Ecological value of the earliest human manipulated coastal habitats: Preliminary insights into the nursery function of a pre-colonial stonewalled fish trap in South Africa

Abstract

Pre-colonial stonewalled fish traps, an ancient engineering feat in the intertidal region, represent the earliest proof of human manipulation of the coastline in Southern Africa, specifically by the First Indigenous Peoples of South Africa. We investigated the ecologically functioning of a fish trap located on the southeast coast of South Africa from a larval fish and invertebrate perspective. This research was done in collaboration with the Khoi traditional custodians of the area of study. Samples were collected using a light trap on four separate spring tide occasions, deployed for 3 consecutive nights during 2 full moon trips and 2 new moon trips during the known peak larval settlement period (November 2020–February 2021). Although time-dependent, the importance of this novel microhabitat for the development of coastal fishes and invertebrates was highlighted. Even with the high intertidal location of the stonewalled fish trap sampled at Cape Recife, the presence of a pool of permanent non-stagnant water within the fish trap, even during low spring tide, could provide protection to larvae, in the form of more stable environmental conditions, as well as less exposure to marine predators and harsh physical environmental conditions. This research aims to raise awareness of the stonewalled fish traps located on the southeast of South Africa with a view towards developing a more inclusive management of these marine cultural heritage sites, specifically involving the First Indigenous Peoples of South Africa.