Ski-Boat — May-June 2017

driving baitfish up against the shore
makes casting from the beach possible
at times too. Very good catches are reg-
ularly made from the Rooikrantz rocks
at Cape Point.
Sadly, despite an ever growing keen
interest, I’ve never had the chance to
explore its biological makeup, taxono-
my and persona. However, following
some flights through cyberspace and
especially with the assistance of Belinda
Swart who did her doctorate in genet-
ics, I’ve collected some very interesting
information on this species.

THE YELLOWTAIL
The Cape yellowtail (Seriola lalandi)
— related to the amberjack (Seriola
dumerili)and the tropical yellowtail
aka the longfin amberjack (Seriola rivo-
liana)which are also found in South
Africa — is known worldwide as the
southern yellowtail. It is also referred
to by some as the albacore, yellowtail
kingfish, yellowtail amberjack,
Californian yellowtail, hoodlum yellow-
tail,Tasmanian yellowtail or gold-striped
amberjack.
Occurring in tropical and temperate
waters in various locations around the
globe, it actually consists of three sub-
species — the Southern yellowtail
(Seriola lalandi lalandi), the California
yellowtail (Seriola lalandi dorsalis)
and the Asian yellowtail (Seriola lalan-
di aureovittata). See the distribution

chart below from Swart et al (2016).

A recent phylogeography (the study

of historical processes responsible for

contemporary geographic distributions

of different fisheries by using genetic

analyses) by Dr B L Swart et al (2016),

discovered that although the yellowtail

is still classified as one species, three

genetically distinct groups correspond-

ing to the three subspecies can be

found. It turns out the Cape yellowtail

is a different stock to the Southern yel-

lowtail found in the South Pacific.

These subspecies are the direct fallout

of the unique distribution of these dif-

ferent fisheries, hence the absence of

interaction between them.

Being a pelagic schooling fish, the

yellowtail belongs to the Carangidae

family, a diverse family that includes

fishes of ecological and economic

importance and includes jacks, scads,

trevallies, pompano, amberjacks and

queenfishes. Members of this family are

found in all three major ocean basins —

the Pacific, Atlantic and Indian oceans

— and are generally fast-swimming

predatory fish that hunt mainly in

waters just above reef structures.

Contingent on lunar cycles, the yellow-

tail preys during varying times of the

day predominantly on small fish, inver-

tebrates and pelagic crabs.

Yellowtail have been described as

having torpedo-shaped bodies with very

small, smooth scales. The combination

of its body shape and carangiform loco-

motion (there’s very little effort of the

head whilst movement is concentrated

in the very rear part of the body and tail

which results in rapidly oscillating tails)

make the yellowtail kingfish a very fast,

strong swimmer. Although the Cape yel-

lowtail specimens taper out at around

25kg, the species can grow up to 2.5m

in length and weigh up to 70kg.

Juvenile yellowtail are rarely seen

but are apparently often found far from

land where they’re associated with

floating debris or weed which provides

camouflage. Seasonal migratory shoals

generally consist of several hundred

smaller size fish (under 7kg) which are

found close to the coast. The larger fish

tend to prefer smaller aggregations and

becomes more territorial and less

migratory as they grow bigger, with

especially the 15kg-plus specimens

being more solitary. They are common-

ly found around deep reefs and offshore

islands.

MIGRATION AROUND

SOUTH AFRICA

During my research into the Cape yel-

lowtail’s migratory route around the

South African coastline I realised that

information about the species in gener-

al is rather scanty.

Fortunately some of the old-hands

kindly shared their knowledge and

know-how gained over many years.

These are some of those leading iron-

men, individuals who are still walking

around with seriously scarred hands —

injuries resulting from deep cuts caused

by years of fighting and finally wrestling

those strong and heavy squirming yel-

lowtails over the gunnel, mostly using

>120kg rated handlines.

Dr Swart also referred me to a very

interesting news publication produced

by the Oceanic Research Institute

(ORI). In their Tagging News report

published in July 2012, which sum-

marised the 2011 tagging results, they

noted a single Cape yellowtail’s mission

up our east coast.

According to the abovementioned

report, during 2011 a total of 557 active

members tagged 10 262 fish of 167 dif-

ferent species. Only 697 recaptures

SKI-BOAT May/June 2017 • 69

A boat executing the so-called “Cowboy Launch” off the Arniston slipway. It can be a hairy experience if the sea is rough.

Distribution ranges of Seriola lalandi subspecies: S. l. dorsalis (USA), S. l. aureovittata

(Japan – JA), S. l. lalandi (Chile – CH,South Africa – SA, Australia – AUS, New Zealand –

NZL) (Smith-Vaniz 1986; Smith-Vaniz et al. 1990; Martinez-Takeshita et al. 2015).