A new study highlights the unevenness of our knowledge of ocean biodiversity. Despite decades of ocean exploration, basic answers to one of the most fundamental ecological questions is still lacking: where is marine life found, and why?

Biodiversity data underpin everything from habitat protection to climate impact modelling. The current data gaps mean that scientific models and management plans risk being skewed, trained on better-known regions and taxa while overlooking some of the most threatened and least studied parts of the planet.

By systematically processing nearly 19 million records from the Ocean Biodiversity Information System (OBIS), the study reveals that global marine biodiversity data from below 30m are heavily biased—towards:

• Shallow waters (50% of benthic records come from just the shallowest 1% of the seafloor)
• The Northern Hemisphere (over 75% of records)
• Vertebrates, namely fish

Dr Bridges, lead author on the study, commented: 

“Our findings show just how uneven our knowledge of ocean life really is, and that has major implications for how we protect it. If we want to manage the ocean sustainably, we first need to understand where life exists, and right now, we’re working with an incomplete map.”

Prof Howell, senior author on the paper and Deep Sea Ecologist at Plymouth Marine Laboratory, added: 

“This research will now help guide the work being done under the UN Ocean Decade Challenger 150 Programme, a global cooperative of deep-sea scientists whose aim is to map life in the deep ocean to support sustainable management. We now know where the gaps are and can focus our efforts on filling them. It’s a first step toward building a more balanced, global understanding of marine biodiversity.”