Acoustics Finds New Purpose: Quantifying Marine Life Abundance through Innovative Techniques

Researchers have found that hydroacoustics, a method using sound waves to survey marine life, could be a faster and less expensive alternative for assessing fish populations in marine protected areas (MPAs). The study, titled "Hydroacoustics as a tool to examine the effects of Marine Protected Areas and habitat type on marine fish communities," was published in the journal Scientific Reports on January 15.

The international team of researchers, led by Jack Egerton from the University of California San Diego, used hydroacoustic equipment mounted on boats to survey the waters of Cabo Pulmo National Park. They scanned the water column in rows, providing valuable data on fish abundance within and outside the MPA.

Cabo Pulmo National Park, a site of several Scripps researchers' studies since 2002, has been identified as the most successful MPA in the world in terms of maintaining a sustainable fishery. The study found that the abundance of fishes was four times greater in the park compared to areas outside.

Animal abundance in reefs was as much as 50 times higher inside the MPA compared to outside, highlighting the importance of both habitat complexity and protection from fishing for fish populations. Fish density, total biomass, and the size of individuals were significantly greater inside the MPA compared to waters outside.

The study's co-authors include Scripps postdoctoral scholar Andrew Johnson, researchers from Bangor University, and researchers from the Centro para la Bioversidad Marina y la Conservación in La Paz, Mexico. They concluded that hydroacoustics could be a more cost-effective method for assessing fish populations, potentially reducing the costs for governments in ocean conservation.

Octavio Aburto, a marine ecologist at Scripps and co-author of the study, stated that the results demonstrate the potential for using acoustic technologies to generate information about marine resources inside MPAs. He added that it is novel to use hydroacoustics to assess the effectiveness of marine protected areas.

The research was funded by the National Science Foundation, the Baja Coastal Institute, the International Community Foundation, David and Lucile Packard Foundation, and The Helmsley Charitable Trust. The study's findings could potentially revolutionise the way fish populations are monitored within MPAs, offering a more affordable and efficient solution.

In conclusion, the study "Hydroacoustics as a tool to examine the effects of Marine Protected Areas and habitat type on marine fish communities," published in Scientific Reports, provides compelling evidence that hydroacoustics could be a valuable tool for assessing fish populations within MPAs. The Cabo Pulmo National Park, in particular, appears to be of significant importance for fish populations in the area.