LINGCOD EGG MASS SURVEY
30 years of citizen science needs your help!
In 1994 the Marine Life Sanctuaries Society started the Lingcod Egg Mass Survey, or LEMS. The program has divers from the community count spawning lingcod along BC’s coast to gather data to monitor lingcod populations. Since its inception the LEMS program has passed on to Ocean Wise and the Vancouver Aquarium, then over to MERS , and now as of 2023 is back in the hands of MLSS.
Since the 1980’s lingcod have been in decline in the Strait of Georgia, with their biomass dropping down to only around 1% in Howe Sound. Because of this, in 1990 the Strait became closed to commercial fishing. Despite this closure, lingcod were still in decline, so in 2002 all sport fishing for lingcod was banned in the Strait and surrounding waters. 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 hook-and-line fishing for groundfish (which includes lingcod) was banned in Howe Sound and Burrard Inlet.
Despite all these bans, lingcod populations remain in critically dwindling numbers. To better protect these depleted fish, we must provide evidence of their population, or lack thereof. Hense the Lingcod Egg Mass Survey.
Lingcod spawn primarily in January / February along the rocky shores of Western North American. They chose areas with strong currents to allow for egg respiration and are usually in depths of 15 – 60 ft. The eggs stick together to form an egg mass that looks like a clump of Styrofoam. New eggs will be white / pink, while older eggs will be eyed / dark grey. The older the female laying the eggs, the larger the egg mass will be. Egg mass sizes can be lumped into three categories; grapefruit sized, cantaloup sized, and watermelon sized. Grapefruit sized masses are produced by three-year-old females and hold about a liter of eggs. Cantaloup sized masses are produced by four-year-old females and hold about two liters of eggs. Finally, watermelon sized egg masses are produced by five-year-old and older females.
Egg masses, or nests, are usually tucked into crevasses and guarded by the male parent. Smaller males may partially fertilize some eggs while spawning, so spawning reefs may have more males than nests. Dominant males may guard multiple nests, usually separated by no more than a meter. These males are the ones that initiate the spawning and are the main fertilizer of the mass. If the area has enough water flow and the male can protect against predators then the eggs will hatch after 5 –11 weeks, depending on water temperature and current flow.
Two to three months after hatching larvae will grow to about 70mm and start feeding on juvenile herring. By their first year of life, they will grow to about 21cm. They will grow to about 45cm by the time they are two years old. Males will keep growing until they are 8 and will live around 14 years. Females will grow until they are 12-14 and live around 20 years. Female lingcod 10-12 years of age are roughly twice the weight of males of the same age.
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 large females. It is still too early to draw many conclusions from this though. Another key indicator of population viability is the guarding male, as egg masses tend to be eaten before they hatch without one.
With this much valuable data to be gained from surveying, it is time to start!
Gathering egg mass data is easy and can be done during a regular dive. All data is good data, even if no egg masses are sighted. The depth range for most masses is between 15-60 feet, so make sure you note how long you spent in that range instead of just the dive time. If you spent most of your time diving down at 100 feet, it wasn’t much of a survey dive.
While diving if you see an egg mass, note the depth where you found it in feet. Estimate the size by stating if the egg mass is roughly the size of a Grapefruit, Cantaloupe or Watermelon. Note the condition; new (white/pink), eyed (dark grey), or rotten, as well as how it is situated, loose in a crevice, secure in a crevice or out in the open. Finally record if you see a guarding male. One male may guard more than one egg mass though, so indicate accordingly. If the male is guarding only one nest, record a P. if it is guarding multiple masses record a P2 for each individual nest. If there is no male, record an A, for absent.
When you submit the data gathered, you will also need to include the date, diver information, area and dive site. Try to be as accurate as possible and use GPS headings when possible. Data can be emailed to LEMS@MLSSBC.com or once it is live to MLSS’s online portal.
Submitting data is easy and can help future lingcod stocks through research and monitoring. While out for a dive from January to March, please keep the LEMS in mind and send in your information! Lingcod are counting on you!