Gulf of Carpentaria

Barramundi in the Southern GoC stock are taken commercially as part of the Gulf of Carpentaria Inshore Fin Fish Fishery (GOCIFFF), which extends from Slade Point near the tip of Cape York Peninsula to the Queensland/Northern Territory border. The GOCIFFF is a multi-species fishery that includes an inshore (N3 symbol) commercial net fishery that harvests inshore species such as barramundi and king threadfin, and an offshore (N9 symbol) commercial net fishery that targets offshore species such as shark and grey mackerel. The inshore N3 fishery uses set mesh nets (i.e., gill nets) in rivers, on foreshores and in more offshore waters out to seven nautical miles. See Roelofs (2003) and Ward (2003) for a detailed description of the GOCIFFF, including commercial fishing methods. The GOCIFFF is managed separately from the East Coast Inshore Fin Fish Fishery, with different management arrangements applying in each fishery. The GOCIFFF requires a Wildlife Trade Operation (WTO) for export approval and protected species accreditation under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999, to demonstrate that the fishery is operating under national sustainability guidelines.

Previous research into sea-level change following the Last Glacial Maximum (LGM) indicated that rising sea levels during the most recent post-glacial marine transgression (PMT) breached the restricting Arafura sill between 12,000 and 11,500 cal. yr BP and that the culmination of PMT occurred between 6,500–6,000 cal. yr BP, reaching a maximum of 2 m above present mean sea-level (PMSL) in the southern region of the Gulf of Carpentaria (Rhodes et al. 1980; Chappell et al. 1982). The Holocene highstand was short-lived, and sea- level fell smoothly to present level over the last 6,000 years. Rhodes et al. (1980) and Chappell et al. (1982) attribute the relative sea-level fall to hydro-isostatic loading in the northern and central basin, and on the eastern Australian continental shelf. The hydro-isostatic loading resulting in differential crustal movement across north Queensland, represented by regional subsidence in the northeast and uplift of between 0.2 – 1.4 m for the western Cape (Edward River), and 1.7 – 3.1 m in the Flinders-Leichhardt Region (Karumba; Fig. 1A; Chappell et al. 1982).

For the years 2004–2014, the GOCDFFTF Total Allowable Commercial Catch (TACC) was fixed at 1250 tonnes (t) for Crimson Snapper, Saddletail Snapper, Red Emperor and other Emperor species (for more detail see: GOCDFFTF developmental permit conditions). The TACC was based on report findings (Ramm 1994; Ramm 1997a; Ramm 1997b; Sainsbury 1990; Sainsbury, Campbell et al. 1991) and management committee interpretations of stock survey and modeling results from the early 1990s. The TACC evolved from a limited yield-per-recruit analysis scaled by the 1990 survey estimate of tropical snapper biomass (called all large Lutjanus species in: Sainsbury, Campbell et al. 1991). For the whole of Gulf of Carpentaria, a sustainable yield of about 3000 t of all large Lutjanus was used as a basis by management. This value was divided by two for the eastern gulf, with the GOCDFFTF TACC set equal to 1250 t and 250 t kept by management and industry in reserve. A summary of GOCDFFTF fishery harvests to compare against the TACC is provided in Table 1.

Figure 3.8 Mainland river catchments that expel substantial amounts of meteoric runoff into the southern Gulf of Carpentaria during the wet season. .......................................................... 70 Figure 3.9 Modern boundaries claimed by the four Aboriginal language groups of the Wellesley Islands (redrawn from Rosendahl 2012:46 after National Native Title Tribunal 07/12/2004; www.nntt.gov.au). ...................................................................................................................... 73 Figure 3.10 The Kaiadilt concept of country as drawn by a Kaiadilt informant. Note the central positioning of the sea (redrawn from Tindale 1977:248). .......................................................... 74 Figure 3.11 A Kaiadilt fish trap complex located at the mouth of Catfish Story, Bentinck Island (Photograph: Sean Ulm, 2013). ................................................................................................... 76 Figure 3.12 Two tropical cycles coincide with the reported tidal surge in February 1948 (BOM 2015c). ......................................................................................................................................... 80 Figure 4.1 Distribution of G. pectinatum across the Indo-Pacific (after GBIF 2013a; SeaLifeBase 2012a). ........................................................................................................................................ 88 Figure 4.2 In situ live G. pectinatum specimen at Raft Point, Bentinck Island, South Wellesley Islands (Photograph: Daniel Rosendahl, 2014). .......................................................................... 89 Figure 4.3 A mixed shellfish scatter including G. pectinatum on Sweers Island (Photograph: Daniel Rosendahl, 2012). ............................................................................................................ 90 Figure 4.4 Section of a G. pectinatum live-collected from the South

Sim and Wallis (2008) presented a model for Holocene coastal and island abandonment for the southern Gulf of Carpentaria. They proposed that as sea-levels rose in the early Holocene populations retreated to the elevated mainland strip. Subsequent island occupation attempts failed owing to inclement weather and changing environments. It was not until landscape and sea-level stabilisation and climate amelioration after 2500 years ago that permanent island settlement became possible. This hypothesis was developed using data from Vanderlin Island in the Sir Edward Pellew group and extrapolated across north Australia (Figure 1).

The Gulf of Carpentaria Developmental Finfish Trawl Fishery (DFTF) predominantly captures tropical red snappers including the crimson snapper (Lutjanus erythropterus) and the saddletail snapper (Lutjanus malabaricus), however a variety of other valuable species are also retained as saleable product. Both crimson and saddletail snapper are commonly caught in northern Australian waters. They inhabit coastal and inshore reefs. Mixed aggregations occur over shoals, hard or sandy-mud substrate, and sponge and gorgonian dominated habitats (FAO 2001). Both species are long-lived with low natural mortalities. They are slow growing once reproductively mature and have protracted spawning periods throughout the year (Fry et al. in press).

1 Environmental Context for Late Holocene Human Occupation of the South 2 Wellesley Archipelago, Gulf of Carpentaria, Northern Australia 3 4 Patrick Moss1, Lydia Mackenzie1, Sean Ulm2, C[r]

In coastal areas of the globe, open shell matrix sites are commonly used to establish regional chronologies of human occupation and identify patterns of cultural change, particularly for the Holocene, post-sea-level stabilisation period. Despite this, many basic sedimentary analyses that are routinely applied to rockshelter deposits (e.g. geophysical characterisation, particle size etc) are rarely applied to these sites. Magnetic susceptibility, occasionally used in rockshelters, has never been used to investigate shell matrix sites in Australia, despite several international studies identifying its efficacy for other types of open sites. This paper reports a pilot project applying a range of conventional sedimentary and archaeological analyses, as well as magnetic susceptibility at three anthropogenic shell mounds on Mornington Island, Gulf of Carpentaria, Australia. Results are compared to, firstly, assess site integrity and, secondly, to ascertain whether magnetic signatures are related to cultural or natural site formation processes. The results establish that the mounds were repeatedly visited, despite the archaeological evidence, including radiocarbon ages, suggesting effectively ‘instantaneous’ deposition. This has important implications for studies of other shell mounds where the limitations of radiocarbon dating precision may also mask multiple deposition events.

We used the same range of values of dugong density as Grech and Marsh (2007) to categorise dugong management units as low, medium, medium-high or high ecological value for dugongs in the Gulf of Carpentaria (Appendix 4). Our approach assumes that dugong density is a robust index of a region’s conservation value for dugongs. This assumption is justified because: (1) density estimates are regarded as suitable surrogate measurements of habitat use; and (2) no critical habitats for dugongs have been identified other than the seagrass meadows where they spend most of their time. By using the time series of data collected over 16 years, the model accounts for temporal changes in the use of various regions by dugongs including movements resulting from events such as seagrass dieback. The resultant model of ecological value allowed us to quantify the importance of the Gulf of Carpentaria as dugong habitat in the context of the north-eastern coast of Australia (Appendix 5). We define the north-eastern coast of Australia as the shallow water regions of the Gulf of Carpentaria, south-east Queensland, Great Barrier Reef and Torres Strait. The model indicates that the Gulf of Carpentaria comprises 6 % of the total high ecological value dugong habitats and 29 % of the total medium-high value habitats on the north-eastern coast of Australia.

This study investigates the palynological remains (both fossil pollen and charcoal) recovered from the Thundiy shell midden deposit, Bentinck Island, Gulf of Carpentaria, northern Australia, to provide a vegetation and fire record for this site, which sheds light on human occupation of the southern Wellesley Archipelago over the late Holocene. Results show that the development of a high density shell deposit by human activities was directly responsible for pollen preservation, possibly through the creation of a moist, anaerobic environment that reduces oxidation of pollen grains. The presence of recoverable pollen from a shell midden deposit from Bentinck Island provides a valuable new proxy to provide greater context for archaeological records, particularly in terms of local vegetation information and potential insight into human land management practices.

While many people have assisted and supported me through my thesis I would particularly like to recognise the Gulf of Carpentaria Commercial Fishermans Association (GoC CFA) Karumba, namely the members; Rick Crossland, the Lollo family (Eric, Steven, and Blanche), Jeff and Sandy Newman, the Fisher family (Eddie, Diane and Hilton), Warren Luscombe, Greg Muzic, David and Donna Lane, Peter Tonon, Gary and Claudine Ward, Greg Howard, Alan Vickers, Dave Wren, and Russell Butterworth for help in the recording of sawfish information and by participating in the fisheries observer program. I also gratefully acknowledge the crew of these fishing operations for their cooperation and patience. I also gratefully acknolwegde the assistance of Cairns Marine Aquarium (CMA), in particular Lyle Jnr. Squire, Julian Baggio, and Jeff Oak for their participation in the collection of biological samples and sharing of information on sawfish.

absolute sea level anomalies from 2015 and 2016 (black lines) and the average seasonal cycle (blue lines). The sea level was very low through most of 2015 and into 2016. .............................. 12 Figure 5: A panel plot indicating the monthly climatologies (1994–2013) and 2015 anomalies for sea level (m; from BRAN). In 2015, the sea level was unusually low from April until November, a period which historically (from the climatology) experiences a lowered sea level. ......................... 13 Figure 6: A time series showing the standardised anomalous sea level in the Gulf of Carpentaria (16.8–14.5°S, 135.0–138.8°E). Sea level was determined by taking the six-month moving average of each of the four sea level data sources. Their strong agreement is apparent. Key features are a significant drop in late 2015, an extended period of elevated sea levels from 2008 to 2015, and a more significant drop in 1997. ................................................................................ 14 Figure 7: A time series of the standardised salinity anomalies in the Gulf of Carpentaria (16.8– 14.5°S, 135.0–138.8°E) using the BRAN data. Note the large positive anomaly in 2015, but also note that similar positive anomalies occur many times in the data. ............................................... 15 Figure 8: A panel plot showing the monthly climatologies (1994-2013) and 2015 anomalies of salinity in the Gulf of Carpentaria from the BRAN data (psu). ........................................................ 16 Figure 9: Sea surface temperature monthly anomalies (in °C, not units of standard deviation), from NCEP/NCAR reanalyses, averaged over 16.8–14.5°S, 135.0–138.8°E. The seas in the Gulf were not unusually warm throughout 2015, although there were warm peaks in March of both 2015 and 2016. ..................................................................................................................... 17 Figure 10: A decile map of rainfall in Gulf Country from 1 May 2014 to 31 October 2015 (18

Abstract. A numerical model is used to investigate the res- onances of the Gulf of Carpentaria and the Arafura Sea, and the additional insights that come from extending the analysis into the complex angular velocity plane. When the model is forced at the shelf edge with physically realistic real values of the angular velocity, the response functions at points within the region show maxima and other behaviour which imply that resonances are involved but provide little additional in- formation. The study is then extended to complex angular velocities, and the results then show a clear pattern of grav- ity wave and Rossby wave like resonances. The properties of the resonances are investigated and used to reinterpret the response at real values of angular velocity. It is found that in some regions the response is dominated by modes trapped between the shelf edge and the coast or between opposing coastlines. In other regions the resonances show cooperative behaviour, possibly indicating the importance of other phys- ical processes.

CHAPTER 6 RELATIVE SEA LEVEL, MID-HOLOCENE TO THE PRESENT SEA LEVEL INDICATORS THE GULF OF CARPENTARIA RECORD Relative sea level o~ the chenier plain Relative sea level on the beach-ridg[r]

Cobourg Peninsula and northeast Arnhem Land. Less attention has been given to sites at the geographical peripheries of Macassan industrial activities. Archaeological studies show that the eastern extremity of Macassan activities extended to the Sir Edward Pellew Group. However, ethnographic and historical accounts show that Macassan presence extended to the South Wellesley Islands, over 200km further east, in the south east Gulf of Carpentaria. Recent archaeological fieldwork reveals new evidence for Macassan activities at the eastern margin. This paper reports preliminary data from five Macassan sites in the South Wellesley Islands.

Many juvenile barramundi move to permanent freshwater habitats when the seasonal coastal habitats dry out (Russell and Garrett 1985). Such movement may be stimulated by the lowering of water levels and depletion of food sources (Russell and Garrett 1985). In the Gulf of Carpentaria, floodwaters recede around March. As such, juvenile barramundi are moving upstream to freshwater habitats at about three to five months of age. Movement upstream to freshwater habitats can also occur when barramundi are between one and two years old (Milton et al. 2008). Dunstan (1959) suggested that “1+ fish are found in deep holes of the upper reaches, with 1+ fish being plentiful below the falls on the Burdekin River that are about 120 miles from the mouth, 1+ fish are common in the Dawson River and other tributaries of the Fitzroy River”. Fishway studies on the Queensland east coast have

relationships exist for other regions including the Gulf of Carpentaria but the data are not yet adequate to confirm them statistically (Type 2 error). This relationship between dugong fecundity and rainfall lagged by two years is congruent with our knowledge of dugong life history and the dynamic responses of the coastal seagrasses on which dugongs feed to changes in water turbidity and sediment deposition, which in turn are linked to extreme rainfall events (Preen and Marsh 1995, Preen et al. 1995, Larcombe and Woolfe 1999, Longstaff and Dennison 1999, Waycott et al. 2007). The negative relationship between the proportion of calves and rainfall with a two/three-year lag is presumably a result of: (1) the negative impact of increased turbidity on some of the coastal seagrass species eaten by dugongs (Preen et al. 1995, Longstaff and Dennison 1999); (2) the need for dugongs to be in good condition prior to and during pregnancy and lactation (Kwan 2002, Marsh and Kwan in press) and (3) the life history of the dugong: pregnancy lasts approximately 14 months and lactation up to 18 months (Marsh et al. 1984 b, Boyd et al. 1999, Kwan 2002). Marsh and Kwan (in press) also found a negative relationship between dugong fecundity and seagrass dieback in Torres Strait where seagrass dieback is thought to be caused by sediment resuspension resulting from prolonged periods of strong winds (Saint- Cast in press).

Studies have revealed a rich archaeological record across the Gulf region, characterised by changing site densities (Williams et al. 2010), site and/or regional (including island) abandonments (Sim and Wallis 2008), and the emergence of new site types such as shell mounds (e.g., Faulkner 2008; Morrison 2003, 2010). The general late Holocene patterns of coastal and island use in the Gulf parallel broader trends in the Australian archaeological record. For example, regional chronologies across northern Australia feature a marked increase in the numbers of sites in the last millennium (Ulm and Reid 2000; Williams et al. 2010), except for some notable declines in site numbers between 1250-950 BP and 450-250 BP, which have been argued to correlate with changes in ENSO frequency and intensity (Williams et al. 2010). Sim and Wallis (2008:101) proposed a three-phase model for occupation of Vanderlin Island in the Sir Edward Pellew Group with dates ranging from pre-6700 BP (before islandisation) to modern times. Two occupation hiatuses are identified for Vanderlin Island (6700-4200 BP and 2500-1700 BP) that Sim and Wallis (2008:103) argued were caused by periods of climatic instability, and extrapolate as potentially being a pan-northern Australian signature.

Mackenziee,f and Sean Ulma,b* a ARC Centre of Excellence for Australian Biodiversity and Heritage, James Cook University, PO Box 6811, Cairns, QLD 4870, Australia; b College of Arts, Soc[r]

acoroides seagrass in the Northern region of the Gulf of Carpentaria NE Australia to determine whether environmental factors related to tidal exposure cycles correlate to changes in seag[r]