Social systems are the outcomes of natural and sexual selection on individuals' efforts to maximize reproductive success. Ecological conditions, life history, demography traits and social aspects have been recognized as important factors shaping social systems. Delphinids show a wide range of social structures and large variation in life history traits and inhabit several aquatic environments. ...

The pelagic juvenile stage of sea turtles is poorly studied. We present a growth model and estimates for duration of the pelagic juvenile stage for loggerhead sea turtles Caretta caretta in the North Atlantic based on length-frequency analyses and sizes of young-of-the-year stranded in the Azores. The size-specific growth model is a monotonic, nonlinear, declining function. The growth model is ...

Trait combinations that lead to a higher efficiency in resource utilization are important drivers of divergent natural selection and adaptive radiation. However, variation in environmental features might constrain foraging in complex ways and therefore impede the exploitation of critical resources. We tested the effect of water transparency on intra-population divergence in morphology of Eurasi...

Pelagic larval duration (PLD) can influence evolutionary processes ranging from dispersal to extinction in aquatic organisms. Using estimates of PLD obtained from species of North American darters (Percidae: Etheostomatinae), we demonstrate that this freshwater fish clade exhibits surprising variation in PLD. Comparative analyses provide some evidence that higher stream gradients favour the evo...

Uptake of D-glucose in the range 2.5 X lOP9 M to 4.0 X I O ~ M by an oligotrophic marine bacterium, LNB-155, could be represented by 4 phases of a single, multiphasic mechanism. Other kinetic models did not give a good fit. Sharp transitions occurred at about 1.6 X 1OV6 M, 10-5 M and 2 X 10-4 M. Values for K, and V,,, increased regularly upon transition to higher phases. Multiphasic uptake mech...

Weightand carbon-specific rates of respiration for 4 mesopelagic gelatinous zooplankton (2 ctenophores, 1 trachymedusa and 1 pelagic holothurian) measured in situ were 2 to 5 times higher than those from shipboard incubations. These results support the theory that removal of deep-living gelatinous species from natural environments can adversely affect their metabolism. The disparity between in ...