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Old Man of the Sea

Just as South Africa is diverse in culture, so are the names of our fish. The Black Musselcracker (Cymatoceps nasutus) goes by many names. Also known as Black Steenbras, Bank Blouer, Blou-Biskop, Stompkop, Witbek, Saqomolo and Poenskop or “Poensie”; this is one of the largest members of the Seabream family formally known as Sparids. Included in this family, amongst others, is the Bronze Bream, Blacktail, Englishman, Stumpnose, and Pignose Grunter. These are true South African fish whose characteristics make them vulnerable to over-exploitation; such as long-life span, slow growth, sex change, late age at maturity, reef residency and of course delicious meat. Juvenile “Cracker” have a slightly pointed head and are brown to olive-green with irregular white blotches on the head and body. Older juveniles develop two dark vertical bars. Maturing fish lose these bars and have variable colouration; mostly grey to black mottling with a conspicuous white lower jaw. Very old individuals develop the well-known fleshy white bump on the snout, responsible for so many of the descriptive names. ECOLOGY – Like many other members of the family, the Cracker has a very complex life-history. It is endemic, meaning that the southern African population of Cracker is the only one in the world. They live for a whopping 45 years and reach weights of approximately 38 kg based on previous records (the South African angling record stands at 37.8 kg and spearfishing at 36 kg). But, it is only when we compare this to other species such as Dorado that reach 40 kg in about 4 years that we place the fish in context. Cracker are opportunistic feeders, but appear to prefer mollusks, crustaceans and echinoderms. The adults prefer deep, high profile rocky reefs down to 100 m. Their distribution is from the Western Cape up to Maputo and spawning takes place in the Eastern Cape between May and October each year. Although adults in KZN are only found in fairly deep water, in the Eastern Cape they often make an appearance in shallower water. While the reason for this is not clear, it is thought to be temperature related. All Cracker start off life as females and only reach sexual maturity after about 10 years; however it is not until the Cracker reaches a staggering 18 years of age before she turns into a male! This age corresponds roughly to a fork length (length between head and inner fork of tail) of between 70 and 95 cm. This means that most individuals over 95 cm are males, most of those less than 70 cm are females and those in the middle are…well somewhere between male and female. The young prefer sub-tidal reefs shallower than 10 meters and I have even seen 10 cm juveniles on the KZN south coast just behind the backline in the vicinity of white water! Although there is some evidence that spawning adults migrate from the Cape towards the Eastern Cape and KZN, the ORI Tagging Program has confirmed that this species is generally highly resident. It is likely that the juveniles remain in the same vicinity for extended periods of time but once reaching maturity, adults move onto deeper reefs and may move progressively northwards similar to species such as Red Steenbras. However, with resident reef fish species such as Cracker they are extremely vulnerable to overfishing and it is easy for some better known reef areas to become “fished out” quite quickly. CATCH REGULATIONS – According to the Marine Living Resources Act, only one Cracker is allowed to be caught per person per day and it has to be over a minimum size of 50 cm (recreational and commercial). Unfortunately this length is less than the age at which these fish mature and therefore the regulations allow us to catch young Cracker which have more than likely not yet had a chance to spawn. The current size restriction is, however, a drastic improvement on what it was in the old days; a tiny 25 cm! THE FISHERY – Although, large volumes of this species have been taken in the past (as much as 15 tons were taken in KZN during 1987 by all sectors) this is relatively low compared with other species. It was found that in the 1980s Cracker were only contributing about 1.4% to the total catch of spearos in the Eastern Cape and as little as 0.1 % of the commercial linefish catch. The catches taken by KZN spearos is likely to be even less as larger legal sized specimens are generally found on deeper reefs and are therefore only targeted by select spearos who can dive greater than 20m. When you hit the beach after a dive either by boat or shore-dive and the Ezemvelo KwaZulu-Natal Wildlife (EKZNW) officers inspect your catch, that data is recorded on the National Marine Linefish System (NMLS). The NMLS is a database of catch and effort for all fishing sectors in South Africa and with it we can monitor trends. During 2008, EKZNW officials inspected 205 boat-based spear fishing outings; being 47% of the overall boat-based spear fishing outings as recorded by the compulsory boat launch site registers. However, neither the NMLS nor the boat launch site register, recorded any Cracker being caught by spearos. This is unfortunate, because it tells us that if there were cracker shot during 2008 they were simply not reported. The biological data on this species is limited, but what is known of its lifestyle makes good fisheries management very difficult. The strict daily bag limit ensures that only a few fish are caught and that the catch is more fairly distributed. The minimum size limit should theoretically give the fish at least one chance to spawn before being taken by the fishery and it should also serve to protect the young fish when they are growing at their fastest rate. Consequently, larger adult fish are targeted by the fishery. However, by targeting the adults, breeding success may be compromised, especially in a sex changing species where there may only be a few large males in the population (i.e. skewed sex ratios). CONCLUSION – Because of the resident nature of the species and the other difficulties involved in managing it, perhaps the best method of conserving this species is by the establishment of well-sited marine protected areas (MPAs or marine reserves). As long as they are large enough and contain sufficient good reef habitat, these protected areas provide a sanctuary for fish to reach ripe old ages. Generally larger, older fish produce more eggs and the eggs and larvae they produce are more viable than those produced by smaller, younger fish. Furthermore, the larger fish found within MPAs are also genetically “fitter” than those in exploited areas. MPAs can act as reservoirs for resident reef fish populations and can serve to enhance yield in adjacent exploited areas through “seeding” of eggs and larvae and by “spillover” of juvenile and adult fish which move into exploited areas. Bottom line – MPAs are worthy of support by all who use the sea. Legendary fighting ability and rugged “good looks” certainly earns this fish a position of stature and since it only occurs in southern Africa, it is a species to be proud of (and for us to be responsible for its future well being). Some of them swimming today are older than… well… most of us. So we urge you to declare your catches of Poenskop to the EKZNW official or, if not available, then do so in the boat launch site register which is available at all launch sites. This will hopefully enable us to ensure future catches of this highly esteemed fish. So, when that day comes and you are lining up on a nice Cracker and you’re dreaming of all the stories you gonna tell your mates, just consider that you are literally face to face with the old man of the sea. And those who are fortunate enough to be graced by his presence on more than one occasion, please exercise discretion.

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