Rockfish Recompression Research

 

 

Temporary Moorings attached to VR2W acoustic receivers

Southwest Fisheries Science Center researcher John Hyde with acoustic receivers used to monitor tagged fish survival and behavior

For decades, fishery managers have been faced with the problem of maintaining access to viable fish stocks while avoiding excess bycatch mortality on overfished species. For species such as rockfish (Sebastes spp.) it has long been assumed that fish captured from great depths were incapable of being released due to their high incidence of barotrauma injury. Created by the change of pressure from being caught at great depths and brought rapidly to the surface, barotrauma is a common issue with rockfish that often leads to death of discarded fish as they are unable to swim back down due to their excessive buoyancy and eventually succumb to their injuries, exposure and predation. Over the years, this has become increasingly problematic as several species of rockfish have become overfished and management to protect these species has resulted in large area or depth-based closures, leading to dramatic limitations on both recreational and commercial fishing opportunities along the West Coast. “Putting Rockfish Back Where They Belong”,The previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries Disclaimer published by Science Magazine in early November, discusses encouraging research findings regarding the use of recompression devices to release rockfish suffering from barotrauma injury. 

 

Encouraged by earlier work by other researchers that suggested in-situ recompression showed promise for releasing some species of rockfish captured from intermediate depths, Fisheries Resources Division researchers, John Hyde, Nick Wegner and Alena Pribyl , have begun studies focused on the post-release survival of several species of management concern caught at greater depths. The early results of this research were recently discussed at the Pacific Fishery Management Council's November meeting. The Council’s Scientific and Statistical Committee discussed the prospect of reducing mortality rates of certain heavily impacted rockfish species while maintaining fishery access by incorporating the use of descending devices into recreational groundfish management. While preliminary results for species of management concern (i.e. cowcod) are promising it was requested that additional research be conducted to better determine species-specific mortality rates.  
  

Boccaccio with barotrauma

 Bocaccio with injury (everted stomach) caused by

rapid ascent to the surface. The fish is equipped

with an acoustic tag to to monitor post-release

survival and behavior

Boccaccio before recompression 

In recompresion cage just below surface

  

 

 

Boccaccio after recompression 

Recompressed in cage at 42m

 

 

 

    

Visit our Barotrauma page for more information, videos and websites to get your own recompression device.

Learn more about the Fish Ecology group