Complex sentence: It is not known what the long term effect of this will be on this neighbourhood of the ocean, and this has aroused the concern of conservationists, however the wider scale survival of the species is not believed to be threatened.
Split into simpler sentences: It is not known what the long term effect of this will be on this neighbourhood of the ocean, and this has aroused the concern of conservationists. However, the wider-scale survival of the species is not believed to be threatened.