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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