Predicting the future to reduce shark bycatch
by NOAA Fisheries 15 Aug 18:31 UTC
Shortfin mako shark swimming near the ocean surface © NOAA Fisheries
Many people would like to be able to predict where sharks are found in the ocean. From fishermen and shark enthusiasts to scientists and fishery managers working to reduce bycatch and keep fisheries sustainable, we need reliable ways to locate sharks.
Sharks choose their habitats based on a combination of biological and environmental conditions like water temperature, oxygen levels, food availability, salinity, and ocean currents.
Additionally, as climate change influences the migratory patterns of shark species, we need more tools to predict the likely movement of sharks in shifting environmental conditions. These tools can also be used to assist in understanding shark populations as well as assessing the impacts of offshore energy production on fishing.
NOAA Fisheries is developing and using these modeling tools to help reduce bycatch and predict the effects of climate change on sharks. One tool created by the Atlantic Highly Migratory Species Management Division is called the Predictive Spatial Modeling Tool (PRiSM).
PRiSM combines observer and environmental data to predict fishery and species-specific interactions. For example, the map below shows where shortfin mako sharks are likely to interact with the pelagic longline fishery in August. Areas in yellow and orange on the heat map show where interactions are more likely to occur. Areas in purple are where interactions are less likely to occur. Fishermen could use this information to avoid yellow and orange areas and reduce bycatch of shortfin mako sharks.
In another example, this map shows where dusky sharks are likely to interact with the bottom longline fishery during December. Managers can use this information by shifting closed areas to help conserve shark populations and keep fishery operations sustainable.
While some level of bycatch is inherent in fishing operations, NOAA Fisheries continues to find new and innovative scientific approaches to reduce bycatch in support of sustainably managing fisheries and recovering and conserving protected species.