Lingcod Egg Mass Surveys (LEMS)
In 1994 MLSS started the Lingcod Egg Mass Survey, or LEMS monitoring program. The purpose of the program was to have divers from the community count spawning lingcod along BC’s coast in order to monitor lingcod populations. Since its inception the LEMS program has passed on to Ocean Wise and the Vancouver Aquarium, to the Marine Education and Research Society (MERS) in 2022, and now, as of 2023, is back in the hands of MLSS.
Why monitor lingcod populations?
Since the 1980’s lingcod have been in decline in the Strait of Georgia as result of overexploitation by commercial fisheries. Due to rising concerns, Fisheries and Oceans Canada (DFO) closed to Strait of Georgia to commercial lingcod fishing in 1990 and to sport fishing in 2002. The ban was lifted on the east coast of Vancouver Island in 2006 but is still in place for the Vancouver area. In 2007 all retention of lingcod was banned in Átl’ka7tsem/Howe Sound and Burrard Inlet, and these regulations remain in place today (learn more about the history of the lingcod fishery here).
Despite all these bans, lingcod populations remain in critically dwindling numbers. In Átl’ka7tsem/Howe Sound, their biomass is estimated to be around 1% of their levels pre-exploitation. To better protect these depleted fish, we must provide evidence of their population, or lack thereof. Hence the LEMS program.
Because lingcod are unlikely to stray more than 10km from where they settle as juveniles, looking at data from abundance and spawning populations on a year-to-year basis allows scientists to understand changes on a much smaller geographic scale.
Since egg masses began to be surveyed in 1994, there has been little indication of an increase in lingcod population despite all efforts to help them. Since the survey’s inception an average of 50% of the egg masses recorded have been produced by the largest females, who also produce the most viable larvae. The smallest age group of females, producing the smallest egg masses only account for on average 10% of the spawn. The past few years however, data has shown a decrease in the amount of large females. It is still too early to draw many conclusions from this though. Another way these surveys provide insight into population health is by providing data on the presence (or absence) of a guarding male. Male lingcod will aggressively defend egg masses from predators and if a male is removed (which can occur if illegally fished or poached), the egg mass will be eaten, causing the entire nest to be lost (learn more about lingcod biology here).
With this much valuable data to be gained from surveying, it is time to start! Check out our “how to” page to learn how you can conduct your own surveys and contribute critical lingcod data.
Want to learn more about this program? Think your dive shop or club would benefit from an informational session? Learn more here or contact us today!
Lingcod Egg Mass Survey Methods
