Approximately 32 species of marine mammals of the Gulf of California (GC) share habitat and resources in this ecosystem. Unusually high δ 15 N values at the base of the food web in the GC permeate up all trophic levels, distinguishing the isotopic signature of the GC from other ecosystems in the Eastern North Pacific. Values of δ 13 C and δ 15 N were acquired from particulate organic matter (POM) of surface sediment, zooplankton, mollusks, crustaceans, fish, and marine mammals in the GC to construct a general trophic structure and were complemented with additional isotope data from the literature. Aims were to: estimate marine mammal trophic levels and habitat preferences; distinguish between GC residents and visitors; and assess potential trophic overlap among the most common and abundant cetacean species. Trophic level 1 (TL1), represented by POM, showed average (± SD) δ 13 C and δ 15 N values of −21.4 ± 0.5 ‰ and 9.6 ± 0.7 ‰, bulk zooplankton (TL2) showed −18.8 ± 0.7 ‰ and 11.8 ± 1.4 ‰, while TL3, represented by baleen whales, some fish, squid, and seabirds, showed δ 13 C values between −13 and −16 ‰ and δ 15 N values between 16.5 and 20 ‰. Marine mammals occupied the entire coastal and pelagic isotope gradient (δ 13 C values from −12 to −18.1 ‰), with most of the species at TL4 (δ 15 N values from 17 to 23 ‰), whereas Orcinus orca occupied TL5 (25.8 ‰ maximum value). The odontocetes Mesoplodon peruvianus, Globicephala macrorhynchus, Grampus griseus, Kogia sima, Delphinus delphis, D. capensis, and Tursiops truncatus had both GC resident and visitor representatives, and the latter 3 species showed a significant degree of trophic and habitat overlap. KEY WORDS: Trophic levels · Habitats · Stable isotope analysis · Marine mammalsResale or republication not permitted without written consent of the publisher LITERATURE CITED

A trophic niche partitioning between Galapagos fur seals and Galapagos sea lions in the west of the archipelago is suggested by our results. At intraspecific level, the western population of the Galapagos sea lion (ZwW) showed higher trophic breadth than the eastern population, a strategy adopted by the ZwW to decrease the interspecific competition levels in the western region.

Background Preterm infants have a low level of bone mineralization compared to those born at term, since 80% of calcium incorporation occurs at the end of pregnancy. The purpose of the present study was to investigate the effect of reflex locomotion therapy on bone modeling and growth in preterm infants and to compare its effect with those of other Physiotherapy modalities. Methods A multicentre randomized controlled clinical trial was conducted (02/2016 – 07/2020). 106 preterm infants born at the Virgen de la Arrixaca University Clinical Hospital, the General University Hospital of Elche and the Torrecárdenas University Hospital of Almería, between 26 and 34 weeks with hemodynamic stability, complete enteral nutrition and without any metabolic, congenital, genetic, neurological or respiratory disorders were evaluated for inclusion. Infants were randomly assigned to three groups: one group received reflex locomotion therapy (EGrlt); another group received passive mobilizations with gentle joint compression (EGpmc); and the control group received massage (CG). All treatments were carried out in the neonatal units lasting one month. The main outcome measure was bone formation and resorption measured with bone biomarkers. A mixed ANOVA was used to compare the results of bone biomarkers, and anthropometric measurements. Results Infants were randomized to EGrlt (n = 38), EGpmc (n = 32), and CG (n = 36). All groups were similar in terms of gender (p = 0.891 female 47.2%), gestational age (M = 30.753, SD = 1.878, p = 0.39) and birth weight (M = 1413.45, SD = 347.36, p = 0.157). At the end of the study, significant differences were found between the groups in their interaction in bone formation, measured with osteocalcin [F (2,35) = 4.92, p = 0.013, ηp2 = 0.043], in benefit of the EGrlt. Conclusions Reflex locomotion therapy has been effective in improving bone formation, more so than other Physiotherapy modalities. Therefore, reflex locomotion therapy could be considered one of the most effective physiotherapeutic modalities for the prevention and treatment of osteopenia of prematurity. Trial registrstion Trial retrospectively registered at ClinicalTrials.gov. First posted on 22/04/2020. Registration number: NCT04356807.

The vaquita (Phocoena sinus) is the world's most endangered cetacean and has experienced a 60% reduction in the size of its population in the past decade. Knowledge of its basic ecology is essential for developing successful management plans to protect and conserve this species. In this study, we identified vaquita foraging areas by creating an isoscape of the Upper Gulf of California (UGC) based on sediment and zooplankton carbon (δ13C) and nitrogen (δ15N) isotope values. Our results confirm that this species is confined to the western region of the UGC, which is characterized by relatively high δ15N values (sediments: 10.2‰ ± 2.0‰, zooplankton: 15.8‰ ± 1.3‰), higher sea surface temperatures (∼16°C–25°C), higher concentrations of silt in sediments, and the highest turbidity. In contrast, the eastern region of the UGC had relatively low sediment (7.7‰ ± 2.4‰) and zooplankton (14.6‰ ± 1.0‰) δ15N values, and the highest concentrations of sand in sediments. Our approach is an effective use of marine isoscapes over a small spatial scale (<200 km) to identify the environmental characteristics that define the critical habitat for an extremely endangered marine mammal.