Spearfishing in southern and eastern Africa

The contrast between the two South African coasts is worth understanding because the mechanism operates elsewhere too — off Iberia, off California, off Peru and Chile, off north-west Africa.

UPWELLING happens where wind and coastal geometry combine to draw deep water towards the surface. That water is cold and rich in nutrients, so it drives high biological productivity, which produces plankton, which produces green water and reduced visibility. The result is a coast that is biologically abundant and visually poor.

A WESTERN BOUNDARY CURRENT like the Agulhas does something close to the opposite: it carries warm, comparatively nutrient-poor tropical water polewards, so the water is clear and warm and the productivity is lower and more patchy, concentrated around structure.

SO THE TRADE IS BETWEEN ABUNDANCE AND VISIBILITY, and it repeats around the world. A diver who understands that will read an unfamiliar coast much faster than one who has only learned local rules of thumb — which is exactly the sort of transferable intelligence this family exists to record.

The practical consequence here is equipment: the west coast needs the thermal protection, weighting and short-range technique of cold green water, and the east coast needs the specification of warm clear water. They are two different disciplines sharing a coastline.

Offshore blue-water diving removes almost every reference a diver normally uses.

NO BOTTOM. Depth perception and orientation both rely on the seabed, and without it a diver can descend further than intended without registering it. Depth awareness becomes an instrument matter rather than a perceptual one.

NO STRUCTURE, SO NO REFUGE. There is nowhere to hold, nothing to shelter behind, and current moves diver and boat independently.

LARGE FISH AND LARGE PREDATORS. Pelagic species can be far heavier than the diver, and a shot fish can take a diver's line with considerable force. Line management is a serious safety subject here rather than a tidiness one, and so is having the release discipline to let go.

TOTAL DEPENDENCE ON THE BOAT. The boat is the safety system: the buddy, the platform, the recovery, and the only way home. Blue-water diving without a competent boat handler is not a reduced version of the activity; it is a different and much worse-considered one.

FishingHQ describes blue-water diving because it is a real and regionally important part of the discipline. It does not publish technique for it, and anybody moving into it should do so through training and through people who already do it, in that order.

Spearfishing rules here vary by country, by region, by site and by species, and they change. Nothing on this page states what is currently permitted anywhere. Check the current position with the national fisheries or marine authority, the protected-area manager where one applies, and a local club or federation, who will usually know the site-level detail a national statement does not carry.