New Zealand has over 200 species of freshwater macroinvertebrates. An invertebrate is an animal that lacks a backbone. ‘Macro’ means the invertebrates are large enough to be seen without magnification – even though some can be as small as 1 mm in length. Examples of aquatic macroinvertebrates include crustaceans (such as sand hoppers), insects (such as beetles and mayflies), molluscs (such as snails) and segmented worms (such as leeches).