Southern California Shelf Rockfish Hook and Line Survey
The Hook and Line Survey uses rod and reel gear to sample fish in areas that are difficult to survey using traditional research trawl nets.
The Hook and Line Survey uses rod and reel gear to sample fish in areas that are difficult to survey using traditional research trawl nets. These areas include hard seafloor habitats like rocky reefs, boulder fields, and large undersea cliffs and pinnacles.
Our West Coast Groundfish Bottom Trawl Survey targets commercially valuable groundfish species over low relief, or flat, habitats that are easy to trawl. However, we lose vital information on population biology, recruitment, and movement if we also don't sample untrawlable habitats.
We developed the Hook and Line Survey in response to declining rockfish stocks in the Southern California Bight. We sample many rockfish species including:
- Bocaccio (Sebastes paucispinis)
- Cowcod (S. levis)
- Greenspotted rockfish (S. chlorostictus)
- Vermilion/sunset rockfish complex (S. miniatus and S. crocotulus)
We work collaboratively with the local sportfishing industry onboard commercial passenger fishing vessels. Together, we sample approximately 200 fixed sites each year. Our survey biologists collect information about the abundance, biology, ecology, and genetics of species that are important to both the sport and commercial fishing industries.
Stock assessors combine this survey information with data from many other sources to produce a stock assessment. This single document summarizes all we know about the health and biology of a particular population. Fishery managers use stock assessments to inform management decisions and help set sustainable catch quotas and size regulations for harvested marine species.
As of 2019, data from the Hook and Line Survey have been incorporated into 14 stock assessments representing eight species, and will likely be included in several additional assessments in 2021.
Data from fisheries surveys have been instrumental in tracking the groundfish rebuilding. These data have led to several species removals from the overfished list. Continued long-term monitoring of these species is essential as many previously overfished groundfishes like bocaccio, lingcod, and cowcod are still recovering and vulnerable. Cowcod, a large and long-lived rockfish species, were declared overfished in 1999 and were declared rebuilt in 2019, supported in part by findings from the Hook and Line Survey.
The Hook and Line Survey began in 2003, sampling commercially and recreationally important shelf rockfish species over untrawlable habitats in the Southern California Bight. The Survey is a cooperative effort between NOAA Fisheries, Pacific States Marine Fisheries Commission, and the Southern California sportfishing industry. We work with fishermen to identify sampling sites, species of interest, and to develop standardized methods of sampling so that data collected yearly are comparable.
Between 2014 and 2018, we added about 80 new sampling sites within the Cowcod Conservation Areas (CCAs). The CCA is actually two regions, totaling 4,300 square miles, that has been closed to most sport and commercial bottom fishing since 2001 (see the map of the Survey’s sampling area below). Like other Marine Protected Areas (MPAs), the Fishery Management Council implemented CCAs to help rebuild overfished populations of rockfish, specifically deep-dwelling species like bocaccio and cowcod.
We have been tagging and releasing fish caught within some MPAs since 2016. Because rockfish species all have internal gas bladders, they experience barotrauma where their gas bladders expand when reeled to the surface. We use a Seaqualizer™ descending device to ensure that the rockfish is released back to the same depth where we caught it. Since tagging began in 2016, we have identified two known recaptures of fish tagged on this survey.
In 2017, we implemented in the Hook and Line Survey a back-deck electronic data collection system to replace the use of the pencil-and-paper approach we used since 2003. We developed this wireless, multi-station system (HookLogger) to capture catch and biological data using a network of ruggedized tablets, digital scales, and barcode label printers and scanners. These electronic devices communicate with each other and a centralized server and database located in the vessel's galley. HookLogger results in more efficient at-sea data collection and improves data quality and data delivery times through real-time data validations and the elimination of 6-8 weeks of postseason data entry.
In addition to the survey's primary objective of collecting information to promote our fisheries' sustainable management, we conduct a variety of supporting research on the ecology and oceanography in the region.
Camera-sled habitat surveys
Since 2004, we have collected habitat information in our sampled sites using a towed portable camera sled. The sled is towed just above the seafloor to collect video so we can learn more about the habitat types encountered by our survey and the types of fish living there. Linking habitat associations to vulnerable fish stocks allows us to protect and manage sensitive ecosystems appropriately.
Marine reserve effects on fish and fisheries
The use of marine protected areas (MPAs) is becoming increasingly common as a fisheries management tool for reef-associated fishes; however, researchers are still studying the benefits of MPAs for fishery management. We include MPAs and CCAs in our sampling frame to track the response of rockfishes to large-scale fishing closures over time. These data improve our understanding of how rockfish response might vary due to reserve factors, such as site size, age, and location.
Oceanographic trends in the Southern California Bight
We also lower a CTD (Conductivity-Temperature-Depth) sensor into the water and descend it to the bottom at each site. This special device is outfitted with oceanographic sensors to gather information on the temperature, salinity, dissolved oxygen, chlorophyll concentration, and turbidity of the water at each site from the surface to the seafloor. This information helps us understand how short- and long-term oceanographic trends can influence the recruitment, abundance, and behavior of fish.
Genetic analysis to identify cryptic species
Our survey team works with geneticists whose research identifies and uses the tiny differences in DNA between cryptic rockfish species. One application of this genetics research is to identify a fish to the correct species conclusively. There are over 100 species of rockfish in the genus Sebastes, and several of them can look very similar to one another. Our ability to positively distinguish one species from its cryptic pair helps fishery managers manage the correct species properly.