Poster abstracts and manuscripts from the Third International ...

Cliff, Geremy, Sheldon Dudley and Peter G. Ryan
Large Sharks and Plastic Debris in Natal, South Africa
Fitzpatrick Institute, University of Cape Town, Rondebosch,
South Africa
31
Approximately 1,440 large sharks, comprising 14 species, are
caught annually in the nets which protect users of the tourist
beaches of Natal against shark attack. Between 1978 and 1993,
13,371 of these sharks (60% of the catch) were examined in the
laboratory. The presence of plastic either in the stomach or
entangled around the shark's body was recorded. Fishing line was
excluded.
Of the 12,737 sharks with recorded stomach contents, 51 (0.40%)
had ingested plastic items. The most common items were packets
or sheets, which were found in 32 stomachs; four of these were
labelled as bait packets and two contained meat remains. Other
items included nylon rope (three stomachs), vegetable sacks (two
stomachs), 250 ml drink containers (two, in one stomach), a gum
boot (one stomach) and an ice cream container (one stomach). All
the sharks appeared to be healthy and unaffected by these items.
Of the 411 tiger sharks Galeocerdo cuvier examined, 8.3% had
ingested plastics. The frequency of occurrence of plastics in
the stomachs of each of seven other species was less than 1% and
no plastics were found in 'six species. There was no evidence of
any increase in the ingestion of plastics with time.
Twenty-three sharks (0.17% of those examined) were entangled,
each with a single polypropylene band such as is used to secure
cartons. The bands were wrapped around the gill region and were
prevented from moving toward the tail by the pectoral fins. The
severity of abrasion of the skin and of damage to underlying
tissues varied and probably depended on the amount of time the
band had been in place. Three entangled females were in the late
stages of pregnancy with apparently normal litters.
Less than 1% of individuals from each of eight species were
entangled, and no entanglement was recorded in six species. No
entangled sharks were reported between 1978 and 1982. There was
no evidence of an increasing trend in the incidence of
entanglement from 1983 to 1993.
Forsyth, Marianne L., Anton McLachlan, and Graham Kerley
Dune Litter Pollution: Its Ecological Impacts With Special
Reference to Meiofauna
University of Port Elizabeth, Cape Province, South Africa,
The Alexandria Coastal Dunefield in Algoa Bay in the Cape
Province, South Africa has been found to have a substantial
amount of anthropogenic litter pollution. This survey involved
quantifying and characterizing the litter and investigating the
effect of plastic on dune meiofauna.