Patterns in the Distribution and Abundance of Reef Fishes in South Eastern Australia

138 Pages·2011·3.07 MB·English

Patterns in the Distribution and Abundance of Reef Fishes
in South Eastern Australia

Madhavi A. Colton

Submitted in total fulfilment of the requirements
of the degree of Doctor of Philosophy

March 2011

Department of Zoology
The University of Melbourne
Parkville, Victoria 3010
Australia
ABSTRACT
This research investigated patterns in the distribution and abundance of nearshore
fishes of south-eastern Australia. I used two methods to survey fishes, underwater
visual census (UVC) and baited remote underwater video (BRUV). A comparison
between these methods revealed that BRUV recorded higher relative abundance of
mobile predators, while UVC observed higher relative abundance of herbivores,
territorial species, and small site-attached species. These results suggest that studies
surveying diversity would do best to employ multiple methods. In cases where funds
are limited, UVC may provide a more complete estimate of diversity than BRUV as
UVC recorded higher diversity, species richness and more individuals.

Combining measures of abundance with habitat data, I investigated fish-habitat
associations, specifically exploring how altering spatial grain influenced the strength
of correlations between fish and habitat. Species of different sizes responded to
habitat measured over different scales, with large-bodied species only displaying
strong correlations with habitat when it was measured over large scales. These results
suggest that research quantifying fish-habitat associations needs to take spatial grain
into account. In addition, many species may respond to changes in habitat at scales
larger than are typically investigated. Understanding not only how species interact
with their environment but also the scale at which these associations occur is essential
for management and conservation.

I investigated biogeographic patterns in the distribution of fishes in Victoria using
abundance measured by BRUV and UVC. The BRUV data displayed a cline in
change across the state in which dissimilarities between locations were linearly related
to distance. In contrast, data collected using UVC indicated the presence of a large
faunal break in the vicinity of Ninety Mile Beach, and a second break between Cape
Conran and Cape Howe, suggesting that contemporary habitat discontinuity, flow
and/or temperature may be important factors structuring communities in this region.

At a still larger scale, I explored relationships at upper and lower bounds between
body size, geographic range size and abundance using data collected from Australia
and New Zealand. At maxima, the relationship between body size and abundance was
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negative but steeper than expected, possibly driven by diver-averse behaviour of large
species. At minima, body size and geographic range size were positively related,
implying that body size determines the minimum area that a species must occupy. In
contrast, at the upper bound this relationship was negative for non-perciform fishes, a
K-selected group whose geographic range size could be constrained by their limited
dispersal capacity. Distribution-abundance relationships deviated from predictions,
with a negative relationship at the upper bound for Perciformes, which could be
driven by the high dispersal potential of widespread species that results in diffuse low-
density populations. From these results, I concluded, first, that fishes appear to differ
from terrestrial taxa, which may be attributed in part to large-bodied fishes’ limited
capacity for dispersal. Second, the approach of applying regressions to maxima and
minima uncovered relationships that would have been obscured had they been
investigated at the mean, highlighting the importance of exploring limits in
macroecological relationships.

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DECLARATION
This is to certify that
i. the thesis comprises only my original work towards the PhD except where
indicated in the Preface,
ii. due acknowledgement has been made in the text to all other material used,
iii. the thesis is less than 100,000 words in length, exclusive of tables, maps,
bibliographies and appendices.

7 March, 2011
Madhavi A. Colton Date

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PREFACE
Chapter Four is a meta-analysis of data collected by myself, Dr. Sean Connell of the
University of Adelaide, and Mr. Alejandro Pérez-Matus of Victoria University in
Wellington, New Zealand. I conceived the idea for the chapter, analysed and wrote up
the data. Dr. Connell and Mr. Pérez-Matus supplied measures of fish density that were
made in the field.

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ACKNOWLEDGEMENTS
Thanks are due first and foremost to my supervisor Dr. Stephen Swearer whose
advice and support were invaluable. This work would not have been feasible without
the field assistance of Mr. Dean Chamberlain, Mr. John Ford, Dr. Christian Jung, Mr.
Matthew LeFeuvre and Mr. Malcolm Lindsay. Mr. Michael Sams was immensely
helpful in identifying the invertebrates, algae and seagrasses in habitat photos. The
Parks Victoria staff at the Mallacoota Office went above and beyond in their support
of our research efforts at Gabo Island. Thanks also to the Parks Victoria crew at
Wilsons Promontory. This research was funded by Natural Heritage Trust and Parks
Victoria, and I was supported by an Australian Postgraduate Award and a Helen
McPherson-Smith Scholarship. I was also supported by my husband Zack Kushner
who showed incredible patience with me through this process.
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TABLE OF CONTENTS
General Introduction…………………………………………………………… 1
Literature Cited…………………………………………………………….. 3

Chapter One: A comparison of two survey methods: differences between
underwater visual census and baited remote underwater video……………..... 6
Abstract…………………………………………………………….............. 6
Introduction………………………………………………………….……… 7
Materials & Methods……………………………………………………….. 12
Results………………………………………………………………………. 25
Discussion…………………………………………………………............... 30
Conclusion …………………………………………………………………. 40
Literature Cited……………………………………………………………... 40

Chapter Two: Body size and spatial grain influence fish-habitat associations in
temperate marine fishes ……………………………………………………… 44
Abstract……………………………………………………………................ 44
Introduction………………………………………………………….……… 44
Materials & Methods………………………………………………………... 48
Results………………………………………………………………………. 54
Discussion…………………………………………………………............... 60
Literature Cited……………………………………………………………... 68

Chapter Three: Locating faunal breaks in the nearshore fish assemblage of
Victoria, Australia…...………………………………………………………….. 71
Abstract……………………………………………………………................ 71
Introduction………………………………………………………….……… 71
Materials & Methods……………………………………………………….. 76
Results………………………………………………………………………. 82
Discussion…………………………………………………………............... 87
Literature Cited……………………………………………………………... 96

Chapter Four: Relationships between Geographic Range Size, Body Size and
Abundance in Temperate Marine Fishes…………………..…………………. 98
Abstract……………………………………………………………................ 98
Introduction………………………………………………………….……… 99
Materials & Methods……………………………………………………….. 102
Results………………………………………………………………………. 110
Discussion…………………………………………………………............... 112
Conclusion …………………………………………………………………. 124
Literature Cited……………………………………………………………... 125

General Conclusion……………………………………………………………. 129
Literature Cited…………………………………………………………….. 130

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GENERAL INTRODUCTION
Ecology is fundamentally the study of the distribution and abundance of species, and
these data are essential to any management or conservation plan. Numerous factors
can influence where a species occurs and the densities its populations attain. Results
from ecological studies investigating the mechanisms driving abundance and
distribution are “inextricably scale-dependent” (Sale 1998). At the scale of 1000s km,
for example, the distribution of fishes may be best explained by currents and their
associated temperatures (e.g. Figueira & Booth 2010), while at the scale of a single
reef, a species’ distribution may be strongly associated with structural complexity
(e.g. Leum & Choat 1980, Wiens 1989). To gain a complete understanding of
abundance and distribution requires investigating these parameters at multiple scales
(Eagle et al. 2001, Meyer & Thuiller 2006, Thogmartin & Knutson 2007, Grober-
Dunsmore et al. 2008). In particular, the terrestrial literature indicates that
consideration of the scale at which an organism relates to its environment is important
(Meyer & Thuiller 2006, Murakami et al. 2008), which is ultimately determined by its
body size (Holling 1992). There is considerable evidence in the terrestrial literature,
and some in the marine literature, to suggest that body size places an ultimate
constraint on density (Mohr 1940, Damuth 1981, Marquet et al. 1990, Cotgreave
1993, McGill 2008) and is positively correlated with geographic range size (Brown
1995). In addition, at least in terrestrial systems, range size and abundance are also
frequently related (Brown 1984, Borregaard & Rahbek 2010).

More than just body size, however, determines how an organism relates to its
environment. Behavioural attributes and life history interact to determine where a
species can occur and it population growth. The study of distribution, or range size, is
ultimately the study of dispersal and colonization (Myers 1997). Dispersal capacity
and colonization success are a function of interactions between species-specific traits,
e.g. reproductive mode and body size (e.g. Reaka 1980), and the environment
(Marshall et al. 2010). Whether dispersal is a good predictor of range size in the
marine environment is a matter of some debate (Jones et al. 2002, Hawkins et al.
2007, Pelc et al. 2009, Weersing & Toonen 2009). However, in terrestrial systems,
there does appear to be a link between abundance and connectivity as populations
tend to decline in fragmented habitats (Gonzalez et al. 1998). Colonization can only
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occur in areas where a species’ basic resource requirements are met and sites with
abundant resources may support larger populations. Multi-species interactions can be
very influential in determining a species’ abundance and distribution (Wethey 2002,
White 2007, Sexton et al. 2009), by facilitating or inhibiting range occupation and
population growth. Interactions with Homo sapiens most frequently negatively impact
other species’ population densities and ranges, either through habitat fragmentation or
resource dominance. A less frequently considered way in which humans impact
species’ abundances and distributions is through our observations. The methods we
choose to measure these data will influence our perception of these parameters.

Rocky reefs support a wide variety of flora and fauna, including many species of bony
and cartilaginous fishes. Much of our understanding of the ecology of subtidal
temperate environments comes from the Northern Hemisphere, where systems are
often upwelling-dominated (e.g., the California Current) or impacted by a long history
of fishing (e.g., the North Atlantic). The state of Victoria in south-east Australia has a
dynamic coastline that functions as a convergence zone for several distinct marine
bioregions (Whitely 1932, Hough & Mahon 1994, Lyne et al. 1996). The East
Australian Current carries warmer water from the tropics south to the Tasman Sea,
with eddies moving as far south as Tasmania (Gibbs 1991, Ridgway & Dunn 2003,
Middleton & Cirano 2005). The western part of the state is influenced by the South
Australian Current, which flows east from Western Australia (Ridgway & Condie
2004). In the centre lies Bass Strait, which is a fairly stagnant body of water due to the
actions of currents and tides (Fandry 1983, Baines et al. 1991, Gibbs 1991, Evans &
Middleton 1998).

Victoria’s dynamic oceanography gives this region a high potential for the emergence
of interesting patterns in abundance and distribution. Research in this region has
primarily focused on the biogeography and phylogeography of macroinvertebrates
(e.g. O'Hara & Poore 2000, O'Hara 2001, O'Loughlin et al. 2003, Waters & Roy
2003, Waters et al. 2004, Dawson 2005, Waters et al. 2005, Hidas et al. 2007, Waters
2008). However, there are a few studies that suggest that the fishes of this region also
exhibit biogeographic structure. For example, the life history of the shark
Heterodontus portusjacksoni differs between eastern and western Victoria (Tovar-
Ávila et al. 2007), and there are several species pairs with east-west distributions that
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may have arisen as a result of vicariance during glacial periods, e.g. Paraplesiops spp.
(Hutchins 1987). Finally, there are many species whose ranges terminate in eastern
Victoria (Kuiter 2000, Edgar 2005, Gomon et al. 2008), though it is unclear whether
these terminations occur primarily at Wilsons Promontory or further east.

In this research, I investigated patterns in the abundance and distribution of Victoria’s
rocky reef ichthyofauna. I was specifically interested in understanding the effect that
species-specific attributes, such as behaviour and body size, have upon abundance and
distribution. I began by exploring how two survey methods, underwater visual census
(UVC) and baited remote underwater video (BRUV), compared in the types and
numbers of species they record, and how species’ behaviour and size influenced these
methods (Chapter One). In Chapter Two, I discuss results from a study that quantified
associations between fish and habitat, and that specifically examined how body size
and spatial grain interact to determine species’ habitat associations. From this research
it became apparent that there were larger-scale factors influencing species’
distributions in Victoria. In Chapter Three, I discuss the biogeography of the fishes of
south-eastern Australian with regard to contemporary and historical barriers, currents
and temperature, identifying the site of two biogeographical disjunctions in eastern
Victoria. The final chapter, Chapter Four, investigates macroecological relationships
between body size, abundance and distribution for fishes of southern Australia and
New Zealand, and is the first exploration of relationships between these variables for
temperate marine fishes.

LITERATURE CITED
Baines PG, Hubbert G, Power S (1991) Fluid transport through Bass Strait. Continental Shelf
Research 11:269-293
Borregaard MK, Rahbek C (2010) Causality of the relationship between geographic
distributio and species abundance. Quarterly Review of Biology 85:3-25
Brown JH (1984) On the relationship between abundance and distribution of species. The
American Naturalist 124:255-279
Brown JH (1995) Macroecology, University of Chicago Press, Chicago
Cotgreave P (1993) The relationship between body size and population abundance in animals.
Trends in Ecology and Evolution 8:244-248
Damuth J (1981) Population density and body size in mammals. Nature 290:699-700
Dawson MN (2005) Incipient speciation of Catostylus mosaicus (Scyphozoa, Rhizostomeae,
Catostylidae), comparative phylogeography and biogeography in south-east Australia.
Journal of Biogeography 32:515-533
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