Category: High Risk
RARELY, if ever, are breaksea cod a targeted species for bottom fishing anglers – they are generally a much-appreciated incidental catch. Breaksea cod, or blackarse cod as they are more commonly known, provide a tasty meal especially when prime species like dhufish and snapper are proving elusive. The bite of a blackarse frequently suggests a much larger fish because they are ferocious in attacking even the largest of baits. But having said that their diminutive size means they come to the boat with very little resistance. Indeed, no doubt in part because they provide a nice white fillet for the table, the size of blackarse caught in metropolitan waters seems to be getting smaller. They are an inquisitive fish too, and will approach divers for a closer look. At times they can be seen resting on a reef ledge or the bottom. Just image if these little critters grew to 20 kilos!
The blackarse is similar in shape to other rock cods and turns up in a wide range of colour variations, with fish caught in deeper water tending to be yellowish orange while those taken in shallow water are greenish brown, brown or greyish green. The common name blackarse is derived from a distinctive black blotch surrounding the anus.
Reference books show blackarse reaching around 55cm and weighing up to 3kg, but it’s a long time since I saw one that big. They are more commonly caught around a kilo with a lifter probably weighing 1.5 kilos.
Blackarse are an endemic temperate water species found around inshore reefs from the Recherche Archipelago at Esperance northwards as far as Shark Bay.
Breeding and migration
Blackarse can live up to 21 years but fish aged two to 13 years are the most common encountered by anglers. They grow rapidly for the first eight years and growth slows at around 13 years. This species breeds from December through to April. As a member of the Ephinephilidae family (along with coral trout), they are considered to be batch spawners, which means they breed once or twice a month throughout their spawning season. All other members of this group are protogynous (female first) hermaphrodites (sex changers) and the size structure of blackarse cod, with all the smaller fish being females, suggests this species is the same. Females start spawning from 23cm at three years of age, whereas males start at 27cm at age four.
The little that is known about blackarse indicates that it is not a prolific breeder and could take a long while for stocks to recover from any overfishing. This means that an increasing frequency of smaller specimens being caught is possibly a sign of localised stock depletion. The ratio of old fish to young fish in the population, according to recent research, suggests that fishing pressure is acceptable, so there is no major cause for stock concern at present. However, because larger specimens are being caught outside the metropolitan area at places like Jurien Bay and Albany, there may well be some localised stock depletion where fishing pressure is higher – that is, around the metro area. Given that some blackarse are taken in water deeper than 40m – even down to 150m – it is not uncommon to see bulging eyes or the stomach protruding from the mouth, which are visible adverse effects of a fast ascent. So some small blackarse released in this condition are unlikely to survive the trauma. It is thought that commercial fishing activities have very little impact on the stocks of blackarse along the west coast.
Tackle and bait
As blackarse are generally caught when targeting other species, just about any bottom fishing rig or bait is capable of taking them.
When drifting for dhuies and other demersal or bottom dwelling species, it is common practice for some anglers to have one pair or gang of hooks carrying a big bait for the target species and a smaller single hook to pick up fish like blackarse and baldchin. But primarily blackarse cod are a valued incidental catch.
References: Sea Fishes of Southern Australia by Barry Hutchins and Roger Swainston. Adam Eastman (2001) Age, Growth and Reproductive Biology of the Breaksea Cod -Epinephelides armatus, Honours Thesis, Curtin University of Technology.