Habitat Mapping in Gilbert Bay, Labrador: a Marine Protected Area Phase III Final Report
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Habitat Mapping in Gilbert Bay, Labrador: A Marine Protected Area Phase III Final Report Submitted by: Alison Copeland Dr. Evan Edinger Philippe Leblanc Department of Geography Department of Geography Dept.of Geography Memorial University Memorial University St. Memorial University St. John’s, NL A1B 3X9 John’s, NL A1B 3X9 St. John’s, NL A1B 3X9 Dr. Trevor Bell Dr. Rodolphe Devillers Dr. Joseph Wroblewski Department of Geography Department of Geography Ocean Sciences Centre Memorial University Memorial University Memorial University St. John’s, NL A1B 3X9 St. John’s, NL A1B 3X9 St. John’s, NL A1C 5S7 Standing Offer No. F6161-070001/001/XAQ Requisition No. F6161-07 0012 Draft final report, March 7, 2008 Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report ii Cover image caption: Shoreline habitats in The Shinneys. Nearshore portions of The Shinneys were not mapped using multibeam sonar, due to shallow water and numerous hazardous shoals. The Shinneys constitutes the primary spawning and juvenile habitat for Gilbert Bay cod, yet little is known about the habitats Gilbert Bay cod use in the Shinneys. Recommended citation: Copeland, A., Edinger, E., Leblanc, P., Bell, T., Devillers, R., Wroblewski, J., 2008. Marine Habitat Mapping in Gilbert Bay, Labrador – A Marine Protected Area. Phase III final report. Marine habitat mapping group report # 08-01, Memorial University of Newfoundland, St. John’s, 71 p. Marine Habitat Mapping Group. Trevor Bell, Alison Copeland, Rodolphe Devillers, Philippe Leblanc Department of Geography, Memorial University of Newfoundland, St. John’s, NL A1B 3X9. Evan Edinger Departments of Geography and Biology, Memorial University of Newfoundland, St. John’s, NL A1B 3X9. Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report iii Overview. Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report iv Table of Contents. Overview ………………………………………………………………… iii Table of Contents ………………………………………………………… iv List of Figures …………………………………………………………….. vi List of Tables ……………………………………………………………… ix Research Objectives and Rationale ………………………………………. 1 Research Approach ……………………………………………………….. 5 Field Methods …………………………………………………………….. 6 Laboratory Methods …………………………………………………… 12 Substrate classification …………………………………………… 12 Video substrate and faunal analysis ……………………………… 13 Statistical analysis ………………………………………………………... 14 Interpolation from sounding lines to bathymetric maps ………….. 14 Depth-substrate relationships in areas without multibeam coverage … 15 Faunal analysis ……………………………………………………. 15 Results ……………………………………………………………………. 17 Substrates observed ……………………………………………... 17 The Shinneys …………………………………………………… 26 River Out ………………………………………………………….. 33 Mogashu Tickle …………………………………………………… 37 Potential bedrock wall habitats …………………………………… 42 Habitat Classification …………………………………………….. 43 Defining mappable habitat types ………………………………….. 49 Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report v Study Highlights and Future Directions ………………………………… 57 Summary ………………………………………………………………….. 59 References Cited ………………………………………………………….. 60 Appendix A: Bathymetric and substrate profiles in The Shinneys ………. 62 Appendix B: Faunal list …………………………………………………... 67 Appendix C: sediment grain size and organic content ………………….. 71 Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report vi List of Figures. Figure 1: Locations of management zones associated with Gilbert Bay Marine Protected Area and place names used in the report. Figure 2: Benthic substrate map for entire bay. Figure 3. Substrate map of Zone 1B of the Gilbert Bay Marine Protected Area, including The Shinneys and River Out. Figure 4. Alison Copeland operating the Garmin 178C GPS-sonar and Shark Marine Drop video systems. Figure 5. Philippe Leblanc readying the Petit Ponar hand-deployed grab sampler. Figure 6: Locations of all video and grab samples collected in Zone 1B in 2007 on multibeam backscatter intensity data. Figure 7: Locations of drop video stations in Leg Island Basin to assess potential bedrock wall habitats. Figure 8. Location and numbers of video transects collected in River Out, Mogashu Tickle, and The Shinneys. Figure 9. Video frame grab of muddy gravel substrate, line 16R, Inner Shinneys. Fig. 10. Sandy gravel substrate. Transect 17, Inner Shinneys. Fig. 11A. Coralline algal encrusted gravel substrate, transect 16, Inner Shinneys. Figure 11B . Example of coralline-algae-encrusted-gravel substrate class, as recovered in grab sampler. Fig. 12A. Gravelly mud substrate. Figure 12B. Gravelly mud substrate, Transect 25, Inner Shinneys. Fig 13. Mud substrate. Transect 17, Inner Shinneys. Fig. 14A. Nearshore gravel substrate, Transect 25, Inner Shinneys. Fig 14B. Nearshore gravel substrate, Transect 25, Inner Shinneys. Fig 15A. Sponges, rhodoliths, and sea stars on gravel, Mogashu Tickle Gravel. Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report vii Fig 15B. Gravel with sun star and dead scallop shell, Mogashu Tickle gravel. Fig 16A. Bedrock wall habitat, , site 418, Leg Island Basin. Fig 16B. Bedrock wall, site 409, Leg Island Basin. Figure 17. Distribution of substrates along bathymetric and video transect lines that were surveyed in the inner part of The Shinneys, overlad over multibeam backscatter. Figure 18. Distribution of substrates along bathymetric and video transect lines surveyed in the Inner Shinneys, overlaid over substrate map generated from multibeam backscatter (Copeland et al., 2007a). Figure 19A: Bathymetric profile along line 25, labeled by substrate type. Figure 19B. Bathymetric and substrate profile, transect 28, Barr Tickle. Figure 20. Boxplot showing depth distribution of video transect points in the Shinneys. Figure 21. Linear and exponential regression lines of depth and substrate code in The Shinneys. Figure 22: Fledermaus image of substrate classification draped over bathymetry, River Out (Copeland et al., 2007a). Figure 23. Substrates in River Out, overlaid above multibeam backscatter. Figure 24 Substrates in River Out, overlaid over substrates interpreted from multibeam sonar (Copeland et al., 2007a). Figure 25A. Location of frame grab of muddy gravel occurring on steep slopes near mouth of Snook’s Arm, end of transect 7, River Out. Figure 25B. Bathymetric and substrate profile of transect 7, near mouth of Snook’s Arm, River Out. Fig. 26A, Soft coral, Gersemia rubiformis, on gravel, Mogashu Tickle gravel. Fig 26B. Basket star, Gorgonocephalus, Mogashu Tickle. Figure 27. Substrates in Mogashu Tickle, River Out, and the outer Shinneys, overlaid over multibeam backscatter data. Figure 28. Substrates in Mogashy Tickle, River Out, and the outer Shinneys, overlaid over subsrate classification based on multibeam sonar (Copeland et al., 2007a). Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report viii Figure 29A. Nearshore gravel substrate, shallow water portions of transect 9, Mogashu Tickle. Figure 29B. Bathymetric and substrate profile, transect 9, running across Mogashu Tickle. Figure 30. Boulder gravel, site 419, Leg island Basin. Figure 31: 3-dimensional multidimensional scaling (MDS) plot of video sampled biota. Figure 32: 3-dimensional multidimensional scaling (MDS) plot of biota from grab samples. Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report ix List of Tables. Table 1: Wentworth Grain Size Definitions Table 2. Numbers of video sequences of each substrate analyzed for faunal composition. Table 3: The top 10 taxa from video sampled biota, ranked in order of decreasing contribution to faunal similarity, and their percent contribution to similarity within each substrate class. Table 4: The top 10 taxa from grab sampled biota, ranked in order of decreasing contribution to faunal similarity, and their percent contribution to similarity within each substrate class. Table 5. ANOSIM results comparing faunal composition of identical substrate types in areas covered by multibeam data and areas outside multibeam coverage. ANOSIM of video data revealed significant differences between all pairs. ANOSIM of grab sampled data revealsed significant differences for muddy gravel only. Table 6: ANOSIM results table for 2007 video data. Numbers indicate probability of p- values, in percent, i.e. p=0.05 is represented as 5.0. Table 7 : ANOSIM results table for 2007 grab sample data. Numbers indicate probability of p-values, in percent, i.e. p=0.05 is represented as 5.0. Table 8. Contributions of individual taxa in video data to faunal dissimilarity between identical substrate types in all of Gilbert Bay (2006-7 data) and zone 1B (2007-8 data). Table 9. Contributions of individual taxa in grab data to faunal dissimilarity between identical substrate types in all of Gilbert Bay (2006-7 data) and zone 1B (2007-8 data). Habitat Mapping in Gilbert Bay Marine Protected Area, Phase III final report 1 Research Objectives and Rationale The primary goals of Phase III marine habitat mapping in Gilbert Bay Marine Protected Area (MPA; Figure 1) are to collect detailed data on substrate and biotic composition in Zone 1B of the MPA, especially to extend habitat classification to areas of The Shinneys outside multibeam sonar coverage, to assess the nature of unclassified areas within River Out, and describe the substrate and habitat of the Mogashu Tickle tidal rapids. A fourth research objective was to target potential rock-wall habitats in Zone 1B and in Leg Island Basin (MPA Zone 3).