Mulloway, also known as Jewfish, is a highly sought-after fish in many parts of the world. Its scientific name is Argyrosomus japonicus or Argyrosomus hololepidotus. Native to the coastal waters of Australia and South Africa, mulloway is a prized catch for both recreational and commercial fishers due to its size, flavor, and versatility.
Moreover, growing up to about 2 meters in length, mulloway can weigh up to 60 kg and has delicate white flesh with a subtle, sweet flavor.
Despite its popularity, the species faces lots of challenges. Overfishing and habitat degradation have led to declines in mulloway populations, making sustainable fishing practices essential for the survival of this iconic species. In this article, we will examine the biology and behavior of mulloway, its appearance, the efforts underway to protect this magnificent species for future generations, and more.
Featured image credit: “The Cod Hole,” Julian Rocks, New South Wales, by David Cowdery
Appearance
Mulloway has a distinctive appearance with a silver-colored body, yellow fins, and a pointed snout. They also have solid and streamlined bodies with large scales, making them an excellent swimmer.
Juvenile mulloways are dark-colored with a black spot near their tail, which disappears as they grow older.
Credit: Government of New South Wales
As they mature, they develop a more elongated body shape and a humped back, a characteristic of the species. The average size of a Mulloway is between 50 and 100 cm. However, some individuals can grow up to 1.5 to 2 meters in length and weigh up to 50 – 60kg.
Habitat
Mulloways are commonly found in estuaries and the surf zone along the coast, but they can also be found in the open ocean.
You can find plenty of mulloway in Australia, from southern Queensland to Western Australia’s central coast.
Credit: Australian National Fish Expert Distributions
They prefer habitats with sand, gravel, or rocks and areas with good water quality and food availability. Also, they migrate along the coast in search of food and spawning grounds and can be found in various habitats, from shallow bays to deep offshore waters.
Diet
Mulloway is a predator that feeds on various prey, including fish, squid, and crustaceans.
Juvenile mulloway feeds on small fish and invertebrates, while adult mulloway primarily feeds on larger fish. These animals are opportunistic feeders and will take advantage of seasonal changes in prey availability.
For example, in the winter months, mulloway may feed on schools of small fish, while in the summer months, they may feed on squid and cuttlefish.
Reproduction
Mulloway reaches sexual maturity at about 3-4 years of age and spawns in the open ocean.
These fish are an oviparous species, meaning they lay eggs that are fertilized externally. The eggs are then carried by ocean currents and hatch into larvae.
Spawning usually occurs during the warmer months, and the number of eggs produced varies depending on the size of the female.
Larger females can produce up to several million eggs, while smaller females may only produce a few thousand.
Threats
The primary threats to mulloway populations include overfishing, habitat degradation, and pollution. Overfishing can significantly impact their population, especially if large numbers of adult mulloway are taken before they can reproduce. Note that most fishers use sinker rigs and hooks that target adult mulloway.
Habitat degradation, such as the loss of seagrass beds, can also impact populations by reducing the availability of food and spawning grounds.
Additionally, the construction of dams and weirs on rivers can limit their migration and access to spawning grounds, which can significantly impact populations.
Pollution, including the discharge of pollutants from agricultural and industrial activities, can also negatively impact mulloway populations.
To help protect mulloway populations, fishing regulations and size limits have been implemented in some areas. Additionally, efforts are underway to restore and protect their habitats, such as constructing fish ladders and restoring estuarine and coastal wetlands. Despite these efforts, monitoring mulloway populations and their habitats are ongoing, and more research is needed to understand better and address the threats facing this species.
FAQs
What is another name for mulloway fish?
Mulloway fish is also commonly known as “Jewfish.” The name “Jewfish” is believed to have originated from the species’ distinctive scales, which are said to resemble the coins traditionally worn by Jewish people. Some people use other names, including John Dory, Oyster Thief, and Sea Dory, to refer to the same species. However, “Mulloway” and “Jewfish” are these fish’s most widely used and recognized names.
Can you eat mulloway raw?
Yes, mulloway can be eaten raw, but it is crucial to ensure that it is fresh and adequately prepared to reduce the risk of foodborne illness. If possible, freeze the fish for a minimum of 7 days at a temperature of -20°C or below. This action will kill any parasites that may be present. If in doubt, cooking fish thoroughly before consumption is always safer.
Can mulloway live in freshwater?
Yes, mulloway can live in both fresh and salt water. The fish move between rivers, estuaries, and the ocean, searching for food and spawning grounds. Juvenile mulloway is often found in the fresh waters of rivers and estuaries, where they feed on small fish and crustaceans. As they mature, they move into the ocean, where they can be found along the coast and in deeper offshore waters.
How big does mulloway grow?
Mulloway can grow up to 2 meters in length and weigh up to 60 kg. A mulloway’s size depends on various factors, including age, sex, genetics, and environmental conditions. Juvenile mulloway typically grows rapidly in their first few years of life, reaching sexual maturity at around 3-4. After reaching adulthood, growth rates slow, but they can continue to grow for several years.
Are mulloways endangered?
Mulloways are not currently considered to be endangered. However, their populations have been impacted by various factors, including overfishing, habitat loss, and water pollution. The species is also highly valued for its meat, making it a popular target for commercial and recreational fishing. So, more needs to be done to protect this notable fish species.
