70 years of helping people to care for our ocean

45 Years Survey Data of the KZN Invertebrate Fishery

By: Erika Steyn

ORI’s Invertebrate Catch Statistics monitoring programme is unique in South Africa and is the only long-term monitoring study of a recreational invertebrate fishery in the country.

Each year, the subtropical beaches of KwaZulu-Natal are invaded by holiday makers from all over South Africa, many of them avid fishermen and invertebrate collectors. These recreational collectors target a wide range of ecologically important nearshore marine and estuarine invertebrates, such as the East coast rock lobster, brown mussels and sand prawns, either as bait for fishing, or for consumption.  Most of the animals collected are found in habitats that are easy to access from the shore and require little skill or equipment to collect.  Consequently, this fishery expanded dramatically, particularly during the 1970s and 1980s.  At the peak of the fishery in 1993, more than 41 000 collection permits were sold in KZN.

Recognising the need to monitor this large and diverse recreational invertebrate fishery in KZN, a collaborative catch reporting programme was launched in 1974 by ORI, the Natal Parks Board (now: Ezemvelo KwaZulu-Natal Wildlife (EKZNW)) and the Natal Fisheries Licensing Board (FLB). The initial voluntary catch report form issued by the FLB was later supplemented with catch data collected during EKZNW fishery compliance patrols.  All the catch data were managed and analysed by ORI. Both data sets were subject to certain biases and limitations, but still provided a reasonable indication of harvesting intensity, where there was no other fishery monitoring.

During the 1990s, ORI investigated different means of improving monitoring and by 2002, ORI had implemented a comprehensive Invertebrate Catch Statistics (ICS) monitoring programme that has now been maintained for almost 20 years. Quarterly postal surveys were conducted with collectors, followed by telephone interviews with non-respondents. This approach improved the quality of catch data by reducing recall bias and by estimating non-response bias.

Methods to improve survey participation and data quality of the ICS programme is continually sought. The addition of an online survey and the use of e-mails and bulk short messaging services (SMS) to contact potential survey participants has greatly increased survey reach and response rates. Ground truthing of the questionnaire data by means of fishery independent patrols was initiated in 2017, and a new online catch diary platform was launched in 2020.

ORI’s ICS programme is the only long-term monitoring study of a recreational invertebrate fishery in South Africa. The catch and effort data from this programme have proven invaluable in examining historical fishery trends. Besides the valuable catch statistics data that are directly applicable to resource management, the ICS programme has educated people about the conservation of our marine invertebrate species for almost two decades. The true value of this programme may lie in the way that it has subtly guided recreational invertebrate collectors to a more conservation-conscious mind-set.