Strategies for Rebuilding the Atlantic Mackerel Stock
Commercial Atlantic mackerel landings have decreased considerably in recent years. This stock declined in the late 1990s and then collapsed to an all‑time low in the 2010s. Projections suggest that, given the current quota, the probability of the stock increasing in the next two years is 50%. Analyses suggest that mackerel recruitment and conditions are negatively affected by warming water temperatures and the reduced availability of their prey of choice, zooplankton.
A group of experts, made up of scientists, First Nations representatives, fishers, fisheries managers, environmental groups and provincial governments, has been working since December 2017 to develop a stock recovery plan based on the best management strategies. The working group’s conclusions are expected to be available in March 2020.
An unpredictable but popular fish
Commercial and recreational fishers will tell you that the time when mackerel appear can vary from year to year. Scientific information is consistent with these observations. Experts understand that mackerel go where the food is and where the temperature is above 10°C.
Most mackerel caught are used or sold as bait for the lobster fishery, Canada's most lucrative export fishery. The largest catch volumes are made by Newfoundland seiners.
A highly migratory species related to tuna
Atlantic mackerel (Scomber scombrus) is a migratory fish related to tuna. The Northern contingent (Canadian) of the Northwest Atlantic mackerel stock overwinters off New Jersey. In the spring, mature fish migrate to spawn in June in the southern Gulf of St. Lawrence in successive waves, while juveniles approach the coasts to feed. After spawning, mackerel disperse to feed throughout Atlantic Canada and Quebec then migrate south in the fall. Spawning dates have not changed over the years and are comparable to observations made in the 18th century.
General facts
- Available data have shown Canadian and American researchers that fishing mortality is high. Mackerel are caught throughout Atlantic Canada and Quebec, but methods vary by region and season.
- Several thousand tonnes of mackerel caught each year are not recorded: bait fishing, recreational fishing, discards, at‑sea sales and American winter fishing.
- Stocks are low, and there are fewer young fish. The young‑of‑the‑year can grow from 3 mm to 20 cm in a few months.
- Mackerel can live up to 20 years, but it is becoming increasingly rare to find mackerel over five years old.
- Several tagging studies have shown that mackerel caught in Newfoundland can overwinter as far south as New Jersey.
- No studies have shown that seals have a significant impact on mackerel.
To download the latest Science Advisory Report on Atlantic mackerel:
http://publications.gc.ca/collections/collection_2019/mpo-dfo/fs70-5/Fs70-5-2018-062-eng.pdf
Andrew Smith
Science
Extraction of mackerel otoliths in the laboratory.
The science team was on board the CCGS Teleost until June 17 to assess the mackerel egg abundance index in the southern Gulf of St. Lawrence. This abundance index is the main index used in mackerel stock assessment.
