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Offshore Artificial Reef

Sydney Offshore Artificial Reef (EPBC 2008/4176

and SD2008/882)

Annual Environmental Monitoring Report

(Year 2)

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Table of Contents

Table of Contents.................................. .........................................................2

Tables and Figures ................................. .......................................................2

Background and Aims................................ ...................................................3

2. OAR design and Installation ..................... ................................................4

3. Monitoring Objectives ........................... ....................................................5

3.1 Priority One Objectives........................................................................5 3.2 Priority Two Objectives .......................................................................7

4. Monitoring carried out over last year........... ............................................8

4.1 Priority One Objectives........................................................................8 4.2 Priority Two Objectives .......................................................................9

5. Key findings .................................... .........................................................11

5.1 Fish assemblage ................................ ................................................11 5.2 Angler effort.................................. ......................................................13 5.3 Epibenthic community........................... ............................................14

6. Non compliance and /or Environmental incidents.. ..............................15

Tables and Figures

Figure 1. Dimensions of the Offshore Artificial Re ef (OAR)......................4

Figure 2. Deployment of the Offshore Artificial R eef (OAR).....................5

Figure 3. Water quality sensor (eco triplet) attach ed to the mast of the OAR (top photo) and current meter between the masts to record physical data. ..................................... ..........................................................10

Table 1. List of species identified by video observ ations at the OAR.....11

Figure 3. Comparison between the top of the OAR (to p photo) populated by mobile schooling species and the base dominated by various species of ray, benthic sharks and leatherjacket species... ...................................12

Figure 4. Relative abundance of top ten species ass ociated with the OAR determined by baited remote underwater video (B RUV). ................13

Figure 6. Photograph indicating deployment of exper imental plates to investigate interaction of fish and epibenthic comm unities’ ...................15

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Background and Aims The potential for establishing offshore artificial reefs in NSW coastal shelf

waters is considered by the Ministers Advisory Council for Recreational

Fishing (ACoRF) and the recreational fishing community as a high priority.

Trade and Investment received funding in from the Recreational Fishing

Saltwater Expenditure Committee (RFSTEC) to investigate the potential for

establishing three offshore artificial reefs in NSW coastal shelf waters.

A comprehensive Environmental Assessment (EA) was undertaken in

accordance with State and Commonwealth legislation. The EA was completed

in July 2010 and identified Priority 1 & 2 objectives that needed to be

addressed as part of the conditions for approval. This project also required an

Sea Dumping Permit issued under the Environment Protection (Sea Dumping)

Act 1981 from the Department of Sustainability, Environment, Water,

Population and Communities (DSEWPaC).

Sea Dumping Permits ensure that appropriate sites are selected, materials

are suitable and appropriately prepared, that there are no significant adverse

impacts on the marine environment and that the reef does not pose a danger

to marine users. A condition of the Permit is that the Proponent (Trade and

Investment) implement the proposed Environmental Monitoring and

Management Plan (EMMP) submitted in September 2011.

The purpose of this report is to comply with annual reporting commitments

associated with the EMMP (EPBC 2008/4176 section e [i & ii]) and associated

Sea Dumping permit (SD2008/882).

This Progress Report details;

a. key findings from the post placement monitoring and environmental

monitoring ;

b. a description of the monitoring and management undertaken over the

last 12 months ; and

c. non compliance and /or Environmental incidents involving Threatened

and /or Migratory Species (including sightings and/or incidental capture).

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2. OAR design and Installation The OAR unit design is 12 m x 15 m x 12 m (height x length x width) with the

bulk of the internal structure in the lower 4 m (Fig. 1). The OAR unit is

manufactured from square hollow sections (SHS) and rectangular hollow

sections (RHS) and plates, and weighs approximately 42 tonnes (dry weight).

Four concrete anchor bocks are connected to each corner to ensure OAR

stability.

Figure 1. Dimensions of the Offshore Artificial Re ef (OAR).

The OAR unit has design certification to withstand a 1/100 year storm event

(a wave height of approximately 18 m – HMax) and will have an operational

lifespan of 30 years. The deployment site is approximately 1.9 km (1.3 nm)

south-east of South Head (Sydney Harbour) at a depth of 38 m.

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The OAR was lowered into position on the morning of 12 October 2012 (Fig.

2) this was followed by the attachment of moorings and inspection by divers

prior to commissioning on the 13 October 2011.

Figure 2. Deployment of the Offshore Artificial R eef (OAR).

3. Monitoring Objectives Monitoring objectives are broadly characterised as Priority one and Priority

two. Priority one monitoring objectives were mandatory under approval

conditions Priority two objectives were to be addressed given available

funding and resources.

3.1 Priority One Objectives

Priority One objectives relate to the species composition and residency times

of the fish community associated with the OAR, particularly in relation to how

this differs to the fish assemblage associated with natural (control) reefs in the

immediate vicinity. Additional priorities include an assessment of the level of

interaction between threatened species and the OAR, structural integrity of

the OAR, and the popularity of the OAR with recreational fishing groups.

The following methods are used;

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• Baited Remote Underwater Video (BRUV) provide estimates of the

relative abundance of fish at each location (OAR and control)

interaction with threatened species and a means of assessing the

structural integrity of the OAR.

• Pelagic BRUV systems are used to monitor fish movements associated

with the OAR at a broader scale.

• Tethered (unbaited) video provide estimates of spatial variation in the

assemblage and interaction with threatened species.

• Video surveys to record physical change on the sea floor

(sedimentation and scouring), growth of macroalgal and any structural

changes associated with the OAR.

• Shore mounted video cameras to monitor use of the reef by anglers

also provide assessment of reference locations for comparison.

• Acoustic tagging technology to determine movement patterns of

species (including threatened / endangered species interactions

species interactions) associated with offshore artificial structure.

A range of video monitoring systems (shore based baited and unbaited

underwater) are used in conjunction with ultrasonic telemetry to assess

change in the fish assemblage, quantify fishing effort associated with the OAR

and determine levels of interaction between threatened species and marine

mammals and the OAR. Comparison of assemblage structure (diversity,

species richness and relatively abundance) collected by a combination of

BRUVS and UVC observations between OAR and control locations is used to

assess any differences between the OAR and natural reefs in the immediate

area. This information will be complemented by movement data (ultrasonic

telemetry) of fish tagged on the OAR and on control reefs. Analysis of this

information will provide a more detailed picture of movement patterns and

residency times of selected species between the OAR, naturally occurring

reefs and the broader marine environment. Assessment of popularity

including catch rates associated with recreational anglers will be assessed

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using angler log book programs. Structural integrity will be assessed by

regular visual and photographic inspections of the OAR.

3.2 Priority Two Objectives

Priority two objectives incorporate the assessment of benthic assemblages

(soft sediments) including concentration of heavy metals, potential ‘halo’

effects around the OAR and an examination of the macroinvertebrate

communities (including invasive and pest species) associated with the OAR.

Additional priorities examine the potential for patterns of water movement

associated with the OAR to affect local levels of productivity.

Priority two objectives will be assessed using the following methods;

• Benthic grab samples to determine changes in composition of soft

sediment around the OAR.

• Benthic ‘feeding plates’ to examine potential differences in the

interaction between the fish assemblage and macrobenthic community

between locations.

• Video and photographic surveys to assess benthic diversity.

• Acoustic current meter (ADCP) to assess influence of the OAR on

water movement.

• Optical plankton counts to assess water quality and plankton biomass

around the OAR.

Benthic grazing plates are deployed inside fish-exclusion cages and no-cage

controls at the OAR and control locations to assess the grazing of benthic

assemblages by fish. Feeding plates are deployed removed and redeployed

on the OAR over a 6 month cycle. Video observations are used to document

differences in the benthic communities between OAR and control locations.

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4. Monitoring carried out over last year

4.1 Priority One Objectives

Activities related to meeting priority one objectives are primarily related to the

deployment of monitoring infrastructure. Initial focus has been on establishing

the shore based video systems to monitor angler activity associated with the

OAR and deployment of ultrasonic receiver array to detect fish movements

associated with the OAR. The ongoing work involves sampling the OAR and

proximal natural reefs (control sites) with unbaited and baited video sampling.

Additional work has focussed on the deployment of and retrieval of equipment

and sampling associated with Priority Two objectives, particularly the

sampling of the benthos around the OAR. In addition a comprehensive audit

of project objectives was carried out. Findings identified compliance with

monitoring objectives within the agreed time frames.

Shore based cameras: Two cameras have been deployed providing

continuous daytime coverage of angler activity around the OAR site and

reference location (Nth Head) since November 2011. Preliminary investigation

of the imagery involves a trial comparing insitu observations with camera

imagery in order to validate possible sources of bias associated with

determining the number of anglers directing effort to the OAR.

Video Surveys: Pre and post deployment pelagic and benthic BRUV surveys

have been completed. Post deployment baited and unbaited video surveys

have also been carried out on a monthly basis. Preliminary analysis of the

pelagic and benthic BRUV video has been completed.

Acoustic tagging: Ultrasonic receiver (Vemco VR2W) was deployed on the

in November 2011 and has been replaced and downloaded over 5 cycles

post- deployment. Capture and implantation of transmitters of fish at OAR and

control locations is ongoing.

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4.2 Priority Two Objectives

Under the conditions of the approval (EA ref number) priority two objectives

were to be addressed given available funding and resources. An ARC link

proposal was developed to provide required support to complete priority two

objectives. The ARC link proposal (LP120100592) was successful and

activiated in June 2012 resulting in sufficient resources to adress priority two

objectives.

Benthic grab samples: The sediment particle size distribution (PSD),

concentrations of heavy metals and water quality was surveyed at as part of

the preliminary environmental assessment (PEA). Concentrations of heavy

metals within the sediments were well below the ANZECC interim sediment

quality guidelines (ISQG) lower trigger values for marine systems at all

locations and provide a baseline for future assessment. Additional post

deployment sampling has been carried out to investigate potential impacts of

the deployment of the OAR on benthic infauna.

Benthic ‘feeding plates’: Benthic feeding plates have been deployed on the

OAR and at control locations. Plates on the OAR have been retrieved and

replaced as part of the second evolution of sampling.

Video and photographic surveys (benthic diversity): Complementary

video surveys of the OAR structure have been carried out in conjunction with

the BRUV sampling. A total of 18 video surveys of the structure and additional

5 diver based surveys have been carried out post deployment.

Deployment of current meter and optical plankton co unter: Mechanical

current meter and water quality sensor (eco triplet) have been deployed on

the OAR (Fig. 3).

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Figure 3. Water quality sensor (eco triplet) attached to the mast of

the OAR (top photo) and current meter between the m asts to

record physical data.

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5. Key findings

5.1 Fish assemblage

Results from the post placement monitoring are primarily derived from video

observations (baited and unbaited) around the OAR. Baited remote

underwater video (BRUV) has identified a total of 22 species (Table 1).

Species Scientific name Yellowfin bream Acanthopagrus australisEastern smooth boxfish Anoplocapros inermisMado Atypichthys strigatusSergeant baker Aulopus purpurissatusShorttail stingray Dasyatis brevicaudataMoray eel Gymnothorax prasinusPort Jackson Shark Heterodontus portusjacksoniSixspine leatherjacket Meuschenia freycinetiVelvet Leatherjacket Meuschenia scaberStripey Microcanthus strigatusOcean leatherjacket Nelusetta ayraudiBlue morwong Nemadactylus valenciennesiWobbegong Orectolobus maculatusSnapper Pagrus auratusBlackspot goatfish Parupeneus spilurusBluespotted flathead Platycephalus caeruleopunctatusSilver trevally Pseudocaranx dentexEastern red scorpionfish Scorpaena jacksoniensisYellowtail kingfish Seriola lalandiYellowtail scad Trachurus novaezelandiaeEastern fiddler ray Trygonorrhina fasciataBluestriped goatfish Upeneichthys lineatusJohn Dory Zeus faber

Table 1. List of species identified by video observ ations at the OAR.

The number of species identified per month followed a moderate increase in

diversity from 4 species pre-deployment to a peak of 16 species 8 months

post deployment. Comparison of baited and unbaited video sampling

identified depth related differences in assemblage associated with the OAR.

Species commonly associated with the base of the structure include Port

Jackson sharks (Heterodontus portusjacksoni) Wobbegongs (Orectolobus

maculatus) and various species of rays while schooling species such as

yellowtail scad (Trachurus novaezelandiae) and silver trevally (Pseudocaranx

dentex) dominated the upper sections of the structure.

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Figure 4. Comparison between the top of the OAR (to p photo) populated

by mobile schooling species and the base dominated by various

species of ray, benthic sharks and leatherjacket sp ecies.

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Rapid recruitment of large numbers of mobile schooling species particularly

mado (Atypichthys strigatus), yellowtail scad (Trachurus novaezelandiae) and

Ocean leatherjackets (Nelusetta ayraudi) is reflected in the relative

abundance data (Fig. 4). Several species targeted by recreational anglers

such as Snapper (Pagrus auratus), Silver trevally (Pseudocaranx dentex)

Yellowtail kingfish (Seriola lalandi), and Blue morwong (Nemadactylus

valenciennesi) and were also regularly identified on video samples.

Mado

Yellowtail scad

Ocean leatherjacket

Snapper

Silver trevally

Flathead

Blue morwong

Fiddler RayKingfish

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(Max

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Leatherjacket (sp)

Species

Mado

Yellowtail scad

Ocean leatherjacket

Snapper

Silver trevally

Flathead

Blue morwong

Fiddler RayKingfish

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N)

Leatherjacket (sp)

Species

Figure 5. Relative abundance of top ten species ass ociated with the

OAR determined by baited remote underwater video (B RUV).

5.2 Angler effort

Preliminary analysis of the shore based video information indicated visitation

rates to the OAR that were consistently greater than observed at the

reference location. As expected visitation rates were strongly influenced by

prevailing weather conditions and day type (weekend or weekday). More

recent work has provided an assessment of levels of effort directed by anglers

around the structure (see Fig. 5). Results indicate moderate levels of fishing

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activity with a decrease over the winter period followed by a strong increase in

angler usage over the following summer and autumn.

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Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr

Boa

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2012 2013

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Figure 5. Estimated monthly fishing effort directed towards the OAR

(April 2012-2013).

5.3 Epibenthic community

Comparison of video observations over the three month period following

deployment showed that the majority of the structure had changed from being

bare to completely covered in encrusting organisms including serpulid

polychaetes, barnacles, filamentous algae, bryozoans and hydroids. No

introduced marine pests or species that are protected under conservation

legislation were observed.

More detailed investigation to investigate the interaction of the fish and

epibenthic community involves the deployment of settlement plates on the

structure (see Fig. 6). These plates have been retrieved and analysis is

underway. This information will identify community structure, the rate at which

organisms attach to the OAR and provide a better understanding of trophic

interactions between the fouling community and the fish assemblage.

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Figure 6. Photograph indicating deployment of exper imental plates to

investigate interaction of fish and epibenthic comm unities’

6. Non compliance and /or Environmental incidents Visual inspection and video surveys of the OAR identified no structural flaws

in any of the OAR components. Inspection of areas around the base of the

structure (footings and mooring blocks) did not indicate any significant areas

of deposition or scouring. There have been no recorded incidents of non

compliance and or environmental incidents involving threatened and /or

migratory species. No threatened or endangered species have been identified

by video sampling, direct observation or via ultrasonic telemetry.