In this edition we would like to explore the impact of the REP on marine life on Lord Howe Island.
Safety of the marine environment is a very important component of the REP. There have been more than 490 species of fish recorded in the region and 433 species of fish documented in near shore coastal habitats.
Of the inshore fish species, the majority are wide ranging tropical forms, while some 10% are found only at Lord Howe Island, southern Australia and/or New Zealand.
Approximately 4% (15 species) of the shore fishes are endemic to the Lord Howe region (including Norfolk Island) and 32% are restricted to the south-western or southern Pacific Ocean.
A fish behaviour study was carried out on Lord Howe, June 2017, aimed to understand which fish may be present at the affected sites and how they may respond to pellet drops during the REP. Only 1.5% of the fish swallowed the bait, and these were only found at human feeding areas, where there be no aerial baiting – only hand/station baiting.
The fish study was carried out by Professor David Booth and Gigilia Berett, University of Technology Sydney, UTS Fish Ecology Lab where species potential vulnerability to bait pellets was studied by dropping placebo bait pellets (nontoxic 10mm Pellets to mimic Pestoff Rodent Bait 20R) observing fish behaviour (Ignore, Approach, Mouth, Swallow).
Pellets were delivered from several centimetres above the water surface and rapidly sunk to the bottom.
Fish at each site were surveyed via 50m x 2 m belt transects parallel to shore, in 1-3 m of water on rocky/coral reef.
Overall, 392 individual fish were observed, 73% of the fish did not touch the bait (with 37% of fish ignoring it completely, 25% mouthed the bait then rejected. Pellet swallowing was extremely rare across the study, 1.5% of all observations by Surge wrasse Thalassoma purpureum, Spangled Emperor, Lethrinus nebulosus and Luculentus wrasse Pseudolabrus luculentus.
These were only at the human feeding sites (Ned’s beach and North Bay), where hand baiting will be carried out.
The Human Health Risk Assessment overseen by the NSW Chief Scientist looked at the potential for human exposure from fish and concluded that the transfer of brodifacoum to seafood would not expect to present a risk to residents and visitors – so in short, YES, you can eat fish.
The majority of studies which analysed brodifacoum concentrations in fish tissue 1 day to 45 days following aerial application of baits, were not detected above the laboratory limit of detection (0.0005 to 0.001 mg/kg). Where brodifacoum has been detected in fish, it has been found in liver and gut and not in edible portions of the fish, with concentrations ranging between 0.002 and 0.315 mg/kg and these concentrations reduced to below laboratory detection limits 5 to 32 days following the first aerial application of baits.
How do we know it will be minimal?
Firstly the application rate of Brodifacoum for the LHI REP is a low-moderate amount at 0.4 g brodifacoum/ ha combined in the two applications.
Secondly The Lagoon Sanctuary Zone will not be impacted due to the 50m zone offset from the shore, with the lagoon, Ned’s beach and North Bay being baited by hand or bait station
Thirdly the pilots and Ann De Schutter (GIS expert) will reduce the likelihood of the bait falling into the sea due to their expertise and experience of aerial baiting including use of a spreader bucket with a deflector arm and baiting being carried out in the correct weather conditions.
Fourthly: From previous data from many successful operations – the marine environment remained safe:
Kapiti Island, New Zealand
Anapaca Island, California, USA
Ulva Island, near Stewart Island, NZ.
Little Barrier Island, Hauraki Gulf, NZ.
Rangitoto and Motutapu Islands, NZ.
Shakespear Open Sanctuary, Auckland.
Taranga Island, near Whangarei , Northland, NZ
Minimal impact is seen even when marine life is exposed to very high doses – In 2001 a truck crashed into the sea at Kaikoura (NZ) spilling 18 tonne of Pestoff 20R (20 mg/kg Brodifacoum) cereal pellets into the water. The only sign of measurable residues was found in mussels and paua taken from the immediate location.
Seabird Recovery Project Nominated – Conservation Success of the Year
Prior to arriving on Lord Howe in November as Assistant Project Manager, Jaclyn Pearson managed the successful ‘Isles of Scilly Seabird Recovery Project’ and the project has been nominated as ‘Conservation Success of the Year’ in the UK for BBC Countryfile Magazine Awards 2018.
We hope for similar accolades with this project! You can find out more here: