Bull Kelp
Nereocystis luetkeana
Physical Description
Quickly growing, large, brown kelp that can grow up to 100 feet in length. It has a long, flexible stem called a stipe that anchors it to the ocean floor, and at the top of the stipe is a bulbous floating structure called a pneumatocyst. The leaves of the bull kelp are long and flat, with a frilly edge, and can vary in color from dark brown to olive green.
Habitat
Located throughout the Pacific Coast from Alaska to Southern California. This species is often found in an energetic wave environment, because it typically best thrives in rough nearshore waters. Due to Bull Kelp being an annual species it is most prevalent in winter once it has died off and floats onto shore in large bunches.
Ecological Role
It provides food and shelter for a variety of wildlife species, specifically for young fish species and many invertebrates such as sea urchins, sea stars, snails and crabs. Certain predators also rely on the kelp such as sea otters who hunt on the bottom of the kelp as well as sleep in the kelp canopy to prevent themselves from drifting away. Humans have also relied on bull kelp as a source of food.
Conservation efforts:
This kelp is most commonly harvested in aquaculture, due to the strict regulation of commercial harvesting to protect the california kelp forests. In addition to requiring a license there are certain rules when it comes to harvesting the Bull kelp. The kelp must be trimmed from the top down, and for no more than 4 feet below the surface and in designated areas. The conservation of the kelp forest is also greatly dependent on the well being of sea otters, because they naturally keep the sea urchin population regulated. Without the sea otters, a keystone species, the urchins which live in the kelp could potentially destroy the forest. Other factors that impact the well being of the Kelp include climate change, pollution, habitat destruction and frequent boating.
Reproduction
Bull kelp begins as a small spore that settles on the ocean floor and grows into a small plant called a gametophyte. The gametophyte produces male and female parts that release sperm and eggs for fertilization. The fertilized egg becomes a new plant called a sporophyte, which grows into a mature bull kelp. Bull kelp can also reproduce by breaking into pieces that grow into new plants.
Sources
“Invasive Species Data.” CABI.Org, 14 Nov. 2023, www.cabi.org/projects/invasive-species-data/. Accessed 29 Oct. 2024.