Description of Flora and Fauna in the Proposed Survey Area
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Attachment 5 – Description of flora and fauna in the proposed survey area The results from the EPBC Protected Matters Search Tool (PMST) provide the key means by which species are identified for the area, and are discussed in this section. Additionally, Biologically Important Areas (BIAs) are identified for those species that may occur within the proposed survey area. BIAs are spatially defined areas, defined by the DoEE based on expert scientific knowledge, where aggregations of individuals of a species are known to display biologically important behaviour such as breeding, foraging, resting or migration (DoEE, 2017h). The BIAs do not represent a species’ full distribution range. 5.1 Benthic Assemblages 5.1.1. Regional knowledge The seascape of the region is composed of a series of massive sediment flats, interspersed with small patches of reef, bedrock and consolidated sediment (Wilson and Poore, 1987). OSRA mapping for the Ninety Mile Beach indicates that there is an absence of hard substrate or emergent reefs in the region. The sediment flats are generally devoid of emergent fauna but benthic invertebrates such as polychaetes, bivalves, molluscs and echinoderms are present (Wilson and Poore, 1987). There are also a number of burrowing species, which inhabit the soft seabed, including tubeworms, small crustaceans, nematodes, nemerteans and seapens (OMV, 2001). Bass Strait Surveys of benthic invertebrates in Bass Strait (Poore et al ., 1985; Wilson and Poore, 1987) have shown: • Crustaceans and polychaetes dominate the infaunal communities, many of which are unknown species. • The high diversity of a wide range of invertebrate groups has been a recurrent observation of all surveys in Bass Strait and diversity is high compared with equivalent areas of the northern hemisphere. • Many species are widely distributed across the Strait, suggesting heterogeneous sediments and many microhabitats. • Some invertebrate groups are allied with fauna from Antarctic seas. In winter, when the east coast of Tasmania is supplied with water from the sub- Antarctic, the overlap with the East Australia current contributes to the high diversity. Parry et al (1990) also found high diversity and patchiness of benthos sampled off Lakes Entrance, where a total of 353 species of infauna was recorded. Crustaceans (53%), polychaetes (32%) and molluscs (9%) dominated sample results. Barton et al (2012) report that in the Ninety Mile Beach Marine National Park (14.5 km west of the proposed acquisition area), reefs are dominated by invertebrates (70% coverage), including sponges, ascidians (sea squirts) and smaller bryozoans (resembling coral) and hydroids (colonies of tiny jellies attached to a feather-like base). Given the park’s proximity, this may be expected to be representative of invertebrates present within rocky reefs in the proposed acquisition area. Pelican 3DMSS EPBC Act Referral FOL/17/66208 1 A search of the Victorian Biodiversity Atlas (VBA) database indicates that 30 benthic fauna species have been recorded in the EMBA. These species comprise sea snails, sea stars, sea urchins, sea slugs, rock lobsters and limpets. None of these species are listed as threatened under the EPBC Act. Proposed acquisition area The marine habitat assessment commissioned by CarbonNet and undertaken by Advisian in early April 2017 found the following benthic assemblages within the proposed acquisition area: • Isolated and sparse seagrass beds (sampling sites 4, 13, 16, 44 and 60) (example shown in Photo 5.1); • Isolated occurences of sponge gardens (sampling sites 28-30, 40, 58, 69) (example shown in Photo 5.2). • Isolated occurenced of Pseudogorgia godeffroyi (sampling sites 27, 32, 34, 50 and 51), an unusual soft coral found only in Victoria between McGaurans Beach and Delray Beach (ECC, 2000) (example shown in Photo 5.3). • A small patch of unmapped, flat low profile offshore reef with no ledges or crevices, located between sampling locations 29 and 30 (immediately seaward of the 30 m isobath and on the western side of Esso’s Bream to shore gas pipeline). This reef is dominated by sponges and ascidians (such as stalked ascidian Pyura spinifera ) and smaller bryozoans, hydroids and the odd clump of red algae, with the occasional Chlamys scallop attached to the reef (not commercial scallops) (example shown in Photo 5.4 ). • Live commercial scallops ( Pecten fumatus ) were noted in low abundance (non-commercial beds) at site 1 (32 m water depth) with dead scallops observed at site 62 (23 m water depth) (example shown in Photo 5.5 ). • Southern rock lobsters (Jasus edwardsii ) were not observed at all, even in areas of mapped reef (sites 31, 41, 51, 52, 67) and unmapped areas of reef observed during the survey (at sites 15, 16, 32, 58, 64-66, 68). Pelican 3DMSS EPBC Act Referral FOL/17/66208 2 Source: Advisian (2017). Photo 5.1. Examples of benthic assemblages found within the proposed acquisition area – sparse seagrass beds (water depth of 20 m, site 44) Source: Advisian (2017). Photo 5.2. Examples of benthic assemblages found within the proposed acquisition area – sponge garden (water depth of 27 m, site 28) Pelican 3DMSS EPBC Act Referral FOL/17/66208 3 Source: Advisian (2017). Photo 5.3. Examples of benthic assemblages found within the proposed acquisition area – soft coral Pseudorgorgia godeffroyi (in foreground) (water depth of 15 m, site 51) Source: Advisian (2017). Photo 5.4. Examples of benthic assemblages found within the proposed acquisition area – flat low profile reef (water depth of 29 m, site 29) Pelican 3DMSS EPBC Act Referral FOL/17/66208 4 Source: Advisian (2017). Photo 5.5. Examples of benthic assemblages found within the proposed acquisition area – sparse presence of commercial scallops, as circled (water depth of 32 m, site 1) Nearby petroleum infrastructure seabed assessments The relative homogeneity of sandy seabed sediments across all areas surveyed during the Longtom pipeline route selection process (64 km east of the proposed acquisition area) (Fugro, 2005) suggests that the diversity of benthic invertebrates in the survey area would be similar to this, given the dominance of sandy seabed sediments in the proposed acquisition area. There was no evidence of unusually high benthic invertebrate diversity in the sediment samples collected along the pipeline route. Sediment samples generally show a brown, coarse shelly sand, moderately well sorted with some shells. For the Patricia Baleen Project, located approximately 78 km east of the proposed acquisition area, the inshore area has been characterized as containing scallops and other large bivalves, crabs, ascidians and small aggregations of sponges (porifora) and bryozoans (CEE, 2001). A video survey undertaken along the Patricia Baleen pipeline in 2003 (CEE, 2003) indicates that there are four general habitat associations on the seabed along the pipeline route. Large epibiota are very sparse, with extensive areas of sandy and shell/rubble seabed being devoid of large epibiota except for introduced screw shells and sponges. The habitats and associated biota are described below: • Medium sand and shell grit – extensive areas with pronounced sand waves. Epibiota was generally sparse to relatively commonly occurring sea pens and occasional sponges and stalked colonial ascidians. Sea pends were common in water depths of 22 to 27 m. • Shell accumulations – large patches of seabed comprised of old large shells, predominantly bivalves and scallops, with New Zealand screw shells present Pelican 3DMSS EPBC Act Referral FOL/17/66208 5 in large numbers. The proportion of sand ranged between zero and 20% cover. • Sponge garden – a small and distinct area of large sponges and bryozoans occurs at about 50 m water depth. The sponges varied in form and colour and included fans, spheres, massives, cups and fingers. Bryozoans included lace- like corals, concertina fans, perforated rigid sheets and fern-like branches. These associations indicate that although the seabed is comprised predominantly of sand and shell grit, it is stable enough to allow these associations to grow. Schools of jackass morwong, butterfly perch and individual gurnard and leatherjackets were attracted to the sponge garden. • Introduced New Zealand screw shell aggregations – the NZ screw shell (Maoricolpus roseus ) was common in the survey area, generally in water depths greater than 40 m, sometimes forming dense beds covering 100% of the seabed. Benthic fauna studies (i.e., dredge samples) were undertaken for the area offshore from Ninety Mile Beach at Seaspray for the Tasmanian Gas Pipeline (2000) (12 km west of the proposed acquisition area) in similar sandy substrates to those which have been observed at the survey area. In water depths from 17-20 m (similar to parts of the proposed acquisition area), it was found that there were mobile sands with irregular ripples that contained a variety of small mobile animals such as crustaceans, bivalves, sponges, worm tubes and polychaete worms. 5.2 Flora Literature searches, combined with OSRA mapping, indicate that marine flora, such as seagrasses and kelp, are generally not abundant in the extensive areas of subtidal sand flats in the nearshore waters of the proposed survey area. This is likely to be due to the high-energy nature of the Gippsland coastline and the mobile nature of sands, which prevents many species being able to anchor themselves. A search of the VBA database indicates that 50 marine flora species (macroalgae, excluding seagrass species) have been recorded in the EMBA, with none of these species listed as threatened under the EPBC Act. No marine flora species are listed in the EPBC Act PMST for the proposed survey area. Barton et al (2012) report that in the Ninety Mile Beach MNP (14.5 km west of the proposed acquisition area), reefs have sparse floral communities of small red algae. Given the park’s proximity, this may be expected to be representative of flora present on rocky reefs in the proposed acquisition area. As noted earlier in this section, the CarbonNet-commissioned marine habitat assessment observed some isolated and sparse seagrass beds in the operational area (sampling sites 4, 13, 16, 44 and 60) (see Photo 5.1).