Groote Eylandt survey Apr 2015 final

Department of Health is a Smoke Free Workplace

Groote Eylandt exotic mosquito survey report

27 to 30 April 2015

William Pettit and Nadine Copley

Medical Entomology

Centre for Disease Control

Department of Health

Northern Territory Government

April 2017

DEPARTMENT OF HEALTH


Medical Entomology, Centre for Disease Control

Department of Health, Northern Territory 2017

This publication is copyright. The information in this report may be freely copied and distributed for

• non-profit purposes such as study, research, health service management and public information subject to the inclusion of an acknowledgment of the source. Reproduction for other purposes requires the written permission of the Chief Executive of the Department of Health, Northern Territory.

An electronic version is available at: http://digitallibrary.health.nt.gov.au/prodjspui/

General enquiries about this publication should be directed to:

Nina Kurucz

Director

Medical Entomology CDC Department of Health 7PO Box 41326, NT 0811

Phone:

(08) 8922 8901

Facsimile:

(08) 8922 8820



Background

Medical Entomology (ME) of the Department of Health (DoH) visited Groote Eylandt between 27th and 30st April 2015 to carry out a mosquito survey for exotic and endemic species. Operations included larval mosquito surveys at various properties in Alyangula and Umbakumba (Figs 1 & 2), setting of adult mosquito CO2 baited EVS and CO2 baited BG (Biogents) sentinel adult mosquito traps in the town of Alyangula, and conducting mosquito larval surveys at the Angurugu and Umbakumba sewage ponds.

The activities of the current survey were similar in size and scope to exotic mosquito surveys conducted by DoH in March 2014 in the towns of Alyangula and Angurugu (Pettit and Copley 2017). None of the mosquitoes collected during the survey were exotic species.

Alyangula – mosquito surveillance and exotic incursions

Alyangula is a community of approximately 1400 people who are mainly Groote Eylandt Mining Company (GEMCO) employees or employees of support services for mining operations on the island. The town consists of approximately 400 properties (Fig. 1), with sprinkler irrigation a common practice to maintain gardens (Fig. 3). A wharf area that receives international ore carrying and general cargo vessels is located 600m from the town.

Routine adult mosquito monitoring was established and conducted by GEMCO in Alyangula using CO2 baited EVS traps between July 1981 and October 1983 (Fig. 6). Following a period without routine trapping between October 1983 and January 1995, GEMCO resumed the program in February 1995. A routine fortnightly adult mosquito trapping program was maintained until January 2014, when the program was suspended due to resource unavailability.

The routine adult mosquito monitoring program provides information to GEMCO about endemic mosquito species affecting Alyangula residents and workers at the mine site. It also provides a level of surveillance for exotic mosquito species that may become established in Alyangula.

Routine ovitrap surveillance has been conducted in Alyangula since July 1998. Apart from a short program suspension between 2000 to 2003, GEMCO carried out fortnightly surveillance until March 2014, when the program was again suspended.

The high receptivity of Alyangula for the establishment of exotic Aedes species was confirmed in October 2006 when a routine ovitrap at the port detected the presence of Ae. aegypti. A subsequent larval survey in Alyangula found 45 (10%) properties positive for Ae. aegypti breeding. Four rounds of property survey and insecticide treatment of every property in Alyangula were required to eliminate Ae. aegypti during the successful two year program managed by the NT DoH. During the course of the elimination program a total of 86 properties in Alyangula were found breeding Ae. aegypti, with a single property positive in Angurugu. No Ae. aegypti were found in Umbakumba or any other locations on Groote Eylandt (Kulbac and Whelan 2007).



Umbakumba

Umbakumba is a community of approximately 400 people located 44km east of Alyangula (Fig. 2). Although the town has approximately 90 dwellings, the majority of yards are devoid of items that can collect and hold water following rain. Irrigation of yards to maintain lawns and gardens is uncommon (Fig 4).

Alyangula mosquito larval survey

Groote Eylandt received below average rain during the 2014/2015 wet season. In March 88.4mm of rain was recorded at Groote Eylandt airport followed by 35.2mm in April. This rainfall was sufficient to fill receptacles with water and provide breeding places for a number of mosquito species.

A total of 29 property backyards were surveyed for mosquito larvae between 27/04/15 and 30/04/15 (Fig. 1). Thirteen properties were positive for mosquito breeding. Of 75 receptacles holding water, 26 (35%) were found to be colonised with mosquito larvae (Table 1 and Figs 7 to 10). Aedes notoscriptus was the most commonly sampled mosquito and was present in 16 water holding receptacles. No exotic mosquitoes were collected during the survey.

Alyangula adult mosquito trapping

CO2 baited BG (BioGents) sentinel traps

Four CO2 baited BG (BioGents) sentinel traps (Fig. 5) were set in the residential area of Alyangula on four occasions during the visit, and left running for 24 hours. The number of mosquitoes captured in each trap was low, with Ae. notoscriptus the most abundant species collected in all 4 traps (Table 2). No exotic species were collected.

CO2 baited EVS adult mosquito traps

CO2 baited EVS adult mosquito traps (Fig. 6) were set overnight at two of the three routine adult monitoring sites (Golf course and Township) on two separate occasions (27/04/15 and 29/04/15). Each trap was suspended on steel posts at the trap sites and CO2 gas was supplied to the traps from CO2 gas cylinders. The number of mosquitoes captured in the traps was very low (Table 3). No exotic species were collected.

Umbakumba mosquito larval survey

Most backyards in Umbakumba were able to be assessed for potential mosquito breeding sites while driving past each house. The contents of the yards of most properties were clearly visible from the street. There were very few items in any backyards or properties that were capable of holding water.

The yards of 4 properties were entered and surveyed for mosquito larvae on 29/04/15. Three properties were positive for mosquito larvae. Of seven receptacles that were found to be holding water five were found to be colonised with mosquito larvae. No exotic mosquitoes were collected during the survey.



Umbakumba town swamp survey

A small saline swamp approximately 50m south of the Shire office was holding water at the time of the survey (Figs 2, 14 & 15). Larvae of the salt tolerant mosquito species Culex sitiens were present in considerable numbers among the filamentous algae and Eleocharis reeds. No fish or other mosquito predators were observed to be present in the swamp at the time of the survey. Following rain or high tides Aedes vigilax (northern salt marsh mosquito) is also likely to breed in the swamp and become locally abundant. Both Ae. vigilax and Cx. sitiens will readily bite humans. Aedes vigilax is regarded as the principle vector of Ross River virus and Barmah Forest virus and Cx. sitiens is a potential vector of Ross River virus.

This swamp appears to be man-made. The causeway at the swamp’s eastern end forms a barrier that impedes water flow out of the swamp. The causeway is visible in aerial photography from 1972 and subsequent aerial photos show evidence of works to improve drainage away from the swamp on the east side of the causeway.

The Umbakumba Community Services Manager advised that every year during the wet season, the swamp fills completely to the level of the invert of the culvert under the causeway due to run-off from the catchment area. The base of the invert under the causeway is currently 1 to 1.5 metres higher than the base of the saline swamp (Fig. 15).

While it may not be cost effective to routinely control mosquito larvae in the swamp with insecticide, rectification works could be considered to reduce the amount of water in the swamp, reducing its potential to produce mosquitoes.

The following options are recommended to the Shire to reduce the amount of water being held in the swamp after the wet season. Ideally all these options should be implemented concurrently;

• The lowest sections of the swamp should be filled with sand and levelled. Fill should be collected from the intertidal zone, but should not include marine mud. Sand taken from the intertidal zone will ensure that the fill does not introduce weeds to the swamp. It is unlikely that the level of the base of the swamp can be raised to be level with the base of the invert under the causeway. However, filling of large depressions in the base of the swamp would reduce or eliminate early dry season pooling and thus mosquito breeding.

• A flap gate could be installed on the downstream side of the culvert under the causeway. This would greatly limit the intrusion of salt water into the swamp on all but the highest tides / storm surges that overtop the causeway. While a flap gate would limit the ingress of water to the swamp it would permit drainage of water from the swamp to the level of the invert of the culvert under the causeway (Fig. 15). Debris that gets caught at the flap gate during the wet season would have to be removed following each wet season (when the swamp stops flowing under the causeway). Both ends of the culvert would also need to be desilted after each wet season. Obstructions that prevent the flap gate from closing completely would allow the ingress of salt water into the swamp. Ideally a 5m long concrete invert



should be installed on the downstream side of a flap gate to minimise pooling/gouging and silt and debris build-up around the flap gate that could prevent it from closing.

• Both sides of the culvert under the causeway should be desilted on an annual basis so that water from the swamp exits through the culvert at the level of its invert rather than at the height of the sand obstructing either end if it (Fig. 15). If only this option is carried out, then it is likely that a storm tide will more easily push water up into the swamp since the effective height of the invert will be lower that it currently is (ie - sand partially obstructing each end of the culvert).

• A new larger and deeper culvert could be installed under the causeway such that the invert of the new culvert is at the same height as the base of the swamp. Together with a flap gate on the outflow of the culvert the ingress of tidal flow into the swamp would be minimised. As a result of this option, very little water would be retained in the swamp following rain or tidal ingress.

Angurugu and Umbakumba sewage ponds – site visits

The Umbakumba and Angurugu sewage ponds were surveyed on 29/04/15 and 30/04/15 respectively. Recommendations with respect to minimising mosquito establishment in the ponds and in any environmental releases from the ponds have been communicated to PowerWater.

Pole 13 complex – site visit

The complex at Pole 13 is a three hectare site about 1km south-east of Alyangula where GEBIE Civil and Construction Division, the Anindilyakwa Land and Sea Management unit, the Bakery and Alyangula Mini Mart are located.

During the survey, a number of septic systems that were not sealed to prevent the ingress and egress of mosquitoes were located (Figs 12 & 13). Some of these systems are under the management of the Anindilyakwa Land and Sea Management unit and others are under the control of GEBIE. A large pile of tyres was located at the main gate of the GEBIE property and was found to be colonised by a range of mosquito species (Fig. 11, Table 1). Disused tyres should be stored in a dry state under cover until they can be properly disposed of, or modified so that they do not hold water.

Written advice was provided to GEBIE (7/05/15) and the Anindilyakwa Land and Sea Rangers (5/05/15) specifying the needed actions in regards to septic system rectification and other measures to prevent productive mosquito breeding on their properties.

There are no insecticides that are effective at preventing mosquitoes from colonising septic tanks. The only effective means is by ensuring the system is insect proof with pit lids always replaced, all breather pipes meshed and all damaged tanks and pipes repaired.



Conclusions

The mosquito larval surveys carried out on Groote Eylandt in April 2015 did not detect any exotic mosquito species in either Alyangula or Umbakumba. The detection of a number of endemic receptacle breeding mosquito species during the surveys indicated that suitable breeding sites for Ae. aegypti or Ae. albopictus are commonly available throughout Alyangula if either of these species are introduced to the town. Groote Eylandt remains vulnerable to an incursion of Ae. aegypti or Ae. albopictus. The most likely point of introduction is the international shipping port at Alyangula and the most likely route is via imported cargo from South East Asia. The cessation of the routine mosquito monitoring program (adult mosquito trapping and ovitraps) by GEMCO in early 2014 has greatly reduced the opportunity for early exotic mosquito detection on Groote Eylandt, which is now limited to annual surveys by Medical Entomology. GEMCO should reinstate this important program at the earliest opportunity. In the future, regular adult mosquito monitoring should incorporate occasional setting of CO2 baited BG traps at ad hoc locations about Alyangula to enhance exotic mosquito surveillance. References Pettit W. and Copley N. (2017). Groote Eylandt exotic mosquito survey report 19 to 21 March 2014. NT Department of Health report. Kulbac M. and Whelan P. (2007). Dengue mosquito incursion and the eradication program on Groote Eylandt NT. The Northern Territory Disease Control Bulletin 14:3:30-34.



TABLE 1: Alyangula exotic mosquito survey 27 to 30 April 2015 - Summary of receptacle description and mosquito species collected.

LOCATION CONTAINER DESCRIPTION To

tal

No

. o

f p

ote

nti

al

co

nta

iners

To

tal

No

. o

f co

nta

iners

in

specte

d

To

tal

No

. o

f co

nta

iners

wit

h w

ate

r

To

tal

No

. o

f co

nta

iners

bre

ed

ing

% o

f co

nta

iners

wit

h w

ate

r b

reed

ing

Ae.

(Fin

) noto

scri

ptu

s

Ae.

(Mac)

trem

ulu

s

Ae.

(Stg

) kath

eri

nensi

s

Cx.

(Cux)

quin

quefa

scia

tus

Lu

. (M

et)

hali

faxii

No

t id

enti

fiab

le

Tp

. (P

ol)

pun

cto

late

rali

s

LS1 - Residence Smith St Boat 1 1 0 0 - 0 0 0 0 0 0 0

Bucket (mop) 1 1 0 0 - 0 0 0 0 0 0 0

LS2 - Residence Smith St Plant cutting container 1 1 1 1 100 0 0 0 1 0 0 0

Pool (child's) 1 1 1 1 100 0 0 1 0 0 0 0

LS3 - Residence Smith St Bucket (unspecified) 2 2 1 0 0 0 0 0 0 0 0 0

Pool (child's) 1 1 0 0 - 0 0 0 0 0 0 0

Pot plant base 2 2 0 0 - 0 0 0 0 0 0 0

LS4 - Residence Smith St Nil containers 0 0 0 0 - 0 0 0 0 0 0 0

LS5 - Residence Connie Bush St Bucket (unspecified) 3 3 2 0 0 0 0 0 0 0 0 0

Dog bowl 2 2 2 0 0 0 0 0 0 0 0 0

Pool (Swimming) 1 1 1 0 0 0 0 0 0 0 0 0

LS6 - Residence Connie Bush St Bucket (mop) 1 1 0 0 - 0 0 0 0 0 0 0

Bucket (unspecified) 2 2 1 0 0 0 0 0 0 0 0 0

Dog bowl 1 1 1 0 0 0 0 0 0 0 0 0

Drum (1/2 44 gal) 1 1 1 1 100 1 0 0 0 0 0 0

LS7 - Residence Connie Bush St Bucket (unspecified) 2 2 2 0 0 0 0 0 0 0 0 0

Container (Ice cream) 1 1 1 0 0 0 0 0 0 0 0 0

Pond 1 1 1 0 0 0 0 0 0 0 0 0

Pot (gardening) 1 1 1 1 100 0 0 1 0 0 0 0

Wheel barrow 1 1 1 0 0 0 0 0 0 0 0 0

LS8 - Residence Cypress St bromeliad 10 10 3 2 66.7 1 1 1 0 0 0 0

Plant cutting container 1 1 1 1 100 0 0 0 0 0 1 0

LS9 - Residence Brunker St Dog bowl 1 1 1 0 0 0 0 0 0 0 0 0

Pool (child's) 1 1 1 0 0 0 0 0 0 0 0 0



Pot plant base 1 1 1 1 100 1 0 0 0 0 0 0

Self watering pot plant 1 1 0 0 - 0 0 0 0 0 0 0


Drum (44 gal) 1 1 1 0 0 0 0 0 0 0 0 0

LS13 - Residence Brunker St Bird water 1 1 1 0 0 0 0 0 0 0 0 0

LS14 - Residence Brunker St Toy 2 2 0 0 - 0 0 0 0 0 0 0

Wheel barrow 1 1 0 0 - 0 0 0 0 0 0 0

LS15 - Residence Brunker St Polystyrene box 1 1 0 0 - 0 0 0 0 0 0 0

LS16 - Residence Bougainvillea Dr Bird bath 2 2 2 1 50 1 0 0 0 0 0 0

bromeliad 3 3 3 0 0 0 0 0 0 0 0 0

Bucket (plastic) 1 1 1 0 0 0 0 0 0 0 0 0

LS17 - Residence Bougainvillea Dr Tyre (unspecified) 2 2 0 0 - 0 0 0 0 0 0 0

LS18 - Residence Muninga St Nil containers 0 0 0 0 - 0 0 0 0 0 0 0

LS19 - Residence Ngwunga St Container (Ice cream) 1 1 1 1 100 1 0 0 0 0 0 0

Rubbish bin 1 1 1 1 100 1 0 0 0 0 0 0

LS20 - Residence Taylor St Boat cover 1 1 1 1 100 1 0 0 1 1 0 0

Fish pond 1 1 1 0 0 0 0 0 0 0 0 0

LS21 - Residence Bougainvillea Dr Bin (plastic) 2 2 2 1 50 1 0 0 0 0 0 0

Bucket (mop) 1 1 1 1 100 1 0 0 0 0 0 0

Bucket (unspecified) 1 1 1 1 100 1 0 0 0 0 0 0

Plastic container 1 1 1 1 100 0 0 0 1 0 0 0

Plastic lid 1 1 0 0 - 0 0 0 0 0 0 0

Pot plant base 2 2 1 0 0 0 0 0 0 0 0 0

Self watering pot plant 2 2 1 0 0 0 0 0 0 0 0 0

Tyre (car) 2 2 2 2 100 1 1 1 0 0 0 0

LS22 - Residence Ayawarra Cres Dog bowl 3 3 3 0 0 0 0 0 0 0 0 0



Tyre (car) 3 3 1 0 0 0 0 0 0 0 0 0

LS23 - Residence Ayawarra Cres Dog bowl 1 1 1 0 0 0 0 0 0 0 0 0

Pool (child's) 1 1 1 0 0 0 0 0 0 0 0 0

LS24 - Residence Ngwunga St Nil containers 0 0 0 0 - 0 0 0 0 0 0 0

LS25 - Residence Ngwunga St Bucket (unspecified) 3 3 3 0 0 0 0 0 0 0 0 0

Tyre (truck) 2 2 2 2 100 1 0 0 1 0 0 0

LS26 - Residence Cypress Rd Bucket (unspecified) 4 4 2 1 50 1 0 1 0 0 0 0


Pot plant base 1 1 0 0 - 0 0 0 0 0 0 0

Tyre (car) 2 2 0 0 - 0 0 0 0 0 0 0

Watering can 1 1 1 1 100 1 0 1 0 0 0 0

LS27 - Residence Arnhem Cres Dog bowl 1 1 1 0 0 0 0 0 0 0 0 0

Pot plant base 2 2 0 0 - 0 0 0 0 0 0 0

LS28 - Nursery Alebuwa Street Bunded area 1 1 1 0 0 0 0 0 0 0 0 0

Clam shell 1 1 1 0 0 0 0 0 0 0 0 0


Pot plant base 20 20 0 0 - 0 0 0 0 0 0 0

Trolley 3 3 2 0 0 0 0 0 0 0 0 0

Boat 1 1 0 0 - 0 0 0 0 0 0 0

Drum (Unspecified size) 2 2 0 0 - 0 0 0 0 0 0 0

Tyre (unspecified) 70 3 3 3 100 1 1 0 1 1 0 1

Water tank 2 2 1 0 0 0 0 0 0 0 0 0

202 135 75 26 16 3 6 5 2 1 1

66.8 37.1 12.9 61.5 11.5 23.1 19.2 7.7 3.8 3.8

34.7

PREMISES AND POTENTIAL CONTAINER SUMMARY

TOTALS

% OF TOTALS

% OF CONTAINERS WITH WATER BREEDING

NUMBER OF CONTAINERS POSITIVE FOR EACH

SPECIES

LS29 - Pole 13

commercial/residential complex



TABLE 2: Alyangula exotic mosquito survey 27 to 30 April 2015 - Summary of mosquito species collected in CO2 baited BG adult mosquito traps.

Ad. (Ady) catasticta

Ae. (Fin) kochi

Ae. (Fin) notoscriptus

Ae. (Mac) tremulus

Ae. (Och) vigilax

Ae. (Stg) katherinensis

Cx. (Cux) quinquefasciatus

Cx. (Cux) species

Cx. (Cux) Vishnui group

Tra

p l

ocat

ion

Tra

p t

ype

Date set

Date collected

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

Total No. of females

Total No. of males

BG

1 -

Ngw

unga

St

BG

Tra

p +

CO

22

7-A

pr-

15

28

-Apr-

15

00

00

10

20

00

12

10

00

00

52

BG

2 -

Bo

ugai

nvi

llea

Dr

BG

Tra

p +

CO

22

7-A

pr-

15

28

-Apr-

15

10

00

00

00

00

10

01

00

00

21

BG

3 -

Co

nnie

Bush

St

BG

Tra

p +

CO

22

8-A

pr-

15

29

-Apr-

15

00

10

40

00

10

10

00

00

40

11

0

BG

4 -

War

ren C

lB

G T

rap +

CO

22

8-A

pr-

15

29

-Apr-

15

00

00

00

00

00

00

00

00

20

20

BG

5 -

Cypre

ss R

dB

G T

rap +

CO

22

9-A

pr-

15

30

-Apr-

15

00

00

70

00

10

33

00

00

70

18

3

BG

6 -

Car

penta

ria

Crt

BG

Tra

p +

CO

22

9-A

pr-

15

30

-Apr-

15

00

00

00

00

00

00

00

20

00

20

10

10

12

02

02

06

51

12

01

30

40

6

TO

TA

LS

TO

TA

LS



TABLE 3: Alyangula exotic mosquito survey 27 to 30 April 2015 - Summary of mosquito species collected in CO2 baited EVS adult mosquito traps.

Ae. (Fin) kochi

Ae. (Fin) notoscriptus

Ae. (Mac) species

Ae. (Och) vigilax

An. (Cel) meraukensis

Cq. (Coq) xanthogaster

Cx. (Cui) pullus

Cx. (Cux) annulirostris

Cx. (Cux) Vishnui group

Tra

p l

ocat

ion

Tra

p t

ype

Date set

Date collected

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

No. of females

No. of males

Total No. of females

Total No. of males

EV

S -

To

wnsh

ip S

ite

CO

2 E

VS

Tra

p2

7-A

pr-

15

28

-Apr-

15

00

50

00

00

00

10

00

00

00

60

EV

S -

To

wnsh

ip S

ite

CO

2 E

VS

Tra

p2

9-A

pr-

15

30

-Apr-

15

00

20

01

00

00

10

00

00

10

41

EV

S -

Go

lf C

ours

eC

O2

EV

S T

rap

27

-Apr-

15

28

-Apr-

15

10

10

01

10

00

00

00

10

30

71

EV

S -

Go

lf C

ours

eC

O2

EV

S T

rap

29

-Apr-

15

30

-Apr-

15

00

10

00

10

10

00

60

60

40

19

0

10

90

02

20

10

20

60

70

80

36

2

TO

TA

LS

TO

TA

LS



TABLE 4: Umbakumba exotic mosquito survey 29 April 2015 - Summary of receptacle description and mosquito species collected.

AD

DR

ES

SC

ON

TA

INE

R D

ES

CR

IPT

ION

Total No. of potential containers

Total No. of containers inspected

Total No. of containers with water

Total No. of containers breeding

% of containers with water breeding

Ae. (Mac) tremulus

Ae. (Stg) katherinensis

Cx. (Cux) quinquefasciatus

Bucket

(unsp

ecif

ied)

11

11

10

00

10

Sum

p (

co

ncre

te)

11

10

00

00

Wheel

bar

row

11

11

10

00

10

LS

31

- R

esi

dence

Bo

at (

din

ghy)

11

11

10

00

01

Bucket

(pla

stic

)1

11

11

00

00

1

Pla

stic

co

nta

iner

11

10

00

00

LS

32

- U

mbak

um

ba

superm

arket

Dru

m 2

0L

11

11

10

01

10

Bin

(unsp

ecif

ied)

11

00

-0

00

Fri

dge (

dis

use

d)

10

10

00

-0

00

Tyre

(car

)6

60

0-

00

0

24

24

75

13

2

10

0.0

29

.22

0.8

20

.06

0.0

40

.0

71

.4

PR

EM

ISE

S A

ND

PO

TE

NT

IAL

CO

NT

AIN

ER

SU

MM

AR

Y

NU

MB

ER

OF

CO

NT

AIN

ER

S

PO

SIT

IVE

FO

R E

AC

H S

PE

CIE

S

TO

TA

LS

% O

F T

OT

AL

S

% O

F C

ON

TA

INE

RS

WIT

H W

AT

ER

BR

EE

DIN

G

LS

30

- C

ouncil

wo

rks

buil

din

g

LS

33

- U

mbak

um

ba

Dum

p

(Dry

)



FIGURE 1: Alyangula exotic mosquito survey 27 to 30 April 2015 - CO2

baited BG adult mosquito trap sites, CO2 baited EVS adult mosquito trap sites and larval survey sites.



FIGURE 2: Umbakumba exotic mosquito survey 29 April 2015 - survey sites.



Fig 3: Typical elevated house in Alyangula – high set with irrigated lawn (lawn sprinkler in foreground).

Fig 4: Fairly typical ground level house in a Groote Eylandt community -low set and garden without irrigation.

Figure 5: CO2 baited BG trap set at Alyangula residence for 24hr period to catch adult mosquitoes

Figure 6: Routine trap site at Alyangula golf club – cabinet to hold CO2 gas cylinder, post to hang trap assembly and a hose to deliver CO2 to the trap

Figure 7: A drum under an outboard motor found to be colonised with mosquito larvae

Figure 8: A plant cutting bucket found to be colonised with mosquito larvae



Figure 9: A dog bath found to be colonised with mosquito larvae

Figure 10: A disused drum found to be colonised with mosquito larvae

Figure 11: A pile of disused tyres at Pole 13 – some found to be colonised with mosquito larvae

Figure 12: An unsealed septic tank colonised by mosquitoes at Pole 13

Figure 13: Unsealed breather pipe on side of a building provides possible entry for mosquitoes in and out of septic tank.

Figure 14: Saline swamp on western side of causeway in Umbakumba.



Figure 15: Causeway in Umbakumba with saline swamp in background.

Groote Eylandt survey Apr 2015 final

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