Biology and ecology of the non-indigenous goby Acentrogobius pflaumii (Bleeker 1853) in the Swan- Canning Estuary Submitted by Keyley Hogan-West This thesis is presented for the Degree of Honours in Marine Science 2015 B.Sc Murdoch University Declaration I declare that the information contained in this thesis is the result of my own research unless otherwise cited, and has as its main content work which has not previously been submitted for a degree at any university. Keyley Hogan-West i Copyright Acknowledgement I acknowledge that a copy of this thesis will be held at the Murdoch University Library. I understand that, under the provisions s51.2 of the Copyright Act 1968, all or part of this thesis may be copied without infringement of copyright where such a reproduction is for the purposes of study and research. This statement does not signal any transfer of copyright away from the author. Signed: ___________________________________________ NAME OF DEGREE: Bachelor of Science with Honours in Marine Science THESIS TITLE: Biology and ecology of the non-indigenous goby Acentrogobius pflaumii (Bleeker 1853) in the Swan-Canning Estuary AUTHOR: Keyley HOGAN-WEST YEAR: 2015 ii Acknowledgements Firstly, to my supervisors, all round gentleman and (luckily for me) excellent scientists, I thank you for all of your hard work and effort reading and editing what often resembled a puddle of mental vomit on a page. Further kudos for actually wanting to continue supervising me after those periods of editing. To James, the man full of enthusiasm and endless stories concerning bodily functions and unfortunate friends, thank you. My time this year would have been significantly more dull without chive threads to peruse and weird animal body parts to feel disturbed about. To Pete, thanks for putting up with me and my cluster of papers and pens in your office all year and letting me incessantly pick your brain. If it makes you feel any better about it, there’s some good stuff stored in there. I should also thank you for teaching me how not to spear a fish. Im coming for you morwong. To Neil, your voice of wisdom this year has been invaluable, thank you sincerely for your efforts in structuring, editing and taking the time to be involved. To my honours buddies, this year would not have been the same without you. Brian Poh, you sir, are a legend and I will pay you many fish shells when I become incredibly rich from breeding gobies in the near future. Shares in the company are going cheap at the moment, get in early. To Natasha (don’t kill me) Prokop, we did good? Thanks for not stabbing me in the eye when my music was playing too loud or I was doing annoying things, which is all the time. But seriously, thanks who else would I complain too if not you? Needless to say, I don’t think I can ever look at you the same way again after you ate that sushi. Also, your collections of different sighs and weird angry noises manage to convey levels of disgust and impatience I hadn’t even imagined possible. To all the volunteers throughout the year that helped collect my dirty little gobies, thankyou as well. Thanks must also go to Gordon for producing excellent histological slides for me and dealing with incessant badgering about when they would be ready, cheers! Most of all, thanks to Fe and Hogie, and the rest of my family. Fe and Hogie, thanks for leaving me curry for dinner after long sampling nights, staying up late to make sure I didn’t get into a fight with a tree driving home after sampling and just generally doing lots of little things for me this year which didn’t go unnoticed and were appreciated immensely. You made this possible, therefore I will give you a copy for free. Try not to hit anyone with it. Arlen, thanks for updating my destiny account, reminding me of your clear intellectual superiority and smelling weirdly? Tully and Libby, thanks guys. I didn’t see you much, but a willing ear and painful elbow were always available to make my day seem less terrible. iii Abstract Non-indigenous species can have significant deleterious impacts on the ecosystems in which they become established. Following the recent establishment of the Striped Sandgoby Acentrogobius pflaumii in the Swan-Canning Estuary, south-western Australia, a study was initiated to determine its spatial and temporal distribution and biological characteristics. Although A. pflaumii was not recorded in the coarse sandy sediment present in the nearshore, shallow waters of the estuary, substantial numbers were recorded on soft muddy sediments in the deeper waters, where it comprised 55% of the total number of gobies. While A. pflaumii dominated the gobiid fauna in Lower Melville Water (~98%), its contributions declined progressively upstream, indicating a preference for waters with a salinity close to that of full strength sea water. Size and age compositions determined that the oldest individual was 3.9 years old and 89 mm in total length, but that the population is dominanted by 1+ individuals. Population mortality and turn-over rates are therefore likely to be very high. Both males and females attained > 87% of their asymptotic lengths (L∞) of 74.9 and 69.3 mm, respectively, during the first year of life, which is characteristic of smaller, shorter-lived species of fish. The results from gonadosomatic indices and the histological examination of gonads suggest that A. pflaumii is able to spawn throughout most of the year, with a peak from November to February. The presence of mature, spawning and depleted gonads in A. pflaumii suggests that this species spawns within the Swan-Canning Estuary. Acentrogobius pflaumii can be thus considered an estuarine & marine species like Favonigobius lateralis. As A. pflaumii attains high densities over a relatively large part of the estuary and can breed within the system, it is likely to be a permanent resident and further work is needed to determine its impact on the native gobiid fauna. iv Contents page Acknowledgements .................................................................................................. iii Abstract .................................................................................................................. iv List of Figures ....................................................................................................... viii List of Tables .......................................................................................................... xi Chapter 1: General Introduction .......................................................................... 1 1.1. Estuaries........................................................................................................ 1 1.2. Unique environment of south-western Australian estuaries ............................ 2 1.3. Estuarine fish faunas ..................................................................................... 4 1.4. Non-indigenous species ................................................................................. 5 1.5. Gobiids as non-indigenous species ................................................................ 7 1.6. Gobiid biology .............................................................................................. 8 1.8. Striped Sandgoby ........................................................................................ 10 1.9. Aims ........................................................................................................... 11 Chapter 2: Non-indigenous species in estuaries and coastal marine waters- vectors of transmission, biological and ecological implications and management strategies ........................................................................................................... 13 2.1. Abstract ....................................................................................................... 13 2.2. Introduction ................................................................................................. 14 2.3. Pathways and vectors of dispersal................................................................ 16 2.3.1. Types of non-indigenous species .......................................................... 16 2.3.2.. Pathways of transmission ..................................................................... 16 2.3.3. Shipping activities as a pathway of transmission ................................... 21 2.3.4. Waterways, aquaculture and aquariums as pathways of transmission .... 25 2.3.5. Spatial variation in the pathways of transmission .................................. 26 2.4. Impacts of NIS species ................................................................................ 29 2.4.1. Community health and intrinsic value ................................................... 29 2.4.2. Socio-Economic impacts ...................................................................... 29 2.4.3. Biology/ecology of the system .............................................................. 30 2.5. Contemporary NIS management approaches and suggested amendments .... 31 2.7. Biological characteristics of successful NIS ................................................. 39 2.8. Summary ..................................................................................................... 44 v Chapter 3: Spatial and temporal distribution of Acentrogobius pflaumii in the Swan-Canning Estuary ........................................................................................ 46 3.1. Abstract ......................................................................................................