The amazing wildlife of the Hauraki Gulf
Cat Lea is the Marine Research and Conservation Officer at Auckland Whale & Dolphin Safari which operates a tourism business in the Hauraki Gulf. One of her main responsibilities is to look after the research that they undertake on a daily basis. She’s well poised to see not only the incredible wildlife that’s in the gulf but also the threats that it faces.
What do AWADS do
Auckland Whale & Dolphin Safari’s mission statement is “The preservation of the marine environment through research, education and awareness”.
Whilst we are obviously a commercial tourism business, we also value the importance of marine research. Besides the local ferries, we are quite possibly the only commercial vessel in Auckland that goes out into the Hauraki Gulf Marine Park on a daily basis. Therefore, we have a huge opportunity to collect data that otherwise could not be collected. Doing this on a regular basis for 18 years has built up some long-term datasets which are incredibly valuable when looking to detect changes in the marine environment over a longer time-scale.
We are now also starting to collect data on other aspects of the marine environment as it is important to understand how changes in one area of the ecosystem, may affect another. One of the latest things we are started to collect data on is phytoplankton levels by way of using a secchi disc and this data is fed into a global database.
We incorporate this data collection into our passengers’ experience so not only do they get to observe the incredible wildlife of the Hauraki Gulf, they also have the opportunity to have a interactive learning experience whilst on board and therefore, an increased awareness of the importance of looking after the marine ecosystem.
Details on the amazing wildlife and their threats
The Hauraki Gulf Marine Park is considered to be a highly biologically productive area and thus plays host to a diverse array of marine life – from plankton, to fish and sharks through to seabirds and marine mammals and other megafauna such as turtles and rays.
Over 22 species of marine mammal have been seen at one time or another in the Hauraki Gulf Marine Park and we are so lucky to regularly see 3 species of cetacean (whale and dolphin) as well as 1 species of pinniped on our safaris.
Three of the commonly seen cetaceans are dolphins – common dolphins, bottlenose dolphins and orca/killer whales. Common dolphins are seen year-round and whilst they are normally known as an oceanic species, they come into the shallower more coastal waters of the Gulf mostly likely due to the abundance of food as well the area providing some form of safety for young calves.
Bottlenose and orca can be seen passing along our coastlines throughout the year but as coastal animals, are put under increased pressure from human activity including interactions with vessels (e.g. boat strike) and fishing gear entanglement. Bottlenose are considered to be Nationally Endangered whilst orca are Nationally Critical under the New Zealand Threat Classification System.
The largest of the four cetaceans, the Bryde’s whales is Nationally Critical and considered to be a resident here and this in itself is incredibly rare. Most large whale species are migratory or found in deep water but the Bryde’s whale can be found in shallower water and year round! There’s only a handful of places in the world where this occurs so we are incredibly lucky to have them in Auckland’s backyard. These guys are susceptible to ship strike as they are shallow divers and spend around 73% of their time in the top 8.5m of the water column (which is the average draft depth of large ships). The Hauraki Gulf Transit Protocol was established to tackle this problem and since its creation in 2013, there has not been any confirmed deaths by ship-strike.
However, it is not just the physical things that we can easily see which can have an impact upon our cetaceans (and other wildlife). Toxins, chemicals and pollutants enter into the ocean from the land, travel up the food chain and bioaccumulate as well as biomagnify in cetaceans. Negative consequences of this such as impacting reproductive ability and the immune system have been demonstrated in cetacean populations all over the world. One example of these impacts is that these pollutants are stored in different areas of the body including the blubber (fat) layer. A mother whale or dolphin uses their blubber layer to produce milk for their offspring and so these pollutants are passed onto the offspring as well. Scientific studies in New Zealand have shown that our marine mammals also have pollutants in their bodies.
Wider concerns for the Hauraki Gulf
There are several concerns we have for the future of the Hauraki Gulf Marine Park. It is surrounded by Auckland to the west, Waikato/Hauraki Plains to the South and the Coromandel to the East thus the coastal anthropogenic impacts are flowing into the Gulf from 3 sides!
On a local level, the amount of sediment and chemicals (e.g. pesticides) that are entering into the area from our freshwater and estuarine waterways is reportedly impacting upon our intertidal zones and coastlines. Cleanliness of the ocean is vital for supporting the entire marine food chain. The Hauraki Gulf is a temperate environment with high levels of primary production due to phytoplankton found in upper portion of the water column. Without clean and clear water, phytoplankton (plant plankton) cannot photosynthesise and thus cannot survive thus the food chain collapses – meaning no fish, no birds, no marine mammals.
The impact on our fish populations are also cause for concern. We have already seen in the reports that crayfish and snapper populations have declined dramatically over the years. Whilst the decline of these species may not affect the marine mammals directly, they do feed on small fish and there are currently no stock assessments for these species such as pilchards. Our concern is that if there are no stock assessments, no-one has any idea of how these species are performing out there and thus our marine mammals could be affected at some point in the future not only due to the potential of overfishing but also because these species rely on phyto- and zooplankton as their food source.
On a larger scale, global warming including sea surface temperatures are a cause for concern. Plankton grows well in cool water and is not such a fan of warm water, therefore if the water temperature becomes too warm, the food chain starts to disappear. It is concerning that if the Hauraki Gulf water temperatures increase and continue to increase, there may be permanent changes to the occurrence and distribution of marine species.
Why are you supporting the Sea Change campaign?
We are ambassadors for the Hauraki Gulf. Every stakeholder and user of the Hauraki Gulf has a responsibility to look after it so that we and our future generations can all continue to use and enjoy this incredible resource.
What are your hopes for the future of the Gulf?
We hope that the Sea Change plan will receive sufficient support to be implemented by the Government so that some effective management decisions can be put in to place. We hope that everyone using the Gulf will take responsibility for the abundance of marine life left before it really is too late.
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Add your voice to the campaign. Tell the NZ Government to put the Sea Change plan into action as a package and without delay at www.forestandbird.org.nz/seachange.
