“Fishes of Aotearoa” by Paul Caiger, published by Potton and Burton, Price $79.99. Reviewed by Tony Orman
Being insular in location, totally surrounded by sea, New Zealand with its minor islands has an aquatic ecology both in saltwater and freshwater. Author Paul Caiger, a keen scuba diver has a degree in marine biology topped by a PhD about the evolutionary ecology of New Zealand triple fin fishes. Post doctoral positions in the US researching fish acoustics and deep-sea fish biology add to his deep knowledge and eminent qualifications to write about fishes. Blend in a passion for photography to the knowledge and writing skills and there’s everything you need for a book on this subject.
There’s one last ingredient – a top publisher – and Potton and Burton with their reputation for high quality book productions, fit the bill exactly.
The author has long been captivated by Nature and in particular fishes.
He covers freshwater both native and introduced species such as trout and is not averse to exposing mismanagement. For instance the trout, both brown and rainbow, is often maligned as being an invasive predator. Yet trout have been here for 150 or so years and ecosystems adapt and food chains and predators-prey relationships eventually and usually mesh into equilibrium.
“Our iconic long fin eels (tuna) have the same conservation status as the great spotted kiwi, yet we still export the eels to other countries that have driven their own (eels) to extinction. Absurdly these native eels were recently found to be an ingredient in cat food.” In other words Man’s monetary greed and commercial exploitation is a very much far greater threat than trout and then there’s habitat with irrigation demands for corporate dairying sapping river and stream flows. Add excessive nitrates going into rivers, (toxic to fish life) and it’s obvious the biggest threat to native fish comes from human exploitation either directly of the fish species and indirectly on habitat, i.e. rivers’ flows and quality.
Yet strangely in the chapter on galaxiids, while there is brief reference to the “influential environmental factor: humans” relative to the decline of freshwater habitats, there appears no mention of commercial exploitation, which the Department of Conservation “managing” the whitebait fishery, tends to ignore the adverse impact of with no controls on commercial fishing or clamping down on bogus recreational fishers selling their catch for monetary return.
But I digress.
Overall “Fishes of Aotearoa” is a fascinating insight into the fish particularly saltwater, through the eyes of a marine ecologist. The author skilfully delves into the secret lives of fish, telling of reproduction and sexual dimporhism, camouflage techniques, schooling behaviour and other characteristics.
With his ecologist’s eye, Paul Caiger, explains the importance of interrelationships between two and even three for more species. For example snapper – in Maori language termed tamure.
“Tamure are more than just a major fishing target: due to both their abundance and ecology, they play a significant role in the reef’s ecosystems of New Zealand.”
Part of the snapper’s diet is kina – spiky sea urchins. Kina are kelp eaters. Snapper along with large koura/crayfish are the only animals on the reef that readily eat kina and in areas where snapper and crayfish are heavily over-fished, the balance between predator and prey is skewed and kina graze unchecked. The consequence is the disappearance of the kelp forest.”
“The repercussions of this are far-reaching. This is termed a trophic cascade,” writes the author.
The same consequence also involving snapper – I have been told – was around the severe decline in toheroa along the lower North Island’s west coast beaches where overfishing of snapper resulted in a population explosion of paddle crabs which decimated the shellfish.
It would have been worthwhile to have an insight, in the chapter on pelagic fish of the multi-importance of schooling feeding fish such as kahawai which benefits kingfish preying on kahawai, snapper and other fish below opportunistically grabbing sinking scraps and sea birds wheeling and feeding on surface scraps among the melee of feeding fish.
It seems the Ministry of Fisheries lacks lateral vision to understand these complexities and inter-relationships.
Perhaps in a reprinting that this fine book might deserve down the track, these food chain relationships could be added?
Paul Craiger’s explanations of the lives of fishes enhanced by his often stunning photographs and Potton and Burton’s high quality production, make for a very impressive book that any anyone with an interest in Nature and more especially anglers and divers, will find engaging and educational.