This blog summarises the research work conducted on the ecology and biology of the endemic Australian fish weedy seadragon Phyllopteryx taeniolatus from 2001 to 2009. The research was conducted by Jaime Sanchez-Camara and photos were taken by Juan Fritschi, both marine biologists of the Spanish company Aquadec Aquariums S.L. Work was supervised by Prof. David J. Booth and Prof. Xavier Turon
Phyllopteryx taeniolatus Lacépède is the only member of the genus Phyllopteryx (Family Syngnathidae) and, along with the leafy seadragon Phycodurus eques Günther, are the only representatives of what are commonly known as seadragons. The family Syngnathidae, which also includes seahorses, pipefishes and pipehorses, is unique among fishes with males incubating the eggs deposited by the female in a specialised incubation area or brood pouch on either the tail or the trunk of the male (Herald, 1959). The weedy seadragon is distributed from Port Stephens, New South Wales, on Australia’s eastern coast to Geraldton, Western Australia, on Australia’s western coast, including the waters around Tasmania (Hutchins & Swainston, 1986). They live among the larger algae on exposed reefs and feed mainly on mysid crustaceans (Edgar 2000).
Phyllopteryx taeniolatus is listed as Lower Risk (conservation dependent) by the Department of Environment and Water Resources of Australia (Pogonoski et al., 2002) and as Near Threatened by the IUCN Red List of Threatened species (Connolly, 2006) . Weedy seadragons are protected under the Commonwealth's Environmental Protection and Biodiversity Conservation (EPBC) Act (1999). Additionally, particular protection laws have been deployed in the different Australian states where seadragons are present (Connolly 2006). For instance, the weedy seadragon is fully protected in New South Wales, Australia, under the Fisheries Management Act 1994, considered Protected Aquatic Biota in Victoria and The Tasmanian Living Marine Resources Management Act 1995 prohibits the capture of all syngnathids in Tasmania. However, protection came before knowledge; at the beginning of this Thesis, in 2001, P. taeniolatus was listed by The World Conservation Union (IUCN) as “Data Deficient" meaning that insufficient information was available to make an assessment of the species’ risk of extinction.
The lack of scientific studies on this species is surprising if we consider that P. taeniolatus is a vulnerable, endemic and charismatic fish. For instance, in the state of Victoria, P. taeniolatus is the official marine state emblem, selected by public nomination. This particular nature, added to its extraordinary beauty make P. taeniolatus an iconic and an extraordinary flagship species in marine conservation.
The two main reasons why we started this project in 2001 were; (1) add knowledge to a poorly-known emblematic, vulnerable and endemic fish species, (2) the firm conviction that a better knowledge of P. taeniolatus was necessary for proper management of this flagship fish. Our first aim was to determine, using a non-destructive method of in situ monitoring, the movement patterns and home ranges of weedy seadragons and to record evidence of their site fidelity. A second aim of this study was to provide specific information on the reproductive cycle and growth of the weedy seadragon in their natural environment. We were interested in determining the duration of the breeding and the recruitment period, the number of pregnancies per season, the duration of pregnancies and intervals and the size and age of first maturity. We wanted to determine growth and average and maximum sizes.A third goal was to measure abundance, sex ratios and distribution of weedy seadragons at different locations. We also aimed to determine the habitat and behaviour of weedy seadragons. Our last aim was to provide population dynamics parameters and to determine latitudinal and temporal trends of this protected and potentially threatened fish.
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