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Lagoon soft-bottoms are key habitats within coral reef seascapes. Coral reef fish use these habitats as nurseries, feeding grounds and transit areas. At present, most soft-bottom sampling methods are destructive (trawling, longlining, hook and line). We developed a remote, unbaited 360° video sampling method (RUV360) to monitor fish species assemblages in soft bottoms. A low-cost, high-definition camera enclosed in a waterproof housing and fixed on a tripod was set on the sea floor in New Caledonia from a boat. Then, 534 videos were recorded to assess the efficiency of the RUV360. The technique was successful in sampling bare soft-bottoms, seagrass beds, macroalgae meadows and mixed soft-bottoms. It is easy to use and particularly efficient, i.e., 88% of the stations were sampled successfully. We observed 10,007 fish belonging to 172 species, including 45 species targeted by fishermen in New Caledonia, as well as many key species. The results are consistent with the known characteristics of the lagoon soft bottom fish assemblages of New Caledonia. We provide future users with general recommendations and reference plots to estimate the proportion of the theoretical total species richness sampled, according to the number of stations or the duration of the footage.

Disorders of isolated mineralocorticoid deficiency, which cause potentially life-threatening salt-wasting crisis early in life, have been associated with gene variants of aldosterone biosynthesis or resistance; however, in some patients no such variants are found. WNT/β-catenin signaling is crucial for differentiation and maintenance of the aldosterone-producing adrenal zona glomerulosa (zG). Herein, we describe a highly consanguineous family with multiple perinatal deaths and infants presenting at birth with failure to thrive, severe salt-wasting crises associated with isolated hypoaldosteronism, nail anomalies, short stature, and deafness. Whole exome sequencing revealed a homozygous splice variant in the R-SPONDIN receptor LGR4 gene (c.618-1G>C) regulating WNT signaling. The resulting transcripts affected protein function and stability and resulted in loss of Wnt/β-catenin signaling in vitro. The impact of LGR4 inactivation was analyzed by adrenal cortex-specific ablation of Lgr4, using Lgr4fl/fl mice mated with Sf1:Cre mice. Inactivation of Lgr4 within the adrenal cortex in the mouse model caused decreased WNT signaling, aberrant zonation with deficient zG, and reduced aldosterone production. Thus, human LGR4 mutations establish a direct link between LGR4 inactivation and decreased canonical WNT signaling, which results in abnormal zG differentiation and endocrine function. Therefore, variants in WNT signaling and its regulators should systematically be considered in familial hyperreninemic hypoaldosteronism.

Estimating diversity and abundance of fish species is fundamental for understanding community structure and dynamics of coral reefs. When designing a sampling protocol, one crucial step is the choice of the most suitable sampling technique which is a compromise between the questions addressed, the available means and the precision required. The objective of this study is to compare the ability to sample reef fish communities at the same locations using two techniques based on the same stationary point count method: one using Underwater Visual Census (UVC) and the other rotating video (STAVIRO). UVC and STAVIRO observations were carried out on the exact same 26 points on the reef slope of an intermediate reef and the associated inner barrier reefs. STAVIRO systems were always deployed 30 min to 1 hour after UVC and set exactly at the same place. Our study shows that; (i) fish community observations by UVC and STAVIRO differed significantly; (ii) species richness and density of large species were not significantly different between techniques; (iii) species richness and density of small species were higher for UVC; (iv) density of fished species was higher for STAVIRO and (v) only UVC detected significant differences in fish assemblage structure across reef type at the spatial scale studied. We recommend that the two techniques should be used in a complementary way to survey a large area within a short period of time. UVC may census reef fish within complex habitats or in very shallow areas such as reef flat whereas STAVIRO would enable carrying out a large number of stations focused on large and diver-averse species, particularly in the areas not covered by UVC due to time and depth constraints. This methodology would considerably increase the spatial coverage and replication level of fish monitoring surveys.

Observing spatial and temporal variations of marine biodiversity from non-destructive techniques is central for understanding ecosystem resilience, and for monitoring and assessing conservation strategies, e.g. Marine Protected Areas. Observations are generally obtained through Underwater Visual Censuses (UVC) conducted by divers. The problems inherent to the presence of divers have been discussed in several papers. Video techniques are increasingly used for observing underwater macrofauna and habitat. Most video techniques that do not need the presence of a diver use baited remote systems. In this paper, we present an original video technique which relies on a remote unbaited rotating remote system including a high definition camera. The system is set on the sea floor to record images. These are then analysed at the office to quantify biotic and abiotic sea bottom cover, and to identify and count fish species and other species like marine turtles. The technique was extensively tested in a highly diversified coral reef ecosystem in the South Lagoon of New Caledonia, based on a protocol covering both protected and unprotected areas in major lagoon habitats. The technique enabled to detect and identify a large number of species, and in particular fished species, which were not disturbed by the system. Habitat could easily be investigated through the images. A large number of observations could be carried out per day at sea. This study showed the strong potential of this non obtrusive technique for observing both macrofauna and habitat. It offers a unique spatial coverage and can be implemented at sea at a reasonable cost by non-expert staff. As such, this technique is particularly interesting for investigating and monitoring coastal biodiversity in the light of current conservation challenges and increasing monitoring needs.

Key Words: adrenal, genetics, ZNRF3

The first survey of sea snakes (Elapidae, Hydrophiinae) at the remote Entrecasteaux atolls, Coral Sea, was conducted using remote unbaited 360° video cameras (RUV360), in 2021. We detected 49 snakes belonging to at least six species (Aipysurus duboisii, A. laevis, Hydrophis coggeri, H. macdowelli, H. major and H. ornatus) at the two largest atolls, Surprise and Huon. Three more are probably present (Emydocephalus annulatus, H. peronii, H. platurus), highlighting the richness of these atolls. No snakes were detected at neighboring smaller atolls. The lack of sea snake observations at the five small atolls may be due to the insufficient area of suitable habitat. Compared to assemblages sampled using the same method in New Caledonia (at Nouméa = A. laevis, E. annulatus, Laticauda sp., H. macdowelli, H. major, H. ornatus; at Touho = A. laevis, H. ornatus), and assemblages sampled with different methods at the Chesterfields (A. duboisii, A. laevis, E. annulatus, H. coggeri, H. laboutei, H. peronii, H. platurus), the Entrecasteaux atolls exhibit a high sea snake species richness. RUV360s appear to sample the diversity of sea snakes more effectively than did baited remote underwater video stations (BRUVS) within the Great Barrier Reef (which detected only A. laevis, H. curtus, H. ocellatus).

Abstract Context Determination of steroid levels in the amniotic fluid gives some insight on fetal adrenal and gonadal functions. Objective Our objectives were to establish reference ranges of 12 steroid levels throughout pregnancy and to compare them with steroid levels from pregnancies with fetuses presenting with 21-hydroxylase deficiency (21OHD). Methods Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was applied to 145 “control” amniotic fluid samples from gynecology activity (12 + 6 to 32 + 4 gestational weeks, GW). The following steroids were analyzed according to gestational age and compared to 23 amniotic fluid samples from fetuses with classic 21OHD confirmed by molecular studies: delta-4-androstenedione (D4), dehydroepiandrosterone (DHEA), 17-hydroxyprogesterone (17OHP), 11-deoxycortisol (11OH), 21-deoxycortisol (21OH), corticosterone, deoxycorticosterone (DOC), testosterone, pregnenolone, 17-hydroxypregnenolone (17Pregn), cortisol, and cortisone. Chromosomal sex was determined by karyotype and gestational age by biometric measurements. Results Analysis of control samples showed a statistically significant difference for D4 and testosterone levels according to fetal sex. Cortisol, corticosterone, and DOC had lower concentrations before 20 GW than after 20 GW, whereas 17Pregn and pregnenolone had higher concentrations before 20 GW. This allowed us to establish age- and sex-dependent reference values. We observed higher 21OH, 17Pregn, D4, and testosterone levels in females with 21OHD than female controls. The ratios 17OHP/17Pregn, D4/DHEA, and 11OH/17OHP appeared discriminant for the diagnosis of 21OHD. Conclusion Our study provides information on fetal steroidogenesis and suggests reference values for 12 steroids during pregnancy. This allows a prenatal diagnosis of 21OHD within 24 hours and might be useful in the diagnosis of other variations of sex development.