seagrass in CTB

when and how to report boating IRREGULARITIES at ctb

This page has been written with the aim of sharing the best practice amid the frequent discussions and questions raised on social media by the underwater users of Cabbage Tree Bay, I hope you will find it useful. For comments, edit requests, improvements please contact Marco Bordieri at vizgroupsydney@gmail.com. Last update: 24/9/2024.

What we know

1. Boats are allowed to anchor at CTB.

2. Boaters are expected to pay attention to avoid dropping the anchor and the sweeping chain over the paddle weed seagrass patches which are a source of food for the sea turtles in the bay. It's reasonably hard for a boater to realise whether the anchor will hit the seagrass, limited underwater visibility may not allow it or the captain of the boat may not have a line of sight from the bridge.

3. To help with 2., Transport NSW released a "Fact sheet" in December 2021 where the following indication has been added: "Always check your depth before anchoring and only anchor in water deeper than eight metres. Boating is restricted to waters greater than eight metres (8m) deep to reduce impacts on seagrasses." This was based on the empiric assumption that the paddle weed seagrass is not present at depths greater than 8 m.

4. To amplify awareness among the boaters, in March 2024 VIZ promoted a petition to the boating maps companies to add the 8 m. guideline in the CTB map. Navionics and Zulu waterways amended their maps accordingly, C-Map did not respond (update 5/10/24: they have come back now saying they agree to add a note to the map, it will be visible at the next release).

5. In April 2024 Marco Bordieri (VIZ) did a survey to identify the location of the paddle weed seagrass also in relation to the 8 m. bathymetry lines (low tide and high tide), see below. What the survey revealed is that the seagrass happens to be at depths below 8 m. only in low tide and up to 9.5 m. in high tide, so even respecting the 8 m. guideline does not guarantee total protection of the seagrass.

6. In January 2025 DPI updated the previous Fact Sheet with this one which includes boating guidelines and a map of the 8 m. depth line

What we can do if we suspect a boat is anchored over seagrass

7. Assess the actual situation by snorkeling over the anchor. Photos taken from land and discussed over social media cannot establish whether the anchor is on the seagrass. The fact that the boat is anchored in less than 8 m. of water does not prove seagrass has been damaged as there's plenty of sandy bottom in less than 8 meters. (see image below). Calling authorities over an unverified violation may even become a disadvantage if it turns out no seagrass had actually being damaged (the authorities may not be coming to check if most of the reports are unsubstantiated).

8. If the anchor or chain are on the seagrass: take a single uninterrupted video showing the damage and the registration of the boat. Also, kindly notify the boaters (remember they are likely unaware).

9. Notify the authorities (do both please): 

   1. call NSW Maritime at 131 236, 8:30 am - 5:30 pm (4:30  pm on weekends). Alternately, you can report online here, but note that you cannot attach a video file to the report (photos only). Reporting is important as it gives NSW Maritime the pulse of the situation so they can gauge if there is a need for further intervention.

   2. Report fishing or damage to aquatic habitats including seagrasses to Fisheries using the Fishers Watch phoneline on 1800 043 536 or online via www.dpi.nsw.gov.au/report-illegal-activity. The online reporting form allows upload of photos/videos up to 30mb.
      
      

Other boating breaches (distance from swimmers, snorkelers or dive flags)

10. Powered vessels – including sailing boats over 5.5m long and personal watercraft (PWC) – must keep a minimum distance of 60m from: people in the water, including swimming and surfing areas, a dive flag or float. Take extra care when you're within 200m of divers and spearfishers – they can be up to 100m from their float or flag. Please note: vessels must display the "alpha" flag when associated divers are in the water, when diving from shore it is "recommended" to display a dive flag in the diving area.  

11. In the above cases notify as indicated at point 8

Other events and reporting channels:

1. Illegal or suspect fishing, collecting or damage to aquatic habitats to Fishers Watch 1800 043 536 or online www.dpi.nsw.gov.au/report-illegal-activity

2. Water pollution or fish kills to the Environment Line 131 555

3. Suspected aquatic pests or diseases to the Emergency Animal Disease (EAD) Hotline: 1800 675 888 or email aquatic.biosecurity@dpi.nsw.gov.au

4. Injured, sick or entangled marine mammals, reptiles, penguins and other seabirds to National Parks and Wildlife on 1300 072 757. This includes those accidentally struck by a vessel. Find more information www.environment.nsw.gov.au/topics/animals-and-plants/native-animals/sick-or-injured-animals 

5. Sightings of aquatic threatened species:

a. grey nurse shark, black rockcod, White’s seahorse, cauliflower soft coral, great or scalloped hammerhead sharks online www.dpi.nsw.gov.au/report-it

b. marine mammals (e.g. Australian humpback dolphin and southern right whales) and marine reptiles (e.g. loggerhead and
leatherback turtles and identified sea snake species) to  www.environment.nsw.gov.au/atlaspublicapp/ui_modules/atlas_/atlassearch.aspx