Life History Characteristics of Coexisting Platycephalidae

More than 65 species of Platycephalidae, commonly known as flathead, are found primarily in the Pacific and Indian Oceans although some species inhabit the Atlantic Ocean and Mediterranean Sea. Generally flathead are bottom dwellers occurring on soft substrates such as mud, sand and seagrasses across a variety of habitats, ranging from shallow estuaries to deep sea environments. Along the south eastern Australian coastline five species of Platycephalidae; Platycephalus caeruleopunctatus, P. longispinis, P. richardsoni, Ambiserrula jugosa and Ratabulus diversidens coexist within inner-continental shelf habitats. Of these species P. caeruleopunctatus, P. richardsoni and R. diversidens are commercially and recreationally harvested while P. longispinis and A. jugosa are caught and discarded as by-catch. Despite this anthropogenic exploitation, with the exception of P. richardsoni little is known about the biology and ecology of these species.

The objectives of this study were to develop a greater biological understanding these species to examine the species specific characteristics that enable these species to coexist and to provide biological information on which fisheries management decisions can be based. Specifically we examined the age, growth and reproductive characteristics of these Platycephalidae species at two locations along the coastline of south eastern Australia. Results reveal that variability in the age, growth and reproductive characteristics of each species likely facilitate how these closely related species coexist. Implications of these characteristics for fisheries management purposes will be discussed.