King George whiting

The King George whiting is the only species nested in the genus Sillaginodes, which itself is in the family Sillaginidae, containing all the smelt whitings. The Sillaginidae are part of the Percoidei, a suborder of the order Perciformes. The King George whiting was first officially named by Cuvier in 1829 as Sillago punctata, based on an individual taken from King George Sound in Western Australia. In 1861, Theodore Gill created the monotypic genus Sillaginodes based on a number or morphological characteristics and assigned S. punctatus to it. A number of synonyms have been applied after the initial correct naming, apparently due to Cuvier not designating a holotype, or it being lost. A lectotype was finally designated by McKay in 1985. The species has a variety of common names (many now obsolete), with the most common, "King George whiting", taken from the name of the body of water where the initial description was made. It is also often called the spotted whiting in reference to its obliquely positioned bars of brown spots, with other names used in markets, especially outside of Australia. ==Description==

The King George whiting has the same overall profile as the rest of the sillaginid fishes, an elongate, slightly compressed body with a tapering head and terminal mouth. The genus Sillaginodes is distinguished by a first dorsal fin with twelve or thirteen spines and the second dorsal fin with a single spine and 25 to 27 soft rays. It is the largest member of Sillaginidae, growing to a maximum length of 72 cm long and 4.8 kg in weight. ==Distribution and habitat==

beds amongst sand patches The King George whiting is endemic to Southern Australia, ranging lower Western Australia, South Australia, Victoria and occasionally even lower New South Wales. The westernmost reported capture was in Jurien Bay and the furthest east King George whiting have been reported from is Botany Bay in New South Wales (although this appears to be a rare occurrence). A favourite habitat of young fish appears to be Zostera and Posidonia seagrass beds in protected bays, apparently using the seagrass as protection and for foraging purposes. Juveniles tend to form schools of varying sizes, occasionally schooling with other species, including other members of the family Sillaginidae. Adults tend to be solitary and found in deeper water in a range of habitats including bays, offshore surf gutters, broken bottom and deep reef, also venturing into shallower water on occasion. ==Biology==

Diet The King George whiting's distinctive body shape and mouth placement is an adaptation to bottom feeding, which is the predominant method of feeding for all whiting species. All larger whiting feed by using their protrusile jaws and tube-like mouths to suck up various types of prey from in, on or above the ocean substrate. There is a large body of evidence that shows whiting do not rely on visual cues when feeding, instead using a system based on the vibrations emitted by their prey. Studies of gut content have shown that the primary food items of King George whiting are amphipods, copepods and polychaete worms. Unlike any of its relatives, the King George whiting does not appear to feed on molluscs, which is unusual because in many parts of Southern Australia, the main bait used by recreational fishers to catch whiting is the cockle; a mollusc, but then, it has been deshelled. An excellent bait for catching King George Whiting is raw king prawn, such as banana prawn. They are better bought in the shell and peeled shortly before using, as this keeps the bait fresh. Also rare in the diet are echinoderms, which are frequent prey for other species of Sillago. This may be a function of niche partitioning, as in many areas the King George whiting's habitat overlaps with other species of the genus Sillago. Various species of diving birds, particularly the pied cormorant are also common predators of the species, as are marine mammals such as bottlenose and common dolphins. Reproduction King George whiting reach sexual maturity at three to four years of age, with males reaching 30 cm in length and females 34 cm. These lengths are used as guides when setting minimum legal lengths for the species, allowing adequate time for an individual to reproduce before being taken. Spawning occurs in a range of areas, depending on the geographic locality of the individual; some spawning in deeper water up to 9 m deep, others in estuaries. May and June are the most common times for spawning, with some spawning events recorded as early as February and as late as July. The location of spawning also has implications for the location of the juveniles, as with some estuary breeding individuals. ==Relationship to humans==

The King George whiting is a highly rated food fish and is common in southern Australia and so has become a major component of the commercial and recreational fisheries in this region, with aquaculture potential still being explored but apparently of low value. The fish are sold either whole or as fillets and are generally rated as one of the very best quality Australian fish for the table, and are ubiquitous in Fish and chips shops. Recreational fishery In Southern Australia, the King George whiting is often the sole target for fishermen who seek it for its high quality eating. They are a relatively easy species to catch, with no special baits, rigs or techniques required and are often caught from jetties, beaches and rocks; meaning a boat is not necessary. Simple rigs such varieties of running ball sinker or paternoster rigs are commonly used, with a fixed sinker employed in area of high tidal movement. As mentioned previously, molluscs, particularly the Goolwa cockle are common bait, with varieties of worms, gents, squid, cuttlefish, fish pieces and especially raw king prawn are commonly successful. The larger fish inhabiting deep reefs are often caught on whole pilchards while fishing for snapper and morwong. South Australia is divided into two zones concerning the taking of this species, with fish caught east of longitude 136° restricted to a minimum length of 32 cm and fish caught to the west of longitude 136° having a minimum length of 30 cm. In both divisions, the bag limit is 10 fish per person. Western Australia has set a minimum legal limit of 28 cm and a bag limit of 8 per person. Aquaculture Due to the King George whitings' popularity as a food fish, extensive investigations into the viability of the species as an aquaculture species have occurred, with most initial investigations indicating the long larval cycle is a major barrier to the successful farming of the fish. Other problems have arisen in a parasite previously unknown in the species only affecting the fish in captivity. Thyroid growth hormones may be used in the future to hasten growth of larvae and make such ventures more feasible. ==References==