Dolphins, dugong and turtles

The proposed development of the Port of Townsville is in the heart of the foraging area for Cleveland Bay’s two threatened species of dolphins, the snubfin and the Australian humpback dolphin. The population extends from near the mouth of the Ross River, north along the coast to the Black River, largely following the sea grass beds.

The 2016 Additional Environmental Impact Statement (AEIS) (Figure 8.3), shown below, provides evidence of sightings and ranges of dolphins in and around Cleveland Bay. Given the distribution and range of these threatened species, it would seem inevitable that the proposed port expansion would impinge on these locations.

The AEIS still has insufficient data on the current population size, structure and  trend. Their health is unknown. “Both species have small overall population sizes, and also have small local sub‐population sizes. A substantial decline in dolphin numbers is expected where the viability of local sub‐populations is substantially reduced.”

Neither the EIS nor the AEIS referenced the 2012 Great Barrier Reef Marine Park Authority’s 2012 publication ‘Vulnerability assessment of inshore dolphins‘. Similarly, the AEIS did not reference Isabel Beasley’s 2015 report ‘Looking for Dolphins and Dugongs in Cleveland Bay, Townsville’, which demonstrated the importance of the Bay for dugongs and both Australian Humpback and Snubfin dolphins.

The charasmatic snubby. Cleveland Bay has its own population of Snubfin dolphins, a uniquely and only quite recently discovered new species of Australian dolphin.

The proposed port expansion would threaten Cleveland Bay’s own population of the threatened Snubfin dolphin or ‘Snubby’. Check out Why is one of Australia’s few native dolphin species going extinct?

The importance of Cleveland Bay and of high water quality for dugongs was identified by the Great Barrier Reef Marine Park Authority (GBRMPA) back in 2001, where it was noted 1A-review-of-water-quality-issues-influencing-the-habitat-quality-in-dugong-protection-areas:

A rapid decline of the dugong population in the southern Great Barrier Reef over the last 10 years has raised concerns about the survival of the species in that region. Reasons for the reported decline in dugong numbers are not fully understood, however, because dugongs have very low rates of population growth any impacts such as degradation and loss of seagrass habitat and deterioration of water quality have the potential to threaten the integrity of dugong populations.

On the subject of ports, the review went on to say

A number of significant ports line the GBR coast. Access channels to many of these ports need to be regularly maintained by dredging, which leads to problems caused by increased concentrations of suspended solids and nutrients released from dredged material. Other impacts associated with ports and shipping activities result from increased levels of petroleum hydrocarbons and anti-fouling residues in coastal waters and significant amount of ship-borne litter.

The review identified Cleveland Bay, a Category A Dugong Protection Area, as at moderate risk of activities on adjacent catchments having  adverse effects on habitat quality to occur in DPAs.

The Reef 2050 long-term sustainability plan, prepared by the Australian government for UNESCO’s World Heritage Committee identified (at BA12) the critical need to protect habitat for coastal dolphins.

Regardless, the AEIS assumes no impact on these species, despite the ongoing weakness of the seagrass beds, the loss of 152 ha of habitat to reclamation, and the turbidity that is invariably associated with dredging.

Given the location of the port in the heart of the prime habitat, why isn’t the Port funding studies to understand these species better, and in particular to understand why they are there? Without a better understanding it is not possible to predict what will happen when the habitat is lost and how these dolphins will be affected by contaminants stirred up during the proposed dredging and reclamation.

What are the current impacts on the dolphin population of heavy metals, noise and ship movements?

According to the Additional Environmental Impact Statement for the proposed expansion (AEIS, 8.2.6), “An additional review” of existing information was carried out [which] suggests … Cockle Bay is a significant foraging habitat for turtles, particularly green turtles… The majority of turtles captured …[were]… found to be using the intertidal seagrass and algal flats found within Cockle Bay. Cockle Bay would be classified as supporting a regionally significant population of foraging green turtles. It is therefore important that dredging does not result in modifications to the availability of food resources for turtles, particularly given the recent local population declines due to successive wet weather years.

Cockle Bay, on the south-west tip of Magnetic Island, is particularly affected by sediment from the channel, receiving the plume of water that the south‐easterlies and the flood tides push into the Bay, and then out between Magnetic Island and the mainland. Cockle Bay will be particularly impacted should the project go ahead “coming on top of the recent local population declines”.

The AEIS contains no significant information on dugongs despite the historic significance of the population up until shark netting began. Population studies and monitoring are essential due to the likely impact that the Port is already having on the local population.

Finally, boat strikes are a significant cause of death for both turtles and dugongs. Increased shipping associated with an expanded port can only increase this mortality.

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