executive summary · web viewfish fauna in both artificial reefs areas consists of species...

BAITED REMOTE UNDERWATER REMOTE

SURVEY OF RICK MILLS AND BOTTLE

WASHER ARTIFICIAL REEFS, 2011-2013

(DARWIN HARBOUR, AUSTRALIA).

This document was prepared for the Department of Land Resource

Management. Contributing author Dr Victor Gomelyuk

© Copyright of the Northern Territory Government, 2014.

Permission to copy is granted provided the source is acknowledged.

ISBN: 978-1-74350-062-0

Further information

Contact:

Dr Victor Gomelyuk

Marine Ecosystems, Flora and Fauna Division

Dept. of Land Resource Management

564 Vanderlin Drive BERRIMAH NT 0828

Mail to:

PO Box 496, PALMERSTON, NT 0831, Australia

Ph: +61 8 8995 5024

fax +61 8 8995 5099

Cite report as:

Baited remote underwater remote survey of Rick Mills and Bottle Washer artificial reefs,

2011-2013 (Darwin Harbour, Australia).

ii

Executive summary

Biodiversity and abundance of fish communities were assessed using baited remote underwater system (BRUVS), at Rick Mills and Bottle Washer artificial reefs in Darwin Harbour in 2011-2012. “Artificial reef effect” was evident at Bottle Washer artificial reef. Assemblages of sharks and of fishes targeted by amateur anglers and skindivers as well as reef-associated fishes were more abundant and contained more species at sites adjacent to the reef than at sites located away from the reef. “Artificial reef effect” was far less evident at Rick Mills artificial reef. No statistically significant differences in fish abundance were found between sites close to the reef, but located at different distances from the reef when all fish fauna has been compared. Surprisingly, overall biodiversity was considerably higher at the site located 520 m away from artificial reef. Both mean fish abundance and biodiversity of sharks and fish targeted by anglers and skindivers did not differ significantly among sites close to artificial reef and more distant site. As for reef-associated fish species the results were equivocal: mean biodiversity was significantly higher at the site closest to the reef comparing to second site near the reef. However, no differences have been found in site closest to the reef and the most distant site (520 m away from the reef) comparisons. No differences were found in mean reef-associated fish abundance for all compared sites.

There are several possible explanations for our results:

• Specific of fish fauna in inshore water of Darwin Harbour

• Relatively short period of both artificial reef constructions.

• Relatively large distances of sampling sites from AR

Still, Rick Mills and Bottle Washer artificial areas have twice higher fish biodiversity and almost three times higher overall fish abundance comparing to other monitoring sites in Darwin Harbour in 2011-2013.

iii

Contents Executive summary..................................................................................................................iii

Contents...................................................................................................................................iv

INTRODUCTION.......................................................................................................................7

MATERIAL AND METHODS.....................................................................................................8

Area description.....................................................................................................................8

BRUVS survey procedure...................................................................................................11

Underwater video interrogation...........................................................................................11

Data analysis.......................................................................................................................11

RESULTS................................................................................................................................13

Descriptive results...............................................................................................................13

1. All fish assemblages abundance and biodiversity........................................................13

Rick Mills area.................................................................................................................13

Univariate analyses.........................................................................................................13

Multivariate analyses.......................................................................................................16

Analysis of Similarity (ANOSIM)......................................................................................16

Similarity per cent analysis (SIMPER)............................................................................16

Bottom Washer area.......................................................................................................22


Multivariate analyses.......................................................................................................24



2. Species targeted by anglers and divers abundance and biodiversity..........................29

Rick Mills area.................................................................................................................29


Multivariate analysis........................................................................................................31



Bottle Washer area.........................................................................................................34





Reef-associated fish species abundance and biodiversity..................................................39

Rick Mills area.................................................................................................................39


iv




Bottle Washer area.........................................................................................................45





DISCUSSION......................................................................................................................51

All fish assemblages spatial distribution..........................................................................51

Fishes targeted by anglers and divers............................................................................51

Reef-associated fish species abundance and biodiversity..............................................51

Multivariate analyses of fish assemblages at different sampling sites............................51

CONCLUSION........................................................................................................................53

APPENDIX..............................................................................................................................55

v

List of FiguresFigure 1. Position of artificial reefs Rick Mills and Bottle Washer and BRUVS sampling sites

within each artificial reef area during 2011-2013 studies..........................................................9

Figure 2. Mean number of all recorded fish (MaxN) at different sampling sites at Rick Mills

artificial reef area. Error bars are standard deviation..............................................................14

Figure 3. Mean number of all recorded fish species at different sampling sites at Rick Mills

artificial reef area. Asterisks indicate significance level: * - 0.05 – 0.01; ** - < 0.01 – 0.001; ***

- <0.001...................................................................................................................................14

Figure 4. Mean number of all recorded fish (MaxN) at different sampling sites at Bottle

Washer artificial reef area.......................................................................................................23

Figure 5. Mean number of all recorded fish species at different sampling sites at Bottle

Washer artificial reef area.......................................................................................................23

Figure 6. Mean number (MaxN) of sharks and fish targeted by anglers and skindivers at

different sites at Rick Mills artificial reef area..........................................................................30

Figure 7. Mean number of species of sharks and species of fish targeted by anglers and

skindivers at different sites at Rick Mills artificial reef area.....................................................30

Figure 8. Mean number (MaxN) of sharks and fish targeted by anglers and skindivers at

different sites at Bottle Washer artificial reef area..................................................................35

Figure 9. Mean number of sharks species and fish species targeted by anglers and

skindivers at different sites at Bottle Washer artificial reef area.............................................35

Figure 10. Mean number (MaxN) of reef-associated fish recorded during BRUVS survey at

different sites at Rick Mills artificial reef area in2011-2013.....................................................40

Figure 11. Mean number of reef-associated fish species recorded during BRUVS survey at

different sites at Rick Mills artificial reef area in 2011-2013....................................................41

Figure 12. Mean number (MaxN) of reef-associated fish recorded during BRUVS survey at

different sampling sites at Bottle Washer artificial reef area in 2011-2013.............................46

Figure 13. Mean number of reef-associated species of fish recorded during BRUVS survey at

different sampling sites at Bottle Washer artificial reef area in 2011-2013.............................46

List of TablesTable 1. Sampling sites at Rick Mills and Bottle Washer artificial reefs during fish

assemblages of Darwin Harbour BRUVS survey in 2011-2013..............................................10

vi

INTRODUCTION Darwin Harbour is undoubtedly the most important location for recreational fishing in the

Northern Territory and more than 30% of all recreational fishing in the Territory takes place

in Darwin Harbour, Shoal Bay and nearby areas (Coleman 2003).

Shipwrecks and artificial reefs are important component of Darwin Harbour habitat. The

seafloors in the harbour generally are broad featureless expanses of soft-bottom, fringed by

occasional rocks. The highest concentration of fish can usually be found around natural

reefs, ledges, shipwrecks, virtually any underwater structures (jetties. pontoons, pipelines,

etc.) or any anomalies on the seabed. Underwater structures and fish assemblages

associated with AR in Darwin Harbour attract both divers and fishers.

The costs and logistical difficulties involved in conducting surveys of reef fish assemblages

in the Northern Territory are such that few reef fish surveys have taken place, a situation

which must be addressed if we are to develop effective management strategies for these

important components of the marine biota. Remote ‘video fishing’ techniques using baited

remote underwater video system (BRUVS) will be employed in this study. BRUVS offer

standardised, non-extractive methodologies for estimating the relative fish abundance

(Cappo et al. 2004, 2007; Gomelyuk, 2008, 2012).

Fish fauna in inshore areas of Northern Territory include species from a variety of ecological

groups and many of them have a complex life history, with different habitat preferences

during different stages of their life cycle (Blaber 1986, Robertson and Duke 1987, Blaber et

al. 1989, Sheaves 1995). However, all variety of habitat preferences of inshore fishes can be

conditionally divided into next categories:

Ubiquitous species with broad distribution; some species juveniles and sub adults in

estuaries and river mouths.

Species found on soft bottoms habitats and/or seagrass beds.

Species found mainly on coral and rocky reefs and/or on sandy areas adjacent to the

reef.

Species usually found in brackish waters estuaries and sometimes entering river

mouths.

As all humane-made underwater construction do, Rick Mills and Bottle Washer artificial reefs

create high profile bottom habitat and expand area of habitat available for colonization by

sessile benthic organisms as well as shelter and foraging area for “reef-associated fishes.

7

Both AR are surrounded by areas of low profile soft bottom habitat. Substantial reef

expansion done in 2011 further increased habitat complexity.

It was reasonable to presume that abundance and biodiversity of reef fishes will be higher at

sampling sites in close vicinity of artificial reefs, the close to AR construction, the higher

abundance and biodiversity. As for distribution of ubiquitous species, species associated

with soft-bottom habitat, we expected no significant differences among BRUVS sampling

sites within each artificial reef area.

The aim of present study was to assess “artificial reef effect” on fish species targeted by

amateur anglers and skindivers and sharks as significant component of inshore ecosystems

by assessing and comparing fish diversity and abundance in assemblages in close vicinity of

“Rick Mills” and “Bottle Washer” artificial reefs and sites located away from artificial reefs.

MATERIAL AND METHODS Area description.Both Rick Mills and Bottle Washer artificial reefs were established two decades ago and

expanded by Department of Fisheries in 2011. They located to north-west off Lee Point,

Figure 1. Open low profile sandy and muddy habitat with some rare sea grass is typical for

the area; scarce rocky outcrops, boulders and the hard coral rubbles buried in sediments

with attached macro algae, hydroids occur in the area, but the only extensive

(approximately, 9800 square metres) natural reef is Anglers Reef located 1.3-1.5 km to the

south-east from “Bottle Washer” artificial reef. To obtain a representative samples, three

sites were randomly chosen at each reef. For Rick Mills they were site within 50 m form

artificial reef culvert, site 70 m from nearest artificial reef culvert and site 520 m away from

nearest artificial reef culvert. For “Bottle Washer” one site were within 20 m of artificial reef

culvert, 570 m away from nearest culvert and 160 m away from nearest artificial reef culvert,

Table 1.

All surveys were conducted in September 2011 - September 2013 during neap tides to avoid

high tidal currents and increased water turbidity during spring tides. Surveys were conducted

in daytime (between 8:00 hours and 15:00 hours). A Global

8

Figure 1. Position of artificial reefs Rick Mills and Bottle Washer and BRUVS sampling sites within each artificial reef area during 2011-2013 studies.

9

Table 1. Sampling sites at Rick Mills and Bottle Washer artificial reefs during fish assemblages of Darwin Harbour BRUVS survey in 2011-2013.

Rick Mills Artificial Reef Location

7 1-st site at Rick

Mills location

12–12.5 Open sandy–muddy bottom approximately 50 m

from artificial reef culvert. Some hydroids,

occasional polychaetes worm tubes

8 2-nd site at Rick

Mills location

11–12.5 Open sandy–muddy bottom approximately 70 m

from artificial reef culvert. Scarce (less than 1%

habitat cover) hydroids, sponges.

9 3-rd site at Rick

Mills location

12 –12.7 Open sandy–muddy bottom, approximately 520

m away from nearest artificial reef culvert.

Scarce hydroids, occasional soft corals, macro

algae. In some areas per cent cover of sessile

organism was up to 30%, usually 3-5%.

Bottle Washer Artificial Reef Location

10 1-st site at Bottle

Washer artificial

reef

11–12 Located approximately 20 m from artificial reef

culvert Open sandy–muddy bottom with some

occasional gravel areas. Less than 1% hydroids,

hard coral rubble and algae.

11 2-nd site at Bottle

Washer artificial

reef

11–12 Located on sandy–muddy bottom approximately

570 m from artificial reef culvert. From 1 to 3%

of hydroids, ascidians and macro algae on

occasion hard coral rubble and very scarce

rocks.

12 3-rd site at Bottle

Washer artificial

reef

10–11 Open sandy–muddy bottom approximately 160

m away from artificial reef. Less than 1%

hydroids, very scarce sea whips, hard coral

rubble and algae.

10

Positioning System device was used to navigate to each site. The average accuracy of this

device is ±5–7 m. Depth was measured using the boat depth sounder. The BRUVS gear

used in the survey and the sampling procedure was described in a previous report

(Gomelyuk 2014).

BRUVS survey procedure.At each site, one of the BRUVS apparatus was deployed for video survey (Cappo et al.

2003). The BRUVS remained on the sea floor for 60 minutes, and recorded fish attracted to

the bait canister. Site name, date, the time when survey was started and finished, the depth

and BRUVS device ID number were recorded. Because of relatively large distances between

selected sampling sites and because two BRUVS were never used at the same site, video

replicates were independent (e.g. same fish were unable to visit more than one BRUVS

during the survey). Six one-hour underwater video samples (i.e. replicates) were taken at

each of sampling site each year.

Underwater video interrogation.An interrogation of video was done according to Cappo et al. (2003, 2004). All 60 minutes of

video were screened and each new fish species arriving in the field of view of the camera

was recorded. Only the maximum number of individuals of each species seen together in the

field of view at one time (MaxN) was used in analyses to avoid the possibility of fish double

counting. According to previous studies (Priede & Merrett 1996; Willis & Babcock 2000

Cappo et al. 2003, 2004; 2007, 20011, Watson et al. 2005), MaxN gives a conservative

estimate of fish relative density. Images of the sea bottom were used to identify different

types of bottom cover. In Darwin Harbour this can vary from hard coral, rocks, pebbles and

gravel to sand, silted sand and silt, depending on the depth and location at survey site.

Where possible, fish were identified to species level. Atlas of Living Australia

http://biocache.ala.org.au database

was used as a main source of information on the previous records of fish species in Darwin

Harbour and Northern Territory waters. International Code of Zoological Nomenclature

(1999) and the list of standardised Australian fish names

http://www.marine.csiro.au/caab/namelist.htm was used in this report. ”Checklist of Darwin

Harbour fishes” (Larson 1997) and Atlas of Living Australia

http://biocache.ala.org.au/occurrences/search?taxa were used in this study.

Data analysis.Data for each sampling site collected in 2011-2013 was pooled to increase the power of

analysis, to compensate possible natural variation (related to fish movement) and to make

11

the data more generalizable. Prior to pooling the data at each site was tested for treatment-

by-time interaction, which might be present and would constrain the generalizability of the

finding (Knapp 2013). In all tests no such interactions were found.

Univariate statistics and descriptive statistics were completed with SYSTAT 13 software ®

(2009 SYSTAT Software Inc., Point Richmond, CA, USA). Analysis of variance (ANOVA)

was used to compare differences among compared sites in fish abundance (MaxN) and

species richness (the number of fish species recorded in each 60-minites video sample).

Data were examined for normality and homogeneity of variances using Kolmogorov-Smirnov

test (Lilliefors) and Levene's test. In order to decrease possibility of Type I error one fixed

factor (factor-different monitoring sites in 2011-2012) was used. Tukey’s multiple comparison

tests (HSD) was used for pairwise comparison.

Contrary to univariate statistical analysis that compare either fish abundance or species

abundance, multivariate analysis compare fish assemblages composition and structure.

Multivariate analyses were carried out with statistical package PRIMER 6.0 & PERMANOVA

+ for PRIMER ® (2012 PRIMER-E Ltd., Plymouth, UK (Clarke & Warwick 1994; Anderson,

Gorley and Clarke 2008).

PERMANOVA is a program for testing the simultaneous response of one or more variables

to one or more factors in an ANOVA experimental design on the basis of any distance

measure, using permutation methods. First, the program calculates the distances between

each pair of observation units (sampling units) to obtain a distance matrix. It then calculates

the test-statistics from this according to the relevant experimental design. (Anderson 2001).

One fixed factor (different sampling sites) design was used in this analysis. As ANOVA,

PERMANOVA comparison of 2011-2012 data was done for sites with pooled data from three

monitoring sites at each artificial reef.

Analysis of similarity (ANOSIM) uses The Bray-Curtis similarity matrix which depends on the

relative order (i.e., ranking) of the similarity coefficients in the Bray-Curtis similarity matrix,

rather than their absolute values. The ANOSIM was used to determine whether the fish

assemblages differed statistically among compared sites. The ANOSIM test statistic, R, is

based on the ratio of the between-group to within-group similarity ranking. Pair wise

comparison tests are also calculated which generate an R value and a significance (p) value

for each possible pair of comparisons. Generally, the value of R ≥ 0.75 indicates well

separated communities, 0.75 > R ≥ 0.5 - overlapping but different communities, 0.5 > R ≥

0.25 - overlapping but somewhat different and R <0.25 indicates insufficiently different

communities (Clarke and Gorley 2001). ANOSIM was done using years pooled data for each

of three sampling sites at each artificial reef area.

12

Similarity percentages (SIMPER) were used to examine similarity within the groups (pooled

samples collected at three monitoring sites within each artificial reef) and to inspect that

species contributed to any observed differences among fish assemblages at different sites.

RESULTS Descriptive results.

During our samples in 2011-2013 160 hours of underwater video, 80 hours for each artificial

reef was obtained. Altogether, 4360 fish 90 species of

A total 4360 fish from 90 species from 36 families were recorded during 160 hours of

BRUVS surveys at the 6 sampling sites at Rick Mills and Bottle Washer artificial reefs areas

in 2011–2013 (Appendix, Table 1).

1. All fish assemblages abundance and biodiversity.Rick Mills area.

Univariate analyses.

Analysis of variances of mean fish abundance (mean MaxN) in one 60- minutes video

sample (2011-2013 pooled data) indicated that there were no statistically significant

differences among different sites (one-way ANOVA, df=2, F=0.427, P=0.624), Figure 2.

However, ANOVA of fish biodiversity (mean number of fish species in one 60-minutes video

sample) was significantly different (one-way ANOVA, df=2, F=9.796, P<0.001). Pair wise

comparison shows that site 3RM, located 520 m away from artificial reef (AR) has the

highest biodiversity, higher than site 1RM (50 m from AR) and site 2 RM (70 m from AR),

Figure 3.

13

Figure 2. Mean number of all recorded fish (MaxN) at different sampling sites at Rick Mills artificial reef area. Error bars are standard deviation.

Figure 3. Mean number of all recorded fish species at different sampling sites at Rick Mills artificial reef area. Asterisks indicate significance level: * - 0.05 – 0.01; ** - < 0.01 – 0.001; *** - <0.001

14

Multivariate analyses.

Analysis of Similarity (ANOSIM).

Table 2. Pair wise tests in Analysis of Similarity (ANOSIM) among fish assemblages at 3 BRUVS sampling sites at Rick Mills artificial reef area, pooled data of 2011-2013 surveys. Global R: 0.17, significance level 0.1%.

Groups R-Statistic Significance

level %

Number

Observed

1RM, 2RM 0.059 2.1 26

1RM, 3RM 0.302 0.1 0

2RM, 3RM 0.159 0.1 0

Global statistic value is low and indicate insufficient differences in fish assemblages

composition at statistically significant level. Differences in fish assemblages at sites in close

vicinity to AR are even lower, Table 2. Usually, R-values >0.75 interpreted as “well

separated assemblages”; R>0.5 as “overlapping, but clearly different” and R<0.25 as “barely

separable at all”, in accordance with the PRIMER-manual (Clarke & Gorley 2001). Only

differences between the most close to the AR 1RM site and the most distant 3RM fish

assemblages can be interpreted as “overlapping, but clearly different”; other to tests have

returned “barely separated “ reading, Table 2.

Similarity per cent analysis (SIMPER).

Average dissimilarity between fish assemblages from sampling sites 1RM and 2RM, 77.6%

indicates high differences in assemblages composition and structure. Average similarity

within the same assemblage were low, 30.5% and 18.9%, reflecting frequent changes in

species and fish numbers within each sampling site. Still, assemblage similarity at the site

1RM, closest to the artificial reef was higher, comparing to the more remote site, Table 3.

Mid water trevallies Fringefin Trevally, Pantolabus radiatus, Selaroides leptolepis, Caranx

sp., Fourline Striped Grunter, Terapon teraps, Shortfin Batfish, Zabidius novemaculeatus as

well as demersal Northwest Threadfin Bream, Pentapodus porosus and Ponyfishes

Leiognathus sp. were numerically dominant at both sampling sites and have contributed to

71.5% of total dissimilarity between compared assemblages, Table 3. Dissimilarity between

sample site 1RM, the closest to the AR and 3RM, the most remote one was high 78.2%,

indicating differences between assemblages, but only slightly higher than in previous

comparison, Table 4. Fish assemblages at both sites have comparable average similarity.

16

Similar list fish species dominated in assemblages and have contributed to 62.5% of total

dissimilarity between compared assemblages, Table 4.

17

Table 3. Comparison of fish assemblages at site 1RM (50 m from Rick Mills artificial reef) and site 3RM (70 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%

Site1RM Site 2RM

Average dissimilarity between

compared assemblages: 77.6%

Average similarity:

30.5%

Average similarity:

18.9%

Species Average abundance, N Average abundance,

N

Average dissimilarity, δ Cumulative δ %

Pantolabus radiatus 8.03 7.14 16.63 21.44

Zabidius novemaculeatus 4.86 2.17 11.27 35.97

Selaroides leptolepis 3.41 4.90 9.10 47.69

Caranx sp. 2.79 2.59 8.97 59.26

Pentapodus porosus 0.76 1.90 3.56 63.85

Terapon theraps 0.41 1.59 3.25 68.05

Leiognathus sp. 0.62 1.07 2.69 71.51

Scomberomorus queenslandicus 0.62 1.00 2.23 74.39

Lutjanus erythropterus 0.76 0.45 2.09 77.08

Gnathanodon speciosus 0.38 0.69 1.68 79.24

Chaetodontoplus duboulayi 0.59 0.07 1.25 80.86

Upeneus tragula 0.55 0.03 1.25 82.47

Lutjanus russelli 0.48 0.00 0.99 83.75

Sillago sp. 0.31 0.14 0.82 84.81

Carangoides sp. 0.31 0.17 0.79 85.83

Diagramma labiosum 0.28 0.07 0.67 86.70

Lutjanus carponotatus 0.28 0.00 0.61 87.48

Flounder 0.17 0.21 0.60 88.2618

Carcharhinus dussumieri 0.07 0.17 0.60 89.03

Echeneis naucrates 0.10 0.21 0.58 89.78

Sillago sihama 0.21 0.07 0.56 90.50

Average dissimilarity, δ is average Bray-Curtis dissimilarity between fish assemblages

Cumulative δ %is a cumulative contribution percentage. Species are listed in decreasing order of importance in contribution to δ.

19

Table 4. Comparison of fish assemblages at site 1RM (50 m from Rick Mills artificial reef) and the most remote site 3RM (520 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%

Average dissimilarity: 78.2% Site1RM Site 3RM

Average similarity:

30.5%

Average similarity:

33.2%

Species Average abundance Average abundance Average dissimilarity, δ Cumulative δ %





Caranx sp. 2.79 0.63 5.53 56.77

Upeneus tragula 0.55 1.26 2.44 59.89

Leiognathus sp. 0.62 0.85 2.09 62.55

Lethrinus atkinsoni 0.1 1.07 1.93 65.02

Gymnocranius elongatus 0 1.04 1.88 67.42

Lutjanus erythropterus 0.76 0 1.43 69.25

Paramonacanthus choirocephalus 0 0.78 1.33 70.94



Choerodon cephalotes 0.07 0.7 1.25 75.83


Scolopsis sp. 0 0.56 1.05 78.73

Chaetodontoplus duboulayi 0.59 0.07 1 80.01

20

Terapon theraps 0.41 0.19 0.93 81.2

Lutjanus russelli 0.48 0 0.83 82.26

Siganus fuscescens 0 0.56 0.82 83.3

Carangoides sp. 0.31 0.3 0.8 84.33


Pelates quadrilineatus 0 0.63 0.7 86.22

Chelmon müelleri 0 0.44 0.67 87.07

Sillago sp. 0.31 0.11 0.62 87.86

Choerodon vitta 0.17 0.26 0.58 88.6

Lethrinus sp. 0.03 0.41 0.56 89.31

Sillago sihama 0.21 0.15 0.54 90.01

21

Bottom Washer area.


Statistically significant differences were found in mean fish abundance (mean MaxN) among

sampling sites at Bottle Washer area (one-way ANOVA, df=2, F=5.598, P=0.006). There

were no statistically significant differences between close vicinity sites - 1BW (20 m from AR)

and 3BW (160 m from AR), however fish abundance at distant site 2BW (570 m from AR)

was statistically significantly lower, Figure 4.

No statistically significant differences were found among sampling sites in mean number of

fish species in one video sample (one-way ANOVA, df=2, F=2.095, P=0.131), Figure 5.

22

Figure 4. Mean number of all recorded fish (MaxN) at different sampling sites at Bottle Washer artificial reef area.

Figure 5. Mean number of all recorded fish species at different sampling sites at Bottle Washer artificial reef area.

23

Multivariate analyses.


Table 5. Pair wise tests in Analysis of Similarity (ANOSIM) among fish assemblages at 3 BRUVS sampling sites at Bottle Washer artificial reef area, pooled data of 2011-2013 surveys. Global R: 0.214, significance level 0.1%.


level %

Number

Observed

1BW, 2BW 0.332 0.1 0

1BW, 3BW 0.168 0.1 0

2BW, 3BW 0.123 0.2 1

Global statistic value is low and can be interpreted as insufficient differences among fish

assemblages within the area. Pair wise tests indicated higher differences between closest to

the AR sampling site and most distant site fish assemblages, but only slightly above “barely

separated at all” level, Table 5.


Average dissimilarity between fish assemblages at the site near Bottle Washer artificial reef,

1BW and more remote site, 3BW was high, 78.5%. The list of species numerically

dominated and contributed to 64.7% of dissimilarity between sites was similar to the list of

dominant fish at site 1RM, the nearest to Rick Mills artificial reef; Table 4, 6.

Dissimilarity between fish assemblages notably increased in site 1BW and the most remote

from artificial reef 2BW sampling site, Table 8. Several mid-water species abundant at the

site 1BW (Shortfin Batfish, Golden Trevally, Gnathanodon speciosus, Caranx sp.) were not

recorded at 2BW site. Species with open sandy and muddy bottom preferences

(Yellowstripe Scad, Selaroides leptolepis, Ponyfish, Leiognathus sp.) and ubiquitous species

(Northwest Threadfin Bream, Pentapodus porosus, Fringefin Trevally, Pantolabus radiatus

and some other were abundant both at site 1BW near artificial reef and the most remote

2BW site, Table 8.

24

Table 6. Comparison of fish assemblages at site 1BW (20 m from Bottle Washer artificial reef) and the most remote site 3BW (160 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.

Average dissimilarity: 78.5% Site1BW Site 3BW

Average similarity:

27.2%

Average similarity:

22.2%




Leiognathus sp. 5.35 5.25 9.24 39.99




Caranx sp. 1.04 0.7 2.37 64.76

Nemipterus sp. 0 0.75 1.9 67.17

Nemipterus hexodon 0 1.04 1.84 69.5




Seriolina nigrofasciata 0.26 0.4 1.04 75.9

Chaetodontoplus duboulayi 0.57 0 1.01 77.17


Flounder 0.3 0.4 0.85 79.47

Choerodon schoenleinii 0.43 0.04 0.81 80.49

25

Lutjanus vitta 0 0.42 0.74 81.43

Gymnocranius elongatus 0 0.44 0.71 82.33

Goby 0 0.38 0.69 83.21

Sillago sihama 0.3 0.19 0.69 84.08

Choerodon cyanodus 0.39 0.08 0.67 84.93

Choerodon vitta 0.43 0 0.66 85.77

Carangoides sp. 0.26 0.19 0.62 86.55

Carangoides hedlandensis 0.35 0.08 0.6 87.31

Sillago sp. 0.13 0.21 0.57 88.03

Nebrius ferrugineus 0.26 0.08 0.57 88.74

Neotrygon kuhlii 0.26 0 0.52 89.41

26

Table 7. Comparison of fish assemblages at site 1BW (20 m from Bottle Washer artificial reef) and the most remote site 2BW (570 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

27.2%

Average similarity:

28.3%


Leiognathus sp. 5.35 4.24 12.46 14.53

Zabidius novemaculeatus 5.78 0 11.77 28.26



Gnathanodon speciosus 2.7 0 5.78 53.44


Caranx sp. 1.04 0 2.25 61.83



Flounder 0.3 0.63 1.64 68.12

Nemipterus hexodon 0 0.67 1.61 70

Nemipterus sp. 0 0.71 1.49 71.74

Sillago sp. 0.13 0.6 1.41 73.39



Chaetodontoplus duboulayi 0.57 0 1.24 77.89

Parapercis sp. 0 0.58 1.15 79.23

27

Nemipterus nematopus 0.17 0.33 1.06 80.47

Choerodon schoenleinii 0.43 0 0.95 81.58



Carangoides hedlandensis 0.35 0.08 0.71 84.27

Choerodon cyanodus 0.39 0 0.68 85.07

Neotrygon kuhlii 0.26 0 0.65 85.83

Lutjanus fulvus 0.39 0 0.6 86.54

Goby 0 0.25 0.6 87.24

Lagocephalus sceleratus 0 0.34 0.59 87.93

Sillago sihama 0.3 0 0.58 88.61

28

2. Species targeted by anglers and divers abundance and biodiversity.

Rick Mills area.


No statistically significant differences were found between different sampling sites at Rick

Mills area in abundance of fish targeted by anglers and skindivers (see Table 2), (one-way

ANOVA, df=2, F=2.819, P=0.066), Figure 6.

Analysis of variances also found no significant differences among sampling sites in

biodiversity of fish targeted by anglers and skindivers (one-way ANOVA, df=2, F=2.591,

P=0.081), Figure 7.

29

Figure 6. Mean number (MaxN) of sharks and fish targeted by anglers and skindivers at different sites at Rick Mills artificial reef area.

Figure 7. Mean number of species of sharks and species of fish targeted by anglers and skindivers at different sites at Rick Mills artificial reef area.

30

Multivariate analysis.


Table 8. Pair wise tests in Analysis of Similarity (ANOSIM) among assemblages of targeted fishes at 3 BRUVS sampling sites at Rick Mills artificial reef area, pooled data of 2011-2013 surveys. Global R: 0.237, significance level 0.1%.

Groups R-Statistic Significance level

%

Number Observed

1RM, 2RM 0.046 5.1 Not significant 56

1RM, 3RM 0.431 0.1 0

2RM, 3RM 0.253 0.1 0

Global statistic R in ANOSIM of communities of targeted species at 3 sites at Rick Mills point

to insufficient differences among fish communities; differences between nearest to the AR

sites is not only small, but statistically not significant. However, R in pair wise test between

fish assemblages at nearest to AR and the most remote sites indicate more separate

assemblages, Table 8.


Assemblages of species targeted by anglers and skindivers at sites at relative proximity to

artificial reef, 1RM and 2RM were similar both in sets of species and in their abundance.

Only two species-Stripey Snapper, Lutjanus carponotatus and Moses’ snapper, L. russelli

were absent at 2BW site. Stripey Snapper is typical reef and coral reef fish with strong site

fidelity, therefore it absence at open bottom habitat at the distance from the reef is not

unusual, Table 9.

31

Table 9. Comparison of fish assemblages targeted by anglers and skindivers at site 1RM (50 m from Rick Mills artificial reef) and site 2RM (70 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

26.4%

Average similarity:

18.2%



Caranx sp. 2.68 2.78 19.34 54.99


Lutjanus erythropterus 0.71 0.48 5.37 71.31






Sphyraena jello 0.06 0.22 1.53 87.2

Epinephelus coioides 0.23 0.04 1.16 88.67

Lutjanus carponotatus 0.26 0 1.04 89.99

Choerodon vitta 0.16 0.04 1 91.26

32

Table 10. Comparison of fish assemblages targeted by anglers and skindivers at site 1RM (50 m from Rick Mills artificial reef) and the most distant site 3RM (520 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

26.4%

Average similarity:

27.0%



Caranx sp. 2.68 0.65 14.11 42.52








Lethrinus sp. 0.03 0.42 2.48 81.5

Choerodon vitta 0.16 0.27 1.99 83.74



Diagramma labiosum 0.26 0 1.39 88.98


33

The presence of reef-associated Shortfin Batfish, Zabidius novemaculeatus and Yellowtail

emperor, Lethrinus atkinsoni and Stripey Snapper at open bottom sandy area 520 m away

from artificial reef was least expected. The abundance of the later fish was even higher than

at the site near artificial reef, Table 10.

Bottle Washer area.


The highest targeted fish mean abundance was recorded at site 1BW, nearest to AR,

differences highly significant (one-way ANOVA, df=2, F=36.361, P<0.001). Difference in this

statistic between site 2BW and 3BW, located more remotely from AR were not significant,

Figure 8.

Mean biodiversity was also significantly higher at nearest to AR site, 1BW; the lowest value

was recorded at site 2BW located 520 m away from AR (one-way ANOVA, df=2, F=8.148,

P<0.001), Figure 9.

34

Figure 8. Mean number (MaxN) of sharks and fish targeted by anglers and skindivers at different sites at Bottle Washer artificial reef area.

Figure 9. Mean number of sharks species and fish species targeted by anglers and skindivers at different sites at Bottle Washer artificial reef area.

35



Table 11. Pair wise tests in Analysis of Similarity (ANOSIM) among fish targeted by anglers and skindivers at 3 BRUVS sampling sites at Bottle Washer artificial reef area, pooled data of 2011-2013 surveys. Global R: 0.329, significance level: 0.1%


level %

Number

Observed

1BW, 2BW 0.488 0.1 0

1BW, 3BW 0.181 0.1 0

2BW, 3BW 0.287 0.1 0

The value of Global statistic R value is low, indicating low degree of separation. In pair wise

test the highest dissimilarity between fish assemblages was found in 1BW, the closet

sampling site to AR and 2BW, the most remote. The value of R was close to the level

“overlapping, but still clearly different”, Table 11.


As at sampling sites near Rick Mills artificial reefs, lists of species in assemblages at two

sites adjacent to Bottle Washer AR were similar, Table 12. However, some reef-associated

species – Batfish, wrasses, Blacktail Snapper, Lutjanus fulvus) and some

36

Table 12. Comparison of fish assemblages targeted by anglers and skindivers at site 1BW (20 m from Bottle Washer artificial reef) and more remote site 3BW (160 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

22.6%

Average similarity:

22.6%




Caranx sp. 1.09 0.73 7.31 55.01










Sphyraena obtusata 0.09 0.17 1.44 87.54


Carcharhinus tilstoni 0.09 0.04 1.05 90.25

37

Table 13. Comparison of fish assemblages targeted by anglers and skindivers at site 1BW (20 m from Bottle Washer artificial reef) and the most remote site 2BW (570 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

22.6%

Average similarity:

22.6%



Gnathanodon speciosus 2.82 0 14.51 48.1



Caranx sp. 1.09 0 4.89 69.11




Carcharhinus tilstoni 0.09 0.13 2.16 80.54





Sphyraena sp. 0.32 0 1.15 89.75


38

species with wide distribution (Golden Trevally, Trevally Caranx sp.) were not recorded at

more remote site 3BW, Table 12. This difference between adjacent to artificial reef and more

remote sampling site in fish assemblages composition became even more clear in sites 1BW

and 2 BW comparison. While some ubiquitous fish abundance (School Mackerel, Australian

Blacktip Shark) have similar abundance at both sites, majority of fish recorded at 1BW, near

artificial reef both reef and ubiquitous species either have not been recorded at 2BW site,

570 m from AR or have very low abundance at this site. The only exception was White

Cheek Shark, species preferring sandy and muddy areas of the open bottom, whose

abundance was higher at 2BW when at 1 BW site, Table 13.

Reef-associated fish species abundance and biodiversity.

Rick Mills area.


No statistically significant differences were found in mean abundance of reef-associated

fishes among sites at Rick Mills (one-way ANOVA, df=2, F=3.033, P=0.054), Figure 10.

Mean biodiversity in reef- associated fish species was substantially higher at site closest to

AR, 1RM, no differences found in more remote sites 2RM and 3RM comparisons (one –way

ANOVA, df=2, F=5.19, p=0.008), Figure 11.

39

Figure 10. Mean number (MaxN) of reef-associated fish recorded during BRUVS survey at different sites at Rick Mills artificial reef area in2011-2013.

40

Figure 11. Mean number of reef-associated fish species recorded during BRUVS survey at different sites at Rick Mills artificial reef area in 2011-2013.

41



Table 14. Pair wise tests in Analysis of Similarity (ANOSIM) among assemblages of reef-

associated fishes at 3 BRUVS sampling sites at Rick Mills artificial reef area, pooled data of 2011-2013 surveys. Global R: 0.301, significance level 0.1%.

Groups R-Statistic Significance level

%

Number Observed

1RM, 2RM 0.138 0.7 Not significant 6

1RM, 3RM 0.467 0.1 0

2RM, 3RM 0.299 0.1 0

Global R value remained low, reflecting barely separate fish assemblages in 3 compared

sites, however in pair wise tests the highest dissimilarity was found between fish

assemblages from site closest to AR, 1RM and the most remote site, 3RM, Table 14.


The reef-associated fishes at 1RM and 2RM sites, located close to Rick Mills artificial reef in

general have similar abundance. The only exception was Stripy Snapper, the species did not

found at 2RM. The list of reef fishes was rather short, Table 15. Unpredictably, many reef

fishes were recorded at sampling site 3RM, 520 m away from artificial reef. Abundance of

Yellowtail Emperor, Stripey Snapper and Blue Tuskfish, Choerodon cyanodus was at 3RM

even higher than at 1RM, Table 16.

42

Table 15. Comparison of reef-associated fish assemblages at site 1RM (50 m from Rick Mills artificial reef) and site 2RM (70 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

27.4%

Average similarity:

8.7%





Lutjanus carponotatus 0.26 0 3.37 87.93

Choerodon sp. 0.06 0.11 3.06 91.56

43

Table 16. Comparison of reef-associated fish assemblages at site 1RM (50 m from Rick Mills artificial reef) and the most distant site 3RM (520 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

27.4%

Average similarity:

8.7%





Lethrinus sp. 0.03 0.42 5.99 80.73



Diagramma labiosum 0.26 0 3.24 92.65

44

Bottle Washer area.


Reef fish abundance was several times higher at the site 1BW, nearest to AR, comparing to

more remote sites 2BW and 3BW, differences highly significant (one-way ANOVA, df=2,

F=21.647, P<0.001), Figure 12.

Reef fish biodiversity was higher at site 1BW, nearest to the AR comparing to the most

remote site, 2BW, difference highly significant, the most remote site, 2BW have the lowest

mean value of biodiversity (one-way ANOVA, df=2, F=11.491, P<0.001), Figure 13.

45

Figure 12. Mean number (MaxN) of reef-associated fish recorded during BRUVS survey at different sampling sites at Bottle Washer artificial reef area in 2011-2013.

Figure 13. Mean number of reef-associated species of fish recorded during BRUVS survey at different sampling sites at Bottle Washer artificial reef area in 2011-2013.

46



Table 17. Pair wise tests in Analysis of Similarity (ANOSIM) among assemblages of reef-associated fishes at 3 BRUVS sampling sites at Bottle Washer artificial reef area, pooled data of 2011-2013 surveys. Global R: 0.341, significance level 0.1%.


level %

Number

Observed

1BW, 2BW 0.486 0.1 0

1BW, 3BW 0.198 0.1 0

2BW, 3BW 0.302 0.1 0

ANOSIM of reef-associated fish assemblages indicated that the pattern in dissimilarity

between fish communities remained unchanged: the highest dissimilarity was found in the

closest to AR 1BW sampling site and the most remote, 2BW, Table 17.

47


Reef fishes group recorded at 1BW and 3BW, sites near Bottle Washer artificial reef was

similar, however abundance of some species (Shortfin Batfish, Blackspot Tuskfish,

Choerodon schoenleinii and Blue Tuskfish) was much higher at the site close to AR. Two

species - Yellowtail Emperor and unidentified Emperor recorded at 3BW, 160 m away from

the AR have not been found at 1BW, Table 18.

At the site 2BW, the most remote from Bottle Washer artificial reef 5 species recorded at

1BW were absent. However, unexpectedly, Brown sweetlip, Plectorhinchus gibbosus,

species normally associated with rocky reefs and Brownstripe Snapper, Lutjanus vitta,

occurring on open bottom areas surrounding reefs have been recorded at site 2BW, 570 m

away from artificial reef, Table 19.

48

Table 18. Comparison of reef-associated fish assemblages at site 1BW (20 m from Bottle Washer artificial reef) and more remote site 3BW (160 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

25.3%

Average similarity:

17.8%







Lethrinus sp. 0 0.13 3.36 90.57

49

Table 19. Comparison of reef-associated fish assemblages at site 1BW (20 m from Bottle Washer artificial reef) and the most remote site 2BW (570 m from the reef), pooled 2011-2013 BRUVS survey data. Cut off low contribution: 90%.


Average similarity:

25.3%

Average similarity:

5.0%





Plectorhinchus gibbosus 0 0.13 3.67 83.28


Carcharhinus melanopterus 0.09 0 2.59 89.3


50

DISCUSSION

All fish assemblages spatial distribution.

No differences in all fish abundance and biodiversity were found in comparisons of sampling

sites located close to Bottle Washer artificial reef and more remote sites. Similar results were

obtained during fish abundance comparisons at samples sites within Rick Mills area.

Surprisingly, overall fish biodiversity was considerably higher at the site located 520 m from

Rick Mills artificial reef, comparing to adjacent sites.

Fishes targeted by anglers and divers.

Both abundance and biodiversity of fish targeted by anglers and skindivers did not differed

significantly among all 3 sampling sites at Rick Mills artificial reef area. Distinctive differences

in these fish spatial distribution were found at Bottle Washer area: sampling site closest to

artificial reef culvert has statistically significantly higher abundance and biodiversity

comparing to the most remote site (570 m away from the reef).

Reef-associated fish species abundance and biodiversity.

Results of present study do support presumption of higher abundance and biodiversity of

reef-associated fishes at sampling sites located in close vicinity of Bottle Washer artificial

reef. Fish abundance was ten-fold higher at the site nearest to artificial reef comparing to the

most remote sampling site and threefold higher comparing to the site located 160 m away

from the reef. Biodiversity was also significantly higher at sites adjacent to artificial reef

comparing to the most remote site; the close the site was located to the reef the higher was

biodiversity.

No differences were found in abundance of reef-associated fish among sampling sites at

Rick Mills artificial reef area. Mean biodiversity was significantly higher at the sampling site

closest to artificial reef comparing to more remote site, but it did not differ significantly from

the most distant site, 520 m away from the reef.

Multivariate analyses of fish assemblages at different sampling sites.

ANOSIM (Analysis of Similarity) of all fish assemblages, assemblages when only of sharks

and fish targeted by anglers and skindivers were included and only reef-associated fish

groups in all cases have Global R values below 0.5, indicating only insufficient level of

differences between fish assemblages from different sites. Even when only reef-associated

species groups were compared, in no occasion they have been found to be clearly different.

First, this indirectly reflects the fact that both artificial reefs areas are likely to be inhabited by

51

a mixture of fishes with different habitat preferences. Second, it allows a suggestion about

some level of heterogeneity of bottom habitat outside of artificial reefs, that makes the habitat

suitable for fishes with different environmental requirements, including reef-associated

species.

Similarity percent analysis (SIMPER) examining each species contribution to assemblage

structure results clearly indicate that fish assemblages both in close vicinity to artificial reef

constructions and far away from the reef consist of ubiquitous species, that can live in a

variety of habitats, reef-associated species, and species inhabiting open bottom sandy and

muddy habitat, that dominates areas surrounding both artificial reefs.

Among reef-associated species, Shortfin Batfish was abundant at both artificial reef areas.

Noticeably, the fraction of reef-associated fish (Stripey Snapper, Lutjanus carponotatus,

Painted Sweetlips Diagramma labiosum, Scribbled Angelfish, Chaetodontoplus duboulayi)

was rather small even at sampling sites adjacent to both artificial. Ubiquitous species and

species that prefer open sandy and muddy bottom dominated at both Rick Mills and Bottom

Washer artificial reefs.

The most “discrepancies” in fish distribution were observed at Rick Mills artificial reef.

Unexpectedly, abundance of juvenile Crimson Snapper, Lutjanus erythropterus, fish that

prefer muddy bottom habitat was higher at close vicinity to the reef while at the most remote

sites this species has not been recorded at all. Stripey Snapper, Lutjanus carponotatus,

typical rocky and coral reef species has twice higher abundance at the site away from

artificial reef. Ubiquitous fish Moses' Snapper, Lutjanus russelli was among common species

at the site closest to the reef. However, the fraction of sand and mud bottom associated

fishes (Bartail Goatfish, Upeneus tragula, Swallowtail Seabream, Gymnocranius elongatus,

Pigface Leatherjacket, Paramonacanthus choirocephalus, White Cheek Shark, Carcharhinus

dussumieri, Fourline Striped Grunter, Pelates quadrilineatus was higher at the site, the most

remote from Rick Mills artificial reef.

We suggest that the key factor contributing to these “disagreements” in fish

distribution within artificial reefs areas and Rick Mills AR in particularly is presence of

infrequent rocks, boulders and aggregations of coral rubble in generally homogenous sandy

and muddy flat bottom. These portions of hard substrate provide suitable habitat for sessile

invertebrates (hydroids, occasional soft corals) and macro algae. In several occasions such

small “pseudo-reefs” images surrounded by areas of open sandy or muddy bottom were

recorded during BRUVS survey at both reefs. The importance of complex habitats that

serves as refuge from predators is long known (Heck & Wetstone 1977; Orth et al. 1984;

Rozas & Odum 1987; Nelson W.G. and Bonsdorff 1990). Therefore these “pseudo-reef”

attracting reef-associated fish; that makes fish distribution at Rick Mills artificial reef more

52

complex rather than a simplistic assumption of “fish are concentrated on artificial reef

construction and around it”.

CONCLUSION.

We suggest that the “artificial reef effect” is evident at Bottle Washer artificial reef.

Assemblages of sharks and of fishes targeted by amateur anglers and skindivers as well as

reef-associated fishes were more abundant and contained more species at sites adjacent to

the reef than at sites located away from the reef. However, when all fish fauna components

were included in analysis no differences in fish abundance and biodiversity have been found

in comparisons of sampling sites located close to Bottle Washer artificial reef and more

remote sites.

“Artificial reef effect” was far less evident at Rick Mills artificial reef. No differences in fish

abundance were found between sites adjacent to the reef when all fish fauna has been

compared. Surprisingly, overall biodiversity was considerably higher at the site located 520 m

away from Rick Mills. Both mean fish abundance and biodiversity of sharks and fish targeted

by anglers and skindivers did not differ significantly among sites close to artificial reef and

more distant site. As for reef-associated fish species the results were equivocal: mean

biodiversity was significantly higher at the site closest to the reef comparing to second site

near the reef. However, no differences have been found in site closest to the reef and the

most distant site (520 m away from the reef) comparisons. No differences were found in

mean reef-associated fish abundance for all compared sites.

There are several possible explanations for our results:

Specific of fish fauna

Fish fauna in both artificial reefs areas consists of species associated with open sandy and

muddy bottom (52.2%), ubiquitous species (occurring in a wide variety of habitats, from coral

reefs to muddy open bottom represent 30% of all fish and a fraction of reef-associated fish is

17.8%, Appendix, Table 1. Open bottom and ubiquitous species found suitable habitat on

artificial reef and in close vicinity of the reef, therefore they dominate fish assemblages.

Relatively short period of both artificial reef existence.

It was just 3 years since 2011 when both artificial reefs were substantially upgraded. Reef-

associated fish fauna just started to colonise both reefs.

Relatively large distances of sampling sites from AR

53

In our study we intentionally avoided to employ BRUVS devices close than 20 metres from

the artificial reef construction to avoid possible snagging and interactions with anglers

utilising the reef. It was demonstrated in a recent study, fish association with the artificial reef

is on a localised scale (< 30 m) (Scott et al. in press). Anglers are well aware that the catches

can drop substantially if the position of the reef or rock was identified incorrectly.

Still, Rick Mills and Bottle Washer artificial areas have twice higher fish biodiversity and

almost three times higher overall fish abundance comparing to monitoring sites in Darwin

Harbour entrance and area approximately 1 kilometre from south-west edge of Channel

Island (Gomelyuk 2014). Further studies and monitoring will be required in a future to assess

the success of these artificial reefs implementation.

REFERENCES

Anderson M.J. (2001) A new method for non-parametric multivariate analysis of

variance. Australian Ecology, 26: 32-46.

Anderson M.J., Gorley R.N. and K.R. Clarke (2008) PERMANOVA+ for PRIMER:

Guide to Software and Statistical Methods. PRIMER-E, Plymouth, UK, 214pp

Bartholomew A. (2002) Faunal colonization of artificial seagrass plots: the importance

of surface area versus space size relative to body size. Estuaries, 25, 5: 1045-1052.

Blaber S.J.M. (1986) Feeding selectivity of a guild of piscivorous fish in

mangrove areas of north-west Australia. Australian Journal of

Marine and Freshwater Research 37, 329–36.

Blaber S.J.M., Brewer D.T. and Salini J.P. (1989) Species composition

and biomasses of fishes in different habitats of a tropical northern

Australian estuary: their occurrence in the adjoining sea and estuarine

dependence. Estuarine, Coastal and Shelf Science 29, 509–531.

Cappo M., Harvey E., Malcolm H. and Speare P. 2003 Potential of video techniques

to monitor diversity, abundance and size of fish in studies of marine protected areas. In

Beumer J.P., Grant A. And Smith D.C. (eds) Aquatic protected areas: what works best and

how do we know? World Congress on Aquatic Protected Areas Cairns, Australia. Sydney:

Australian Society for Fish Biology: 455–464.

Cappo M., Speare P. and G. De’Ath (2004) Comparison of baited remote underwater

video stations BRUVS and prawn shrimp trawls for assessments of fish biodiversity in inter-

reefal areas of the Great Barrier Reef Marine Park. Journal of Experimental Marine Biology

and Ecology, 302: 123–152.

54

Cappo M., Harvey E. and Shortis E.M. 2007 Counting and measuring fish with baited

video techniques—an overview. In Lyle J.M., Furlani D.M. and Buxton C.D. (eds)

Proceedings of the 2006 Australian Society for Fish Biology Conference and Workshop

Cutting-edge technologies in fish and fisheries science, Hobart, August 2006. Hobart:ASFB,

pp. 101–114.

Coleman, A. P. M. (2004) The National Recreational Fishing Survey. The Northern

Territory. Department of Business, Industry and Resource Development Fishery Report 72,

95 pp.

Clarke K.R. and R.N. Gorley (2001) PRIMER v5: User manual/tutorial, PRIMER-E.

Plymouth UK, 91.

Clarke K.R. and R.M. Warwick (2001) Change in marine communities: an approach to

statistical analysis and interpretations. Plymouth: Plymouth Marine Laboratory and Natural

Environment Research Council.

Gomelyuk V.E. (2012). Assessment of Darwin Harbour fish communities using baited

remote underwater video station (BRUVS). Report to Department of Land Resource

Management, Darwin, 61 pp.

Gomelyuk V. 2008. Fish assemblages composition and structure in three shallow

habitats in north Australian tropical bay, Garig Gunak Barlu National Park, Northern Territory,

Australia. Journal of the Marine Biological Association of the United Kingdom, 89, 3: 449–

460.

Gomelyuk, V. (2014) Changes in a tropical marine inshore fish communities in a

macro-tidal estuary (Darwin Harbour, Australia). Technical Report for Department of Land

Resource Management, Darwin, 68 pp.

Heck K.L. Jr and Wetstone G.S. (1977) Habitat complexity and invertebrate species

and abundance in tropical seagrass. Journal of Biogeography 4: 135–142.

Nelson W.G. and Bonsdorff E. (1990) Fish predation and habitat complexity: are

complexity thresholds real? Journal of Experimental Marine Biology and Ecology, 141: 183-

194.

Orth, R.J., Heck, K.L., Jr., van Montfrans, J. (1984). Faunal communities in seagrass

beds: a review of the influence of plant structure and prey characteristics on predator-prey

relationships. Estuaries 7: 339-350.

Priede I.G, Merrett N.R (1996) Estimation of abundance of abyssal demersal fishes; a

comparison of data from trawls and baited cameras. Journal of Fish Biology, 49 (Suppl A):

207–216.

55

Robertson A.I. and Duke N.C. (1987) Mangroves as nursery sites: comparisons of the

abundance and species composition of fish and crustaceans in mangroves and other

nearshore habitats in tropical Australia. Marine Biology, 96, 93–205.

Rozas L.P. and Odum W.E. (1987) Fish and macrocrustacean use of submerged

plant beds in tidal freshwater marsh creeks. Marine Ecology – Progress Series 38:101-108.

Sheaves M. (1995) Large lutjanid and serranid fishes in tropical

estuaries: are they adult or juveniles? Marine Ecology Progress Series

129, 31–40.

Watson D. Harvey E.S., Anderson M.J., Kendrik G.A. (2005) A comparison of

temperate reef fish assemblages recorded by three underwater stereo-video techniques.

Marine Biology, 148: 415-425.

Willis TJ and Babcock RC (2000) A baited underwater video system for the

determination of relative density of carnivorous reef fish. Marine and Freshwater Research,

51:755–763.

APPENDIX

Table 1. List of fishes recorded during 160 hours of BRUVS surveys of Rick Mills and Bottle Washer artificial reefs in 2011-2013

FAMILY

SPECIES Rick Mills Bottle Washer

Fish ecological

group*HEMISCYLLIDAE

Chiloscyllium punctatum + RF

GINGLYMOSTOMATIDAE

Nebrius ferrugineus + + RF

CARCHARHINIDAE

Carcharhinus melanopterus + RF

Carcharhinus sorrah + RF

Carcharhinus dussumieri + + OB

Carcharhinus tilstoni + + OB

Galeocerdo cuvier + UB

Negaprion acutidens + UB

SPHYRNIDAE

Sphyrna mocorran + + UB

RHINOBATIDAE

Rhynchobatus djiddensis + OB

DASYATIDAE

Neotrygon kuhlii + + RF

56

Himantura undulata + OB

Himantura uarnak + OB

Himantura jenkinsii + OB

Himantura sp. + OB

Dasyatis sp. + + OB

MYLIOBATIDAE

Aetobatus narinari + OB

MURAENIDAE

Gymnothorax longinquus + + RF

Gymnothorax sp. + RF

SYNODONTIDAE

Synodus sp. + OB

Platycephalus endrachtensis + OB

SERRANIDAE

Epinephelus coioides + + UB

Epinephelus lanceolatus + + RF

CENTROPOMIDAE

Psammoperca waigiensis + RF

SILLAGINIDAE

Sillago sihama + + OB

Sillago sp. + + OB

TERAPONTIDAE

Terapon theraps + OB

Pelates quadrilineatus + OB

APOGONIDAE

Sphaeramia orbicularis + + OB

CARANGIDAE

Pantolabus radiatus + + UB

Selaroides leptolepis + + OB

Carangoides hedlandensis + + OB

Carangoides caeruleopinnatus + + UB

Caranx sp. + + UB

Gnathanodon speciosus + + UB

Scomberoides commersonnianus + UB

Seriolina nigrofasciata + + OB

LEIOGNATHIDAE

Leiognathus sp.* + + OB

ECHENEIDAE

Echeneis naucrates + + UB

LUTJANIDAE

Lutjanus erythropterus + + OB

57

Lutjanus carponotatus + + RF

Lutjanus vitta + + RF

Lutjanus russelli + + UB

Lutjanus fulvus + RF

Lutjanus gibbus + RF

Lutjanus johnii + + OB

HAEMULIDAE

Plectorhinchus gibbosus + RF

Diagramma labiosum + + RF

Pomadasys maculatus + + OB

Pomadasys kaakan + OB

LETHRINIDAE

Gymnocranius elongatus + + OB

Lethrinus atkinsoni + + RF

Lethrinus sp. + + RF

NEMIPTERIDAE

Nemipterus hexodon + OB

Nemipterus nematopus + + OB

Nemipterus sp. + + OB

Pentapodus porosus + + UB

Scolopsis sp. + OB

MULLIDAE

Upeneus tragula + + OB

Pupeneus heptacanthus + + OB

SCIAENIDAE

Protonibea diacanthus + OB

EPHIPPIDAE

Zabidius novemaculeatus + + RF

Platax orbicularis + RF

CHAETODONTIDAE

Chaetodon aureofasciatus + + RF

Chelmon müelleri + + OB

Chelmon marginalis + RF

POMACANTHIDAE

Chaetodontoplus duboulayi + + RF

SPHYRAENIDAE

Sphyraena jello + + UB

Sphyraena obtusata + UB

Sphyraena sp. + UB

LABRIDAE

Choerodon cyanodus + + RF

58

Choerodon cephalotes + + RF

Choerodon schoenleinii + + RF

Choerodon vitta + + OB

Choerodon sp. + RF

PINGUIPEDIDAE

Parapercis sp. + OB

BLENNIDAE

Meiacanthus luteus + + RF

GOBIIDAE

Goby, unidentified + + OB

SIGANIDAE

Siganus fuscescens + + OB

SCOMBRIDAE

Scomberomorus queenslandicus + + UB

BOTHIDAE

Flounder, unidentified + + OB

MONOCANTHIDAE

Paramonacanthus choirocephalus + + OB

Monacanthus chinensis + + OB

Pseudomonacanthus elongatus + OB

Anacanthus barbatus + OB

Paramonacanthus filicauda +

TETRAODONTIDAE OB

Lagocephalus sceleratus + + OB

Lagocephalus lunaris + + OB

Feroxodon multistriatus + + OB

Arothron manilensis + OB

* RF – reef-associated fish; OB – open bottom preference; UB – ubiquitous fish (with very broad distribution)

59

executive summary · web viewfish fauna in both artificial reefs areas consists of species...

Documents