Shorthead Lamprey

Interesting Info

• The Shorthead Lamprey is a primitive, eel-like fish that are found in coastal rivers and estuaries from southern Queensland through New South Wales, Victoria, Tasmania, and eastern South Australia.
• It belongs to the jawless fish group (Agnatha), which split from other vertebrates millions years ago — making lampreys true “living fossils.”
• Their bodies are long, slim, and scaleless, coloured blue-grey to brown on top and silvery below, with no paired fins.
• They lack jaws — instead, they have a round, sucker-like mouth lined with sharp keratin teeth used to latch onto other fish.
• They prefer rivers with clean gravel beds and good flow, which provide suitable spawning habitat.
• Despite their gory feeding style, lampreys rarely kill their hosts and are an important part of the marine food web.
• Adults return to rivers to spawn, completing a catadromous life cycle (opposite of salmon, which are anadromous).
• Breeding occurs in freshwater rivers during winter and spring. Adults stop feeding, migrate upstream, and spawn in gravel nests before dying — they are semelparous (breed once, then die).
• Eggs hatch into worm-like larvae called ammocoetes, which bury themselves in river silt and filter-feed on plankton and detritus for 3–4 years.
• After metamorphosis, juveniles migrate downstream to the sea, where they become parasitic, attaching to larger fish and feeding on their blood and body fluids.
• Lifespan is around 6–8 years, with most of that time spent in the larval stage.