Deep-ocean twilight zone fishing impacts ecosystem carbon regulation

Biologists at the Woods Hole Oceanographic Institution have identified significant knowledge gaps regarding industrial fishing in the ocean’s twilight zone, the mesopelagic layer located 200 to 1,000 meters below the surface.

Research published in Global Change Biology suggests that large deep-water fishes, such as opahs, snake mackerels, and lancetfish, have been increasingly susceptible to capture through various fishing tactics. The authors refer to these species as the ‘dark web’ due to their critical but poorly understood role in marine food webs and their ability to help regulate and store carbon.

Because most midwater species are not subject to mandatory catch reporting, the full extent of the impact on the carbon cycle and marine ecosystems remains unknown. Scientists emphasize an urgent need for better data to understand how these fishing practices affect the deep ocean's ecological functions.