Wow!
This was a brilliant book, everything I have heard claimed about it is true. The Sci-Fi element is excellent and the fact that it is on a Marine based world totally rocked my boat (pardon the pun). I thought the world building was utterly spectacular. There is always something exciting about the really dangerous worlds created in Sci-Fi, this is one of them. On Spatterjay, most life is marine, all of it wants to kill you slowly and painfully and most of it, right down to the prawns, leaches and jellyfish can indeed kill you. The only real way anything survives, human or native, is by being infected with the Spatterjay virus. This virus infiltrates your tissues making you stronger and more invulnerable the longer you live. The flip side to surviving most things is that on this world there is a whole lot of pain to survive.
That is the basic worldbuilding and it is very, very good. I have only read one other book by this author and though I did not enjoy it, even there his world building ability was great. Here, that formidable talent is combined with a book that is very enjoyable to read. As well as the actual world, we have the AI that runs it, the 'Polity' that is an interstellar civilization, a number of alien species that all have interest in Spatterjay and bearing on the plot. One of those is the hive mind of Terrestrial wasps that has become recognised as intelligent and given equal rights to other intelligent species.
The characters are many, diverse, interesting and very equal to carrying the plot along. We have the different sea captains, hundreds of years old, almost invulnerable to injury or death due to the changes the virus has made in them as well as their younger crew members, infected but far from invulnerable. We have some of the BEST villains I have every encountered, no spoilers. However, the first three characters we meet are the ones that introduce us to the world and carry the plot through to the end for the reader. Erlin is a biologist who has worked on Spatterjay before, on the shuttle coming in she is intrigued by two fellow passengers and starts a conversation. One is a "reif" a dead man kept animated through a combination of chemical and mechanical means, the other has a wasp on his shoulder and works for the hive mind. These characters, each with their own agenda, navigate us through the intricate plot, it is a great journey.
About the characters: My main complaint from the last book by this author that I read, was that his characters were impossible to bond with, affecting my capacity to care about the plot. This is, to a certain degree true here as well but it is handled much better. While one can't actually bond with any of the characters here, they are all very interesting and there are a lot of them. So instead of having just one or two characters you don't believe in, Spatterjay has heaps of characters that are interesting and carry us through. The fact that these many characters are at best remote, emotionally, from the reader does not negatively affect the enjoyment of the story. Well done!
Also, each chapter starts with a little vignette describing the harsh violence of life in the seas of Spatterjay. Kill and be killed is the underlying way of all nature, of course, but these serial descriptions of predation fascinated me. So very well done! As a way of introducing us to the different wildlife it was excellent, instead of the narrative having to give us expositions, we went into the story already knowing what the relevant marine wildlife (and how, is it wild) was. And the description of the ocean life made the world so much more real to me.
Only one thing about this book annoyed me. Dingles! Dingles are everywhere on-land. What are Dingles you ask? Well it took me over 400 pages to figure it out. Normally I am very good at figuring out what invented words are from context but here I was utterly mystified and lost. For about 200 pages I assumed it meant a dip in the land as in 'from the dell floor' = "From the dingle floor" [pg 228]. An Australian will almost certainly assume that a dingle is a euphemism for male genitalia, but I was pretty sure that was not it. Google thinks it is a place in Ireland, or maybe India as does Wiki, though they are willing to concede that it may mean a stupid person as in 'ding dong'.
I figured it out eventually from context and I even have a theory about how it happened: Toward the end of editing, nearly ready to send the text to the publishers, when he was tired and not paying attention the poor Author (on a deadline no doubt) accidentally did that 'find and replace all' thing that wordprocesses do, and turned all words 'Jungle' into 'Dingle'. That is the only explanation that makes sense. Jungle, a dingle is a jungle.