Few populations recover rapidly most exhibit little or no change in abundance up to 15 years after a collapse. Reductions in fishing pressure,are often insufficient. Persistence and recovery are also influenced by life history, habitat alteration, changes to species assemblages, genetic responses to exploitation, and reductions in population growth attributable to the Allee effect. Potentially permanent influences on species interactions, food web structure, and trophic dynamics are most dramatically reflected by staggering declines in the abundance of marine fishes.
The depth is remaining constant in the surface layer, so that indicates the surface layer is. well mixed. C. The salinity is fairly constant in the surface layer, so that would indicate the layer is well. mixed
A Bottleneck effect is the sharp reduction of numbers of a population through environmental effects or human activity. It causes a loss of the genetic pool and its variety; genetic variation lowers and increases with time as random mutations occur.
