In March this year Robberg beach experienced a mass stranding of soft-shelled clams, believed to be caused by strong easterly winds and a sudden drop in sea temperature. These conditions most likely dislodge clams from the sand and deposit them on the beach. Recent reports of an increase in clam stranding events is believed by many to not only indicate a possible increase in the frequency and intensity of upwelling events, but also an explosion in the local clam population. But what may have caused such a sudden increase in clam numbers? One possibility is the combined indirect impacts of the re-established Cape fur seal colony and increases in fishing effort in our bay. To explain this, we need to take a step back in time. Historical extermination of the Robberg seal colony by 1890 no doubt had a huge impact on the local marine ecosystem. In fact, the sudden depletion (or addition) of top predator populations by humans have been shown to set off chain reactions that eventually cascade down the trophic ladder to the lowest rung of the food web. In 1980, Robert Paine coined the term trophic cascade to describe this process, and there are many examples in the world’s oceans, some involving changes in clam abundance. It is very possible that after historical hunting of Robberg seals their sudden decline in the bay would have caused an increase in some of their preferred prey species, including octopus and certain species of rays. These demersal animals are known to prey heavily on shellfish, including various species of hard and soft-shell clams, which in effect controls their numbers. This may partly explain an absence of extensive clam strandings until recently. But, since Cape fur seals have regained their prominent position as top predators in the bay their increasing top-down force on rays and octopus would have decreased the predation impact on the local clam population, allowing clams to once again flourish in the bay where they capitalize on the nutrient run-off from estuaries and that released through seal excrement and carcasses at the colony. In addition, the more recent targeting of octopus by an experimental longline fishery in our bay may have exaggerated the recent ‘boom’ in the local clam population. Unfortunately very little baseline data exists on the historical abundance of clams, octopus and sharks in our bay, making a scientific assessment of the impact of historical seal hunting and fisheries very difficult. Only through long-term monitoring of clam strandings, top predator diet and fishery catches can researchers gain further insights. It remains to be seen what ecological impact a growing clam population will have on the local ecosystem, but, if there has indeed been an explosion in their numbers, and we look carefully enough, we could expect to see more chain reactions or changes in biodiversity.