Dwindling rockfish and other species will get more Cal Poly study

The cowcod rockfish — given its bovine name for its beefy appearance — along with a few other species are not doing so well along the Central Coast, despite the fact that populations of other fish in the large swath of protected ocean are on the upswing.

To help boost numbers of the spiny, orange fish that’s one of the largest rockfish in the world, as well as other California marine species, Cal Poly researchers recently received word they’ll have at least three more years of funding to conduct studies off the Central Coast.

A $720,000 grant awarded to Cal Poly’s Center for Coastal Marine Sciences will allow a research project that started five years ago to continue.

The project involves catching and documenting fish species inside and out of state marine reserves.

The data will educate legislators and help to determine how fishing and other factors, including environmental influences, impact fish populations.

The California Sea Grant program and the California Ocean Protection Council sponsored the competitive grant. “This money will take us up to eight years of sampling,” said Dean Wendt, a Cal Poly marine science professor. “That’s important because that’s how long a lot of people think it will take to start to see what’s actually happening in our ocean.”

Populations of some fish species off the Central Coast have increased through implementation of fishing regulations about 10 years ago, though other species have declined.

Numbers of fish such as lingcod and bocaccio have drastically risen in recent years because of fishing closures, said John Field, a research biologist with the National Oceanic and Atmospheric Administration.

But others have decreased, such as the cowcod and yellow-eye, which have been heavily fished and take longer to reproduce.

More than 500 volunteer fishermen on the Central Coast have participated in the project called the San Luis Obispo Science and Ecosystem Alliance (SLOSEA) to catch about 40 species within three miles of the coast — including many rockfish, which inhabit the ocean’s rocky floor areas and reefs.

Cal Poly students and professors board recreational and commercial boats to document data such as the number of fish caught in an hour, average sizes and whether fish are old enough to reproduce. They tag fish before release, so if they’re caught again their growth can be measured.

The data is passed on to federal and state agencies that play a role in management of fishing and ecosystems.

The Cal Poly team and Moss Landing Marine Laboratories participate in catches from San Luis Obispo to San Mateo counties.

Cal Poly biology graduate student Nate Hall said the collaboration will help fishermen maintain their livelihoods and improve fish populations. Hall said the fishermen have been vital to the project.

“Scientists and fishermen can work together and learn from one another,” Hall said. “It helps to fulfill the goal of enhancing our local marine resources.”

The insights can help them rule out fishing as a direct cause of low populations in some instances, researchers say. For example, Wendt said that the blue rockfish — a near-shore species about 20 to 25 inches long commonly found in rocky areas as well as in kelp — is showing low numbers in both the marine protected areas and unprotected fishing sites.

That indicates to him that factors other than fishing may be causing the dip. Climate change in particular, including warmer waters, has led to decreases in numbers of some fish, marine scientists say.

Field has seen similar data with cowcod and yellow-eye rockfish, which haven’t recovered despite closures. Yellow-eye — an orange, bulged-eye fish — can live to be up to 120 years old and reach sexual maturity at 10 to 20 years old. The yellow-eye population has been impacted by fishing.

“They’re bigger fish and people like catching big fish,” Field said. “It’s going to take a long time for them to recover because it takes a longer time for them to reproduce.”

Field said the study that Cal Poly is involved with could be important in transforming the long-term future of marine management in closely comparing reserves to open fishing sites.

“This project has a high probability of success,” Field said. “Conceptually, it can and should work.”