Australian Inland Waters and their Fauna Eleven Studies Edited By A. H. Weatherley Australia’s inland waters are inhabited by an interesting and unique fauna little known even to biologists. The eleven essays in this book are authori­ tative studies on various aspects of this fauna and its environment. The book surveys, first, the inland waters, their main climatic and topo­ graphic influences and chemical char­ acteristics, and their classification. Then follow studies on the crustaceans, molluscs, amphibians, and fishes that inhabit the waters. The concluding section deals with some of the effects wrought by European man on both the animals and their environment. It is a book that will appeal to research workers and teachers; to students; to naturalists, conservation­ ists, and anglers; to all with broad interests in the living world that sur­ rounds them. $A10.50 Printed in Australia This book was published by ANU Press between 1965–1991. This republication is part of the digitisation project being carried out by Scholarly Information Services/Library and ANU Press. This project aims to make past scholarly works published by The Australian National University available to a global audience under its open-access policy. Australian Inland Waters and their Fauna Australian Inland Waters and their Fauna Eleven Studies Edited by A. H. Weatherley Senior Lecturer in Zoology Australian National University AUSTRALIAN NATIONAL UNIVERSITY PRESS CANBERRA First published 1967 Copyright. Reproduction in whole or part, without written permission of the publishers, is forbidden Text set in 10/11 point Linotype Times Roman and printed on 85 gsm Burnie Antique Wove Printing by Halstead Press Pty Ltd, Sydney Printed and manufactured in Australia Registered in Australia for transmission by post as a book National Library of Australia reg. no. AUS 67-888 Preface Ten years, even five years, ago this book could not have been written. This does not mean to say that the inland waters of Australia and their fauna had never previously been considered or described. Indeed, early descriptive studies of the aquatic fauna—fishes, insects, crustaceans, in particular—had led many biologists to a rapid realization of its unique features. But like most field studies of Australian animals at anything beyond the stage of simple natural history (with the exception of animals of acknowledged economic importance, such as sheep, cattle, marine fish, many insects), the development of this work was retarded by the relatively high operating costs. Australia is a very large country with a very small population; distances are huge, communications have been very difficult, and even now travel is far from cheap. Field stations and laboratories on the sites of interesting hydrobiological areas— a commonplace in the civilized parts of the Northern Hemisphere—were, and still are, mostly non-existent, except for a few on coasts and islands. Most universities had not the means to mount serious field investigations necessitating the use of vehicles, expensive field equipment, research and technical staff, or to pay for the corresponding aquarium and laboratory space needed in their biology departments for sustained and detailed study of organisms collected in the field and brought back alive. Even though anglers have esteemed the fish of our inland waters since the earliest settle­ ment of Australia and they are considered to be of, at least, semi-economic importance, it is only within the last fifteen years that, particularly in New South Wales, Victoria and Tasmania, much detailed study of them has been undertaken. However, though they may not have been in a position to do much about it, many biologists were well aware of the existence of fascinating animals in our lakes and rivers, the characteristics of which are as much the result of Australia’s isolation from other large land masses as are, for example, those of the much more famous marsupials of the terrestrial fauna. Further­ more, though few accounts existed of the hydrographic and limnological characteristics of our inland waters, there was general awareness that they differed in a number of ways from most other such waters of the world. The arid climate that dominates Australia’s economy, appearance, and geography also imposes rather strange conditions upon the inland waters and their inhabitants. Consider, for example, the rivers of the Murray-Darling complex, flowing west from the Eastern Highlands. Though they rank high among vi PREFACE the world’s rivers for total mileage, they rank extremely low in terms of volume flow. In addition, Australia’s average rainfall is very low and also very variable. As a result, in many places runoff may not occur for months (sometimes years) at a time, but then, for relatively short periods, may reach quite awe-inspiring dimensions. At these times the tendency for massive discharge will be assisted by the characteristically sparse plant cover, made the worse in all too many instances by careless pastoral and agricultural practices since European settlement. It becomes apparent that animals adapted to such inland waters as the rivers, lakes, and lagoons of Australia must be readily able to tolerate wide fluctuations in physical and chemical conditions in the aquatic environment and, in some instances (e.g. among the river fishes), to show well-marked adaptations to such special conditions as massive, periodic flooding. Australia’s long zoogeographic isolation has not always worked to produce complete uniqueness in its hydrobiology. Our marine coas;tal fishes are in many ways extremely similar to those of other southern hemisphere coasts. On the other hand our native freshwater fishes are unique (see chapters 1, 8, and 10). Crustaceans and insects of the inland waters are a miscellany. Among the former there are evidences of arrivals from the north and the west,, as well as many instances of a high degree of endemicity and radiation at the species level, and some among the higher taxa. Many of the insects may be readily located within northern hemisphere families, but thiere are also unique and primitive representatives in this fauna. In some ways the molluscs would most reassure a visitor from the north by their seemiing familiarity, but a closer look shows that these, too, have their special antipodean characteristics. Because of its size, Australia has provided an excellent stage for large-scale natural experiments in evolution, distribu­ tional ecology, and zoogeography. Almost every general principle relating to what I have written has b>een known to biologists for a long time. It is, therefore, not surprising tthat problems of such fascination should come under detailed scrutiny w/hen sufficient personnel and funds could be obtained for them, as has fimally happened in recent years. Though many of Australia’s institutions of research and higher learming (universities, museums, State-financed laboratories) still have a long way to go before they reach the ideal condition of fully adequate numberrs of trained staff and ample equipment, they have yet come a great distance in the past ten to twelve years. In this period they have shared, not alwvays abundantly or even equitably, but nevertheless in a nearly universal ^ a y , in the generally unparalleled prosperity that has overtaken Australian society. Research on the biology of inland waters is currently under way in at least eight university departments, several State museums, at 1 least three State departments of fisheries. Furthermore, the hydrobiologists thus engaged have derived much in the way of ‘fringe benefits’ from colleagues in the fields of sanitary and civil engineering, soil research, and agricultural PREFACE VÜ and economic hydrology, all of whom have a vital and practical interest in Australia’s inland water resources. It is gratifying, however, to note that some hydrobiologists have recently been able to involve themselves in their work, and in meetings, with these practical hydrologists, apparently with mutual profit. This augurs well for future understanding and sympathy between the groups. This book is a collection of essays by contemporary workers in the field of inland hydrobiology. It is not even a preliminary attempt at a com­ prehensive treatise: several notable areas of active study have perforce been omitted, because although potential authors in these areas existed and were sympathetic to this project, for various practical reasons they could not participate. Each chapter has been planned in the belief that it will contribute something of live interest to the Australian hydrobiological scene today and that the book will illustrate some recent progress in the subject and offer facts, concepts, and ideas in the frame of developments presently taking place, at the same time offering to workers entering the field a series of statements on its present aspects and possible future trends. For overseas hydrobiologists the book may represent a first statement of the way work in the field is moving in Australia, one that perhaps may stimulate them to come and see for themselves and to help in the tasks that lie ahead. We also hope that teachers of biology in both universities and schools will find material of interest to them that has been hitherto unavailable or very difficult of access. To this end nearly all chapters have extensive reference lists. It is worth noting that in the use of the word ‘inland’ in the book’s title I have bowed to the wishes of several contributors (see especially chapters by Williams and Bayly) who have argued cogently over a long period that the term ‘freshwater’ as used in its usual comprehensive fashion to describe our ‘inland’ waters would be both misleading and inexact. A few interconnected topics remain for mention. Australia is both a very large land mass and still, biologically, one of the great terrae incognitae. In certain aspects of ecology Australian research enjoys a high reputation, but almost nothing is known of the ecology, general biology, and physiology of the great majority of our animals—vertebrate or invertebrate.