mf281 yellow bluff benthus survey report 2020

MF281 Yellow Bluff BENTHIC SURVEY Report 2020

ANNUAL REPORT (VERSION 2.1) September 2020

Report to:

Huon Aquaculture Group Pty Ltd

Prepared by:

Institute for Marine and Antarctic Studies

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Document Control and Distribution

Date Name Company Document type Version Copies

31/8/2020 Adam Smark, Matt Whittle Tony Baker

HAC electronic 1.0 1





Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 49, Hobart TAS 7001

Enquires should be directed to: Dr Jeff Ross Institute for Marine and Antarctic Studies University of Tasmania Private Bag 49, Hobart, Tasmania 7001, Australia Email address: [email protected] Ph. +61 3 6226 8281 Fax (03) 6227 8035

The authors do not warrant that the information in this document is free from errors or omissions. The authors do not accept any form of liability, be it contractual, tortious, or otherwise, for the contents of this document or for any consequences arising from its use or any reliance placed upon it. The information, opinions and advice contained in this document may not relate, or be relevant, to a reader’s particular circumstance. Opinions expressed by the authors are the individual opinions expressed by those persons and are not necessarily those of the Institute for Marine and Antarctic Studies (IMAS) or the University of Tasmania (UTas).

The Institute for Marine and Antarctic Studies, University of Tasmania 2020.

Copyright protects this publication. Except for purposes permitted by the Copyright Act, reproduction by whatever means is prohibited without the prior written permission of the Institute for Marine and Anta

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Table of Contents Operational Summary ............................................................................................................................. 4

1. Introduction ........................................................................................................................................ 5

2. Methods .............................................................................................................................................. 5

2.1 Sampling design ............................................................................................................................ 6

2.2 Visual assessment of sediment cores ........................................................................................... 8

2.3 Redox potential ............................................................................................................................. 8

2.4 Sulphide concentration ................................................................................................................. 8

2.5 Particle size analysis ...................................................................................................................... 8

2.6 Stable isotopes and loss on ignition .............................................................................................. 8

2.7 Benthic infauna ............................................................................................................................. 9

2.8 Licence conditions ......................................................................................................................... 9

3. Results and Interpretation ................................................................................................................ 10

3.1 Visual assessment of sediment cores ......................................................................................... 10

3.2 Redox potential ........................................................................................................................... 12

3.3 Sulphide concentration ............................................................................................................... 12

3.4 Particle size analysis .................................................................................................................... 13

3.5.2 Carbon (%), nitrogen (%) and C:N molar ratio ..................................................................... 15

3.6 Benthic infauna ........................................................................................................................... 17

3.6.3 Total abundance .................................................................................................................. 17

3.6.1 Family richness ..................................................................................................................... 17

3.6.2 Annelid abundance .............................................................................................................. 18

3.6.4 Important species ................................................................................................................ 19

3.6.5 Community structure ........................................................................................................... 21

3.7 Performance against licence conditions ..................................................................................... 23

6. References ........................................................................................................................................ 25

7. Appendices ........................................................................................................................................ 26

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Operational Summary

Licence Name and Location: Environmental Licence 10180/1 Activity: Finfish Farming Lease Details: Marine Farming Lease No. 281 (EAST OF YELLOW BLUFF) Location: East of Yellow Bluff, Storm Bay.

Organisation Conducting Monitoring: Institute for Marine & Antarctic Studies (IMAS) ABN 30 764 374 782 19-21 Nubeena Crescent Taroona Tas 7053 Email [email protected]

Lease Holder’s Name: Huon Aquaculture PTY LTD ACN 067386109 Level 13, 188 Collins Street Hobart, Tasmania 7000

Dates of fieldwork: 18/03/2020, 19/03/2020, 20/03/2020, 27/03/2020

Details of permits held authorising sampling (LMRMA/TSPA)

Taking of Sediment Samples and Marine Plants (DPIPWE); Permit Number 19137, valid until 30th October 2020.

Table 1 Operational summary for each sampling day during March 2020 sampling period at Yellow Bluff in fulfilment of Environmental Licence 10180/1

Date 18/03/2020 19/03/2020 20/03/2020 27/03/2020 Vessel Lienna Lienna Lienna Lienna Personnel Andrew Pender

Jess Kube Vere Michels Adam Davey

Andrew Pender Jess Kube Vere Michels Adam Davey

Andrew Pender James Hortle Jess Kube Vere Michels

Andrew Pender Ben Quigley

Wind 5-10 knots N 5 knots N 5-10 knots W 0-5 knots SW Cloud cover 100% 80% 85% 85% Rain Nil Nil 8mm Nil Sites surveyed

14.2

1.2 & 4.2 C1.2, C2.2 & C3.2

1.2, 4.2 & 14.2 C1.2, C2.2 & C3.2

2.2, 7.2, 10.2, 12.2 & 13.2

Methods used

Redox/sulphide, C:N, LOI, particle size, eDNA

Redox/sulphide, C:N, LOI, particle size, eDNA

Infauna Infauna

Positioning for seabed sampling was achieved using ArcPad software in conjunction with an Omnilite 123 differential GPS receiver, giving sub meter position accuracy. The GPS systems were referenced to a State Permanent Mark (SPM) and tracklogs of all field activities were recorded.

mailto:[email protected]

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1. Introduction The Yellow Bluff marine lease MF281 operates under Environmental Licence No. 10180/1 (Environmental Protection Authority 2019) (hereby referred to as the Environmental Licence). As part of the conditions of the Environmental Licence, the results of video and benthic sediment surveys undertaken at compliance and control sites must be reported in the Annual Environment Report, which is submitted to the director of the EPA. This report summarises the results of the first annual benthic sediment survey conducted in March 2020 and includes an assessment of the results against compliance standards outlined in Schedule 2, G1 of the Environmental Licence.

Benthic sediment surveys are conducted annually, within 30 days of lease peak production. The benthic sediment survey requirements are outlined in section 3V1 of the Environmental Licence, and the sites, methodologies and reporting guidelines are described in 3V10, 3V11 and 3V12, respectively.

The Environmental Licence states that “samples must be collected at sites to be co-located with video survey external (compliance) sites and control sites established in the baseline environmental survey report.” The video survey was conducted by Huon Aquaculture on; 24/02/2020 and 03/04/2020. The first video survey was conducted at the compliance sites (1.2, 2.2, 3.2, 12.2, 13.2 & 14.2) and control sites (C1, C2 & C3). Due to escalation of the COVID pandemic in March 2020, the IMAS capacity for field work was limited and ultimately suspended under UTAS policy. This resulted in a revised survey design (Table 2) that was acknowledged by both Huon Aquaculture and the EPA. In March 2020 (Table 1), IMAS surveyed 3 compliance sites1 and 3 control sites. At each site, the benthic sediment survey components included, benthic biota (infauna and bacteria/algal mat identification), sediment chemistry (redox potential, sulphide concentration and stable isotope analysis), sediment core descriptions (Munsell chart) and particle size analysis.

Results from the Baseline Environmental Survey conducted in June 2019 are referenced for context (Aquenal 2019).

2. Methods All sediment sampling and analysis techniques are outlined in the Environmental Licence (Environmental Protection Authority 2019); however, further detail is provided below.

1 Infauna were sampled at 8 compliance sites (Table 2) and these are included in the biological comparison of compliance and control sites

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2.1 Sampling design

The full suite of variables was sampled at three compliance (1.2, 4.2 and 14.2) and three control sites (C1, C2 and C3) and infaunal samples were also collected at a further five compliance sites (2.2, 7.2, 10.2, 12.2 and 13.2).

Figure 1: Map showing compliance and control sites sampled as part of the requirements for the Environmental Licence at Yellow Bluff MF281.

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Table 2: Summary of the survey design for sampling at Yellow Bluff in March 2020 as a requirement under the Environmental Licence 10180/1. Site depth was calculated by overlaying site locations on bathymetry data collected in November 2016 by CSIRO using a multibeam sounder at 300Khz with infill from a multibeam sounder at 30 and 70-100Khz. Stable isotope analysis includes C%, N% and C:N ratio.

Baseline site name

Distance from

nearest pen (m)

Distance from lease

edge (m)

Depth (m)

Infauna Redox Sulphide Stable Isotopes LOI (%) Particle size

distribution Requirement

C1.2 3295 2075 35 triplicate triplicate triplicate triplicate Triplicate triplicate EL (local scale)



1.2 135 35 27 triplicate triplicate triplicate triplicate Triplicate triplicate EL (local scale)

2.2 262 35 27 triplicate - - - - - EL (local scale)







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2.2 Visual assessment of sediment cores

A custom “penta-corer” was used to collect 50 mm diameter sediment cores in clear Perspex tubes. Cores were stored upright in racks and out of direct sunlight to maintain horizontal layering, minimise disturbance and extreme heat flux. On return to the laboratory, cores were photographed, visually assessed, and described by length, colour/layering using the Munsell chart. The presence of plant and animal life, Beggiatoa sp. and smell (after water was removed) were also recorded.

2.3 Redox potential

Redox potential was measured in millivolts at 3 cm depth using a Hach HQ30d oxidation-reduction potential (ORP or redox potential) probe, calibrated with WTW RH28 redox buffer solution (248 mV at 10 °C) prior to analysis. The probe was re-calibrated after every second measurement. Corrected redox potential values were calculated by adding the standard potential of the reference cell to the measured redox potential and all values are reported in millivolts (mV).

2.4 Sulphide concentration

Sulphides in sediments were measured using a TPS WP-90 meter. Using a modified syringe, sediments were extracted from an undisturbed portion of each core, 3cm below the sediment surface using a 5 mL syringe. The samples were then placed in a glass vial containing 2 ml of reagent (sulphide anti-oxidant buffer, SAOB) and sulphide concentration was measured (mV) by placing the probe into the vial, and slowly stirring the sediment / buffer mix until the reading stabilised. The mV readings were converted to sulphide concentration using a calibration curve as outlined in Macleod and Forbes (2004).

2.5 Particle size analysis

The top 100 mm of each core was homogenised and approximately 70 ml of sediment was sub-sampled and frozen for particle size analysis. Samples were thawed and placed into a volumetric cylinder with 30 ml of water and the total volume was recorded. The sample was then gently wet sieved through a sieve stack of 4, 2, 1 mm and 500, 250, 125, 63 µm by hand or using a sieve shaker. The sediment fraction less than 63 µm was allowed to drain away. The material remaining on each sieve was dried of excess water before being carefully removed and placed in a graduated cylinder. The volume of sediment from each size fraction was measured as the displaced volume. The <63μm fraction was obtained by subtracting the sum of all sieve fractions from the initial volume. These data were presented graphed as stacked percentages and cumulative percentages for each site.

2.6 Stable isotopes and loss on ignition

The top 30 mm of a single undisturbed sediment core was placed in a 70ml jar, homogenised and then divided evenly into 70ml specimen jars and immediately frozen. One sample was used for isotope analysis and the other for loss on ignition analysis.

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Samples for carbon and nitrogen content and isotopic composition were freeze dried to remove all moisture, ground, split for carbon and nitrogen and sent to the Water Studies Centre, Monash University. Samples for carbon analysis were acidified with a dilute HCl solution to dissolve solid carbonates before analysis. All samples were then analysed using an ANCA GSL2 elemental analyser interfaced to a Hydra 20-22 continuous-flow isotope ratio mass-spectrometer (Sercon Ltd., UK). The precision of the elemental analysis was 0.5 μg for both C and N (n = 5). The precision of the stable isotope analysis was ±0.1‰ for 13C and ±0.2‰ for 15N (SD for n = 5). Stable isotope data are expressed in the delta notation (δ13C and δ15N), relative to the stable isotopic ratio of Vienna Pee Dee Belemnite standard (RVPDB= 0.0111797) for C and atmospheric N2 (RAir = 0.0036765) for nitrogen.

Samples for loss on ignition analysis were dried in an oven at 60°C for 24-48 hours (or until all moisture was removed). Approximately 5 g sub-samples were then weighed, furnaced at 450°C for 4 hours and reweighed. The difference between the initial weight and post burning weight was taken as the percent loss on ignition and therefore the percent organic carbon.

2.7 Benthic infauna

Benthic infauna was sampled in triplicate at all control and compliance sites (refer to Table 2) using a Van Veen Grab (surface area 0.0675 m2). All grab samples were wet sieved to 1 mm and preserved in 10% formalin: seawater (4% formaldehyde) on return from the field. In the laboratory samples were washed and stored in ethanol. After being sorted, the infauna was identified to the lowest possible taxonomic resolution and counted. For the purposes of this report, data is presented at the family level as required by the Environmental Licence.

2.8 Licence conditions

The licence holder must comply with a range of environmental standards in carrying out operations on the MF281 marine lease (Environmental Protection Authority 2019). It stipulates that there must be no significant visual, physico-chemical or biological impacts at or extending beyond 35 metres from the boundary of the lease area (General conditions; G1 section 1.1.). Licence conditions relevant to this benthic survey are summarised in Table 3. Performance against these conditions is tested and discussed throughout this document. Note that the standards associated with visual impacts (General conditions; G1 sections 1.1 and 1.2) are based on ROV surveys conducted by the licence holder and are reported elsewhere, in accordance with licence condition 3V9.

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Table 3 List of general licence conditions (G1) relevant to the benthic survey at Yellow Bluff under Environmental Licence 10180/1.

Conditions Report Section

1.1.2: Physico-chemical

1.1.2.1.1 A corrected redox value which differs significantly from the reference site(s) or is less than 0 mV at a depth of 3 cm within a core sample. 3.2

1.1.2.2.1 A corrected sulphide level which differs significantly from the reference site(s) or is greater than 250 µM at a depth of 3 cm within a core sample. 3.3

1.1.3: Biological

1.1.2.3.1 A 20 times increase in the total number of any individual taxonomic family relative to reference sites. 3.6

1.1.2.3.2 An increase at any compliance site of greater than 50-times the total annelid abundance at reference sites. 3.6

1.1.2.3.3 A reduction in the number of families by 50 percent or more relative to reference sites. 3.6

1.1.2.3.4: Complete absence of fauna. 3.6

1.1.2.3.5 As natural environmental variation renders some locations more susceptible to significant changes in parameter values, the above thresholds will be considered in addition to baseline environmental information for determining the presence/absence of a significant impact.

3.7

3. Results and Interpretation A comparison of compliance and control sites is described in the following sections and baseline information is included to further contextulaise the results. To provide insight into patterns of spatial variation, control and compliance site data is presented in relation to orientation to the lease.

3.1 Visual assessment of sediment cores

The results from the visual assessment of the sediment cores are summarised in Table 4; all core photos can be found in Appendix 4. The sediments varied markedly throughout the survey sites, and within individual cores, ranging from coarse shell grit to light coloured fine sand, with large patches of black sand.

Sediments varied markedly between compliance and control sites and between different sides of the lease. The control sites C1 and C3 were both light-coloured uniform coarse shell grit, while C2 was primarily comprised of finer sand. When comparing the control and compliance sites, on the same side of the lease, the compliance site on the northern side (2.2) was made up of much finer sediment with a dark top layer compared with the control sites C3. On the eastern side of the lease, the compliance site (4.2) and control site (C2) were very similar in appearance.

There was evidence of animal and plant life in the sediments of most cores. Animal tubes were observed in many cores and a range of animals were observed either in the cores or on the sediment surface. Animals observed included amphipods, bivalves, gastropods, heart urchins and polychaetes (Table 4).

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Table 4 Core descriptions for sediment collected from all sites at Yellow Bluff in March 2020. Colour codes are based on the Munsell soil chart. Compliance and control sites are shaded grey

Core Core Length (cm)

Munsell Chart Code Munsell Chart Colour Sulphorous smell Yes (y) No (n)

Beggiatoa Presence (p) Absence (a)

Tubes Presence (p) Absence (a)

Feed pellets Presence (p) Absence (a)

C1.2.1 13.0 Uniform 10YR 4/2 and course shell grit Dark greyish brown N A A A



C2.2.1 8.9 Uniform 10YR 5/3 Brown N A A A



C3.2.1 8.9 7.5YR 6/4 and course shell grit Light brown N A A A



1.2.1 15.0 Top 1cm 2.5Y 5/3, then 4cm band of GLEY1 3/10Y, rest patches of both. Light olive brown/very dark greenish grey N A A A

1.2.2 15.8 Top 1cm 2.5Y 5/3, then 4cm band of GLEY1 3/10Y, rest patches of both. Light olive brown/very dark greenish grey N A A A

1.2.3 14.7 Top 1cm 2.5Y 5/3, then 4cm band of GLEY1 3/10Y, rest patches of both. Light olive brown/very dark greenish grey N A P A

4.2.1 6.3 Uniform 10YR 5/2 Greyish brown N A A A

4.2.2 8.4 Top 65mm 10YR 5/2, rest patches of GLEY1 3/10Y Greyish brown/very dark greenish grey N A A A

4.2.3 12.0 Uniform 10YR 5/2 Greyish brown N A A A

14.2.1 8.0 Top 2cm 10YR 5/2, rest GLEY1 4/10Y Greyish brown/dark greenish grey N A P A

14.2.2 7.4 Top 2cm 10YR 5/2, rest GLEY1 4/10Y Greyish brown/dark greenish grey N A A A

14.2.3 9.8 Top 3cm 10YR 5/2, rest GLEY1 3/10Y Greyish brown/very dark greenish grey N A A A

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3.2 Redox potential

Redox potential (mV; mean ±SE) for sediment cores collected across 6 sites was 252 ± 40 mV, ranging from -74 mV at the lowest to 419 mV at the highest. Redox potential was lower across compliance sites (119 ± 48 mV) compared to the control sites (385 ± 15 mV; Figure 2); this difference was significant. Redox was lower at the compliance sites on the western and northern sides of the lease compared to the controls; it was also lower on eastern side, but largely due to one replicate. The mean redox potential was >0 mV at all control and compliance sites, the threshold below which is identified as being indicative of degrading conditions and major impacts at sandy sites by Macleod and Forbes (2004). There was one core with a negative redox value (-74 mV) at site 1.2 but the other two cores (167 & 80 mV) and the site average (58 mV) were all positive redox values.

Compared to the baseline survey conducted in June 2019, redox potential at the 3 controls sites (C1, C2 & C3) measured in both surveys was similar (Jun 19: 359 ± 12 mV, Mar 20: 385 ± 15 mV) but lower at the same compliance sites measured in the current survey (118 ± 48 mV) compared to the baseline (324 ± 22 mV).

Figure 2 Boxplot (left) of mean corrected redox values (mV) at 3 cm depth for sediments collected at compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). The boxes represent group quartiles (25th to 75th percentiles), median (horizontal line), mean (cross) and range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. Macleod and Forbes (2004) found that major effects associated with organic enrichment is typically indicated by redox values < 0 mV; this is the threshold level stipulated in the Licence conditions (Table 3) and represented by the dashed line. The plots on the right show the individual core readings (red crosses represent the site mean); the control and compliance are shown according to their position relative to the lease to aid interpretation.

3.3 Sulphide concentration

The mean sulphide concentration (µM) for sediment cores collected across 6 sites was 11.0 ± 3.8 µM, ranging from 0.07 µM at the lowest to 53.0 µM at the highest. Sulphide concentration was higher at the compliance sites (21.54 ± 5.76 µM) compared to the control sites (0.45 ± 0.21 µM); this difference was significant (Figure 3). The higher values were at the compliance sites on the western and northern sides of the lease, on the eastern side sulphide concentrations measured at the compliance site was comparable to the control sites. Sulphide concentrations measured across all control and compliance sites are below

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the < 250 μM threshold set by the licence conditions (Table 3); they are also below 100 µM, the level above which is identified as being indicative of degrading conditions and major impacts at sandy sites by Macleod and Forbes (2004). Compared to the baseline survey conducted in June 2019, sulphide concentrations at the 3 controls sites (C1, C2 & C3) measured in both surveys was negligable and similar (Jun 19: 0.05 ± 0.05 µM, Mar 20: 0.45 ± 0.21 µM) but higher at the same compliance sites measured in the current survey (21.45 ± 5.76 µM) compared to the baseline (2.9 ± 2.9 µM).

Figure 3 Boxplot (left) of mean sulphide concentration (µM) at 3 cm depth for sediments collected at compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). The boxes represent group quartiles (25th to 75th percentiles), median (horizontal line), mean (cross) and range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. Macleod and Forbes (2004) found that major effects associated with organic enrichment is typically indicated by sulphide values >100 µM; this is represented by the dashed line. Licence conditions stipulate a threshold of >250 μM (Table 3). The plots on the right show the individual core readings (red crosses represent the site mean); the control and compliance are shown according to their position relative to the lease to aid interpretation.

3.4 Particle size analysis

Most sites were dominated by fine sand (0.125-0.063mm) and coarse sand (1-0.25mm) with very little silt (<0.063mm) and gravel (4-2mm). Means for each sediment fraction across all sites were gravel: 8.1% (± 5.0%), coarse sand: 43.7% (±9.0%), fine sand: 46.6% (± 10.9%), silt: 1.6% (± 0.9%).

Compliance sites on the western and eastern sides of the lease were of a similar sediment type to the control sites on the same side of the lease (Figure 4). On the northern side of the lease the control site had a much larger proportion of the coarser sediment fractions (gravel and coarse sand) than the compliance site on the same side. The control site to the south also had a higher percentage of coarse sand.

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Figure 4 Mean particle size content (%) of gravel (> 2 mm), coarse sand (0.25-2 mm), fine sand (0.25-0.063) and silt (< 0.063 mm) at compliance and control sites. Results represent % contribution of each broad sediment size category, pooled across three cores at each site.

Figure 5 Cumulative frequency curves for sediment particle size collected at compliance and control sites. Volumetric (V) thresholds are 4 mm (4), 2 mm (2), 1 mm (1), 0.5 mm (.5), 0.25 mm (.25), 0.125 mm (.125), 0.063 mm (.063), <0.063 mm (<.063).

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Figure 6 Boxplot (left) of sediment organic content (measured via LOI) at compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). The boxes represent group quartiles (25th to 75th percentiles), median (horizontal line), mean (cross) and range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. The plots on the right show the individual core readings (red crosses represent the site mean); the control and compliance are shown according to their position relative to the lease to aid interpretation.

3.5.2 Carbon (%), nitrogen (%) and C:N molar ratio

The mean carbon content of sediments at control and compliance sites was very similar (~0.12 %)(Figure 7). The mean nitrogen (%) content of the sediments was higher at compliance (0.017%) compared to control sites (0.011%) (Figure 7), however, there was no evidence of any clear difference based on the variation (Figure 8). Although the mean C:N ratio of sediments at the compliance sites (12.9) was higher than at the controls (8.7), there was no evidence of any clear difference based on the variation (Figure 8).

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Figure 7. Boxplots (left) comparing sediment carbon (%; left) sediment nitrogen (%; right) of the top 3cm of sediment collected at all compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). Boxes represent the 25th to 75th percentiles, the median (horizontal line), mean (cross), range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. The plots on the right show the individual core readings (red crosses represent the site mean); the control and compliance are shown according to their position relative to the lease to aid interpretation.

Figure 8. Boxplot (left) comparing C:N molar ratio of the top 3cm of sediment collected at all compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). Boxes represent the 25th to 75th percentiles, the median (horizontal line), mean (cross), range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. The plots on the right show the individual core readings while red crosses represent the site mean; the control and compliance are shown according to their position relative to the lease to aid interpretation.

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3.6 Benthic infauna

3.6.3 Total abundance

A total of 5566 individuals were collected across the 8 compliance and 3 control sites (Appendix 3), equating to an average abundance of 169 ± 12 ind. per grab (range 41-374). Abundance at the compliance sites (158 ± 13 ind. per grab) was slightly lower than at the control sites (196 ± 30 ind. per grab) (Figure 9). Mean abundance was lower at the 3 control sites (C1, C2 & C3) in March 2020 (196 ind. per grab) compared to the June 2019 baseline survey (281 ind. per grab). However, mean abundance at compliance sites sampled in both surveys was similar (Jun 19: 153 ind. per grab, Mar 20: 158 ind. per grab). There was no clear pattern when comparing the compliance and control sites on each side of the lease (Figure 9).

Figure 9. Boxplot (left) comparing total abundance per grab at compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). Boxes represent the 25th to 75th percentiles, the median (horizontal line), mean (cross), range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. The plot on the right show site means and error bars (standard error) for all compliance and control sites (the control and compliance are shown according to their position relative to the lease to aid interpretation)

3.6.1 Family richness

There were 247 different species from 146 families observed across the compliance and control sites. Arthropods (crustaceans) were the most dominant taxonomic group (~50% of species), followed by annelids (~25%) and molluscs (~20%). The mean number of families per site was 35 ± 1 (range 17-47). The number of families at compliance (35 ± 3 families per grab) and control sites (33 ± 3 families per grab) were similar (Figure 10). Compared to the baseline survey conducted in June 2019, family richness at the 3 control sites (C1, C2 & C3) was lower (Jun 19: 38 families per grab, Mar 20: 33 families per grab). Family richness at compliance sites was similar between surveys (Jun 19: 33 families per grab, Mar 20: 35 families per grab). There was no clear pattern when comparing the compliance and control sites on each side of the lease (Figure 10).

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Figure 10. Boxplot (top) comparing family richness per grab at compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). Boxes represent the 25th to 75th percentiles, the median (horizontal line), mean (cross), range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. The plot on the right show site means and error bars (standard error) for all compliance and control sites (the control and compliance are shown according to their position relative to the lease to aid interpretation).

3.6.2 Annelid abundance

Annelids are considered an important group because many of the taxa are indicators of organic enrichment. Generally, an increase in annelids will be seen in an enriched environment. In the Environmental Licence an increase at compliance sites of greater than 50x the total annelid abundance at control sites is considered a significant biological impact.

The average abundance of annelids per grab (± SE) was higher at compliance (41 ± 7 annelids per grab) compared to control sites (13 ± 3 annelids per grab). This is approximatley 3x the total abundance at control sites, well within the Environmental Licence threshold of 50x (Figure 11). This pattern of higher annelid abundance at the compliance compared to the control sites was evident on each side of the lease (Figure 11). When compared to the annelid2 numbers in the baseline survey at the same sites, the average abundance was lower in the March 2020 survey (13 annelids per grab) compared to the June 2019 baseline (28 annelids per grab) at the control sites, but higher in the March 2020 survey (41 annelids per grab) compared to the June 2019 baseline (27 annelids per grab) at the compliance sites.

2 Numbers expressed as annelid abundance from the baseline survey are polychaete abundance. For the purposes of this comparison these number are extremely similar i.e. there are very few non annelid polychaetes

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Figure 11. Boxplot (left) comparing annelid abundance per grab at compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). Boxes represent the 25th to 75th percentiles, the median (horizontal line), mean (cross), range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. The plot on the right show site means and error bars (standard error) for all compliance and control sites (the control and compliance are shown according to their position relative to the lease to aid interpretation).

3.6.4 Important species

The family Capitellidae includes species recognised as indicators of organic enrichment in south-eastern Australia (Macleod and Forbes 2004). Capitellids were common at compliance (12.2 ± 6 ind. per grab) compared to control (0.3 ± 0.2 ind. per grab) sites (Figure 12). However, their presence at compliance sites was highly variable, with the vast majority collected at sites in the north-west corner of the lease at sites 1.2, 13.2 and 14.2. When compared to the baseline survey, the average abundance of Capitellidae was lower in the March 2020 survey (0.3 ind. per grab) compared to the June 2019 baseline (3.7 ind. per grab) at the control sites, but higher in the March 2020 survey (12.2 ind. per grab) compared to the June 2019 baseline (3.3 ind. per grab) at the compliance sites. In the baseline three species of Capitellidae were collected, Mediomastus sp., Heteromastus sp. and Notomastus sp.; these species are not regarded as organic enrichment indicators. In contrast, Capitella sp. a known indicator of enrichment was the dominant species (222 of 295 individuals) of the Capitellidae family collected in the March 2020 survey. The leptostracean crustacean Nebalia sp.1 and spionid polychaete Malacoceros tripartitus are also known enrichment indicators (Macleod and Forbes 2004) but they were found in only relatively low numbers; ten Nebalia sp.1 were found across a number control and compliance sites and only a single Malacoceros tripartitus was recorded.

Three introduced species found in south-east Tasmania were recorded in this survey, the crab, Metacarcinus novaezelandiae, and the mollusc, Corbula gibba, were found in very low numbers. The introduced American spider crab (Pyromaia tuberculata) was also collected in this survey and is considered a southerly range extension species (Ahyong 2005, Gary Poore pers.com.), becoming more common and widespread throughout southern Tasmania in recent years.

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Figure 12 Boxplot (left) comparing Capitellidae abundance per grab at compliance and control sites at Yellow Bluff as part of monitoring under the Environmental Licence 10180/1 (March 2020). Boxes represent the 25th to 75th percentiles, the median (horizontal line), mean (cross), range (whiskers). Points more than 1.5* the interquartile range from the hinge (intersect of whisker and box) are considered outliers and plotted with site labels. The plot on the right show site means and error bars (standard error) for all compliance and control sites (the control and compliance are shown according to their position relative to the lease to aid interpretation).

Figure 13. Abundances of benthic invertebrates by family within each taxonomic grouping at all sites at Yellow Bluff for sediments collected in March 2020. Brackets following some labels designate the lowest recognisable taxonomic unit where family could not be identified.

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3.6.5 Community structure

The multidimensional scaling (MDS) plots show the relationship between sites based on the benthic community composition (Figure 14). Sites with more similar communities are closer together in ordination space and those with greater differences are further apart. The control site to the north (C3.2) stands out as quite distinct from the other sites (e.g. only sharing the 20% similarity level). There is then a tight cluster (60% similarity level) of compliance sites (2.2, 4.2, 7.2, 10.2, 1.2) and the control site C2.2). The three compliance sites in the north-west corner of the lease (13.2, 14.2 and 1.2) are separate from this group. An overlay of the abundance of capitellid polychaetes (Figure 15) suggests that the community composition at these sites is influenced by organic enrichment (but see below); this is consistent with their proximity and location to the cage grids and the prevailing current direction (Figure 16). The separation of control sites C1.2 and C3.2 most likely reflects that these more distant sites capture more of the background environmental driven variation in community composition.

K- dominance plots also provide insight into the level of impact and enrichment. They show the cumulative percentage of abundance made up by individual families, starting with the most dominant; a large percentage of the total abundance shared amongst a small number of species is often an indication of an impacted site. Single family dominance patterns were low across all control and compliance sites, ranging from ~8-45% (Figure 17). This is typical of relatively diverse and unimpacted communities. The results are also largely similar when compared to the baseline survey in June 2019(range: 10 - 42%, mean 17%). The site with the highest single-family dominance was 1.2 to the north (~45%) which had the highest abundance of capitellid polychaetes; this was an increase from the baseline survey where single taxa dominance was 14.3%3.

Overall, although the presence of Capitellidae, and notably Capitella sp., at the sites in the north-west corner of the lease is consistent with an influence of organic enrichment, the combined analysis indicates that the communities are diverse and relatively unimpacted.

3 Taxa dominance was calculated using species level data in the 2019 baseline survey; however, family level data has been used in this survey.

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Figure 14. Results of non-metric multidimensional scaling analysis (nMDS; 2D stress = 0.0.08) using benthic infauna data collected from eight compliance sites (red squares) and three control sites (blue squares). Points represent averaged abundances three replicates at each site. The ellipses represent community similarity at levels of 20%, 40% and 60% based on cluster analysis.

Figure 15. Bubble plot overlay of the nMDS community ordination showing the relative abundance (bubble size) of capitellid polychaetes at each site.

23

Figure 16. Current speed rosettes from ADCP data collected from the 27th of March 2020 to the 7th of April 2020 on the North West corner of the Yellow Bluff lease. a) surface (1m), b) midwater (13m) and c) bottom (25.5m) are displayed.

Figure 17. Results of k-dominance analysis of averaged samples from all control and compliance sites

3.7 Performance against licence conditions

The licence stipulates that there must be no significant visual, physico-chemical or biological impacts at or extending beyond 35m from the boundary of the Lease Area (Schedule 2, G1; see Table 3). For this Environmental Licence survey, formal assessment against licence conditions is difficult given the reduced sampling design as a result COVID restrictions. For the biological criteria which require an assessment of change against baseline conditions, differences in the sampling design also need to be considered when interpreting change. In the Baseline Survey, single sediment samples were taken from three locations 20 m apart at each site (e.g. 1.1, 1.2, 1.3) and for monitoring under the Environmental Licence, three replicate samples were taken from the central site from the Baseline Environmental Survey

1 10 100Species rank

0

20

40

60

80

100

Cum

ulat

ive

Dom

inan

ce%

T ype

ComplianceControl

a) b) c)

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(i.e. 1.2, 2.2……11.2). For the purposes of this assessment we have only used data from samples collected at the central site4.

Mean redox and sulphide values were lower and higher, respectively, at the compliance sites compared to the control sites, and the differences were significant. However, all compliance site means are above and below the threshold values identified in the Environmental Licence conditions for redox (0 mV) and sulphide (250 µM) respectively.

Compared to the baseline survey conducted in June 2019, redox potential at the controls sites measured in both surveys was similar but lower at the same compliance sites measured in the current survey compared to the baseline. Compared to the baseline survey conducted in June 2019, sulphide concentrations at the controls sites measured in both surveys was negligable and similar (Jun 19, Mar 20) but higher at the same compliance sites measured in the current survey compared to the baseline.

For the biological criteria, a comparison against the baseline data, does not indicate:

• a 20 time increase in the total abundance of any individual taxonomic family relative to the reference site,

• an increase at any compliance site of greater than 50-times the total Annelid abundance at reference sites,

• a reduction in the number of families by 50 percent or more relative to reference sites, • or a complete absence of fauna.

The largest increase in the total abundance of an individual taxonomic family was for the Capitellidae and this represented a 3-4 times increase relative to reference conditions in the Baseline survey. For total Annelid abundance, the largest increase at any compliance site was 2.6 times increase in Annelid abundance at site 4.2 relative to reference conditions in the Baseline survey. There was a very minor increase in the number of families at the compliance sites (35 families per grab) relative to reference conditions in the Baseline survey (33 families per grab). With respect to the final condition, an abundant and diverse fauna was observed at all compliance sites, with the number of families ranging from 24-43 per site and total abundance ranging from 316-694 per site (Appendix 3).

4 i.e. the change at each site was calculated as the difference between the average of the three replicates collected in the Environmental Licence survey and the single sample collected at the baseline

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6. References Ahyong, S. T. (2005). Range extension of two invasive crab species in eastern Australia: Carcinus maenas (Linnaeus) and Pyromaia tuberculata (Lockington). Marine Pollution Bulletin, 50(4), 460-462. Aquenal (2019). Trumpeter Bay MF281 - East of Yellow Bluff: Baseline environmental assessment. Hobart, Tasmania. Macleod, C. and S. Forbes (2004). Guide to the assessment of sediment condition at marine finfish farms in Tasmania. Aquafin CRC Project 4.1 (Extension). Hobart, Tasmania, Tasmanian Aquaculture and Fisheries Institute. Environmental Protection Authority. (2019). Environmental Licence No. 10180/1.

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7. Appendices

Appendix 1 Survey coordinates for sediment sampling, based on the Mapping Grid of Australia Zone 55 (GDA94).

Site name Easting Northing

C1 535242 5222870

C2 537046 5226485

C3 533856 5228936

1.2 534061 5226914

2.2 534372.9 5226986

4.2 535049 5226653

7.2 535324.6 5225474

10.2 534565.4 5224807

13.2 534000.4 5226015

14.2 533912 5226389

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Appendix 2 Corrected redox and sulphide data for each core collected at Yellow Bluff in March 2020.

Sample Redox Corrected 3cm (mV)

Sulphide Corrected 3cm (µM)

C1.2.1 415.16 0.11

C1.2.2 418.59 0.07

C1.2.3 402.77 0.09

C2.2.1 365.50 0.36

C2.2.2 408.07 0.42

C2.2.3 415.64 0.29

C3.2.1 291.69 0.34

C3.2.2 419.39 0.29

C3.2.3 329.67 2.06

1.2.1 166.86 31.12

1.2.2 -73.99 33.56

1.2.3 79.76 18.35

4.2.1 335.85 1.64

4.2.2 57.85 4.72

4.2.3 351.07 1.12

14.2.1 99.97 21.42

14.2.2 25.05 28.97

14.2.3 24.31 52.99

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Appendix 3 Raw data: Benthic infauna at all sites (data is pooled by site)

1.2 C3.2 4.2 C2.2 C1.2 14.2 2.2 7.2 10.2 12.2 13.2

No. Replicates 3 3 3 3 3 3 3 3 3 3 3

Family name Phylum Ampharetidae Annelida 3 1 0 0 0 0 0 0 0 0 1 Amphinomidae Annelida 0 7 0 0 0 0 0 0 0 0 3 Apistobranchidae Annelida 0 0 0 0 0 0 0 0 0 0 0 Capitellidae Annelida 174 2 2 1 0 54 0 1 2 4 55 Cirratulidae Annelida 0 0 1 0 1 0 1 0 0 0 0 Dorvilleidae Annelida 0 0 6 1 1 0 3 0 0 1 8 Glyceridae Annelida 0 1 5 3 3 0 6 4 5 3 5 Hesionidae Annelida 0 4 0 0 1 0 0 0 0 0 17 Lumbrineridae Annelida 0 0 0 0 0 0 0 1 0 0 7 Maldanidae Annelida 1 0 2 0 0 0 0 1 1 0 1 Nephtyidae Annelida 0 0 0 0 0 2 0 1 0 0 0 Nereididae Annelida 0 0 0 0 0 2 0 1 0 2 2 Oenonidae Annelida 0 1 0 0 0 0 0 0 0 0 0 Oligochaeta (sCl) Annelida 0 2 0 0 0 0 0 0 0 0 0 Onuphidae Annelida 6 0 20 4 3 11 20 4 12 8 1 Opheliidae Annelida 0 0 0 0 9 0 0 0 0 0 1 Orbiniidae Annelida 4 0 1 0 0 0 0 0 0 0 1 Oweniidae Annelida 3 4 10 3 1 12 12 5 1 9 5 Paraonidae Annelida 0 2 0 1 1 1 0 0 1 0 28 Pectinariidae Annelida 3 0 1 0 0 10 2 0 0 2 0 Phyllodocidae Annelida 4 0 4 2 0 2 2 2 2 0 0 Poecilochaetidae Annelida 0 0 0 0 0 0 1 0 1 2 0 Polygordiidae Annelida 0 0 3 0 2 0 1 0 1 0 3 Polynoidae Annelida 0 4 0 0 0 0 0 0 0 1 0 Sabellidae Annelida 0 0 30 4 2 1 2 7 2 4 0 Serpulidae Annelida 0 2 1 0 0 0 0 0 0 0 0 Sigalionidae Annelida 0 0 0 0 0 0 0 0 0 1 0 Spionidae Annelida 29 0 35 25 6 53 41 38 40 30 12 Syllidae Annelida 4 12 13 1 1 1 3 1 3 1 4 Terebellidae Annelida 0 2 0 0 0 0 0 0 0 0 1 Ampeliscidae Arthropoda 4 1 3 0 8 0 0 4 9 19 0 Amphipoda (O.) Arthropoda 0 0 0 0 7 0 0 0 0 0 0 Anthuridae Arthropoda 0 2 1 0 4 1 2 7 5 8 6 Aoridae Arthropoda 1 0 11 18 50 0 9 12 5 16 22 Apseudidae Arthropoda 3 107 10 17 293 2 1 16 10 1 2 Arcturidae Arthropoda 0 0 0 0 0 0 0 0 0 0 0 Austrarcturellidae Arthropoda 0 0 5 6 0 0 0 9 2 0 0 Axiidae Arthropoda 0 0 0 0 0 0 0 0 0 0 0

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Bodotriidae Arthropoda 9 10 31 14 20 4 18 29 13 14 10 Bopyridae Arthropoda 0 0 0 0 0 2 0 0 0 0 0 Brachyura (iO) Arthropoda 0 0 0 0 0 0 1 0 0 0 0 Callipallenidae Arthropoda 0 0 1 0 0 0 0 0 0 0 0 Cancridae Arthropoda 0 0 0 0 0 0 0 0 0 0 1 Caprellidae Arthropoda 0 0 0 0 0 0 0 0 0 0 0 Chaetiliidae Arthropoda 0 0 3 0 0 0 0 0 0 1 0 Cirolanidae Arthropoda 0 0 0 0 0 0 0 1 1 1 0 Copepoda (sCl.)3 Arthropoda 0 0 0 0 0 0 0 0 0 0 0 Copepoda (sCl.)4 Arthropoda 0 0 1 0 0 0 1 0 3 0 0 Corophiidae Arthropoda 0 3 129 22 20 0 24 61 155 8 10 Crangonidae Arthropoda 0 0 1 0 0 0 0 0 1 0 0 Cylindroleberididae Arthropoda 0 0 18 6 4 0 3 5 2 14 2 Cypridinidae Arthropoda 0 0 0 1 3 0 0 3 7 0 1 Dexaminidae Arthropoda 2 0 3 1 16 1 1 6 1 1 6 Diastylidae Arthropoda 5 0 19 21 0 2 6 14 5 6 2 Dogielinotinae Arthropoda 0 3 0 0 0 0 0 0 0 0 0 Eusiridae Arthropoda 2 9 4 12 24 3 4 15 9 16 22 Galatheidae Arthropoda 0 2 0 0 0 0 0 0 0 0 0 Gnathiidae Arthropoda 0 0 0 0 4 0 0 0 0 0 0 Gynodiastylidae Arthropoda 1 0 2 6 1 2 4 4 2 3 0 Hexapodidae Arthropoda 0 0 0 0 0 0 0 0 0 0 1 Hymenosomatidae Arthropoda 0 0 0 0 0 0 0 0 0 0 0 Inachoididae Arthropoda 1 0 0 0 0 0 1 0 1 1 0 Isaeidae Arthropoda 62 1 93 16 2 24 41 52 58 36 1 Ischyroceridae Arthropoda 2 0 0 0 0 0 0 0 0 2 0 Janiridae Arthropoda 0 1 0 0 0 0 0 0 0 0 0 Kalliapseudidae Arthropoda 0 3 0 0 8 0 0 0 0 0 0 Leptocheliidae Arthropoda 0 0 0 0 1 0 0 0 0 0 1 Leucosiidae Arthropoda 0 0 0 1 0 0 1 1 0 1 0 Leucothoidae Arthropoda 0 0 0 0 3 0 0 0 0 0 0 Liljeborgiidae Arthropoda 2 0 2 1 0 7 2 5 0 1 18 Luciferidae Arthropoda 0 0 0 0 1 0 0 0 0 0 0 Lysianassidae Arthropoda 3 0 12 3 33 1 12 12 5 9 0 Maeridae Arthropoda 0 192 0 0 14 0 0 1 0 0 15 Majidae Arthropoda 0 0 0 0 0 0 0 0 0 0 0 Melitidae Arthropoda 0 9 3 0 0 0 0 0 2 1 2 Melphidippidae Arthropoda 0 0 0 0 9 0 0 4 1 0 0 Myodocopa (SCl.) Arthropoda 0 0 10 1 0 0 8 4 5 2 0 Mysidae Arthropoda 0 0 0 1 0 0 0 0 0 0 0 Nebaliidae Arthropoda 1 0 0 1 0 2 1 0 1 4 0 Oedicerotidae Arthropoda 4 0 4 5 17 0 1 2 2 1 0 Ostracoda (Cl.)1 Arthropoda 0 0 1 3 7 1 6 3 0 2 0

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Ovalipidae Arthropoda 0 0 0 0 1 0 0 0 0 0 0 Paguridae Arthropoda 0 17 2 0 9 6 0 1 7 5 18 Palaemonidae Arthropoda 0 8 0 0 0 1 0 0 0 0 0 Paramunnidae Arthropoda 0 0 0 0 0 0 1 0 0 0 0 Pasiphaeididae Arthropoda 0 0 3 1 0 1 1 0 0 2 1 Philomedidae Arthropoda 5 0 37 18 22 3 34 47 44 22 0 Photidae Arthropoda 0 2 12 7 44 0 1 4 1 2 9 Phoxichilidiidae Arthropoda 0 0 0 0 0 0 0 0 0 0 0 Phoxocephalidae Arthropoda 3 15 10 3 21 13 5 1 8 17 19 Pilumnidae Arthropoda 0 1 0 0 0 0 0 0 0 0 0 Pinnotheridae Arthropoda 0 0 0 0 0 0 0 0 0 1 2 Platyischnopidae Arthropoda 0 1 4 2 2 0 0 2 3 2 0 Pseudocumatidae Arthropoda 0 0 1 2 0 0 0 0 1 0 3 Rutidermatidae Arthropoda 0 0 0 0 0 0 0 1 1 0 0 Sarsiellidae Arthropoda 0 0 3 0 0 0 2 6 5 6 1 Sebidae Arthropoda 0 11 0 0 0 0 0 0 0 0 0 Serolidae Arthropoda 0 2 0 0 3 0 0 0 0 0 0 Sphaeromatidae Arthropoda 3 139 20 2 29 0 8 6 14 1 10 Synopiidae Arthropoda 2 8 8 3 60 1 0 11 5 1 43 Talitridae Arthropoda 0 0 0 0 0 0 0 0 0 0 2 Urohaustoriidae Arthropoda 0 0 7 2 0 0 0 7 0 2 0 Whiteleggiidae Arthropoda 0 0 11 24 2 0 0 18 0 4 0 Branchiostomatidae Chordata 0 3 0 0 0 0 0 0 0 0 0 Holozoidae Chordata 0 0 0 0 0 0 1 0 0 0 0 Edwardsiidae Cnidaria 0 0 1 1 1 1 6 0 0 5 14 Amphiuridae Echinodermata 0 0 0 0 0 0 0 0 0 0 1 Asteriidae Echinodermata 0 0 0 0 0 2 0 0 0 0 0 Cucumariidae Echinodermata 0 0 0 0 0 0 0 1 0 0 0 Loveniidae Echinodermata 0 0 2 1 0 34 10 0 4 6 0 Ophiuridae Echinodermata 20 2 42 17 3 19 37 78 30 13 13 Synaptidae Echinodermata 0 0 0 0 0 0 0 0 0 1 0 Temnopleuridae Echinodermata 0 2 0 0 0 0 0 0 0 0 0 Enteropneusta (Cl.) Hemichordata 0 0 0 0 0 0 0 0 3 0 0 Anabathridae Mollusca 6 1 4 5 2 0 1 15 6 5 0 Calyptraeidae Mollusca 0 9 0 0 4 0 0 0 0 1 0 Cardiidae Mollusca 0 0 0 2 0 0 0 0 2 4 0 Carditidae Mollusca 0 0 0 0 4 0 0 0 0 0 1 Cerithiopsidae Mollusca 0 1 0 0 0 0 0 0 0 0 0 Cingulopsidae Mollusca 0 1 0 0 0 1 0 0 0 0 0 Columbellidae Mollusca 0 0 10 5 0 0 1 4 5 9 0 Condylocardiidae Mollusca 1 9 0 0 1 5 0 58 10 4 27 Corbulidae Mollusca 0 0 0 0 0 2 0 0 0 0 0 Galeommatidae Mollusca 3 0 0 0 4 1 1 1 2 0 0

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Glycymerididae Mollusca 0 0 0 0 0 0 0 2 0 0 1 Hiatellidae Mollusca 0 0 0 0 0 0 0 0 0 0 0 Lepetidae Mollusca 0 1 0 0 0 0 0 0 0 0 0 Limidae Mollusca 0 2 0 0 0 0 0 0 0 0 0 Lucinidae Mollusca 0 0 0 0 0 0 0 0 0 0 0 Mactridae Mollusca 0 0 0 0 1 0 0 0 0 0 0 Mangeliidae Mollusca 0 0 0 0 0 0 0 0 0 0 0 Marginellidae Mollusca 0 0 4 2 0 0 1 0 1 0 0 Muricidae Mollusca 0 0 0 0 0 0 0 1 0 1 0 Myochamidae Mollusca 0 0 0 0 1 0 0 0 0 0 0 Mytilidae Mollusca 0 0 1 0 1 0 0 0 0 0 0 Nassariidae Mollusca 4 6 0 7 0 4 1 0 0 2 3 Naticidae Mollusca 0 0 1 0 0 0 1 1 1 4 0 Nuculanidae Mollusca 0 0 0 0 0 0 0 0 0 0 0 Nuculidae Mollusca 1 0 1 0 0 0 0 0 0 0 0 Olivellidae Mollusca 0 0 0 0 0 0 0 0 0 0 0 Philinidae Mollusca 4 0 0 0 0 0 1 1 0 0 0 Pleurobranchidae Mollusca 0 1 0 0 0 1 0 0 0 0 0 Psammobiidae Mollusca 1 0 0 2 0 0 1 0 0 0 1 Pyramidellidae Mollusca 0 0 0 0 1 0 0 0 0 0 0 Retusidae Mollusca 0 0 0 0 0 0 0 0 0 2 0 Solenidae Mollusca 0 0 0 0 0 0 0 0 0 0 0 Terebridae Mollusca 0 0 1 0 0 0 0 0 0 0 0 Thraciidae Mollusca 0 0 0 0 0 3 0 0 0 0 0 Trochidae Mollusca 0 2 0 0 0 0 0 0 0 0 0 Turritellidae Mollusca 0 0 0 0 0 1 0 0 0 0 0 Veneridae Mollusca 0 0 0 7 3 9 0 1 0 1 0 Nematoda (P.) Nematoda 0 0 3 4 1 0 18 7 2 25 3 Nemertea (P.) Nemertea 2 8 5 3 6 7 7 3 6 6 33 Phoronida (P.) Phoronida 0 0 0 0 0 0 0 0 0 0 0

Tot. Abundance 388 639 694 321 806 316 380 613 537 390 482

Tot. Annelids 231 42 134 45 31 149 94 66 71 68 155

Mean Families 24 27 43 33 39 26 34 40 37 42 35

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Appendix 3 Core images from all survey sites sampled at Yellow Bluff in March 2020.

1.2.1 1.2.2 1.2.3

C3.2.1 C3.2.2 C3.2.3

33

14.2.1 14.2.2 14.2.3

4.2.1 4.2.2 4.2.3

34

C2.2.1 C2.2.2 C2.2.3

C1.2.1 C1.2.2 C1.2.3

35

Appendix 4 Raw data: Particle size: Particle size analysis

Vi V water V 4 V 2 V 1 V 0.5 V 0.25 V 0.125 V 63 Sample ml ml ml ml ml ml ml ml Ml C1.2.1 33 30 30.25 31.5 33 41.75 59 63 63 C1.2.2 27.5 30 30 30.25 31.25 37.5 55 57.5 57.5 C1.2.3 31 30 30 30.5 33 44 59 61 61 C2.2.1 32 30 30.5 31 31.25 32 40.75 60 61.75 C2.2.2 31.75 30 30.75 31 31.5 32.25 40 59.5 61.5 C2.2.3 31 30 30.75 31 31.75 32.75 42.75 59.25 61 C3.2.1 28 30 35.5 40 46 53.5 56.75 57.75 58 C3.2.2 27 30 34 38.5 42.5 53.5 56 56.75 57 C3.2.3 33 30 39 45 50 55 61.5 62.75 63 1.2.1 31.75 30 30 30 30.25 31 39 57.5 61 1.2.2 30 30 30.5 30.75 31 31.25 34 54 58 1.2.3 31.5 30 31 31.75 32.25 33 36.75 57 60.5 4.2.1 33 30 30 30.25 30.75 31 42 61 62.75 4.2.2 32 30 30 30.25 30.75 31.25 43 61 62 4.2.3 31 30 30.25 30.5 31 31.75 45 60 61 14.2.1 30 30 30.75 31 31.25 32 38 55.5 59 14.2.2 29 30 30.25 30.5 31 31.25 36.75 53.5 58 14.2.3 36 30 30 30 30.5 32 40 58 63.5

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Appendix 5 Raw data: Loss on ignition

Sample LOI%

C1.2.1 2.02

C1.2.2 1.89

C1.2.3 1.68

C2.2.1 1.06

C2.2.2 0.89

C2.2.3 1.00

C3.2.1 1.52

C3.2.2 1.55

C3.2.3 2.23

1.2.1 1.40

1.2.2 1.60

1.2.3 1.23

4.2.1 0.98

4.2.2 1.05

4.2.3 1.03

14.2.1 1.34

14.2.2 2.30

14.2.3 1.51

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Appendix 6 Raw data: Carbon and nitrogen isotopes

Sample %C %N C:N

(mass) C:N

molar δ13C δ15N C1.2.1 0.13 0.01 13.03 15.20 -22.51 7.20 C1.2.2 0.18 0.01 20.16 23.51 -22.48 7.60 C1.2.3 0.07 0.01 11.13 12.98 -21.18 5.94 C2.2.1 0.06 0.01 6.60 7.70 -19.47 7.02 C2.2.2 0.03 0.01 3.95 4.61 -21.18 8.13 C2.2.3 0.08 0.01 8.34 9.72 -22.16 7.65 C3.2.1 0.13 0.01 16.27 18.98 -19.45 7.38 C3.2.2 0.18 0.03 6.57 7.66 -20.21 4.95 C3.2.3 0.22 0.02 13.15 15.34 -23.04 7.09 1.2.1 0.15 0.02 9.05 10.56 -21.40 5.42 1.2.2 0.16 0.02 9.31 10.86 -20.78 6.35 1.2.3 0.15 0.01 11.97 13.96 -22.73 6.74 4.2.1 0.05 0.01 6.62 7.72 -21.94 5.73 4.2.2 0.05 0.01 5.68 6.63 -21.32 6.18 4.2.3 0.07 0.01 7.65 8.92 -20.88 7.87 14.2.1 0.13 0.02 5.97 6.97 -21.86 7.64 14.2.2 0.12 0.02 5.75 6.71 -20.92 5.97 14.2.3 0.20 0.04 5.19 6.06 -21.61 6.96

mf281 yellow bluff benthus survey report 2020

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