In Part 1, I described what kelp was, where it grew and the many purposes it serves for the marine and terrestrial environments.
Here I will illustrate the extent of the losses of kelp forests and describe some of the efforts that are ongoing or planned to preserve and restore this important natural resource.
How much kelp are we losing now?
The magnitude of the loss of kelp forests can not be overstated and is akin to the dramatic disappearance of the Westcoast sea stars that I wrote about previously. It will come as little surprise that the decline of these two nearshore critters are related in some locations. I’ll get to that shortly.
Although across the globe there is a significant decline in kelp forests, the losses are not uniform and many of these losses appear to be associated with regional factors as well as more global issues such as climate change. One of the broadest studies of world-wide kelp loss examined data from 34 global kelp ecoregions and found that 38% of these regions had a net loss of kelp forests, 27% had a net gain, while 35% were stable with no observable change. Although it showed a net loss in kelp forests, some areas fared better than others. This study is not definitive as they had data on less than half of the global kelp ecoregions. However, it demonstrates that there has been a net global loss over the past 50 years and this serves as a global baseline for the future study.
Closer to home, the kelp forests along the California coast and in Puget Sound have been more intensively studied and are shown to have experienced significant losses. One recent study used USGS Landsat satellite based data of kelp forest canopies in the off-shore waters stretching 200 miles north from San Francisco. This study found that upwards of 95% of the Bull Kelp canopies have disappeared since 2014. Given the dependence of marine flora and fauna on these beds, this loss is devastating to the larger ecosystem and has ravaged the many commercial enterprises that rely on these kelp forests.
Several resent studies have also examined the changes in kelp forests in Puget Sound, WA. One study focused on the southern part of the sound. These researchers synthesized data from 48 historical and current kelp surveys between 1878 and 2017. The oldest data were from the early explorers of this region who carefully charted these kelp forests as they posed serious navigation hazards for their sailing ships.
Their findings were consistent with others in that in South Puget Sound there was an overall 63% loss of kelp, with some basins having lost as much as 96%, akin to the northern California losses. As with other studies the areas of loss are not uniform and varied with a variety of local circumstances that provide strong hints of the factors contributing to the losses. There was more loss in those kelp beds closer to urban and industrial centers and that had higher water temperatures. Those closer to Pacific Ocean waters with stronger tidal movement bringing in cooler nutrient rich ocean water with turnover were more stable.
Another ongoing study has recently reported Bull Kelp canopy cover changes based on digitized aerial photography samples from the Islands of San Juan County (essentially the San Juan Islands which constitute the Northern Puget Sound Area). This study compared total acreage of kelp canopies around the islands from a 2006 survey with another survey taken a decade later. In this time, the kelp canopy area decreased from about 845 acres in 2006 to 539 acres in 2016, a 36% loss. (The above link has some very illustrative graphics of the kelp change as well as some historical information on San Juan Islands kelp.)
It is clear to all studying this matter that our kelp forests are diminishing regionally and globally. Losses are occurring along all ocean shores in both hemispheres. It is truly a global event with a combination of global and regional contributing factors.
Why is this happening now?
Although kelp forests have been known to wax and wane over time with oscillating ocean and atmospheric cycles, they have typically rebounded rather quickly. Giant Kelp have been particularly resilient as they have been documented to grow as much as two feet a day under ideal conditions. However, those forests lost in California have not been rebounding as they have before and many have been continuously decreasing since at least 2014. Similarly, the huge kelp forests in Chile where there continues to be ideal oceanic conditions, continue to lose canopies. There are clearly many factors at work here and most if not all have to do directly or indirectly with human activity. I will point out some of the known and suspected contributors below.
Global Warming/Climate Change affecting ocean temperatures and currents.
Much of this loss, particularly in coastal California can be attributed to cascading effects of global and ocean warming. A recent case in point follows from the 2013 to 2016 ocean warming event called the “Blob” which showed up in the Gulf of Alaska and affected temperatures in large portions of the north eastern Pacific Ocean. Its influence pushed warm surface waters into coastal Alaska, British Columbia, Washington, Oregon and northern California. This warming water interrupted the upwelling of deep cold nutrient rich waters from off shore. Since kelp growth requires nutrient rich cold water mixing with the surface water, the forests began declining and continue to do so though now perhaps for other down stream causes.
Loss of predators:
At about the same time as the blob appeared, west coast sea stars began to succumb to the Sea Star Wasting Disease (SSWD) which over the past seven or eight years has devastated many species from Alaska to Baja. The disease(s) were particularly devastating for the sunflower sea star (Pycnopodia helianthoides), whose absence from the kelp forests is highly implicated in the kelp losses. Neither these stars nor the kelp forests have recovered. The sunflower star went from being highly abundant all along the California coast up through Alaska just eight years ago to be largely extinct. Today it is listed as a critically endangered species with losses ranging from 100 % in California to 90% or greater from Oregon to Alaska.
Purple urchins feeding on a kelp stem on the way to creating an “urchin barren.” credit Dan Schwartz
Part of this kelp-related ecosystem included the sunflower star and the purple urchin (Strongylocentrotus purpuratus) that live within the kelp forests. Since the sunflower stars had been the major predator of the purple urchin, the urchins had free run to feast on the kelp forests. And feast they did and still do, leaving the ocean bottom stripped clean of kelp and resulting in what they called “urchin barrens.”
Another urchin predator is the sea otter but on the whole there are insufficient numbers and their colonies are too spotty to take up the slack left by the sunflower stars. And the otters that exist only eat the larger urchins leaving the smaller ones free to graze. Sea otter population was nearly wiped out due to over-hunting in the 1800s all along the west coast until they finally received International protection in 1911 and Federal protection in 1972. Their recovery has been spotty and very slow in some areas. Alaska’s Norther Sea Otter has rebounded well and some of those otters have been slowly migrating south into British Columbia coastal waters. A small population of otters survived the initial slaughter in the Northern Channel Islands off California. Due to considerable federal and local efforts these otters have grown to where some are close to coming off the endangered species list in a couple of colonies. Many were translocated from the substantial Alaska population to WA, OR and Cal in the 1960s and 1970s with varying degrees of success.
Southern Sea Otter with Purple Urchin. photo Credit: Morgan Rector
The same loss of sunflower sea stars occurred in Monterey Bay, Mendocino and Sonoma coasts on the Central and north CA coast and some of their kelp forests were decimated into the urchin barrens, while others maintained their structure. The local otter population stepped in to pick up the slack left by the sunflower losses. Although these otters ate three times their normal intake of urchins, it was not enough to fully replace the sea stars’ take. There are a few other lesser predators along the California waters that I’ll note shortly.
Pollution:
No surprise here as kelp is sensitive to environmental pollutants of all sorts. Kelp beds are generally nearshore and within range of terrestrial based pollutants such as the usual suspects: sewage, industrial disposal, and coastal runoff from urban areas and along tributary rivers. I noted above that kelp lives and grows by photosynthesis and therefore requires clear water that sun light can penetrate. Pollution related turbidity (murky water) decreases the opportunity for photosynthesis and therefore kelp growth. In addition to the murky water the many toxins in the various pollutants themselves are harmful.
Sewage pipe draining into the sea. Marine pollution is one of major causes of kelp forest loss. Credit: WorldAtlas
Information from the kelp survey of South Puget Sound (the southern part of the Salish Sea) showed that the areas where most loss occurred were close to urbans areas where there was minimal active current flow to bring in cold fresh water with needed nutrients. Also kelp growing in sheltered bays were found to be more sensitive to toxic input from shore. Less loss occurred in areas of strong current, cold water flushing the kelp beds and being closer to ocean condition. (It has recently been shown that street runoff containing residue from worn tires can kill Coho salmon. I wonder what it does to kelp and sea stars?)
A sad case of raw sewage deposit has existed until recently in the Strait of Juan de Fuca, the inlet from the Pacific Ocean to the Salish Sea. Victoria BC which is on the Strait has since 1894 piped their municipal raw sewage directly into the strait such that when the tide flooded from the open ocean it carried the sewage into the Salish Sea basin. Until January 2021, when its sewage treatment plant went online, Victoria was the last major North American coastal city to pump raw sewage into communal waters.
Oil spills from industry, refineries and container and tanker ships are a constant hazard as well. The Salish Sea has three major shipping ports in Vancouver BC, Seattle and Tacoma WA. Additionally, there are three large oil refineries that bring in crude oil and ship out refined products. Further, in our area there numerous derelict boats that sink or run aground in the Salish sea with inevitable oil and fuel leaks. Although there is little research documenting the direct adverse effects of oil spills on kelp forests, it takes little imagination to see the damage one can do.
Derelict vessel being raised from Puget Sound.
The Washington State Dept. of Natural Resources is has a program dedicated to recovering derelict boats and has recovered 900 over the past 19 years. It is an ongoing although expensive and limited program.
Over - harvesting of wild kelp:
Given the recent popularization of kelp for food and nutritional supplements its harvest has increased proportionately and in some places quickly became over-harvesting as was the case along the South American coast of Chile which is the largest macro kelp producer in the world. Despite the fact the kelp forests along the coastal waters of Chile have near ideal growing conditions with cold nutrient rich waters off its coast, they are losing kelp forests due to over harvesting that exceeds what it can sustain with natural growth. They are however instituting an aggressive research program to learn more about kelp and how to sustainably farm it.
There seems to be consensus among marine scientists that the losses of kelp forests globally are real and in many cases sustained. A common denominator is global and sea surface warming along with varying regional effects which are largely if not totally caused by human behavior. At this time the outlook for kelp forest restoration is not great. As noted above, when given the proper environmental conditions kelp can rebound rather quickly. However currently those ideal growing conditions in many areas of the global oceans are far from ideal and getting worse.
It seems that there are two basic categories of action needed to save the kelp ecosystem: Preserve and restore what can be restored and regulate those factors that are responsible for the ongoing degradation.
Restoration of lost resources:
A number of programs are currently operating or planned for restoring the kelp beds and the keystone critters who keep (kept) them safe.
Increase predator population. For those areas where the loss of kelp is due to loss of sea stars and other predators, a logical solution would be to restore the predators. An ongoing research program at University of Washington’s Friday Harbor Laboratories on San Juan Island in collaboration with the Nature Conservancy has for the first time succeeded in breeding sunflower stars nurturing them to juvenile stage in their lab in hopes that one day they might be able repopulate the remaining kelp forests. Their first brood of stars have now reached a year old but are only about an inch across — at full size they are two feet across. They will need two to three more years to reach adult size where they can once again dine on the purple urchin. Whether this research program will be successful in sustaining and transplanting these juveniles into the natural environment is yet to be seen. There is yet much to work out and the vast numbers needed to have an affect might take years to grow.
Similarly, an increase in sea otters through extended protections and translocation from successful colonies in Alaska to areas of Washington and Oregon was once partially successful. Some of those moved to the northern Washington coast of the Olympic Peninsula did survive and now number about 2,000. There are none in Puget Sound itself. Those transplanted to Oregon did not flourish at all. Just recently at the request of Oregon Senator Jeff Merkely, the Oregon Fish and Wildlife department began looking into reintroducing otters from Alaska. However, the fishing and crabbing industries on the Oregon Coast are strongly opposed to this as are their counterparts in California. The Northern Sea Otters might not transplant well into California where their southern cousins are considered a subspecies. And even if it were to be successful, it would take some years to produce them at a level sufficient to make a difference in restoring the kelp forests.
Reduce the Number of Urchins:
Jon Holcomb dislodges purple sea urchins from rocks off the coast of Fort Bragg in Mendocino County in April 2018. A white, vacuum-like machine called an air lift sucks up the urchins and deposits them in a bag for disposal; the air lift can now remove almost 200,000 urchins daily (Photo by Brian Feulner / San Francisco Chronicle / Polaris)
Yet another direct strategy to take on the urchin scourge is to attack them directly. Divers in Monterey Bay are being trained to kill the urchins using a welding hammer. Apparently that does the job swiftly.
Another devise used is a vacuum system to suck them up off the bottom to be disposed of on shore. It is too soon to know how well these methods work to save the kelp but every little bit helps.
Regulation of the use and abuse of natural resources and actions that affect kelp forest
Clearly we need to curb ocean warming which is the major driver and that must be a global effort. At the same time we need to focus on more local and regional remediation and regulation of those factors that contribute the kelp losses.
Regulate and enforce freshwater and saltwater polluting by industries and municipalities. The solutions to freshwater and sea water pollution are well known such as reduce storm and sewage waste water that often runs directly into the marine environment. Local regulation or increased regulation of municipal and industrial discharge would go a long way to dealing with this problem. As long as oil products are transported by large ships, there can be no sure solution to the potential spills. Granted that there are currently numerous local and EPA regulations, enforcement is always after the fact and if caught, a relative slap on the wrist is little deterrent. We know what to do but need the financing and the will to make it happen. (Recall that it took Victoria BC 127 years to clean its sewage act up.)
California’s Marine Protected Areas: One model State program is the California system of Marine Protected Areas. As noted throughout this post, a balance among the numerous ecosystem components is critical to sustaining these kelp forests. Loss of critical components of the system leads to breakdown of the system as a whole. Recognizing that it’s coastal waters were under significant stresses from fishing, harvesting and pollutants, in 2003 California designated a network of 124 Marine Protected Areas (MPAs) comprising about 16% of its coastal waters. Some of these MPAs totally prohibit taking anything from the waters i.e. no fishing or harvesting of kelp. A recent study demonstrated how such protection can positively contribute to the maintenance of their kelp forests even in the face of larger forces beyond their immediate control such as those that led to the loss of the sunflower star and the flourishing of the purple urchin.
Recognizing the dramatic loss of some, but not all kelp forests off the coast, a team of marine scientists from Marine Science Institute at UC Santa Barbara conducted a study in the Northern Channel Islands that examined the effects of various predators on the purple urchin before and after the demise of the sunflower sea star. They noted that kelp forests within the MPAs were substantially less ravaged than those areas adjacent to, but outside of the protected areas. Fortunately they had extensive data on size of the forests, presence of urchins and various urchin predators for 20 years prior to the loss of the sea stars that they could compare with the state of the forests and their denizens after the losses.
In addition to the sunflower star, other urchin predators exist in the southern California waters: The spiny California Lobster, the California Sheephead fish and the sea otter. Although these three are not exclusively urchin predators, they do eat them and contribute to keeping them under control within the kelp forest. The UCSB researchers found that abundance and size of the Sheephead fish and the Spiny lobster was greater within the MPAs where no fishing was allowed than they were in adjacent areas outside the MPA. Consequently, protecting the fish allowed them to grow larger and in greater numbers, rendering them more effective predators of the urchins. In these protected areas the kelp was largely sustained in spite of the loss of the sunflower stars because of the redundancy of urchin predators.
Washington State totally prohibits the commercial harvest of wild kelp, sea weed and grasses and tightly regulates recreational harvesting which requires a license. Recreational harvest is allowed at only three State Parks. And the season is open for only one month in the spring. Individuals are limited to 10 pounds. Further to ensure continued growth, Bull Kelp fronds must be cut at least two feet above the floating bulb. It hardly seems worth the effort to motor out to a kelp bed to cut a few fronds.
Comprehensive State Plans to restore Bull Kelp and marine resources:
Clearly the loss of kelp is a multifaceted problem and thus will need a large integrated cooperative attack to achieve any degree of resolution of the losses and restoration. Washington State is gearing up just such a plan. This plan was formulated with multiple group inputs including seven Universities, seven local tribes, numerous Federal, State and county entities and NGOs.
This Puget Sound Kelp Conservation and Recovery Plan (Kelp Plan) provides a frame work for coordinated research and management actions to protect these fundamental and iconic kelp species from a suite of global and local stressors.
The report on this plan was completed in May 2020 and is currently in action.
Although called Puget Sound plan, the multiple agencies involved will be collaborating with Canadian officials and with them will include the entire Salish Sea.
Concurrent with the Washington Plan, California’s Ocean Protection Council has implemented a five year strategic plan to preserve and revitalize its marine shores and resources. Like Washington’s plan, California’s calls together numerous agencies, local, state and federal to attack the marine resources issues confronting them.
We wish them well.
IF ALL ELSE FAILS, TRY THIS: EAT MORE URCHIN:
Finally if all of these efforts fail to bring back Giant and Bull Kelp forests, there is one final solution that is being promulgated in Oregon. In Portland OR urchins are popular sushi items called “uni.” Uni are urchin gonads of which they have five. According to the report, they are also good on sourdough toast.
According to “urchinomics”, they also popular on sushi menus internationally.
Sea urchin served with pasta.
Stephani Gordon / OPB
If anyone wants to buy in on this new craze, you can contact Urchinomics, a Norwegian company that collects and nurtures urchins and sells them commercially to restaurants as a luxury seafood dish. Other proposed uses of these urchins include fertilizer and animal food.
I find it a bit ironic that one of the uses for harvested kelp was fertilizer and animal food!
Addendum:
An Oscar winner in a kelp forest:
“My Octopus Teacher” is a documentary that you can see on Netflix if you have not already seen it. It provides wonderful views of a kelp forest set on South African Coast. Although perhaps a bit hokie, it has great cinematography and a human attempt to connection with another intelligent animal. Although some have criticized the documentary for its anthropomorphism, if you can get past that, it remains a beautiful documentary of life in a kelp forest. Instead of sea stars, sea otters and urchins, it nourishes an octopus and a human.
After this amazing experience, Craig Foster, the human subject of the documentary, a cinematographer himself and his brother have started a foundation to preserve the kelp forests of the world. Further, during the course of his underwater tracking of the octopus, Foster discovered eight new species of shrimp. One of them, Heteromysis fosteri, was named after him.
I am sure that readers are doing their part to preseve our kelp beds, even if you don’t live by the sea.
Keep up the good work and tell us what exciting nature events are happening in your part of the world. We are all here to enjoy and marvel at the natural world of which we are a part. Let’s keep it going.
