At the edge of a current-washed headland, a school of sweep holds mid-water with the practiced ease of fish that have spent considerable evolutionary time in exactly this situation. They face into the flow, mouths working occasionally, and the plankton comes to them. This is the sweep's arrangement with the ocean, and by most measures it is a successful one. Scorpis lineolata, the silver sweep, is a deep-bodied, laterally compressed fish with a small mouth and large eyes, grey-silver overall with darker upper flanks, black margins on the leading tail edge and fin tips, and a black rear edge to the gill covers that reads as a spot at distance. The body is covered in very small scales and the profile is almost rectangular when viewed from the side. Adults reach about 36 centimetres, though growth slows dramatically once sexual maturity is reached at two to three years. What the sweep lacks in fast growth it compensates for in time: otolith analysis has recorded individuals exceeding 54 years old, making this one of the longest-lived inshore reef fish in New Zealand waters. A fish working a current edge in front of a northern headland may well have been working the same edge since the 1970s. Schools of adult sweep are a reliable feature of northern New Zealand rocky reefs, headlands, and offshore islands, typically found mid-water in association with current edges and reef structure where plankton concentrates. They are almost always found alongside blue maomao, their close relative in the same subfamily, and the two species school together freely. The distinction is immediately obvious: the blue maomao is a vivid sky-blue, the sweep a pale grey-silver. Together they form the dominant plankton-feeding assemblage of northern New Zealand inshore waters. Juveniles use a different habitat entirely, occurring in estuaries, harbours, and shallow rock pools before moving to open reef as they grow. This inshore nursery phase provides some insulation from predation during the most vulnerable period. The sweep is not commercially targeted in New Zealand and carries no threat classification. It is caught incidentally by anglers fishing over reef for snapper and other species, and it is edible, though not particularly sought. Its ecological role as a major consumer of zooplankton at reef edges is more significant than its value on a plate, and the schools visible on almost any northern reef dive represent a consistent link between open-water productivity and the reef community below.