Earlier this year I published a book called Ecology of Urban Environments. It’s a text book for university students, but it contains lots of great stories about urban nature that I’d like to share with everyone! So I’m starting a series of blog posts – Urban Ecology Stories.
The spotted handfish – a fish that walks!
The spotted handfish (Brachionichthys hirsutus) is a fabulous fish from the Derwent River estuary in Tasmania, Australia. It’s called a handfish because it ‘walks’ slowly along the seabed using its pectoral and pelvic fins, which look like human hands. The spotted handfish is listed as critically endangered by the Commonwealth of Australia and the International Union for the Conservation of Nature (IUCN).
Why is the spotted handfish endangered?
Populations of the spotted handfish have declined since the northern Pacific seastar (Asterias amurensis) was introduced to the Derwent River estuary in the 1980s. This seastar is a voracious predator! It eats the stalked sea squirts (ascidians) that the female handfish use as handy places to attach their egg masses, and it may even eat the eggs themselves. Poor water quality in the estuary is also a problem for the spotted handfish.
What’s urban about this story?
The two main threats to this species – an introduced predator and poor water quality – are both the result of urbanization; that is, the construction of the city of Hobart on the estuary that the fish calls home. We often think about the impacts of urbanization on terrestrial environments (land), but it also has many important impacts on marine and freshwater environments (oceans, estuaries, streams and lakes). Ships visiting from distant international ports bring non-native marine species on their hulls or in their ballast water. Rivers that flow through urban areas bring silt, rubbish, heavy metals, pesticides, nutrients and other pollutants into estuaries and out to sea. We can work together to address these problems in cities around the world.
Barrett, N. (2013) Australian endangered species: Spotted Handfish. The Conversation July 4, 2013.
Coughanowr, C. and Whitehead, J. (2013) The Derwent Estuary Program: A collaborative model for science-based management, Tasmania, Australia. Ocean & Coastal Management 86, 110–118.
Parris, K.M. (2016) Ecology of Urban Environments (Wiley-Blackwell, Oxford), Chapter 3.