Weekly Sea Discovery: Bay Pipefish and Eelgrass Beds

As you walk through or snorkel around the eelgrass beds of Mayne Island, you may not see the excellently camouflaged bay pipefish. Found swaying amongst the eelgrass, bay pipefish look almost identical to the plant’s blades. Eelgrass beds and other seaweed patches that these pipefish live in are usually found in more protected ocean areas, like bays, and estuaries.  

Bay Pipefish (Syngnathus leptorhynchus). Photo: Mark Mauno

The diet of bay pipefish consists of small crustaceans and plankton, which they eat by suction feeding. This feeding technique is used by many aquatic animals, including the bay pipefish’s close relative, seahorses!

 Pipefishes and sea horses are part of the same Family, sharing many of the same behaviours and morphologies. One of their most fascinating behaviours occurs during mating and brooding. Instead of the females carrying the fertilized eggs until they fully develop, the males carry them in their brood pouch. If you ever see a pipefish with a swollen looking abdomen, this is not a pregnant female, but a brooding male! After the eggs fully develop into tiny pipefish, the males release them into the water to fend for themselves. 

Around the world, the shallow habitats that pipefishes and seahorses live, grow, and mate in, are increasingly threatened by various pressures. Our eelgrass mapping and monitoring project works towards conserving these habitats and detecting possible reasons for losses of eelgrass in our local areas.

Killer Whales. Photo: Vijay Somalinga

Not only are eelgrass beds vital habitat for various fish and invertebrates, but also larger animals like cetaceans. This habitat is critical for whales and porpoises because this is where their prey lives and grows in, like juvenile salmon. With the loss of eelgrass habitats, we will see declines in species that rely on them, from bay pipefish to southern resident killer whales. 


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