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ANIMALS Crabs the Gladstone Mud Crab (Scylla Serrata)

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ANIMALS Crabs the Gladstone Mud Crab (Scylla Serrata) SEA ANIMALS Crabs The Gladstone mud crab (Scylla serrata ) fishery is the most productive in the state. Mud crabs are taken by trapping in pots. Sand crabs (Portunispelagicus ) and spanner crabs (Ranina randina) are also of considerable commercial importance. There are many other crab species present. Fiddler crabs (Uca spp) are abundant in some areas (ca. 2-3/m2). They inhabit the muddy shoulders of creeks and inlets in association with mangroves. Dangerous fauna Talk of dangerous marine life will probably bring to mind images of swimming with Saltwater Crocodiles (Crocodylus porosus ) or sharks; and while their fearsome reputation, popularized by the media, certainly needs to be respected, they is not a conspicuous danger. The Sea Wasp or Box Jelly (Chironex fleckeri ) is found in mangrove inlets. The sting from these Cniderians may be lethal; with the animal particularly prevalent from November to March. However, protection from the nematocysts or stinging cells can be obtained by wearing "stinger suits" made of Lycra or similar material. The Estuarine Stonefish (Synanceja trachynis ) .whose smooth skin is covered with warty protrusions, is a master of camouflage. Lying motionless, it is hard to detect; yet its "sting", from its 13 dorsal spines, causes immediate and intense pain. Fortunately, an anti-venene has been developed. Gladstone enjoys a largely safe reputation for water activities. Fish A large fish fauna, including both recreational and commercial species, is associated with the extensive mangrove-wetland system in the Gladstone-Port Curtis region. The shallow foreshore area is dominated by small bait fish species such as Harrengula abbreviata , Ambassis marianus and Gerres ovatus , with the larger commercial species moving into these areas with the flood tide to feed. Juveniles of many larger species utilise the mangrove creek and inlets, moving out into the deeper waters of Port Curtis upon maturity. Toadfish (Marilyna pleurosticta and Tettactenus Hamilton) are common in the shallow creek and inlet systems. The mudskipper (Pertophthabnus argentineatiis ) is abundant. It shelters along the muddy creek banks in small turret-like burrows, where it grazes on benthic algae and invertebrates. Fishing industry The species of commercial importance to the area include Barramundi (Lates calcarifer ), Threadfin Salmon (Polydactylus sheridon ) Sand Whiting (Sillagocila ), Banana Prawns (Penaeus merguiensis ) and the Mud Crab (Scyra serrata ). The Fitzroy Region Fishery, which includes Gladstone - Port Curtis, is an important one; comprising 7% of Queensland's fishing fleet. The Gladstone fleet represents approximately 38% of the vessels in the Fitzroy Region. The three major categories fishing activities in the area can be considered as the trawl, net and crab fisheries. Both otter and bream trawlers operate in Gladstone. Whereas, the breamtrawl operators work the sheltered port and estuarine areas, including the many creeks, other trawling is usually restricted to oceanic waters outside the harbour. The trawl fishery targets a number of prawn species. Molluscs The most abundant Gastropods are Telescoptum telescopium , Salinator solida , as well as Ltttoraria, Terebra, and Melampus . Prawns Several species of Penaeid prawns are found. Most of these are of commercial importance forming the second largest, next to Moreton Bay, prawn industry in Queensland. Seven commercially important prawns are present in this area. Of these, Banana prawns (Penaeus merguiensis) are the most abundant showing an increase in total catch from 10853 kg in 1989 to 51520 kg in 1992. Endeavour prawns (Metapenaeus endeavourii), King prawns ( P. plebeius ) and the Tiger prawn (P. esculentus ) showed an increase in total catch from 1991 to 1992 of almost 1 50% to 200%. Zooplankton The zooplankton (i.e. animal) community shows less diversity than the phytoplankton (ie plant) .The zooplankton component of the planktonic community shows a predominance of Copepods fol- lowed by Rotifers and Protozoa for both creek systems and Port Curtis. There are marked differences in zooplankton community composition and relative abundance between creeks and estuary. Maximum community composition exists during the dry cooler months (April-September). PROTECTED FAUNA Bottlenose dolphin (Turstops truncatus ) are commonly sighted from within Port Curtis. Other species of dolphin, including the rare Irrawaddy dolphin (Oracaella brevirostris ) have also been re- corded. The Green turtle (Chelonia mydas ), Loggerhead turtle (Caretta caretta), and Flatback turtle (Natator depressus ) may be seen in the Port Curtis region. The main (ocean) beach at Curtis Island, south of Conner Bluff supports one of the largest known breeding populations of Flatback turtle. Each species of turtle is listed by the IUCN as 'rare and threatened'. Dugong (Dugong dugong ) are commonly reported by fishermen within Port Curtis and the Narrows. However, the region is not recognised as supporting a major population of these animals. The IUCN lists the dugong as 'vulnerable to extinction'. Seagrass is an important food for both the green turtle and dugong. A range of wader-birds and sea-birds, protected by State and Commonwealth statutes and international agreements (e.g. Ramsar Convention), and including the Eastern Curlew (Numenius madagascariensis ). Beach Thick-knee (Esacus magnirostris ), Asian Dowitcher ( Limnodromus semipalmatus ), and Little Term (Sterna albtirons ), can be seen in the region. These birds are likely to use as a feeding ground the extensive marine plains of Port Curtis. PLANTS In tidal inlets, estuaries and coastal marine waters receiving minimal river flows and material transport, planktonic communities are usually the primary producers of biological activity in association with benthic algae, seagrasses and mangroves. Benthic Algae Benthic algae are often as important as producers of biological activity as seagrass communities, particularly in shallow bays and coastal areas. The brown algae Sargassum crassifolium occurs in dense clumps just below the low tide level, whilst Padina, Zonaria, Halimeda opuntia, Neomeris, and Udotea occur less abundantly. Phytoplankton Species The phytoplankton species composition indicates a predominance of Diatoms; representing almost 75% of the total species composition. The other 25% of the planktonic algae are represented by various groups, including Dinojlagellates, Chlorophytes, Cyanobacteria and other planktonic taxa. All planktonic communities show a predominance of euryhaline organisms. The species diversity is at its highest for August. Seagrass Seagrass communities were dominated by Zostera capricorni with some mixed associations o f Z. capricorni, Halophila ovalis, H. spinulosa, Halodule pinifolia , and Huninervis forming sparse patches in the shallow waters. Some sparse growths of Halophila ovalis mixed with H. decipiens can be found in both the Spillway and Sandy Creek systems. Most other areas around BITS are devoid of seagrass. Sometimes, despite moderately sparse seagrass above-ground cover, the rhizome mat is healthy and dense, suggesting the above ground cover may have been higher, for example in early summer. .
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