East Gippsland Nearshore Marine Habitat Mapping & Assessment Sean Blake, Peter Young, David Ball and Allister Coots
June 2010 Fisheries Victoria Department of Primary Industries
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East Gippsland Marine Habitat Mapping
ii
Copyright © The State of Victoria, Department of Primary Industries, 2010. This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968. Authorised by the Victorian Government, 2a Bellarine Hwy, Queenscliff, Victoria 3225 Printed by Fisheries Victoria, Queenscliff, Victoria Preferred way to cite: Blake, S., Young, P., Ball, D. and Coots, A. (2010) East Gippsland Nearshore Marine Habitat Mapping and Assessment. Fisheries Victoria Technical Report Series No. 87, 68 pages, Department of Primary Industries, Queenscliff, Victoria, Australia. ISSN 1835‐4785 ISBN 978‐1‐74264‐264‐2 (print)
Executive Summary This project aimed to map and assess the nearshore coastal waters in East Gippsland to improve knowledge about the location, spatial distribution, condition, and extent of marine habitats and associated biodiversity in the Twofold Shelf bioregion. The study area extended from Ewing Marsh, west of Marlo to the NSW border.
Sessile invertebrate and urchin communities dominated the deeper water. High densities of urchins and large areas of urchin barrens were present to depths of 30 m to the east of Point Hicks. No urchins were observed west of Petrel Point. While some areas were clearly denuded of macroalgae (barrens), others had high densities of urchins but some algae remained.
The shallow near‐shore environment up to depths of approximately 10–15 m was mapped from aerial imagery (aerial photography and Quickbird satellite imagery). Underwater video systems were used to collect information on seabed topography, habitat and biota to ground‐ truth the aerial imagery.
The sessile invertebrate communities in this region were dominated by sponges, and also included ascidians and sea pens. Basket stars were also present. Urchins were often observed associated with areas of sessile invertebrates, although this may have been due to the absence of a kelp canopy obscuring the underlying sessile invertebrates in other locations. Pyura stolonifera was frequently observed on intertidal and shallow subtidal reef.
A total of 19.7 km2 of reef habitat was mapped consisting of 17.1 km2 of reef, 1.3 km2 of patchy reef and 1.3 km2 of intertidal rock platform. An area of 127.7 km2 of sediment habitat was also mapped from the aerial imagery. The video ground‐truthing surveyed 137 drop sites and 15 transects covering 13.2 km between July 2008 and March 2009. The substratum types surveyed by the towed video consisted of 44% reef, 33% reef/sediment (i.e. patchy reef) and 23% sediment. The reef habitat was 53% high profile and 47% low profile. A clear depth zonation in the dominant biota was observed across the study area. Durvillaea potatorum was present fronting exposed rocky platforms to depths of approximately 3.5 m. The occurrence of D. potatorum was probably underestimated due to difficulties in accessing the shallow exposed habitat of this species during the field‐work.
Patches of Caulerpa sp. growing in sediment were observed to the west of Gabo Island. This was the only observation of vegetated sediment in this study. The overall mapping accuracy was 80%. The mapping errors were primarily due to 19 video sites classified as patchy reef being mapped as reef and 4 video sites classified as patchy reef being mapped as sediment. If the separate reef and patchy reef categories are combined into a single reef category the overall mapping accuracy increases to 95%. This indicates that the mapping had a high degree of accuracy in discriminating rocky reef from sediment.
Phyllospora comosa was the dominant canopy species in shallow depths 75%) / Sediment (1 m)
Continuous
Broken
EG8
13/07/2008
‐37.580302
149.775892
15.5
Low Profile Reef (1 m)
Continuous
Solid
EG10
13/07/2008
‐37.592875
149.737787
4.2
High Profile Reef (>1 m)
Continuous
Broken
Sessile invertebrates
EG11
13/07/2008
‐37.594020
149.735940
3.8
Low Profile Reef (1 m)
Continuous
Broken
Durvillaea potatorum Durvillaea potatorum
149.719657 149.719733
Phyllospora comosa Phyllospora comosa
Sessile invertebrates Sessile invertebrates Sessile invertebrates
EG17
13/07/2008
‐37.618545
149.727550
10.9
High Profile Reef (>1 m)
EG18
13/07/2008
‐37.620162
149.735555
17.1
EG19
13/07/2008
‐37.621652
149.719180
EG20 EG20_2
13/07/2008 13/07/2008
‐37.615137 ‐37.615122
EG21
13/07/2008
Urchins
13/07/2008
‐37.628772
149.718753
11.9
High Profile Reef (>1 m)
Patchy
Broken
‐37.634890
149.712302
4.9
High Profile Reef (>1 m)
Continuous
Solid
Phyllospora comosa Durvillaea potatorum
13/07/2008
Ecklonia radiata Phyllospora comosa
Sessile invertebrates Undifferentiated
EG22 EG23
Urchins
Urchins Urchins
East Gippsland Habitat Mapping
65
EG24
13/07/2008
‐37.638727
149.713363
9.5
High Profile Reef (>1 m)
Continuous
Broken
EG25
13/07/2008
‐37.641782
149.715348
14.6
High Profile Reef (>1 m)
Patchy
Broken
EG26
13/07/2008
‐37.649628
149.703362
7.1
High Profile Reef (>1 m)
Continuous
Broken
EG27
13/07/2008
‐37.656872
149.692983
4
High Profile Reef (>1 m)
Patchy
Broken
EG28
13/07/2008
‐37.662472
149.696433
15.2
High Profile Reef (>1 m)
Continuous
Broken
EG29
13/07/2008
‐37.666338
149.687900
10
High Profile Reef (>1 m)
Continuous
Broken
EG30
13/07/2008
‐37.673298
149.680272
3.5
High Profile Reef (>1 m)
Patchy
Broken
EG31
13/07/2008
‐37.673805
149.684672
11.7
Low Profile Reef (1 m)
Continuous
Broken
EG34 EG35 EG36 EG37 EG38
13/07/2008 13/07/2008 14/07/2008 14/07/2008 14/07/2008
‐37.781760 ‐37.780320 ‐37.782517 ‐37.781390 ‐37.783153
149.145312 149.169477 149.213138 149.204637 149.192850
8.1 3.1 10.4 7.1 6.4
Bare Sediment Bare Sediment Bare Sediment Bare Sediment High Profile Reef (>1 m)
Continuous
Solid
EG39
14/07/2008
‐37.809290
149.289065
11.6
High Profile Reef (>1 m)
Continuous
Solid
EG39_2
14/07/2008
‐37.808837
149.288585
22.4
High Profile Reef (>1 m)
Continuous
Broken
EG40
14/07/2008
‐37.803938
149.290930
3.5
High Profile Reef (>1 m)
Continuous
Solid
EG41
14/07/2008
‐37.796615
149.289385
3.8
High Profile Reef (>1 m)
Continuous
Broken
EG42 EG43 EG44 EG45
14/07/2008 14/07/2008 14/07/2008 14/07/2008
‐37.791505 ‐37.787325 ‐37.795328 ‐37.787862
149.288952 149.299657 149.305942 149.320010
3 3.3 15.9 12.6
Bare Sediment Bare Sediment Bare Sediment High Profile Reef (>1 m)
Continuous
Broken
EG46
14/07/2008
‐37.787583
149.333625
16.3
High Profile Reef (>1 m)
Continuous
Broken
EG47 EG48 EG49 EG50 EG51
14/07/2008 14/07/2008 14/07/2008 14/07/2008 14/07/2008
‐37.781165 ‐37.781687 ‐37.778525 ‐37.779338 ‐37.781545
149.331013 149.341660 149.351755 149.364980 149.376858
3.2 9.3 3.1 7.3 10.6
Bare Sediment Bare Sediment Bare Sediment Bare Sediment High Profile Reef (>1 m)
Continuous
Broken
EG52
14/07/2008
‐37.779573
149.379830
3
High Profile Reef (>1 m)
Patchy
Solid
EG52_2
14/07/2008
‐37.779712
149.379678
3.7
High Profile Reef (>1 m)
Patchy
Solid
Ecklonia radiata
Phyllospora comosa
Phyllospora comosa Phyllospora comosa
Ecklonia radiata Ecklonia radiata
Ecklonia radiata Phyllospora comosa Phyllospora comosa
Phyllospora comosa Durvillaea potatorum Ecklonia radiata
Phyllospora comosa Ecklonia radiata Ecklonia radiata Phyllospora comosa Phyllospora comosa Ecklonia radiata Ecklonia radiata Ecklonia radiata
Ecklonia radiata
Ecklonia radiata
Urchins
Sessile invertebrates Urchins
Urchins
Pyura stolonifera
Undifferentiated algae Sessile invertebrates
Undifferentiated
Pyura stolonifera
Urchins
Urchins
Sessile invertebrates
Urchins
Ecklonia radiata Ecklonia radiata Phyllospora comosa
Sessile invertebrates Undifferentiated Sessile invertebrates Sessile invertebrates Sessile invertebrates Sessile invertebrates Undifferentiated algae Pyura stolonifera
Durvillaea potatorum
Phyllospora comosa
Phyllospora comosa
Macrocystis angustifolia
Urchins
Undifferentiated Undifferentiated
East Gippsland Habitat Mapping
66
EG53
14/07/2008
‐37.778890
149.389233
4.5
High Profile Reef (>1 m)
Patchy
Broken
EG54
14/07/2008
‐37.780830
149.396513
10.5
High Profile Reef (>1 m)
Continuous
Broken
14/07/2008 14/07/2008 14/07/2008
‐37.779590 ‐37.779947 ‐37.778867
149.404725 149.414558 149.419883
9 12.1 5.1
Bare Sediment Bare Sediment High Profile Reef (>1 m)
Continuous
Broken
EG58
14/07/2008
‐37.779538
149.431242
7.5
Low Profile Reef (1 m)
Continuous
Broken
EG60
14/07/2008
‐37.773650
149.449017
4.7
High Profile Reef (>1 m)
Patchy
Solid
Phyllospora comosa Phyllospora comosa Ecklonia radiata Phyllospora comosa
EG55 EG56 EG57
Ecklonia radiata Ecklonia radiata Phyllospora comosa Ecklonia radiata
EG61 EG62 EG63
14/07/2008 14/07/2008 14/07/2008
‐37.772355 ‐37.772593 ‐37.774330
149.462120 149.472463 149.480370
4.3 5.6 3.4
Bare Sediment High Profile Reef (>1 m) Low Profile Reef (1 m)
Continuous
Broken
14/07/2008
‐37.773012
149.494015
11.5
High Profile Reef (>1 m)
Continuous
Broken
EG66
14/07/2008
‐37.767527
149.496915
8.4
High Profile Reef (>1 m)
Continuous
Broken
EG67
14/07/2008
‐37.757030
149.499407
3.5
High Profile Reef (>1 m)
Continuous
Broken
EG68 EG69
14/07/2008 14/07/2008
‐37.758880 ‐37.756522
149.506472 149.516970
13.2 8.6
Bare Sediment High Profile Reef (>1 m)
Continuous
Broken
EG70
14/07/2008
‐37.752328
149.512537
5.2
High Profile Reef (>1 m)
Continuous
Solid
EG71
14/07/2008
‐37.745315
149.519170
3.9
Low Profile Reef (1 m)
Continuous
Sand Inundated Broken
Ecklonia radiata Phyllospora comosa Phyllospora comosa Phyllospora comosa Ecklonia radiata Phyllospora comosa Ecklonia radiata Phyllospora comosa
Durvillaea potatorum
EG65
EG73 EG74
15/07/2008 15/07/2008
‐37.739615 ‐37.733525
149.544648 149.543008
18.3 3.4
Bare Sediment Low Profile Reef (1 m)
Continuous
Sand Inundated Solid
EG76
15/07/2008
‐37.730752
149.560788
7.4
High Profile Reef (>1 m)
Continuous
Solid
EG77
15/07/2008
‐37.732547
149.563792
14
High Profile Reef (>1 m)
Continuous
Broken
EG78
15/07/2008
‐37.729813
149.575102
11.9
High Profile Reef (>1 m)
Continuous
Broken
EG79
15/07/2008
‐37.730165
149.576888
10.6
High Profile Reef (>1 m)
Continuous
Broken
Phyllospora comosa Ecklonia radiata Ecklonia radiata Ecklonia radiata Phyllospora comosa Ecklonia radiata Phyllospora comosa Macrocystis angustifolia Ecklonia radiata Macrocystis angustifolia Not discernable Phyllospora comosa Ecklonia radiata Phyllospora comosa
Ecklonia radiata
EG80 EG81
15/07/2008 15/07/2008
‐37.727885 ‐37.726858
149.583773 149.591908
9.6 6.4
Bare Sediment Low Profile Reef (1 m)
Continuous
Broken
EG83
15/07/2008
‐37.722140
149.601300
12
High Profile Reef (>1 m)
Continuous
Broken
EG84
15/07/2008
‐37.713908
149.601790
1.4
High Profile Reef (>1 m)
Continuous
Broken
EG85
15/07/2008
‐37.711497
149.605267
5.1
High Profile Reef (>1 m)
Continuous
Solid
EG86 EG87
15/07/2008 15/07/2008
‐37.707285 ‐37.700007
149.611903 149.628947
8.6 9.3
Bare Sediment High Profile Reef (>1 m)
Patchy
Broken
EG88 EG89
15/07/2008 15/07/2008
‐37.699367 ‐37.696988
149.628922 149.635387
6.9 2.9
Low Profile Reef (1 m)
Continuous
Broken
EG95
15/07/2008
‐37.685085
149.678840
5.9
High Profile Reef (>1 m)
Patchy
Broken
EG96
15/07/2008
‐37.686055
149.680783
14.3
High Profile Reef (>1 m)
Continuous
Broken
EG97
15/07/2008
‐37.569883
149.911062
11
Low Profile Reef (1 m)
Continuous
Solid
EG99
15/07/2008
‐37.567685
149.917722
6
High Profile Reef (>1 m)
Continuous
Broken
EG100
15/07/2008
‐37.566317
149.918945
13.9
Low Profile Reef (1 m)
Continuous
Broken
EG101
15/07/2008
‐37.559432
149.916872
5
High Profile Reef (>1 m)
Continuous
Boulders
EG102
15/07/2008
‐37.548510
149.906918
1.6
High Profile Reef (>1 m)
Continuous
EG103
15/07/2008
‐37.549785
149.904590
3.5
Low Profile Reef (1 m)
Continuous
Boulders
Ecklonia radiata Phyllospora comosa
Undifferentiated red algae Undifferentiated red algae
Urchins
149.893945
33
Vegetated Sediment
Caulerpa sp.
Sessile invertebrates
Urchins Sessile invertebrates Urchins Sessile invertebrates Urchins
East Gippsland Habitat Mapping
68
EG108 EG109 EG110 EG111 EG112
16/07/2008 16/07/2008 16/07/2008 16/07/2008 16/07/2008
‐37.810917 ‐37.805425 ‐37.804485 ‐37.807343 ‐37.812090
148.656623 148.671212 148.691585 148.715435 148.725917
18.7 8.9 7.3 9.2 1.4
Bare Sediment Bare Sediment Bare Sediment Bare Sediment High Profile Reef (>1 m)
Continuous
Broken
EG113 EG114
16/07/2008 16/07/2008
‐37.813518 ‐37.808913
148.741887 148.736508
16.2 5.8
Bare Sediment High Profile Reef (>1 m)
Patchy
Broken
EG115
16/07/2008
‐37.799868
148.754380
6.5
High Profile Reef (>1 m)
Continuous
Broken
EG116
16/07/2008
‐37.803743
148.764358
16
Low Profile Reef (1 m)
Continuous
Solid
EG118
16/07/2008
‐37.793465
148.787282
6.9
High Profile Reef (>1 m)
Continuous
Broken
EG119 EG120 EG121 EG122 EG123
16/07/2008 16/07/2008 16/07/2008 16/07/2008 16/07/2008
‐37.790408 ‐37.787585 ‐37.787495 ‐37.788787 ‐37.791085
148.800495 148.823092 148.845515 148.868328 148.876432
6.9 4.4 7.2 7.3 9
Bare Sediment Bare Sediment Bare Sediment Bare Sediment High Profile Reef (>1 m)
Continuous
Solid
EG124
16/07/2008
‐37.796347
148.887507
11.7
Low Profile Reef (1 m)
Continuous
Broken
EG126
16/07/2008
‐37.795442
148.902428
17
High Profile Reef (>1 m)
Continuous
Broken
EG127 EG128 EG129 EG130 EG131 EG132 EG133
16/07/2008 16/07/2008 16/07/2008 16/07/2008 16/07/2008 16/07/2008 16/07/2008
‐37.787022 ‐37.783898 ‐37.793523 ‐37.783093 ‐37.788078 ‐37.784063 ‐37.788548
148.921533 148.947293 148.968848 148.996983 149.015303 149.033477 149.059692
10.6 5.3 19.4 3.4 15.5 7.5 13.7
Bare Sediment Bare Sediment Bare Sediment Bare Sediment Bare Sediment Bare Sediment Low Profile Reef (
