Flatfish are an economically and ecologically important component of continental shelf ecosystems worldwide. These species are impacted from fishing activities, both as direct targets and through indirect effects on habitat and food supply. We examined 25 years of diet data for juveniles and adults of nine species of flatfish in the Northwest Atlantic on the continental shelf off of the USA and parts of Canada in order to understand how flatfish feeding ecology may have changed after decades of fishing and related impacts on the ocean bottom. Atlantic halibut (Hippoglossus hippoglossus), summer flounder (Paralichthys dentatus) and fourspot flounder (P. oblongus) were generally piscivorous. American plaice (Hippoglossoides platessoides) ate primarily ophiuroids. Yellowtail flounder (Limanda ferruginea), winter flounder (Pseudopleuronectes americanus), windowpane (Scophthalmus aquosus), witch flounder (Glyptocephalus cynoglossus) and gulfstream flounder (Citharichthys arctifrons) ate primarily polychaetes, gammarids and other benthic invertebrates. American plaice, summer flounder and fourspot flounder exhibited significant ontogenetic shifts in diet, consuming fewer polychaetes with increasing size. Summer and fourspot flounder also exhibited significant shifts in diet across the time series. None of the benthivorous flatfish exhibited significant changes in diet composition across the time series. The mean weight of stomach contents declined in all species over the past 20 years. The role of flatfish trophic dynamics is discussed in the context of major changes that have occurred in this continental shelf ecosystem.
Identification of species in natural populations has recently received increased attention with a number of investigators proposing rigorous methods for species delimitation. Morphologically conservative species (or species complexes) with deep phylogenetic histories (and limited gene flow) are likely to pose particular problems when attempting to delimit species, yet this is crucial to comparative studies of the geography of speciation. We apply two methods of species delimitation to an ancient group of lizards (genus Xantusia) that occur throughout southwestern North America. Mitochondrial cytochrome b and nicotinamide adenine dinucleotide dehydrogenase subunit 4 gene sequences were generated from samples taken throughout the geographic range of Xantusia. Maximum likelihood, Bayesian, and nested cladogram analyses were used to estimate relationships among haplotypes and to infer evolutionary processes. We found multiple well-supported independent lineages within Xantusia, for which there is considerable discordance with the currently recognized taxonomy. High levels of sequence divergence (21.3%) suggest that the pattern in Xantusia may predate the vicariant events usually hypothesized for the fauna of the Baja California peninsula, and the existence of deeply divergent clades (18.8%-26.9%) elsewhere in the complex indicates the occurrence of ancient sundering events whose genetic signatures were not erased by the late Wisconsin vegetation changes. We present a revised taxonomic arrangement for this genus consistent with the distinct mtDNA lineages and discuss the phylogeographic history of this genus as a model system for studies of speciation in North American deserts.
This paper details the steps to design and implement a positive deviance-informed, "Hearth" approach for the nutritional rehabilitation of malnourished children in the district of Leogane, Haiti. Groups of four to five children met daily for two weeks at the home of a local volunteer mother for nutritional and health messages and a well-balanced meal. Health messages and meal components were determined using information gathered from interviews with the mothers of positive deviant children in the community who are well nourished despite their family's limited economic resources. Hearth participants were then followed for six months in their own home by the program "monitrices," women hired from each village and intensively trained to supervise the Hearth program, periodically weigh the children to evaluate their progress, and liaise between the hospital and the community. Monitoring from the first cycle indicated that 100% of children in eight villages and 66% of children in the remaining five villages continued to gain weight as fast or faster than the international standard median six months after participating in a Hearth program. At the conclusion of this cycle, programmers interviewed participant and non-participant families and made six modifications to the model, including the addition of a microcredit option for participating mothers.
This paper details the steps to design and implement a positive deviance-informed, "Hearth" approach for the nutritional rehabilitation of malnourished children in the district of Leogane, Haiti. Groups of four to five children met daily for two weeks at the home of a local volunteer mother for nutritional and health messages and a well-balanced meal. Health messages and meal components were determined using information gathered from interviews with the mothers of positive deviant children in the community who are well nourished despite their family's limited economic resources. Hearth participants were then followed for six months in their own home by the program "monitrices," women hired from each village and intensively trained to supervise the Hearth program, periodically weigh the children to evaluate their progress, and liaise between the hospital and the community. Monitoring from the first cycle indicated that 100% of children in eight villages and 66% of children in the remaining five villages continued to gain weight as fast or faster than the international standard median six months after participating in a Hearth program. At the conclusion of this cycle, programmers interviewed participant and non-participant families and made six modifications to the model, including the addition of a microcredit option for participating mothers.
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