What can we learn about African Penguin conservation by listening to the ocean? Last month, the Seabird Conservation Programme began a new hydro-acoustic research project around African Penguin colonies on South Africa’s south coast. Through monthly surveys of fishing closures around Stony Point and Dyer Island, we are working to understand the abundance and distribution of the small pelagic fish that African Penguins rely on.
The African Penguin is now considered Critically Endangered. Over the past 10 years, the South African breeding population has almost halved. African Penguins rely largely on sardines and anchovies, which are also targeted by the commercial purse-seine fishery, creating competition for these important prey resources.
Recently implemented fishing closures around penguin colonies are intended to reduce competition for these fish, but it is important to monitor whether they are delivering the expected conservation benefits. By following predetermined transects through these areas and measuring fish abundance, we can systematically sample the same areas. This helps us to build a better understanding of the resources available to penguins and how these change around the colonies and over time.
Our surveys use a scientific echo sounder and transducer mounted on the research vessel. The instrument sends sound pulses into the water and records the echoes that return from fish and other marine organisms below the surface, such as zooplankton and jellyfish.
Returning echoes are displayed as an echogram, a computer-generated image showing the underwater environment and concentrations of organisms at different depths over time. The data can then be processed to produce estimates of the abundance, density and distribution of small pelagic fish along our survey transects.
The data collected during these surveys will contribute to a longer-term picture of local prey availability around African Penguin colonies. By combining this information with data from BirdLife South Africa’s African Penguin Monitoring Systems (APMS) and biologging projects, we can begin to understand how changes in fish abundance are reflected in penguins’ condition, foraging behaviour and the time and distance the birds need to travel to find food. Together, these projects will help us evaluate the effectiveness of fishing closures and provide scientific evidence to support the sustainable management of forage fish. Ultimately, they will contribute to our efforts to prevent the extinction of the African Penguin.
We extend our sincere thanks to Neville Isdell for funding this work and to the Dyer Island Conservation Trust (DICT) for its generous logistical support.
