The lingcod is not a particularly sexy fish, so why do we at the Vancouver Aquarium care so much about it? Lingcod numbers have plummeted in the last 100 years, and even though the commercial fishery for lingcod in the Strait of Georgia was banned in 1990 and sport fishing in 2002, lingcod stocks are just 7-22 per cent of what they were a century ago. In Vancouver, the numbers are even worse – less than one percent. Imagine having 100 of your friends over for a party and then everyone but one person disappearing – that’s what’s happened to the lingcod.
Because we were not willing to just stand by and watch a species disappear completely off our coast, we decided in 1996 to join a Marine Life Sanctuaries Society initiative to monitor lingcod egg masses in local waters. Since then, we’ve spearheaded this program, which relies on “citizen science” in the form of volunteer diver involvement. By counting the number of lingcod egg masses each year, researchers can determine lingcod abundance and the age of spawning females (the older a female is, the more eggs she will lay and the younger a female is, the fewer eggs she will lay).
Female lingcod spawn from December to early April in the Strait of Georgia, with most spawning activity taking place in mid-February. This year’s Lingcod Egg Mass Survey was set to take place from early February to early March, but was extended to the end of March because of the La Nina winter. The lingcod were probably responding to the temperature and therefore, spawning was delayed in comparison to an average season.
The results of this year’s survey are in: Aquarium and volunteer divers undertook 77 dives, during which 233 egg masses were counted (100 in Howe Sound and 133 outside Howe Sound). The divers were on the lookout for either Styrofoam-looking egg masses or guarding male lingcod that would lead them to the egg masses. Dr. Jeff Marliave, the Aquarium’s vice president of marine science, says there are a couple of things we can take away from this year’s results. One: lingcod abundance is not continuing on the upward trend that we’ve seen during the last two years. Two: lingcod numbers are still in a plateau at relatively higher abundance since the turn of the millennium, compared to the decade of the 1990s. He adds that minor fluctuations between years may relate to sampling error as much as to actual population changes.
Read the report in its entirety here.
There will be another call for volunteer divers for next year’s Lingcod Egg Mass Survey, but for the time being, we’re looking for help with the Rockfish Abundance Survey, taking place from late August to the end of September. Volunteer divers will help collect information about the size, age and species of rockfish, which will enable researchers to determine the abundance of local rockfish that have also seen their numbers decline (like the lingcod).