Aquaculture Survey and Macro-Invertebrate Analysis Report

Transcription

1 Aquaculture Survey and Macro-Invertebrate Analysis Report Shelburne Harbour - Former Sandy Point Lease Site October 2013 Inka Milewski February 2014

2 P a g e 2 Table of Contents Summary List of Tables List of Figures Project Overview Methodology Field Work Sediment Sampling Macrobenthic Sample Processing Seabed Photography and Video Sediment Sampling and Imaging Results Redox Potential and Sulphides Percent Organic Matter Trace Metal Analysis Imaging Results Macrofaunal Analysis Diversity Measures Conclusions Acknowledgements References Appendix 1 - Sampling station and transect depths and coordinates Appendix 2 - Nomogram for benthic organic enrichment zonation Cover Photo: The Sandy Point fish farm (lease #0602) in Shelburne Harbour is pictured in this aerial photograph taken September 18, 2010 and obtained from NS GIS Services in December The farm ceased operations in September 2011.

3 P a g e 3 Summary The Conservation Council of New Brunswick (CCNB) began a study in 2011 to survey the benthic environment at the former Sandy Point fish farm (lease #0602) in Shelburne Harbour, Nova Scotia. The former fish farm began operating in 1991, expanded in 1995, transferred ownership in 2006 and the lease was surrendered back to the Province in September This report covers the benthic survey conducted on October 22, 2013 and the imaging survey on November 19, Survey results from 2011 and 2012 are found in separate reports. The 2013 survey included seven sampling stations whose locations were close to the sampling stations in 2011 and None of the sampling stations were located directly under the former fish cages. Sediment samples were collected for geochemical (redox, sulphides, % organic content, copper, zinc and lithium) and macrobenthic infaunal analysis. Video and still photography imaging was performed along four transects. Sediment sulphides, % organic matter, copper and zinc exhibited an increasing trend from the reference station to the area around the former fish farm. Percent organic matter for sampling stations in the vicinity of the former fish farm remained above the mean level reported at the reference stations ( ). Sediment sulphide values around the former fish farm ranged from 1820 µm to 3250 µm and the highest sediment concentrations of copper and zinc (139 mg/kg and 433 mg/kg respectively) were found around the former fish farm. Despite limited visibility, imaging results documented extensive bacterial mats of Beggiatoa sp. near the former fish farm. Increased presence of Beggiatoa sp. corresponded to increased sediment sulphide levels. In total, 35 animals and 11 species were recorded from the seven samples and, as in 2011 and 2012, polychaetes were the dominant group. A station in the vicinity of the former fish farm had the highest abundance of polychaetes, specifically Capitella capitata which is an indicator species for organic enrichment. Statistical measures of diversity for all stations in 2013 were lower than 2011 and With the exception of the reference station, diversity values in the vicinity of the former fish farm were lower than stations leading up to the former farm site. The trend of decreasing diversity from the reference site to the former farm site was consistent for all sampling years. After two complete years of fallowing, sediment geochemistry and macrobenthic infaunal recovery in the vicinity of the former Sandy Point fish farm is incomplete relative to the sampling stations leading up to the farm. Another year of sampling at the Sandy Point site is warranted.

4 P a g e 4 List of Tables Table 1 - Sandy Point sediment redox potential and sulphides (2013) Table 2 - Nova Scotia Environmental Quality Definitions for Nova Scotia Marine Aquaculture Monitoring Table 3 - Sandy Point percent organic matter ( ) Table 4 - Summary of sediment trace metal analysis for Sandy Point ( ) Table 5 - List of macrobenthic infaunal species at Sandy Point (2013) Table 6 - Summary of diversity measures List of Figures Figure 1 - Location of sampling stations at the former Sandy Point salmon farm lease site (#0602) Figure 2 - Sandy point sediment sulphides (2013) Figure 3 - Sediment sulphides at the former Sandy Point fish farm lease (#0602) ( ) Figure 4 - Sandy Point percent organic matter ( ) Figure 5 - Percent organic matter at the Sandy Point farm site sampling stations only ( ) Figure 6 - Sandy Point sediment copper concentrations ( ) Figure 7 - Sandy Point sediment zinc concentrations ( ) Figure 8 - Copper and zinc concentrations in surface sediments (Loring et al. 1996) Figure 9 - Sandy Point sediment lithium concentrations ( ) Figure 10 - Location of imaging transects at the former Sandy Point lease site Figure 11 - Selected images from 2013 seafloor photography Figure 12 - Ovoid fecal pellets Figure 13 - Diversity measures for the Sandy Point site ( )

5 P a g e 5 1 Project Overview The Conservation Council of New Brunswick (CCNB) began a study in 2011 to survey the benthic environment at the former Sandy Point salmon farm (lease #0602) in Shelburne Harbour, Nova Scotia. The former Sandy Point salmon farm began operating in 1991, expanded in 1995, transferred ownership in 2006 and the lease was surrendered back to the Province in September of CCNB contracted McGregor GeoScience Ltd to conduct a one-day field survey of the Sandy Point farm on October 27, 2011 and again on October 18, The results from those field surveys are contained in two reports: McGregor GeoScience Ltd (2012) Shelburne Harbour Aquaculture Survey Report; and McGregor GeoScience Ltd (2013) Shelburne Harbour Survey Report. These reports were sent to the Nova Scotia Department of Fisheries and Aquaculture and are available from CCNB. This report covers the benthic survey conducted by Dominator Marine Services Inc. (Saint John, NB) on October 22, 2013 and the imaging survey on November 19, McGregor GeoScience was unavailable to conduct the survey in Methodology 2.1 Field Work Field work was conducted on October 22, 2013 by a 3-person team from Dominator Marine Services, CCNB and Dalhousie University. The vessel used to access the study site was a 22 ft. fishing skiff piloted by Captain Bill Rapp. The 2013 survey included seven sampling stations whose locations were close to the sampling stations from 2011 and The location of six of these stations and a reference station are shown in relation to the location of the former Sandy Point fish farm and lease area in Figure 1. S1 was the reference station and stations S2 to S7 were located with decreasing distance to the fallowed fish farm. Water depths were greatest at sampling stations in the vicinity of the former fish farm (S5, S6, S7) (Appendix 1). None of the sampling stations were located directly under the former fish cages. 2.2 Sediment Sampling Dominator Marine staff deployed a Ponar grab, with a total surface area of 529 cm 2 and a depth of approximately cm, to collect benthic samples. The grab was rinsed and cleaned of any sediment prior to each grab sample. The GPS location and water depth at each grab location was recorded. A grab sample was taken at seven sampling stations. Half of each grab sample was used for chemical analysis and the other half for infaunal analysis. The samples for infaunal analysis were washed and "puddled" in a 500 µm sieve onboard and backwashed into 500 ml glass containers for later preservation on shore.

6 P a g e 6 Subsamples from each grab were collected for sediment chemistry. Redox measurements were recorded immediately after grab samples were onboard using an Accumet AP63 Portable ph/ion meter. Samples were kept on ice for the duration of the field work until ready for processing. An Accumet AP-125 meter was used to measure sulphides. The probe was calibrated by Ferris Chemicals Ltd., Saint John, New Brunswick. 2.3 Photography and Video Underwater photography and video transects could not be completed on October 22, 2013 due to a malfunction in the equipment. Dominator Marine Services staff returned to the site on November 18, 2013 to complete four transects in locations close to transects taken in 2011 and 2012 (see Figure 10). Medium angle video and pictures were captured using a Go Pro Hero 3 set at 1080 P resolution. The narrow angle video was completed using a Sony HDR-CX12 handycam inside an Ikelite pressure case. 2.4 Macrobenthic Infaunal Sample Processing Benthic samples were preserved in a final concentration of 10% Formalin and kept in an air tight container. Samples were kept in the formalin preservative for a total of hours before analysis. Samples were sent via courier to Envirosphere Consultants Limited (Windsor, Nova Scotia) on October 25, 2013 for biological analysis (sorting and identification and assessment for biological species composition and abundance).

7 P a g e 7 Figure 1 - Location of sampling stations at the former Sandy Point salmon farm lease (#0602), Shelburne Harbour, Nova Scotia

8 P a g e 8 3 Sediment Sampling and Imaging Results 3.1 Redox Potential and Sulphides Sediment redox (oxygen reduction) potential is an indicator of presence (aerobic) versus absence (anaerobic) of free oxygen conditions in the sediments. Redox potential (Eh NEH ) is measured in millivolts (mv). Total dissolved sulphides are measured in micromolars (µm) and are a measure of organic enrichment impact in sediments. Redox potential and sulphides are inter-related measures through the sulphur cycle. As organic loading in sediments increases, sulphate reduction, where sulphates are changed or reduced to sulphides, becomes the major metabolic pathway predominating over oxic (aerobic) respiration (Hargrave et al. 2008). An increase in conditions that reduce sulphates to sulphides results in a decrease in ph and oxidation reduction (Eh NHE ) potentials. Redox potential and sulphide analysis followed the methods described in the Standard Operating Practices for Environmental monitoring of Marine Finfish for the Monitoring of Marine Finfish Cage Aquaculture industry in New Brunswick (2012) which is similar to Nova Scotia's Standard Operating Procedures for the Environmental Monitoring of Marine Aquaculture in Nova Scotia (2011). The results of the analyses are presented in Table 1. Table 1 - Sandy Point sediment redox potential and sulphides (2013) Station Redox Potential Sample Temperature ºC Redox Potential (mv) Final Redox Potential (Adjusted to Reference Electrode) (mv) Sulphide Sample Temperature ºC Sulphide (µm) S1 14ºC ºC 912 S2 14ºC ºC 273 S3 14ºC ºC 1180 S4 14ºC ºC 725 S5 14ºC ºC 2570 S6 14ºC ºC 3250 S7 14ºC ºC 1820

9 P a g e 9 Redox potential and sulphide values at the reference station (S1) and three stations leading up to the farm (S2, S3, and S4) were all in the Oxic A or Oxic B range (Table 1, Table 2). Redox potential and sulphide values for stations S5 and S7 were in the Hypoxic A range and S6 was in the Hypoxic B range. Figure 2 presents the sulphide concentrations for all stations relative to the 2011 Nova Scotia environmental quality definitions for marine aquaculture monitoring and the organic enrichment classification proposed in the DFO Expert Opinion Document (Hargrave 2006). Table 2 Nova Scotia Environmental Quality Definitions for Nova Scotia Marine Aquaculture Monitoring Measurement Sediment Classification Oxic Hypoxic Anoxic Sulphides (µm) < 750 (A) (A) > (B) (B) Redox Potential (mv) > 100 (A) -50 to -100 (A) < to -50 (B) -100 to -150 (B) Organic Matter (%) = reference site * 1.5 to 2 X reference > 2 X reference site * site * Microbial Presence no sulphur bacterial present patchy sulphur bacteria widespread bacterial mats *Values compared to reference assume that reference and lease sites have similar levels in pre-culture conditions. Sediment sulphides were not sampled in 2011 or 2012, but data were available for the Sandy Point lease site for 2004 to Figure 3 compares the sulphide levels (including reference stations) at the Sandy Point lease ( ) to levels reported in this study. Historic sulphide data were obtained from the NS Department of Fisheries and Aquaculture.

10 P a g e 10 Figure 2 - Sandy Point sediment sulphides (2013) Figure 3 - Sediment sulphides at the former Sandy Point fish farm lease (#0602)( )

11 P a g e Percent Organic Matter Samples were analyzed by loss on ignition (LOI) method by RPC Fredericton, New Brunswick and the results are presented in Table 3 and illustrated in Figure 4. Sediment organic matter exhibited an overall increasing trend from the reference station (S1) to the former fish farm (S5 to S7)( Table 3, Figure 4). Percent organic matter in sediments declined across all stations sampled in 2011 to 2012 except for station S4 which exhibited a slight increase from 2012 and station S5 which saw a more significant increase from 2012 (11.5%) to 2013 (23.3%). Percent organic matter for sampling stations at the former fish farm remained above the mean level reported at the reference station ( ) and were comparable to levels reported at the former fish farm site between 2004 and 2009 (Figure 5). Table 3 Sandy Point percent organic matter ( ) Station 2011 Organic Matter (%) 2012 Organic Matter (%) 2013 Organic Matter (%) S S S S S S S7 N/A Figure 4 - Sandy Point percent organic matter ( )

12 P a g e 12 Organic matter in surface sediments is an important source of food for benthic organisms (Hyland et al. 2005). High levels of organic matter may lead to reductions in species richness, abundance, and biomass due to oxygen depletion and the buildup of toxic by-products (i.e., sulphides) which are associated with the breakdown of these materials (Hyland et al. 2005) Percent organic matter is often used as a measure of organic loading (NS DFA 2011). Figure 5. Percent organic matter at the Sandy Point former fish farm ( ) (Results from sampling stations near the fish farm only)

13 P a g e Trace Metal Analysis Sediment samples were analyzed for three trace metals (copper, zinc and lithium) at RPC Fredericton. Samples were air-dried and sieved at 2 mm, portions were digested with nitric acid and hydrofluoric acids and the resulting solutions were analyzed for trace elements by ICP-MS. Sediment concentrations of copper and zinc exhibited a clear trend of increase from S1 to S7, with the lowest values reported at the reference station (S1) (Table 4, Figure 6 and Figure 7). This trend is consistent with the trend in Most stations exhibited either a slight decrease (S1, S2, and S3) or a more significant decrease (S6 and S7) in concentration. Two stations (S4 and S5) exhibited a significant increase. Table 4 Summary of sediment trace metal analysis for Sandy Point ( ) Station Copper (mg/kg) Zinc (mg/kg) Lithium (mg/kg) S S S S S , S S Figure 6 - Sandy Point sediment copper concentrations( )

14 P a g e 14 Figure 7 - Sandy Point sediment zinc concentrations( ) The Canadian Council of Ministers for the Environment (CCME) has established interim sediment quality guidelines (ISQGs) and probable effect levels (PELS) for copper and zinc. Copper is known to be toxic to aquatic organisms at elevated concentrations and the CCME PEL guidelines refer to levels of copper or zinc in sediments at which adverse biological effects are likely to occur (CCME 1999). The CCME ISQG for copper is 18.6 mg Cu/kg dry weight and the PEL is 108 mg Cu/kg dry weight (CCME 2002). For zinc, the ISQG is 124 mg Zn/kg dry weight and the PEL is 271 mg Zn/kg dry weight (CCME 2002). Based on these values, the copper and zinc levels at S5 exceed the CCME s PEL level in In 2012, copper and zinc levels at S7 exceed the CCME's PEL levels. S5 and S7 are stations at the former Sandy Point farm site. Copper and zinc concentrations at all stations in 2012 and 2013 exceed the CCME's ISQGs. Loring et al. (1996) assessed the abundance and distribution of metals in Shelburne Harbour (Figure 8). Copper levels averaged 15.8 mg Cu/kg ±11.3 and ranged 2 44 mg Cu/kg. Zinc averaged 44.5 mg Zn/kg ±24.7 and ranged 8-90 mg Zn/kg.

15 P a g e 15 Figure 8 - Copper (Cu) and zinc (Zn) concentrations in surface sediments (Loring et al. 1996) Relative to the values reported by Loring et al. (1996), copper and zinc levels in the vicinity of the Sandy Point salmon farm were significantly (3 to 10 times) higher than the mean values reported in The highest values for copper and zinc in 2013 were reported at station S5 (Cu = 129 mg/kg; Zn = 433 mg/kg). Copper, zinc and other heavy metal concentrations in the sediments are related to grain size and the natural mineralogy of the sediments (Yeats et al. 2005). High levels of heavy metals in sediments can be natural in origin or linked to anthropogenic sources. In order to distinguish the source, normalization procedures using lithium, aluminum and grain-size are measured along with heavy metal analysis (Loring et al. 1996). Lithium is a surrogate for grain size of sediments larger lithium values reflect finer grain sediments. Loring et al (1996) reported a mean sediment concentration of 32.5 ± 11.5 mg/kg for lithium in Shelburne Harbour. In this study, lithium sediment concentrations in 2012 and 2013 ranged from 35 to 40 mg/kg except for station S7 in S012 and S5 in 2013 (Figure 9). These stations had the highest sediment copper, zinc and organic content in their respective years which strongly indicates an anthropogenic source rather than a natural source for the metals.

16 P a g e 16 Figure 9 - Sandy Point sediment lithium concentrations ( ) Copper and zinc are additives in fish feed and are used in anti-fouling products found in marine paint and coatings for nets and rope. These metals enter the environment from fish farms through several pathways: (1) excretion in concentrated levels in fish feces, (2) leaching from nets, rope and other surfaces; and (3) accumulation and breakdown on the sea bottom of uneaten feed. High concentrations of copper and zinc in sediments have been reported in several studies examining the impacts of open net pen salmon farms on the benthic environment (Loucks et al. 2012, Sutherland et al. 2007, Yeats et al. 2005, Smith et al. 2005, Brooks et al. 2003, Chou et al. 2002, Burridge et al. 1999). Elevated levels of copper and zinc relative to the reference station (S1) at the Sandy Point study site are likely associated with the former fish farm rather than natural sources. Trace metal analysis (copper and zinc) are not required as part of Nova Scotia's environmental monitoring program for aquaculture operations.

17 P a g e Imaging Results Four transects were recorded (Figure 10). The clarity and resolution of the video images and photographs were compromised by high turbidity caused by heavy rains in the Shelburne area the previous day. Video and still images were examined for marine flora, fauna and sediment composition. Transect SH1 began near the reference site (S1) and progressed approximately 75 meters in a westerly direction. The seafloor appeared uniform, soft and greyish-brown. Some small holes, possible openings for faunal burrow were visible as well as debris (Figure 11). No conspicuous flora or fauna were observed. Transect SH2 began near station S4 and progressed north-easterly for approximately 75 meters. Portions of the transect covered some of the same area as transects taken in 2011 and The seafloor appeared greyish-brown with occasional white patches of white bacteria, likely Beggiatoa sp. A clump of what appeared to be decomposing uneaten fish feed was observed (Figure 11). No conspicuous flora or fauna were observed. Transect SH 3 began at station S6 and progressed west for approximately 75 meters toward the edge of where the fish cages had been formerly positioned. The seafloor was very soft (semiliquid), black and extensively (80-90%) covered with white bacterial mats, likely Beggiatoa sp. (Figure 11). No conspicuous flora or fauna were observed. Transect SH4 began at station S7 and progressed south across an area formerly occupied by the former fish cages for approximately 75 meters. The seafloor appeared soft and grey-black. White bacterial mats were visible, covering approximately 50% of the bottom (Figure 11). No conspicuous flora or fauna were observed. Increased presence of Beggiatoa sp. corresponded to increased sediment sulphide levels. Station S6 had the highest sulphide levels (3250 µm) and was located in an area where Beggiatoa sp. mats covered 90% of the seafloor. Areas with no (S1, S2, and S3) or a few small patches (S4) of bacterial mats had lower sulphide levels.

18 P a g e 18 Figure 10 - Location of imaging transects at the former Sandy Point lease site

19 P a g e 19 Figure 11 - Select images from 2013 seafloor photography Grey-brown soft sediments with possible faunal burrows (left) and tire debris (right) from transect SH-1 Grey-brown soft sediments with small patches of white bacterial mats (above left) and a patch of decomposing uneaten fish feed (above right) from transect SH-2.

20 P a g e 20 Figure 11 - Select images from 2013 seafloor photography (con'd) Black semi-liquid sediments extensively (80-90%) covered with white bacterial mats from transect SH-3. Grey-brown sediments covered (50%) with patches of white bacterial mats from transect SH-4.

21 P a g e 21 4 Macrofaunal Analysis In total, 35 animals and 11 species were recorded from the 7 samples collected in October 2013 and, as in 2011 and 2013, polychaetes were the dominant group. Station S5 had the highest abundance of polychaetes, specifically Capitella capitata which is an indicator species for organic enrichment (Pearson and Rosenberg 1978). Sediment samples at all stations were dominated by large volumes of ovoid fecal pellets measuring less than 500 um (Figure 12). Infaunal analysis did not reveal which species could be responsible for producing such large quantities of fecal pellets. It is possible that the Ponar grab did not penetrate to a sufficient depth to capture the species responsible for these pellets. Figure 12 - Ovoid fecal pellets (Grid dimensions are 1 mm.) The number of species and abundance of individuals across all stations was very low (Table 5). Station S1 had only one individual and station S7 had no individuals. The absence of infauna in S7 is consistent with the results at that station in 2012 where only two individual animals were found. The virtual absence of species from S1 is not consistent with results from 2011 or 2012 where 131 and 107 individuals and 16 and 22 species, respectively, were reported. Different sampling equipment was used in 2013 (Ponar grab) than in 2011 and 2012 (Ekman grab) and could explain the significant difference in infaunal abundance. Several studies have been done comparing the efficiency, effectiveness and accuracy of various benthic sampling devices. Flanagan et al. (1970), Howmiller (1971) and Nalepa et al. (1988) reported that the Ponar grab can underestimate benthic abundances in sandy, silty and muddy environments. Blomqvist (1991) reported that experimental studies on the bite profile of various grabs, including the Ponar grab, suggest that unequal depth sampling is a potential source of error.

22 P a g e 22 Table 5 List of macrobenthic infaunal species at Sandy Point (2013) Species NEMERTEA Cerebratulus lacteus Station S1 S2 S3 S4 S5 S6 S7 1 ANNELIDA Polychaeta Capitella capitata Cirratulidae? Cossura longocirrata 2 1 Mediomastus ambiseta 1 Nephtys neotenus Parougia? 1 Prionospio steenstrupi 2 1 Scoloplos ar miger 2 Spionid juv 2 1 HYDROZOA Hydroid sp.? 5 Diversity Measures A summary of statistical diversity measures appear in Table 6. Measures such as the Shannon- Wiener Index and Margalef's richness index take into account both the number of species (species richness) and the distribution of individuals among species (eveness). The use of diversity indices is one way of quantitatively acknowledging the intuitive understanding that two areas, which may have the same number of species and the same number of total individuals, may still be considered more or less diverse depending on whether one or more species are presented much more strongly than most others. The more evenly individuals are distributed among all species present, the higher the diversity, if the overall species richness and abundance of total individuals is constant. Diversity measures for all stations in 2013 where lower than 2011 and 2012 (Figure 13). The trend of decreasing diversity from the reference station to the former fish farm however was consistent for all years (Figure 13). With the exception of S1, diversity values at the former fish farm (S5, S6 and S7) were lower than stations leading up to the former fish farm (S2, S3 and S4).

23 H' No. of Species P a g e 23 Table 6 Summary of diversity measures Station Abundance Species Richness Shannon-Wiener (log base e) Margalef's Richness S S S S S S S7 NS * 2 0 NS * 2 0 NS * NS * NS * 0 * Not sampled in 2011 Figure 13 - Diversity measures for the Sandy Point site ( ) Species Richness S1 S2 S3 S4 S5 S6 S7 Station Shannon-Weiner Index S1 S2 S3 S4 S5 S6 S7 Station

24 d P a g e 24 Figure 13 - Diversity measures for the Sandy Point site ( ) con'd 5 4 Margalef's Index S1 S2 S3 S4 S5 S6 S7 Station Changes in the structure and composition of the macrobenthic infaunal community in marine sediments are linked to increasing levels of organic sedimentation that result in low oxygen and high sulphide levels. The range of biogeochemical changes that occur in the macrobenthos as a result of organic enrichment have been compiled in a classification nomogram (Appendix 2)(Hargrave et al. 2008). One aspect of this classification relates to changes inbiodiversity levels in the macrobenthic infaunal community as measured by Shannon-Weiner Index, Hurlburts Index and/or Infaunal Trophic Index. Based on this classification tool, the 2013 biodiversity rating at S2, S3 and S4 would be classified as reduced (Shannon-Weiner values of <3 and >1) and very low (Shannon-Weiner value of <1) at S1, S5, S6 and S7. The very low diversity measure at the reference site (S1) may be anomalous for 2013 as diversity measures for this station in 2011 were in the reduced category (<3 and >1). As discussed in section 5 (Macrofaunal Analysis), the differences in the sampling equipment used in 2013 compared to 2011 and 2012 could explain the low infaunal abundance at all stations. Despite the different sampling equipment, the results of statistical analysis reflect the same pattern of decreasing diversity from the reference station to the former fish farm site in 2011 and Conclusions All geochemical measures (sulphides, % organic content, zinc and copper) in 2013 were higher at sampling station closest to the former Sandy Point fish farm relative to a reference station (S1). A distinct pattern of increasing values in geochemical measures from the reference station to the former farm farm was observed in This pattern is consistent with the pattern observed in 2011 and Geochemical recovery of the benthic sediments in the vicinity of the former Sandy Point fish farm is incomplete relative to the reference station.

25 P a g e 25 Macrobenthic infaunal analysis suggests that the ecological status of the sea bottom in the vicinity of the former fish farm remains low relative to the stations leading up to the former fish farm. However, the biodiversity rating of all stations in 2013 remain reduced or very low as they were in 2011 and Low abundance and diversity at S5, S6, and S7 suggest that these sites may be under high stress due to high sulphides (>1500 µm S),organic content (>15%) and/or zinc and copper contamination (> CCME interim sediment quality guidelines). Recovery of the benthic infaunal community in the vicinity of the former Sandy Point fish farm is incomplete relative to the stations leading up to the former fish farm. Since recovery of the benthos in the vicinity of the former fish farm is incomplete after two years of fallowing, benthic and biological community sampling of the former Sandy Point fish farm in the fall of 2014 is warranted. 7 Acknowledgements This study was conducted in cooperation with, and assistance from, the Friends of Shelburne Harbour, in particular Marian and Herschel Specter who provided key logistical support and historical information on the Sandy Point lease site. Captain Bill Rapp generously provided his time and fishing vessel which enabled the study team to access the sampling sites. Lauren Kay, a graduate student at the Dalhousie University's biology department, provided field assistance and equipment. Lawrence Wuest plotted the sampling and transect coordinates onto aerial photographs obtained from the Nova Scotia GIS Services. This study would not have been possible without the financial support of the Echo Foundation and the Sage Environmental Program. 8 References Blomqvist, S Quantitative sampling of soft-bottom sediments: problems and solutions. Marine Ecology Progress Series. 72: Brooks, K. M., Stiernsa, A.R., Mahnken, C.V.W., Blackburn, D.B., Chemical and biological remediation of the benthos near Atlantic salmon farms. Aquaculture 219: Burridge, L.E., Doe, K., Haya, K., Jackman, P.M., Lindsay, G., and V. Zitko Chemical analyses and toxicity tests on sediments under salmon net pens in the Bay of Fundy. Canadian Technical Report of Fisheries and Aquatic Sciences No. 2291, iii + 39 p. Canadian Council of Ministers if the Environment (CCME) Canadian sediment quality guidelines for the protection of aquatic life: Copper. In: Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg.

26 P a g e 26 Canadian Council of Ministers if the Environment (CCME) Canadian sediment quality guidelines for the protection of aquatic life: Zinc. In: Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg. Canadian Sediment Quality Guidelines for the Protection of Aquatic Life, < (accessed ). Chou, C.L., Haya, K., Paon, L.A., Burridge, L., Moffatt, J.D Aquaculture-related trace metals in sediments and lobsters and relevance to environmental monitoring program ratings for near-field effects. Marine Pollution Bulletin 44, Flannagan, J. F Efficiencies of various grabs and corers in sampling freshwater benthos. Journal of the Fisheries Research Board of Canada 27(10): 169l Hargrave, B.T., Holmer, M., Newcombe, C.P., Towards a classification of organic enrichment in marine sediments based on biogeochemical indicators. Marine Pollution Bulletin 56, Hargrave, B.T Science expert opinion on effects of free sulphides in marine sediments on macrobenthic infaunal biodiversity. DFO Maritime Region Expert Opinion 2006/001. Howmiller, P.P A comparison of the effectiveness of Ekman and Ponar grabs. Transactions of the American Fisheries Society 100(3): Hyland, J., Balthis, L., Karakassis, I., Magni, P., Petrova, A., Shines, J., Vestergaard, O., and R. Warwick Organic carbon content of sediments as an indicator of stress in the marine benthos. Marine Ecology Progress Series 295: Loring, D.H., Rantala, R.T.T., Milligan, T.G Metallic contaminants in the sediments of coastal embayments of Nova Scotia. Can. Tech. Rep. Fish. Aquat. Sci. 2111: viii p. Loucks, R.H., Smith, R.E., Fisher, C.V., Fisher, E.B., Copper in the sediment and sea surface microlayer near a fallowed, open-net fish farm. Marine Pollution 64: McGregor GeoScience Ltd Aquaculture survey and macro-invertebrate analysis report: Shelburne Harbour Sandy Point Station McGregor GeoScience Ltd Aquaculture survey and macro-invertebrate analysis report: Shelburne Harbour Sandy Point Station Nalepa, T.F., Quigley M.A., Ziegler R.W. 1988, Sampling efficiency of the Ponar grab in two different benthic environments. Journal of Great Lakes Research 14(1):89-93.

27 P a g e 27 New Brunswick Department of Agriculture, Aquaculture and Fisheries (NB DAAF) Standard Operating Practices for the Environmental Monitoring of the Marine Finfish Cage Aquaculture Industry in New Brunswick. Nova Scotia Department of Fisheries and Aquaculture (NS DFA) Standard Operating Procedures for the Environmental Monitoring of Marine Aquaculture in Nova Scotia. Pearson, T.H., Rosenberg, R., Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanogr. Mar. Biol. Ann. Rev. 16, Smith, J.N., Yeats, P.A., Milligan, T.G., Sediment geochronologies for fish farm contaminants in Lime Kiln Bay, Bay of Fundy. In Hargrave, Barry (Ed.), Environmental Effects of Marine Finfish Aquaculture, The Handbook of Environmental Chemistry, 5 M. Springer, pp Sutherland, T.F., Peterson, S.A., Levings, C.D., Martin, A.J., Distinguishing between natural and aquaculture-derived sediment concentrations of heavy metals in the Broughton Archipelago, British Columbia. Marine Pollution Bulletin 54, Yeats, P.A., Milligan, T.G., Sutherland, T.F., Robinson, S.M.C., Smith, J.N., Lawton, P., Levings, C.D., Lithium-normalized zinc and copper concentrations in sediments as measures of trace metal enrichment due to salmon aquaculture. In: Hargrave, Barry (Ed.), Environmental Effects of Marine Finfish Aquaculture, The Handbook of Environmental Chemistry, 5 M. Springer, pp

28 P a g e 28 Appendix 1 - Sampling station and transect depths and coordinates Benthic Sampling Stations - October 22, 2013 Station Depth (m) Latitude Longitude S S S S S S S Underwater Video Survey - November 19, 2013

29 P a g e 29 Appendix 2 - Nomogram for benthic organic enrichment zonation based on redox potentials and free sulphides (Hargrave et al Marine Pollution Bulletin 56, page 820)