (HMMs) on high-resolution acceleration data using a temporal and spatial control while controlling for a set of environmental variables (i.e. photoperiod, time-of-day, moon phase, temperature, wave height, and intensity and direction of marine currents) within a multiple-use marine protected area, and diving tourism hot-spot, of the western Mediterranean Sea. Our results underlined the more decisive influence of environmental-related stressors on the activity patterns of the dusky grouper compared to the impact of scuba diving. A high heterogeneity existed in the response against most of the stressors, including the presence of scuba divers. Overall, the activity of dusky grouper was higher at night than at day, showing a positive relationship with wave height, water temperature, and current intensity and a negative one with the moon phase. Remarkably, our findings, based on novel biotelemetry tools, differed substantially from the common wisdom accepted for this species. In conclusion, there is no clear evidence of scuba divers influence on the general activity patterns of the dusky grouper. Beyond their relevance from an ecological perspective, these results provide useful insights for the sustainable management of coastal resources, suggesting that scuba diving, when properly carried out, can represent an important sector to foster for the blue growth of coastal communities.

Seasonal influence on the bathymetric distribution of an endangered fish within a marine protected area.

The spatio-temporal variability of fish distribution is important to better manage and protect the populations of endangered species. In this sense, the vertical movements of a vulnerable and protected species, Sciaena umbra, were assessed in a marine protected area (the Réserve Naturelle Marine de Cerbère-Banyuls, south of France) to study the variability of their bathymetric distribution at different time scales. Twenty adults were marked with acoustic transmitters and acoustically monitored over 2.5 years. This revealed that some individuals remained at shallow waters (< 8 m) all year round, while others presented vertical segregation at deeper waters during the cold months (mean depth of 22.5 ± 0.04 m) and all aggregated in shallow waters during the warm months. The brown meagre was more active during the night, except in June and July when peaks of activity were observed at dusk. These patterns are likely associated with foraging and reproductive behavior during the cold and warm periods, respectively, and likely regulated by water temperature and the depth of the thermocline. Here, we provide valuable information on when and where in the water column critical periods of S. umbra life cycle are expected to occur, which should be considered in management and protection plans.

Persistent natural acidification drives major distribution shifts in marine benthic ecosystems.

Ocean acidification is receiving increasing attention because of its potential to affect marine ecosystems. Rare CO2 vents offer a unique opportunity to investigate the response of benthic ecosystems to acidification. However, the benthic habitats investigated so far are mainly found at very shallow water (less than or equal to 5 m depth) and therefore are not representative of the broad range of continental shelf habitats. Here, we show that a decrease from pH 8.1 to 7.9 observed in a CO2 vent system at 40 m depth leads to a dramatic shift in highly diverse and structurally complex habitats. Forests of the kelp Laminaria rodriguezii usually found at larger depths (greater than 65 m) replace the otherwise dominant habitats (i.e. coralligenous outcrops and rhodolith beds), which are mainly characterized by calcifying organisms. Only the aragonite-calcifying algae are able to survive in acidified waters, while high-magnesium-calcite organisms are almost completely absent. Although a long-term survey of the venting area would be necessary to fully understand the effects of the variability of pH and other carbonate parameters over the structure and functioning of the investigated mesophotic habitats, our results suggest that in addition of significant changes at species level, moderate ocean acidification may entail major shifts in the distribution and dominance of key benthic ecosystems at regional scale, which could have broad ecological and socio-economic implications.

[Genetic composition of the Chilean population: the Yamanas from Ukika]. / Composición genética de la población chilena: los Yámanas de Ukika.

The genetic composition of a group of 24 Yamana indians that survive in Puerto Williams, Navarino Island, Chile (parallel 55 south of Tierra del Fuego), was studied. Results showed that these indians have a different genetic composition than Pehuenche indians, specially for HLA system and esterase D. This fact validates the hypothesis, based on archeological and anthropological evidence, about the paleoindian origin of Yamanas.

[Genetic composition of Chilean population: the Pehuenches from Trapa-Trapa]. / Composición genética de la población chilena: los Pehuenches de Trapa-Trapa.

This study describes the genetic composition of Pehuenche indians from Trapa-Trapa. The admixture analysis revealed that this group has conserved most of its pre-Columbian gene pool and therefore, is representative of the indians that lived in Southern Chile before the Spanish conquest. A relatively high frequency of a esterase D variant seems to indicate that this is a Chilean aboriginal population marker. The Chilean Pehuenches are genetically similar to their Argentinean relatives, which is not surprising since this last group crossed the Andes Mountains in historic times.

[Paleodemography in mummies of prehispanic populations from Africa]. / Paleodemografía en momias de poblaciones prehispánicas de Arica.

Mummies' demographic information of 10 prehispanic cultures that developed in the Arica region of Chile about 7000 years ago is analyzed and related to the present population structure. A paleoepidemiological analysis supports a relationship between cultural development and demographic structure. In chronological sequence, 4 demographic patterns can be distinguished: 1) archaic, a mature population with the highest life expectancy and the lowest dependence from prehispanic populations; 2) later archaic, a population in demographic explosion with its larger fraction under 15 years of age, elevated fertility rates and the greatest prehispanic dependence; 3) andean, a transition population with moderate fertility rates and dependence index; and 4) modern, an aging population with the highest proportion over 45 years of age and the highest life expectancy. The present demographic analysis may help to understand the relationships among disease, individual and culture from the perspective of genetic epidemiology.

[Prevalence of Streptococcus mutans in pehuenche children, Chilean ethnic group]. / Prevalencia de Streptococci mutans en niños pehuenches, un grupo étnico Chileno.

We studied 26 pehuenche children between 9 and 13 years of age and 12 non-pehuenche controls. Samples were obtained from saliva and from the bacterial plaque of 6 year molars and cultured anaerobically for 48 hr at 37 C in TYCSB medium. S mutans were obtained from 90% of children in both groups, all corresponding to biotype I (Coykendall). Nutritional and hygienic habits did not differ between groups. These results confirm the ample distribution of S mutants in Chilean subjects.