Evaluating the effectiveness of drones for quantifying invasive upside-down jellyfish (Cassiopea sp.) in Lake Macquarie, Australia.

Upside-down jellyfish (Cassiopea sp.) are mostly sedentary, benthic jellyfish that have invaded estuarine ecosystems around the world. Monitoring the spread of this invasive jellyfish must contend with high spatial and temporal variability in abundance of individuals, especially around their invasion front. Here, we evaluated the utility of drones to survey invasive Cassiopea in a coastal lake on the east coast of Australia. To assess the efficacy of a drone-based methodology, we compared the densities and counts of Cassiopea from drone observations to conventional boat-based observations and evaluated cost and time efficiency of these methods. We showed that there was no significant difference in Cassiopea density measured by drones compared to boat-based methods along the same transects. However, abundance estimates of Cassiopea derived from scaling-up transect densities were over-inflated by 319% for drones and 178% for boats, compared to drone-based counts of the whole site. Although conventional boat-based survey techniques were cost-efficient in the short-term, we recommend doing whole-of-site counts using drones. This is because it provides a time-saving and precise technique for long-term monitoring of the spatio-temporally dynamic invasion front of Cassiopea in coastal lakes and other sheltered marine habitats with relatively clear water.

A new species of Paraproto (Crustacea: Amphipoda) from southern New SouthWales, Australia.

A new species of the caprellid genus Paraproto, P. murrayae n. sp. is described based on specimens collected from New South Wales, Australia. The new species was collected from brown algae in shallow water (16-19 m deep). Paraproto murrayae n. sp. is very similar to P. tasmaniensis Guerra-García Takeuchi, 2004 but can be distinguished mainly by the following characteristics: (1) adults of P. murrayae are significantly smaller than P. tasmaniensis (5-6 mm and 10-11 mm respectively); (2) in larger males of P. tasmaniensis, gnathopod 2 is inserted on the anterior half of pereonite 2, rather than the posterior half as in P. murrayae; (3) the dactylus of the male gnathopod 2 is thickened medially in P. murrayae, but not thickened in P. tasmaniensis; (4) the setal formula of mandibular palp is 1-3-1 in P. murrayae versus 1-9-1 or 1-10-1 in P. tasmaniensis; (5) the lower lip is glabrous in P. murrayae but strongly setose in P. tasmaniensis; and (6) the anterolateral projections on pereonite 2 are lacking or vestigial in males of P. murrayae rather than distinct as in P. tasmaniensis. An illustrated key to the species of Paraproto is provided.