Photo: Bob Turner
Deeper Waters
Northern Anchovy
(Engraulis mordax)
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Anchovy are a small fish with a huge impact on the overall health of Atl’ka7tsem/Howe Soundand Kwilákm and our enjoyment of nature. If a school of anchovy is nearby, you are sure to know because it creates a spectacle that you cannot miss. All sorts of birds and mammals are in on the feast!
Anchovy are a small (18-25 cm) silvery schooling fish similar to herring, smelt, and sardines that together are referred to as forage or bait fish. Northern anchovy are most abundant further south off the coast of California and Oregon, but southern BC has always been within the northern limit of their range. But since 2015, likely related to a warming ocean, anchovy have become the most commonly observed forage fish in outer Atl’ka7tsem/Howe Soundand around Bowen Island.
Anchovy of all stages of life, except eggs, have been observed in Kwilákm. Anchovy are open water spawners, with females laying their eggs and males fertilizing them with sperm in offshore waters. This spawning is rarely observed.
However juvenile anchovy 2 to 3 cm long have been observed by snorkelers in Kwilákm most summers since 2015.
The summer of 2021 was especially remarkable, with large schools of juvenile anchovy resident in Kwilákm throughout the summer months. Some schools of smaller anchovy 2 to 3 cm long were likely hatched in 2021. Some schools of larger fish, 5 to 6 cm long, were likely hatched in 2020. Cutthroat trout ranging in size from 15 to 20 cm. long were commonly seen hunting these anchovy. The trout swim below the schools, darting up to seize their prey.
But it is the schools of adult anchovy that really create the drama. These schools can be herded into bays and towards shores by diving ducks such as cormorants and merganser, as well as by seals and sea lions. Then a frenzy begins.
Gulls quickly gather to feast on the anchovy school forced up to the surface by the underwater attacks of birds and mammals. Such an event was captured by Bob Turner in his video “Howe Sound Ballet”. While screaming gulls circled above, other gulls plunged to catch anchovy near surface, and seals, a sea lion, cormorants and a merganser attacked from below.
All this time the anchovy school, perhaps 4 metres wide and 3 metres deep, continuously changed shape as fish evaded the attackers but remained as a school.
Anchovy grow to 18 to 25 cm long and can live seven years. They are primarily filter feeders and swim with their mouths agape, straining plankton.
This open-mouth feeding flares the gill covers, causing a circular reflection in sunlight. Aa school of anchovy produce a glittering mass of silver-dollar flashes that distinguishes them from herring.
