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The northern river shark (Glyphis sp. C)
in Western Australia
Report to the
D.C. Thorburn, D.L. Morgan, A.J. Rowland and H.S. Gill
Centre for Fish and Fisheries Research
February 2004
ISBN: 0642553351 Disclaimer The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment and Heritage.
TABLE OF CONTENTS
1 INTRODUCTION 1
1.1 Background 1
1.2 Previous freshwater surveys of northern Australia 1
1.3 Identification of Glyphis spp. 3
1.4 Conservation status 4
1.5 Objectives 5
2 METHODS 6
2.1 Sampling strategy 6
2.2 Sample sites 6
2.3 Sampling equipment and protocol 6
2.4 Species data collection 7
2.5 Environmental variables 8
3 RESULTS 9
3.1 Catch composition and species distribution 9
3.2 Physico-chemical environment 9
3.3 Species data 10
4 DISCUSSION 13
4.1 The current survey 13
4.2 Morphology and biology of Glyphis sp. C in King Sound 13
4.3 Survey techniques and limitations 14
4.4 Recommendations 15
5 REFERENCES 17
6 APPENDICES 19
1 INTRODUCTION
1.1 Background
While many of the ~166 shark species that inhabit Australian waters (Last and
Stevens 1994) are known to penetrate estuaries (Last 2002), only the bull shark
Carcharhinus leucas, speartooth shark (or Bizant River Shark) Glyphis sp. A and
northern river shark Glyphis sp. C occur in oligohaline environments of the upper
reaches of rivers far from the coast (Thorburn et al. 2003). Until recently, Glyphis sp.
A and Glyphis sp. C were known in Australia from approximately 25 records
collected from a few freshwater or weakly saline riverine habitats in the Northern
Territory and Queensland (Compagno and Niem 1998, Larson 2000, Last 2002,
Thorburn et al. 2003). There is also anecdotal evidence to suggest that members of
this genus occur in marine coastal habitats of Van Diemens Gulf and the Wessel
Islands (Arnhem Land). Furthermore in 2002, one Glyphis sp. C was collected from
the macrotidal Doctors Creek, a macrotidal mangrove habitat in King Sound near the
Kimberley town of Derby, Western Australia. This is approximately 1500 kilometres
(following the shortest distance along coast) from its nearest previously known
locality in the Adelaide River (Northern Territory), and thus represents a significant
range extension for the species.
1.2 Previous freshwater surveys of northern Australia
Prior to 2002, there were only two reported surveys of rivers in northern Australia
targeting freshwater sharks and rays. The first was conducted in two rivers in each of
the eastern Gulf of Carpentaria (Gilbert and Mitchell rivers) and Northern Territory
(Adelaide and Daly rivers) in 1989 (Taniuchi et al.1991), and resulted in the capture
of one Glyphis specimen from the Adelaide River (Table 1). The following year a
similar survey was made of the Ord and Pentecost rivers of the northern Kimberley
(Ishihara et al. 1991), however no Glyphis species were recorded. There are however
additional records of Glyphis spp. from several rivers in Queensland and the Northern
Territory (see Table 1). The lack of specimens, and subsequent morphological
descriptions, made it difficult for Taniuchi et al. (1991) and Larson (2000) to
differentiate between Glyphis sp. A from sp. C within their samples, and thus were
consequently recorded as the single Glyphis sp. However, Dr Peter Last (CSIRO
Marine Research, Hobart) examined several specimens collected during surveys of the
Alligator Rivers by Larson (2000), and was able to determine the presence of both
1
species. Thus, Glyphis sp. A has been recorded from the Bizant River in Queensland
(however it has not been recorded since the collection of the original two specimens),
and the Adelaide River, East, West and South Alligator rivers, and Murganella Creek
in the Northern Territory (Museum and Art Galleries of the Northern Territory
records). In contrast, Glyphis sp. C records only exist for specimens from the
Adelaide River, and the East and South Alligator rivers in the Northern Territory.
Table 1 Previous Australian records of Glyphis sp. A and Glyphis sp. C.
(NT- Northern Territory, Qld- Queensland).
Author Year Glyphis sp. Glyphis sp. A Glyphis sp. C McPherson pers.comm.1 1983 Qld: Bizant
Taniuchi et al. 1991 1989 NT: Adelaide
Larson 2000 1999 NT: East, West , South Alligator
Berra pers comm.2 2001 NT: Adelaide NT: Adelaide
Last 2002 2002 Qld: Bizant NT: South Alligator
1. Geoff McPherson, Fisheries Biologist, Northern Fisheries Centre, Qld Department of Primary Industries. 2. Tim Berra, Professor Emeritus, Dept. of Evolution, Ecology & Organismal Biology, The Ohio State University
Due to the paucity of data on the occurrence, distribution and biology of shark and ray
species in freshwater and estuarine reaches of northern Australian rivers, and an
overall concern regarding the population decline and status of elasmobranchs around
the globe, a Commonwealth funded (Environment Australia, Natural Heritage Trust)
survey of rivers across northern Australia was conducted in 2002 (Thorburn et al.
2003). Although 137 sample sites, in 39 river/creek systems were sampled, no
Glyphis specimens were recorded by the core sampling teams during that study.
However, during another research project studying fishes of the Fitzroy River and
King Sound, Western Australia, one of the authors collected a single Glyphis sp. C
(Morgan et al. 2002). Figure 1 shows the sites sampled for fishes throughout King
Sound and the lower Fitzroy River prior to this study, including those sampled by
Thorburn et al. (2003), and other sites sampled by the authors (including Morgan et
al. 2002), and the location of the first record of Glyphis sp. C in Western Australia.
2
Figure 1 Previous sites sampled in Doctors Creek, King Sound and lower Fitzroy
River, and the site of the original capture of Glyphis sp. C (Morgan et al. 2002,
Thorburn et al. 2003).
Fitzroy River
May River
Robinson River
King Sound
DoctorsCreek
WesternAustralia
Derby
Glyphis sp. C
Other sites sampled by authors
Thorburn (2002)et al.
1.3 Identification of Glyphis spp.
Currently, the number of Glyphis species that exist is uncertain, however there are
considered to be at least four to five. In addition to the two species known from
Australia (i.e. Glyphis sp. A and C), Glyphis glyphis (speartooth shark), Glyphis
gangeticus (Ganges river shark) and Glyphis sp. B (Borneo river shark) have been
reported from elsewhere in the world. However, due to lack of specimens and loss of
type material, the validity of all these species and nominal species is unclear.
3
Glyphis sp. A and C can be distinguished from a count of total vertebrae, i.e. sp. A
possesses approximately 217, as opposed to the 147-148 of sp. C (Compagno and
Niem 1998). Their age at maturity, fecundity, diet, maximum size and longevity is
unknown. The lack of records possibly reflect naturally low population sizes of these
animals, however the difficulties in distinguishing Glyphis from other shark species
may also be a contributing factor, often requiring close examination, dissection or X-
ray.
1.4 Conservation status
While the lack of information on these species is a point of concern in itself, this is
increased considering that Glyphis has not been seen in Queensland (the Bizant River)
for 20 years (one of the early collection sites) despite fishing still occurring in the
area. After the recognition of the occurrence, and subsequent identification of
Glyphis sp. A and C in Australia, the Commonwealth has adopted legislation for the
protection of these species in Commonwealth waters, by listing them under the
Environmental Protection Biodiversity and Conservation Act 1999, as critically
endangered and endangered, respectively. Similarly, Pogonoski et al. (2002) also
listed these species in these categories. A recent workshop, and subsequent report by
the IUCN Shark Specialist Group of Australia and Oceania Regional Red List has
however recently upgraded the status of Glyphis sp. C to critically endangered
(Pogonoski and Pollard 2003).
In Western Australia, Commonwealth waters begin three nautical miles from the low
water mark (under the Offshore Constitutional Settlement 1987, 1988 and 1995) and
thus the State Government is responsible for the waters between this three nautical
mile limit and the coast (see Boulter 2002). Even though Glyphis sp. A and C are
protected in Commonwealth waters, they are not listed under Schedule 2 (Protected
Fish) of the Fish Resources Management Regulations 1995, which preclude them
from protection in Western Australia. Thus, both commercial and recreational fishers
can take Glyphis, from the inshore waters in which they occur.
4
1.5 Objectives
It was the discovery of a single Glyphis sp. C from the macrotidal marine mangrove
system Doctors Creek, that indicated that the remoteness of its locality may provide
refuge for this cryptic species. This projects primary aims were to:
• determine the relative abundance of Glyphis sp. C in Doctors Creek
• determine whether Glyphis sp. C occurs in other saline mangrove systems and
river mouths in the surrounding areas
If Glyphis sp. C was collected in sufficient numbers the project also had the potential
to collect both biological information about the species, and describe its habitats.
5
2 METHODS
2.1 Sampling strategy
The strategy was to sample a range of sites throughout Doctors Creek and other
habitats, including additional macrotidal mangrove systems, inshore areas of King
Sound, and the lower reaches of the Fitzroy River. Due to the large tides present in
King Sound and the susceptibility of these areas to strong winds, and thus rough
waters during different times of the year, sampling was conducted in areas only
accessible by boat from Derby on selected days (noting tides and weather patterns)
over two periods in June and November.
2.2 Sample sites
A total of 22 sites were sampled (Figure 2). Eight sites were sampled in Doctors
Creek, six sites in King Sound, including near Airports Creek, and eight in the lower
reaches of the Fitzroy River, in particular at Snag Pool, Telegraph Pool and on the
Yeeda River. Longitude and latitude were recorded at each sample site using a Global
Positioning System (GPS). The sampling site and distribution maps were created
using the GPS data and MapInfo (MapInfo Corporation 1998). Sample site locations
are provided in Appendix 1.
2.3 Sampling equipment and protocol
Sampling was primarily conducted using a combination of 20 m (2 m drop)
monofilament gill net panels of 5, 7.5, 10, 15 and 20 cm stretched mesh. The 5 and
7.5 cm stretch mesh were joined and set in slower moving/still waters, while a
combination of the stronger 10, 15 and 20 cm stretched mesh was often used in
slightly higher flowing waters. Gill nets were primarily anchored to run at right
angles to the river bank or to block as much of the channel as possible, however they
were set parallel to the bank when the flow rate was high (during peak tidal
movement). At sampling sites that were affected by excessive tidal influence, gill
netting was conducted during periods of slow and slack water, and usually two hours
either side of low tide when fishes are retreated into deeper holes. Net set times
varied with tidal flow, size of tidal influence and change of tide. Nets were checked
at regular intervals to ensure bycatch was not excessive. Handling times were also
minimised, and animals released when fully revived.
6
Figure 2 Sites sampled for Glyphis sp. C during this study and the locations where it
was found.
Fitzroy River
May River
Robinson River
King Sound
DoctorsCreek
WesternAustralia
Derby
Glyphis sp. C
This study
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In addition to gill nets, baited longlines and handlines/rod and lines were used
throughout the set period. Due to access limitations, sampling on the Yeeda River
(sites 21 and 22) was only conducted with rod and line.
2.4 Species data collection
All elasmobranchs were identified before release or returned to Murdoch University
for further examination. In the case of Glyphis sp. C, digital images were taken, sex
and total length recorded, and DNA sample taken (finclip). Specimens were also X-
rayed to determine the number of vertebrae. One large female was also fully
7
dissected to provide an insight into the size of maturity. These specimens will
eventually be lodged at museums after further investigation.
2.5 Environmental variables
Water chemistry
The salinity (ppt) and temperature (oC) were recorded at each sample site using either
a YSI 30 portable salinity, conductivity and temperature meter, or a model RHS-
10ATC portable refractometer and thermometer, respectively. A secchi disc was used
to obtain water clarity values.
Habitat
The depth, estimated flow rate and direction of the tide (if present) were recorded for
each site. The habitat was also described on the basis of substrate type, vegetation
and detrital cover of the substrate, snag density and bank form.
8
3 RESULTS
3.1 Catch composition and species distribution
A total of 46 individuals of eight species of elasmobranch were caught while sampling
in June and November 2003 (Table 2). The most abundant species encountered
during the two sampling periods was the dwarf sawfish, Pristis clavata, constituting
~57% of the total catch, followed by the freshwater sawfish Pristis microdon (~15%).
Surprisingly, Glyphis sp. C was the next most abundant elasmobranch encountered
(~13%), and although overall shark catches were low, this was the most abundant
Carcharhinidae (see Appendix 2 for netting times and sampling gear used at each
sampling site).
Table 2 Elasmobranch catch composition.
Family Species N % composition
Carcharhinidae Carcharhinus amboinensis 1 2.2
Carcharhinus leucas 3 6.5
Carcharhinus tilstoni 1 2.2
Glyphis sp. C 6 13.0
Negaprion acutidens 1 2.2
Dasyatidae Himantura undulata 1 2.2
Pristidae Pristis clavata 26 56.5
Pristis microdon 7 15.2
Total individuals 46
The six Glyphis sp. C were collected while sampling in Doctors Creek and other areas
of King Sound (Figure 2). All six specimens were taken during the June sampling
period, with two individuals collected near a small tidal feeder of Doctors Creek (site
number 1 and 3) (and in very close proximity to the site of capture by Morgan et al.
2002). The four remaining specimens were collected from site 9, adjacent to the
mouth of a small tidal feeder, ~7 kilometres south of Derby, during a single sampling
period.
3.2 Physico-chemical environment
The sites at which Glyphis sp. C were encountered during this study were marine
9
environments with salinities ranging from 32.1 to 33.4 ppt, and water temperatures
ranging from 22.3 to 23.5 oC (Appendix 3). Sites 1, 3 and 9, at which the six Glyphis
sp. C specimens were captured, are all highly effected by the large tides present
throughout King Sound. At the time of capture, waters were therefore extremely
turbid (ranging from 3-5 centimetres secchi depth), with flow rates ranging from ~0.2
to 0.5 ms-1. The sites had sandy or silt bottoms with little structure in the form of
snags or root mats.
3.3 Species data
Of the six Glyphis sp. C specimens collected, four were male, ranging in length from
906 to 1418 mm TL, while the two female specimens were 957 and 1350 mm TL
(Table 3). Dissection of the largest female specimen (1350 mm TL) revealed that this
individual was immature, however the largest male (1418 mm TL) possessed fully
calcified claspers, suggesting that it was fully mature. In contrast, the next largest
male collected during this study (1191 mm TL) was immature, as evident by the
possession of small non-calcified claspers. In comparison, the smaller original
specimen collected by Morgan et al. (2002) was 994 mm TL, and possessed semi-
calcified claspers, indicating semi-maturation. The severe curvature of the spine
observed in this specimen however (Figure 3 and 4), may mean that its total length is
not representative of a specimen of this age and maturity.
X-rays and dissection revealed that vertebral counts of all Glyphis sp. C captured
ranged from 142 to 151 (Table 3). In comparison, the original specimen collected by
Morgan et al. (2002) had 140 vertebrae. Inspection of the X-rays of this specimen
however revealed the reason for its deformed appearance, showing severe fusing of
vertebrae and curvature of the spine (Figure 3 and 4). Some degree of the fusing of
vertebrae (Figure 5) was also observed in the largest male (1418 mm TL) and in the
largest female (1350 mm TL) collected in 2003.
X-rays also revealed that the stomachs of three of the five specimens contained fork
tailed catfishes (likely Arius graeffei), easily identified by their barbed spines and
distinctive head plate of the upper skull, whilst the stomach of the dissected specimen
was comprised largely of threadfin salmon (Polydactylus macrochir).
10
Table 3 Biological parameters of the Glyphis sp. C collected during sampling for this
study, and the original specimen (italicised) collected by Morgan et al. (2002).
Maturity: I immature; SM semi-mature; M mature.
Location Sex Maturity TL (mm) Weight (g) Total Vertebrae
Doctors Ck M SM 994 N/A 140
Doctors Ck M I 906 5150 147
Doctors Ck F I 957 5970 147
King Sound F I 1350 16830 151
King Sound M I 1191 10560 148
King Sound M M 1418 18640 142
King Sound M I 1022 7700 147
11
Figure 3 Glyphis sp. C (994 mm TL) collected by Morgan et al. (2002) illustrating
the distorted appearance, as a result of the curved spine and fused vertebrae (see
Figure 4).
Figure 4 X-ray showing severe fusing of vertebrae (and curvature of the spine) in the
Glyphis sp. C specimen collected by Morgan et al. (2002).
Figure 5 X-ray showing fused vertebrae in the largest male Glyphis sp. C (1418 mm
TL) collected during this study.
12
4 DISCUSSION
4.1 The current survey
During this study, Glyphis sp. C was encountered in Doctors Creek, and
approximately seven kilometres south of Derby (and ~ 20 km south of the mouth of
Doctors Creek) near a small tidal feeder creek in King Sound. While often referred to
as a freshwater species, it was not encountered in the Fitzroy River estuary or
freshwater reaches during this study or by those by Morgan et al. (2002) and
Thorburn et al. (2003), and thus far in Western Australia has only been caught in the
marine environment of King Sound.
4.2 Morphology and biology of Glyphis sp. C in King Sound
Although only six Glyphis sp. C were captured within the sites sampled, they were the
most abundant carcharhinid caught during this study. However, one of the authors on
previous occasions has encountered large numbers of milk sharks (Rhizoprionodon
acutus). Of the six Glyphis sp. C captured, four were caught together in one net set,
and two were taken from the same locality in Doctors Creek over two consecutive
days. This may indicate that this species habitually moves in and out of the same tidal
feeder with high and low tides. While sampling in King Sound, nets were generally
only set in deeper holes throughout the low tide or in times of slow water flow.
However, these deeper holes often comprise the only refuge for fishes, as much of the
inshore areas of King Sound become exposed at low tide. Glyphis sp. C also appears
well adapted to live in the highly turbid, fast flowing highly tidal waters (often over
40 m of tidal movement per day) of King Sound, for example, it possesses a reduced
eye and a large number of sensory papillae useful in highly turbid waters, and large
fins for efficiency, stability and agility.
Data collected from specimens returned to Murdoch University (from this study and
that by Morgan et al. 2002) provided valuable information on a species, about which
virtually nothing is known. X-rays and dissections revealed that vertebral counts can
have greater variation (140 to 151 vertebral centra) than the 147-148 total vertebral
centra reported by Compagno and Niem (1998). The disparities in vertebral count
may be a result of only a few specimens being examined, or that this population has
some morphological differences. Furthermore, spinal deformities in elasmobranchs
are rarely reported, with only a few cases of individuals of several species noted
13
(Heupal et al. 1999). While the cause of the deformities is often unknown, they may
be caused by parasitic infection, arthritis, injury, disease, tumors, malnutrition or by a
genetic abnormality. Considering that three of the seven specimens collected from
King Sound possess some degree of spinal deformation (one severe), it is possible that
the malformations may be caused by a genetic abnormality. That is, the high
occurrence of the deformity may represent inbreeding within a small gene pool.
Specimens collected during this study also provided preliminary data on size at sexual
maturity. Dissection of the largest female revealed her to be immature, thus
indicating that females may mature at greater than 1350 mm TL. Alternatively, at
1418 mm TL, the largest male collected possessed fully calcified claspers indicative
of the attainment of sexual maturity. The next largest male (1191 mm TL) however
was immature, and it is suggested that maturation may occur between these sizes.
The specimen collected by Morgan et al. (2002) was 994 mm TL, and possessed
semi-calcified claspers, indicating semi-maturation. This discrepancy may be
attributed to the deformation of the specimen, impeding growth, and not reflect a total
length typical of an individual of that age.
4.3 Survey techniques and limitations
The large tidal variation (over 40 m per day), susceptibility of King Sound to
prevailing winds and presence of estuarine crocodiles makes sampling in King Sound
at times difficult. While conditions were more favourable for transit in King Sound
during the June sampling period, sampling in November was hindered due to high
winds associated with seasonal thunderstorms. Additionally, the presence of large
quantities of water-borne debris/detritus throughout King Sound in November, may
have influenced fish abundances in the area. We were however able to sample at a
range of locations throughout the region. Although gill nets are the best means of
sampling in the area, nets can only be used at low tide or periods of slower water
movement (i.e. either side of the low or high tide). Furthermore, access to boat
launching facilities are only usable either side of high tide. The window of
opportunity for travel and sampling is very narrow, as much of the sound becomes
exposed at low tide, and remains so for several hours.
14
4.4 Recommendations
Of immediate concern to the conservation of Glyphis sp. C is the lack of protection of
this species in coastal waters between the low water mark and three nautical miles
offshore, within which this species has been found during this study. If this species
becomes listed as a ‘totally protected fish’ in Schedule 2 of the Fish Resources
Management Regulations 1995, than this would afford the species maximum
protection in waters under Western Australian jurisdiction.
This brief survey provides baseline data upon which a comprehensive long term
survey of Doctors Creek and the King Sound area can be designed. To fully
understand the population status of Glyphis sp. C, seasonal/monthly sampling at both
high and low tides, during night and day, at a number of locations throughout King
Sound would provide a better understanding of the conservation status of this species,
and also illustrate migration and movement patterns. Sampling in this format, will
also allow a large amount of information on the critical habitat in which Glyphis sp. C
is found to be collated, on feeding habitats and ranges, morphology and on the
breeding cycle of this species. Additionally, expanding the survey to those areas
immediately north of King Sound (such as Stokes Bay and Walcott Inlet), and in other
parts of the Kimberley will clarify if this is the only area that this species is found in
Western Australia.
Although Glyphis sp. C is currently protected by Commonwealth legislation in
Commonwealth waters, a significant amount of ecological data can be collected using
non-fatal research techniques. Tagging is an effective way to observe migration
patterns, and recapture data can be useful in estimating population numbers in the
immediate area. Satellite tracking is another efficient way to observe daily
movements (such as in and out of tidal feeders), and migration of individuals over a
period of time. Additionally, the collection of genetic material in the form of a tissue
sample before release, can be used to clarify taxonomic problems and study the
various existing populations.
Probably of greatest benefit to the survival of Glyphis sp. C in King Sound is the
education of recreational fishers accessing waters from Derby. Sharks are readily
attracted to baits, however if fishers are aware of the conservation status of this
15
species, and are able to distinguish Glyphis sp. C from other sharks caught in the area,
individuals are more likely to be released upon capture. The erection of signs
describing and distinguishing the species, and its conservation status, at boat ramps
and access points in Derby and in the lower Fitzroy River will make all users aware of
the presence of Glyphis sp. C and its conservation status.
16
5 REFERENCES
Boulter, S.L. (2002). Coast Law in Western Australia. Environmental Defenders
Office WA, Perth, Australia.
Compagno, L.J.V. and Niem, V.H. (1998). Order Carcharhinidae. pp 1312-1360. In:
Carpenter, K.E. and Niem, V.H. (Eds), FAO Species Identification Guide for
Fisheries Purposes. The Living Marine Resources of the Western Central
Pacific. Volume 2. Cephalopods, crustaceans, holothurians and sharks. FAO,
Rome.
Heupal, M.R., Simpfendorfer, C.A. and Bennett, M.B. (1999). Skeletal deformities in
elasmobranchs from Australian waters. Journal of Fish Biology 54: 1111-1115.
Ishihara, H., Taniuchi, T., Sano, M. and Last, P.R. (1991). Record of Pristis clavata
Garman from the Pentecost River, Western Australia, with brief notes on its
osmoregulation, and comments on the systematics of the Pristidae. University
Museum, University of Tokyo, Nature and Culture 3: 43-53.
Larson, H.K. (2000). Report to Parks Australia on Estuarine Fish Monitoring of
Kakadu National Park, Northern Australia, Australia. Museum and Art Gallery
of the Northern Territory, Darwin.
Last, P.R. (2002). Freshwater and Estuarine Elasmobranchs of Australia.
Elasmobranch Biodiversity Conservation and Management. In: Fowler, S.L.,
Reed, T.M. and Dipper, F.A. (Eds), Proceedings of the International Seminar
and Workshop, Sabah, Malaysia, July 1997. Occasional Paper IUCN Species
Survival Commission, 185-92.
Last, P.R and Stevens, J.D. (1994). Sharks and Rays of Australia. CSIRO Division of
Fisheries, CSIRO, Australia.
17
MapInfo Corporation. (1998) MapInfo Professional Users Guide, MapInfo
Corporation, New York, USA.
Morgan, D., Allen, M., Bedford, P. and Horstman, M. (2002). Inland Fish Fauna of
the Fitzroy River Western Australia - including the Bunuba, Gooniyandi,
Ngarinyin, Nyikina and Walmajarri Aboriginal names. Report to the Natural
Heritage Trust: 56 pp.
Pogonoski, J.J. and Pollard, D.A. (2003). Northern river shark. pp 120-121. In
Cavanagh, R.D., Kyne, P.M., Fowler, S.L., Musick, J.A., and Bennett, M.B.
(eds.), The Conservation Status of Australian Chondrichthyans: Report to the
IUCN Shark Specialist Group Australia and Oceania Regional Red List
Workshop. The University of Queensland, School of Biomedical Sciences,
Brisbane, Australia: 170 pp.
Taniuchi, T., Shimizu, M., Sano, M., Baba, O. and Last, P.R. (1991). Description of
freshwater elasmobranchs collected from three rivers in Northern Australia.
University Museum, University of Tokyo, Nature and Culture 3: 11-26.
Thorburn, D.C., Peverell, S., Stevens, J.D., Last, P.R. and Rowland, A.J. (2003).
Status of Freshwater and Estuarine Elasmobranchs in Northern Australia.
Report to the Natural Heritage Trust: 79 pp.
18
6 APPENDICES
Appendix 1 Sites sampled for Glyphis sp. C.
Site number Sampling location Latitude (oS) Longitude (oE)
1 Doctors Ck (Feeder Creek) 17.219 123.684
2 Doctors Ck 17.218 123.685
3 Doctors Ck (Feeder Creek) 17.221 123.686
4 Doctors Ck (Feeder Creek) 17.120 123.597
5 Doctors Ck (Feeder Creek) 17.199 123.666
6 Doctors Ck 17.219 123.685
7 Doctors Ck (Luggers Creek) 17.160 123.633
8 Doctors Ck (Luggers Creek) 17.153 123.629
9 King Sound (Feeder Creek) 17.350 123.579
10 King Sound 17.351 123.586
11 King Sound 17.356 123.575
12 King Sound (Feeder Creek) 17.350 123.579
13 King Sound 17.351 123.587
14 King Sound (Airport Creek) 17.341 123.600
15 Fitzroy River (Telegraph Pool) 17.638 123.567
16 Fitzroy River (Snag Pool) 17.598 123.574
17 Fitzroy River (Snag Pool) 17.596 123.565
18 Fitzroy River (Snag Pool) 17.596 123.568
19 Fitzroy River (Telegraph Pool) 17.636 123.567
20 Fitzroy River (Telegraph Pool) 17.644 123.568 21 Yeeda River 17.555 123.634 22 Yeeda River 17.577 123.638
19
Appendix 2 The lengths and set times of gill nets used at sampling sites. N.B. All mesh panles are 20m long. Additional capture techniques:
LL-long line; RL-hand line/rod and line.
Site # Date Gill net (5 and7.5 cm) set (hrs) Gill net (10, 15 and 20 cm) set (hrs) Additional techniques
1 06/06/2003 1 6 RL2
06/06/2003 3.17 4.67 RL3 07/06/2003 2 5.33 LL; RL
4 21/06/2003 - 55 21/06/2003 - 2.5 RL6 01/11/2003 6 6 RL7 02/11/2003 3 3.25 RL8 02/11/2003 3 3 RL9 09/06/2003 3.5 6.92 RL10 09/06/2003 3.5 7.4211 09/06/2003 2.25 3.0812 14/11/2003 3 3 RL13 14/11/2003 3.17 314 14/11/2003 1.25 1.2515 11/06/2003 2.33 3 RL16 12/06/2003 1.5 2 RL17 22/06/2003 2.75 2.9218 30/10/2003 16.5 17 RL19 06/11/2003 3 3.25 RL20 07/11/2003 3 3.2521 13/11/2003 - - RL22 13/11/2003 - - RL
20
Appendix 3: Glyphis sp. C habitat data.
Site Location Date Secchi (cm)
Temp (ºC)
Salinity (ppt)
Depth (m)
Flow (ms-1) Tidal Sediment Habitat surface area n
1 Doctors Ck 6/06/03 3 23.4 33.4 6-2 0.5 out, over low, in silt low detrital cover, few root mats 1 3 Doctors Ck 7/06/03 4 23.5 33.0 6-2 0.5 out, over low silt low detrital cover, few root mats 1 9 King Sound 9/06/03 5 22.3 32.1 4-7 0.2 high, out, over low silt low detritus, few root mats, few snags 4
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