Remote sensing of marine mammals

How do remote sensing technologies help to improve methods of monitoring marine mammal populations?

Marine mammals are impacted directly and indirectly by commercial fishing, water pollution and climate change. These mammals play an important role in the marine food chain as predators and prey and without effective conservation efforts, loss of biodiversity in their ecosystem can have substantial consequences. Surveying efforts can contribute to the conservation of marine mammals by improving knowledge of their distribution, abundance, density, and population trends. Automation of marine mammal monitoring can increase the cost-efficiency of satellite images and remote sensing techniques in terms of time, coverage, and accessibility 

 Human population growth and unsustainable production and consumption systems are a threat to Earth’s other species. However, changes and disturbances in ecosystems because of a loss of biodiversity can have environmental, social and economic impacts. Species interact to maintain the natural balance of their ecosystems, and healthy ecosystems provide clean air and water, and food sources for humans and animals. For instance, marine mammals are impacted directly and indirectly by commercial fishing, water pollution and climate change. These mammals play an important role in the marine food chain as predators and prey and without effective conservation efforts, loss of biodiversity in their ecosystem can have substantial consequences.   

 Surveying efforts can contribute to the conservation of marine mammals by improving knowledge of their distribution, abundance, density, and population trends.  

Surveys are conducted from land, aircraft, ships, satellite and unoccupied aerial systems, a type of remote sensing. These involve direct human observation or data collection through computer systems. The method is selected considering the type of marine mammal, research needs, cost-effectiveness, safety, weather conditions and regulations. Each method has its own advantages and disadvantages.  

The presence of humans during ground, aerial and vessel platforms surveys can influence animals’ behaviour and can be unsafe for researchers, costly, time-consuming, and unsuitable for some types of marine mammals. Satellites and remote sensing technologies have wider geographic coverage, can be used for different types of marine mammals, and provide photos and videos for analysis. However, in some instances, the systems can be expensive, may not be allowed due to government regulations and. some remote sensing devices can produce noises that may be heard by animals, disrupting their behaviour.   

 Automation of marine mammal monitoring can increase the cost-efficiency of satellite images and remote sensing in terms of time, coverage and accessibility. Automated analysis is divided into methods that classify individual pixels into animal or background classes, and object-based methods that classify groups of similar pixels into different classes. These methods are more accurate when using computing systems used to analyse visual imagery than when only relying on statistical differences.   

Adapted from: Rodofili, E. N., Lecours, V., & LaRue, M. (2022). Remote sensing techniques for automated marine mammals detection: a review of methods and current challenges. PeerJ, 10, e13540.

Read the original article .

Questions for students: 

1. Identify factors that have led to a loss of marine biodiversity. 
2. Describe the economic and social reasons for preserving species. 
3. Identify issues impacting marine ecosystems. 
4. Explain the role a remote sensing technology plays in conservation efforts for marine systems.  

Key words for students to understand: 

• Conservation 
• Biodiversity 
• Ecosystem 
• Distribution 
• Abundance 
• Density 
• Automation 
• Remote sensing 
• Production 
• Consumption 
• Environmental 
• Social 
• Economic 
• Observation 
• Regulation