Responses of fish assemblages of sandy beaches to different anthropogenic and hydrodynamic influences.

This study tested whether some attributes of the diversity, communities and populations of surf-zone fish assemblages varied with different hydrodynamic and anthropogenic influences at four Guanabara Bay sandy beaches: Dentro (sheltered with limited human access), Fora (exposed with limited human access), Urca (sheltered with unlimited human access) and Vermelha (exposed with unlimited human access), between autumn 2011 and summer 2012. Twenty-nine species and 1613 individuals were recorded from 76 trawls. The 10 most abundant species accounted for 94·5% of the total number, but only four species (Diplodus argenteus, Harengula clupeola, Sardinella brasiliensis and Sphoeroides greeleyi) were recorded at all four beaches, revealing a high level of species substitution. Fish assemblages differed not only for diversity attributes, but also at community and population levels, with lower values of the Shannon-Wiener index, richness and total fish abundance and biomass at Vermelha beach, and higher densities of Trachinotus carolinus, Atherinella brasiliensis and S. greeleyi related to beaches with high anthropogenic influence. The findings reveal that fish assemblages of Dentro, Fora, Urca and Vermelha beaches differed not only in response to hydrodynamic influences, but also due to the effects of different degrees of human interference (i.e. presence of solid residues, population density and fishing impacts), emphasizing the importance of the sheltered and less anthropogenically affected beaches, as spawning, nursery and growth areas.

Experiments in the measurement of intrauterine pressure.

A series of experiments investigating the quality of the signals obtained from intrauterine catheters was conducted in the labour rooms and laboratories. Clear evidence of signal attenuation due to partial blockage of catheters was obtained. Some methods which might help to overcome these problems are discribed.

Investigation of some problems associated with the Cardiff infusion pump.

Since there is some concern about the use of the Cardiff infusion pump in the automatic mode, experiments were devised to simulate some possible problems. The possibility of misleading information allowing overstimulation to occur was demonstrated. Even when the input signal was accurate there could, at least theoretically, be excessive stimulation. Some suggestions about future design and ways of correcting the problems are discussed.