This past winter, more than 20 commercial fishing boats beamed their lights and worked their nets over La Jolla’s submarine canyon to haul in 2,500 tons of the market squid Loligo opalescens. I had not before seen such a flotilla of fishing pressure in the area. Why have squid suddenly become a hot commodity?
In 2001, authors of an article published in the journal Nature presented evidence that Chinese fisheries drastically falsified their catch reports, leading to a global realization that the majority of the world’s fisheries stopped being sustainable. They wrote, “The global catch trend is not increasing, it is not even stable, but rather it has been decreasing steadily since the late 1980s.”
Overfishing has so efficiently removed top predators that fisheries have been forced to shift to prey species such as squid. The squid fishery, which began up north in Monterey, began to include San Diego in the mid-1990s. Subsequently, the market squid fishery has grown to be one of California’s most important in terms of landings and profits. The state generates millions of dollars annually in domestic and foreign sales of market squid, with Asian countries representing the chief export market. Though market squid benefit the commercial fishery, they are principally eaten by a minimum of 19 species of fish, 13 species of birds and six species of mammals. It is therefore crucial to properly manage the fishery for the millions of animals that compete for this resource. Should we irreversibly deplete the market squid population, it is unclear how oceanic food chains will respond.
Not until 1998 did the California Department of Fish & Game (CDFG) began logging squid fishery data (number of boats and landings) in San Diego. Since records have been officially kept, 1999 holds the biggest landing record. My dive logs concur there was a good squid show that year (unfortunately coinciding with poor underwater visibility), but this run didn’t compare with the motherlode squid run I witnessed during repetitive scuba dives in 1989-90. In 2004, California’s Fish & Game Commission finally adopted a statewide market squid fishery management plan to protect and manage the species over the long haul. The following year, 2005, the plan was implemented.
Squid limits for California are 118,000 tons, and that’s in toto so there is no local cap on squid taken from La Jolla’s submarine canyon. How do we know the La Jolla catch still supports a local, sustainable population? Market squid live, on average, six to nine months, reproduce at the end of their lifespan and are harvested on spawning grounds, so the fishery must allow for enough eggs to be spawned prior to harvesting. CDFG monitors what proportion of the population should be allowed to spawn before being captured by the fishery.
Dale Sweetnam, CDF&G marine biologist, says, “The limit is continually evaluated from each year’s catch numbers and it provides a fairly precise estimate over time. However, its accuracy is only as good as the many years of fishery data that have been collected for comparison.”
Since market squid have been managed here for only a short time, the limit is not based on local data but is surmised from information collected elsewhere where squid is harvested. Consequently, we don’t know for sure what local population of squid can be sustained before collapsing.
To add to the challenge, squid are difficult to manage because they are a boom-and-bust animal. As noted, squid spawning run numbers ranging from nothing to explosive. A strong El Nião brings warmer waters and low squid spawning levels due to the mollusks remaining at great depths. Cooler waters brought by a strong La Niãa portend the advent of droves of squid to near surface waters. However, weak El Niãos and La Niãas do not allow for effectively predicting spawning levels. It’s clear that to better determine future landings and population stability, continually monitoring how the environment affects the squids’ behavior is key.
Now that I’ve cleared up the mystery of last winter’s armada off La Jolla for myself, I can only guess why I haven’t seen a squid run to mirror the epic run of 1989-90. It may be that the Holy Grail for many arriving squid is the head of the submarine canyon, located in the San Diego-La Jolla Underwater Park Ecological Reserve. Since the commercial fishers are camped out over unprotected waters, they may be siphoning off squid before they reach the canyon’s head. But it’s not just the squid I didn’t see because I could have been diving at the wrong times to see them; it’s the lack of egg cases that confirms the squid didn’t arrive. Data show that half the squid landed are females, meaning up to half those females are carrying eggs, which could account for the lack of squid egg cases laid down.
I’m fortunate I witnessed this mystery of nature in its mammoth proportions 10 years ago. Now that commercial fishers are targeting the lower end of the food web, the squid fishery is here to stay as long as it lasts, meaning my chance to dive another blockbuster squid run is increasingly unlikely.
” Judith Lea Garfield, biologist and underwater photographer, has authored two natural history books about the underwater park off La Jolla Cove and La Jolla Shores. www.judith.garfield.org. Questions, comments or suggestions? Email [email protected].