THIS is the first of a two-part column on yellowfin bream (Acanthopagrus australis).
The yellowfin bream belongs to the family Sparidae and there are about 155 species in the family. In addition to the yellowfin bream, there are a further four species in the family found in Queensland: snapper, fryingpan snapper, tarwhine and the pikey bream of more northern waters.
Most coastal areas of the world have at least one species of sparid fish present. Globally, important recreational species in the family include the white steenbra of southern Africa, the common dentex of the Mediterranean and surrounding waters, and the sheepshead which is found in the western Atlantic from Nova Scotia to Brazil and is most abundant in Florida.
The yellowfin bream is endemic to the Australian east coast – meaning that is the only coastal region in the world where the species occurs. They are found in a variety of coastal habitats including throughout river systems, along all the coastal foreshores of Moreton Bay, the surf zone and around rocky headlands.
Let’s look at the likely movements of adult yellowfin bream in Moreton Bay in a given year:
From October to April, they tend to be in the rivers and creeks (or at least adjacent to them) feeding in these diverse and highly productive habitats. The condition of the fish in October tends to be poor and they used to be referred to as “razorbacks”, when I was teenager at Sandgate. If there is substantial rain over the summer period, they do end up highly dispersed but they still tend to be more abundant in around the rivers and creeks.
The spawning period for yellowfin bream in Moreton Bay is in line with the winter months, with a peak in July to August. Spawning occurs at, or adjacent to, surf bars. As the day length shortens, the fish, from May onwards, are stimulated to commence their migration to their main spawning locations, although they may have already moved downriver for example in the Brisbane River and the Pine River in March/April.
They do not leave the rivers and creeks en-masse and not all fish participate in the migration, so there are some fish available in the rivers and creeks all year round. It is likely that some fish go back and forth to the principal spawning locations during the winter from adjacent areas. Whether the proportion of adult fish participating in the annual spawning migration varies between years is unknown.
Yellowfin bream do not readily utilise the more open expanses of Moreton Bay and tend to hug the shoreline and this is where they can be targeted. When fishing the shorelines, you are fishing along their migratory path. Unlike sea mullet, yellowfin bream feed along the way and their energetic needs are likely to be higher, hence they are hungry and will readily take a bait.
Why do they migrate to the surf bars? By spawning on the flood tide at surf bars, they maximise the dispersal of larvae throughout the system. It is a good breeding strategy. Most post-larvae enter the estuary at night during the full moon on the flood tide, and they transition from planktonic animal to a juvenile fish from August to November when they are 13-14mm total length. From September onwards, most of the spawning bream are heading back to the river and creeks.
In the next edition, I’ll explain feeding, age and growth, and the reproductive biology of yellowfin bream.