Shifts in the composition and distribution of Pacific Arctic larval fish assemblages in response to rapid ecosystem change.

The Pacific Arctic marine ecosystem has undergone rapid changes in recent years due to ocean warming, sea ice loss, and increased northward transport of Pacific-origin waters into the Arctic. These climate-mediated changes have been linked to range shifts of juvenile and adult subarctic (boreal) and Arctic fish populations, though it is unclear whether distributional changes are also occurring during the early life stages. We analyzed larval fish abundance and distribution data sampled in late summer from 2010 to 2019 in two interconnected Pacific Arctic ecosystems: the northern Bering Sea and Chukchi Sea, to determine whether recent warming and loss of sea ice has restricted habitat for Arctic species and altered larval fish assemblage composition from Arctic- to boreal-associated taxa. Multivariate analyses revealed the presence of three distinct multi-species assemblages across all years: (1) a boreal assemblage dominated by yellowfin sole (Limanda aspera), capelin (Mallotus catervarius), and walleye pollock (Gadus chalcogrammus); (2) an Arctic assemblage composed of Arctic cod (Boreogadus saida) and other common Arctic species; and (3) a mixed assemblage composed of the dominant species from the other two assemblages. We found that the wind- and current-driven northward advection of warmer, subarctic waters and the unprecedented low-ice conditions observed in the northern Bering and Chukchi seas beginning in 2017 and persisting into 2018 and 2019 have precipitated community-wide shifts, with the boreal larval fish assemblage expanding northward and offshore and the Arctic assemblage retreating poleward. We conclude that Arctic warming is most significantly driving changes in abundance at the leading and trailing edges of the Chukchi Sea larval fish community as boreal species increase in abundance and Arctic species decline. Our analyses document how quickly larval fish assemblages respond to environmental change and reveal that the impacts of Arctic borealization on fish community composition spans multiple life stages over large spatial scales.

Demographic and reproductive plasticity across the depth distribution of a coral reef fish.

As humans expand into natural environments, populations of wild organisms may become relegated to marginal habitats at the boundaries of their distributions. In the ocean, mesophotic coral ecosystems (30-150 m) at the depth limit of photosynthetic reefs are hypothesized to act as refuges that are buffered from anthropogenic and natural disturbances, yet the viability and persistence of subpopulations in these peripheral habitats remains poorly understood. To assess the potential for mesophotic reefs to support robust coral reef fish populations, we compared population density and structure, growth, size, and reproductive output of the bicolor damselfish (Stegastes partitus) from shallow (<10 m), deep shelf (20-30 m), and mesophotic reefs (60-70 m) across the Florida Platform. Population densities decreased and size and age distributions shifted toward older and larger individuals in deeper habitats. Otolith-derived ages indicated that S. partitus found on mesophotic reefs reach larger asymptotic sizes and have longer lifespans than fish in shallower habitats. Based on measurements of oocyte area and batch fecundity, mesophotic fish also have higher reproductive investment. These demographic patterns indicate that mesophotic fish populations composed of large, fecund individuals produce high condition larvae and rely on longevity of individuals for population persistence and viability.

Assessment of cognitive and adaptive behaviour among individuals with congenital insensitivity to pain and anhidrosis.

AIM: Individuals with congenital insensitivity to pain with anhidrosis (CIPA) are reported to have mental retardation* but to our knowledge no detailed study on the subject has ever been published. The present study assessed and documented cognitive and adaptive behaviour among Arab Bedouin children with CIPA. METHODS: Twenty-three Arab Bedouin children (12 females, 11 males) with CIPA aged between 3 and 17 years (mean 9 y 7 mo, SD 4 y 2 mo) were assessed. They were compared with 19 healthy siblings of the affected children aged between 5 and 13 years (mean 8 y 11 mo, SD 2 y 10 m). All of the children in the comparison group, but only half of the CIPA group, were attending school. The children were evaluated using a standardized, non-verbal intelligence test, the Leiter International Performance Scale--Revised, and an adaptive behaviour questionnaire, the Vineland Adaptive Behaviour Scales, 2nd edition. RESULTS: Based on scores on the intelligence test and the adaptive behaviour scale, children with CIPA functioned in the mental retardation range (mean IQ scores: CIPA group 53.8, comparison group 83.32 [p<0.001]; adaptive behaviour: CIPA group 68.1, comparison group 104.88 [p<0.001]). IQ was significantly higher among the children with CIPA aged up to 7 years 11 months than among the older children 73.83 vs 45.21 (p<0.001). INTERPRETATION: As a group, the younger children with CIPA may be functioning above the mental retardation range. We propose that early intervention addressing these children's needs and developing an appropriate educational system, might improve their outcome.

Predictive value of amplitude-integrated electroencephalography pattern and voltage in asphyxiated term infants.

The aim of this study was to correlate amplitude-integrated electroencephalography soon after birth with neurodevelopmental outcome in children who suffered from hypoxic-ischemic encephalopathy. Near term infants with hypoxic-ischemic encephalopathy and amplitude-integrated electroencephalography recording before 6 hours of age were included. Neurologic and cognitive outcome were assessed at 30 months of age and over. Outcome was correlated with either the pattern or voltage of the tracing. Thirty-nine infants were included. Eight died in the immediate neonatal period. At the age of 3 and 6 hours, sensitivity of low voltage to poor outcome was 33% and 42% respectively and of burst suppression pattern to poor outcome was 83% and 75% respectively. Association of voltage to outcome was significant only at 6 hours of age (P = 0.025). Association of pattern to outcome was significant both at 3 and 6 hours of age (P = 0.003, 0.008). These data on amplitude-integrated electroencephalography predictive value early in life were similar to previous studies. Burst suppression pattern, as early as 3 hours of age, is associated with poor outcome. At the age of 6 hours, both low voltage and burst suppression are associated with poor outcome. Pattern seems more sensitive than voltage.