Keep your eyes peeled for deep-sea fishes while strolling along our shores. In the last month, three King-of-the-Salmon (Trachipterus altivelis) have washed up in the Salish Sea. Two were found in September (21st and 26th) in the Oak Bay area, Victoria. One of these was still swimming when found. A third was found October 3rd in Hood Canal, in Puget Sound. The first Oak Bay specimen will be preserved for the Shaw Centre for the Salish Sea in Sidney, the second was not recovered, and the third will be preserved in the Burke Museum’s collection. The Royal BC museum has 18 Trachipterus specimens, with several of these from the Salish Sea area.
The King-of-the-Salmon from Hood Channel, photographed by Randi Jones.
Is this species new to the region? No. The species ranges from Alaska to Chile, and knowledge of this species pre-dates European arrival on this coast. Is this trio of King-of-the-Salmon a case of post-spawn mortality? A sign of change in our oceans? We don’t know. Actually, when you look at the diversity of marine fishes off our coast, there is a lot of basic biology that we don’t know. We also get Longnose Lancetfishes (Alepisaurus ferox) washing up from time to time, although it has been a few years since I have heard report of a Lancetfish in the Victoria region.
King-of-the-Salmon swim by passing a sine wave down their dorsal fin – they can get a fair bit of speed just by doing that. They can also reverse using the same fin flutter. They slowly turn by putting a curve in the body. However, in the first few seconds of the linked video you can see that they also swim in a more typical fishy way (using eel-like body oscillation) when they need a burst of speed or a really quick turn. If you’d like to see this form of locomotion in person – you can see it in a pet shop. Knife fishes use the same basic locomotion method – except they use their anal fin rather than the dorsal.
Close up of the head of the King-of-the-Salmon showing the premaxillary (red) and maxillary (green) bones extended, photographed by Randi Jones.
Note also in the video that the fish has a very short face compared to the Hood Channel specimen photographed onshore. As with many fishes, the jaws of the King-of-the-Salmon are protrusible – the premaxillary and maxillary bones swing out to create a tube – the gill chamber dilates, and water rushes into the mouth along with the prey. The same sort of suction pump mechanism is used by a wide variety of fishes – from tiny seahorses to giant groupers. Once the prey item is inside the fish’s mouth, the mouth closes, water is released through the gills and the prey is swallowed. The entire sequence is lightning fast – even in pipefishes and seahorses – blink and you miss it. In some fishes, the process is even audible – you can hear a snapping sound when seahorses slurp up crustaceans (and fishes). You can’t hear the same snapping sound when larger fishes engulf their prey, but it is no less dramatic an effect.