Mulloway (Argyrosomus japonicus), also known as Jewfish in the eastern states of Australia (but not to be confused with the Atlantic Goliath Grouper also known by the same name), is a highly sought-after fish in many parts of the world.
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.
But the mulloway’s story goes beyond the hook and line, encompassing fascinating behaviors, a vital role in the marine ecosystem, and a growing concern for its future.
In this article, we will examine the biology and behavior of this fish, its appearance, the efforts underway to protect this magnificent species for future generations, and more.
Appearance
Mulloway has a distinctive appearance with a silver-colored body, yellow fins, and a pointed snout.
Their solid and streamlined body with large scales makes them excellent swimmers.
For many anglers, the elusive mulloway is a prized target species, sought after for its size and fighting ability.
As they mature, they develop a more elongated body shape and a humped back, a characteristic of the species. Juveniles are dark-colored with a black spot near their tail, which disappears as they grow older.
Habitat
Mulloway is commonly found in estuaries and the surf zone along the coast but can also be found in the open ocean, often patrolling the turbulent waters around rocky headlands, ambushing prey that is swept past by the currents.
A large number of mulloway are found in Australia, from southern Queensland to Western Australia’s central coast.
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.
Mulloway are often found in deeper channels and drop-offs, requiring anglers to adjust their fishing depth accordingly. Anglers targeting mulloway need to be prepared to cast their lines several meters out from shore, reaching the depths where these fish prefer to hunt.
Diet
Mulloway is a predator that feeds on various prey, including fish, squid, and crustaceans.
Juveniles feed on small fish and invertebrates, while adults feed on larger fish. These animals are opportunistic feeders and take advantage of seasonal changes in prey availability.
Mulloway are known for their nocturnal habits, making dawn and dusk prime fishing times. They are also more active during cooler months and around the full and new moon phases when tides are stronger.
In the winter months, they may feed on schools of small fish, while in the summer months, they may feed on squid and cuttlefish.
The mixing of salt and freshwater at river mouths creates ideal feeding grounds for mulloway, attracting baitfish and offering prime ambush points. Offshore reefs, with their complex structures and abundant prey, provide ideal habitat for them to grow to impressive sizes.
Reproduction
Mulloway are known for their aggregations, where large numbers of fish gather in specific areas to spawn. These events are often triggered by environmental cues like water temperature and lunar cycles, creating a frenzy of activity that attracts both fish and fishermen alike.
Mulloway reaches sexual maturity at about 4-5 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 the population of this fish 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.
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. Pollution, including the discharge of pollutants from agricultural and industrial activities, can also negatively impact mulloway populations.
To help protect its populations, fishing restrictions 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.
4 More Facts About Mulloway
- Mulloway is famous for the nickname “silver ghosts” from their stunning silver scales, reflecting light and making them appear almost ghost-like when they flash through the water, especially at night.
- Some anglers believe barometric pressure changes influence their feeding patterns.
- This fish holds cultural importance for many Aboriginal Australian groups, featuring in stories, songs, and art.
- Rare cases of hybridization with other species like Teraglin have been documented.
FAQs
Can you eat Mulloway raw?
Yes, it can be eaten raw, but it is crucial to ensure 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.
Is it true that Mulloway can “talk”?
While they don’t speak in the human sense, mulloway is known to produce a distinctive “grunting” or “croaking” sound when caught or spawning. This sound is produced by their swim bladder and is thought to be a distress call or a warning to other fish.
Can Mulloway be caught 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.
Why is Mulloway commonly called Jewfish?
Do Mulloway ever hybridize with other fish species?
While rare, there have been documented cases of mulloway hybridizing with other closely related species like teraglin (also known as dusky flathead). These hybrids often exhibit physical characteristics of both parent species and can be a curious find for anglers.
