Going Deep Off Point Arena
The fish waited patiently, suspended in the water, half-concealed by a fanlike coral. At depths of 400 ft., no red light reached her to betray her Technicolor brilliance. She appeared a pallid gray to her predators and to her prey - if she appeared at all. Her skills in the art of hunting, honed over her 14-year lifetime, brought shrimp, small fish, crabs (and their luscious eggs!), and even small octopuses to her table. Today, it was a crab that caught her eye, and she took her chance. Afterwards, she came to rest on a conveniently nearby sponge (is this the life, or what?!!). This is the rosy rockfish, Sebastes rosaceus, a native of the Eastern North Pacific, and a mainstay for fisheries all along our coast.
Rosies are related to the more fearsomely-named scorpionfish, but are otherwise known—especially on the menu—as rock cod or Pacific red snapper. Adults are generally solitary, but when they get together, they are prolific breeders, with females spawning up to 95,000 eggs, from April through July, in northern California. They have been caught at depths of 850 feet, but are more commonly found much shallower.
LA VIE EN ROSE: Rockfish thrive in rocky areas where they can lurk, alert to danger or opportunity. But from recent studies of seafloor communities in the wider region, we know that other marine creatures such as sponges and corals provide important living habitats within the rockfish’s “landscape.” Termed biogenic species, i.e., corals, sponges and kelp as well create habitats that support other life. Scientists are increasingly aware how essential these biogenic communities are, in combination with geological features, to fish populations. They contribute to an optimistic future for rockfish, simply by being themselves. But the habitats they need to survive must be protected.
ON THE HOOK FOR CONSERVATION: Rosy rockfish are delicious and in high demand; but their very succulence is their downfall. They are a prime catch on sport fishing party boats and are taken in the commercial hook-and-line fishery operations as well. This has greatly reduced once-plentiful rockfish populations along our coasts. To help rebuild these populations, certain underwater zones have been set aside as refuges or reserves, where spawning rockfish would be protected from harmful fishing tools. To support such actions, scientific data are needed to ensure these measures will be effective. Our local marine sanctuaries, which support healthy fisheries, are gathering that data.
Information on the geology and biological assemblages is needed to protect fish habitats against destructive types of bottom-contact fishing gear. Therefore, in May 2019 NOAA’s Greater Farallones National Marine Sanctuary and Ocean Exploration Trust (OET) will conduct a mission to map seafloor habitats using multibeam sonar in the ocean off Point Arena, the “Pt. Arena South Essential Fish Habitat.” The sonar can identify areas likely to host important biogenic habitats that may support robust fish communities.
TESTING THE WATERS: The sanctuary and OET will use data from the May expedition to target specific sites for more detailed visual examination using remotely operated vehicles (ROVs), using the research ship E/V Nautilus, this October. They will send ROV-mounted video cameras to depths of 2,500 ft. and use video cameras to document the seafloor and its inhabitants and sample an array of seafloor organisms. The sanctuary does not manage fisheries, but it does conduct the research that contributes to sound conservation efforts to protect fish habitats.
Mapping and characterizing marine life habitats are of high importance to sanctuary management. These areas must be assessed, via sonar and ROV, in order to determine if NOAA Fisheries can make these areas available to certain types of fishing without damaging sensitive or endangered coral species, or degrading habitats essential to ensuring healthy fish populations for generations to come.
For information: • NOAA Fisheries WCR website: https://www.westcoast.fisheries.noaa.gov/ • PFMC website: https://www.pcouncil.org/ • GFNMS website - https://farallones.noaa.gov/science/seafloor.html
Photo: Top left: Matt Vieta/BAUE; EIB; Middle: NOAA CBNMS; Bottom: Credit: NOAA.