Salmon
What's the Deal with Rockfish and Seals?
Harbor seal populations have exploded nearly tenfold in the Salish Sea since the 1970s, while at the same time many rockfish species have plummeted. Some fishermen blame that on the increase in hungry seals. But coincidence is not science. So who ya gonna call?
In the second year, 12% of the samples contained rockfish remains, particularly in the winter when there are fewer salmon locally. With all the seals in the Salish Sea, those numbers could impact rockfish recovery. That doesn't mean, however, that we should start controlling seal populations: this study showed seals also have a taste for dogfish, another major fish predator. So fewer seals could mean more dogfish. The real answer is to remember that all parts of our ecosystem are tightly intertwined. Rockfish recovery depends upon ecosystem recovery, including salmon recovery, herring recovery and so on around the Sea.
More information on this topic:
- The original report on this study (so you can see what we've learned since the first round)
- The Puget Sound Partnership's resource page on rockfish.
- SeaDoc's comments on the proposed (12/2009) rockfish conservation plan by the WA Dept of Fish & Wildlife.
- All the info on our site about rockfish (automatic search)
- All the info on the site about predator/prey relationships (automatic search)
(You can do these last two searches yourself by choosing "browse by species" or "browse by issue" from the Salish Sea menu at left.)
Species of concern within the Salish Sea Marine Ecosystem: changes between 2002 and 2008
When Food Can Kill: Salmon and Killer Whale Populations
A study published in Environmental Toxicology and Chemistry explains the process by which threatened and endangered killer whales in the waters of northwestern North America become contaminated with persistent organic pollutants, particularly polychlorinated biphenyls (PCBs), that are present in chinook salmon, their primary food source.
Two years of this study were funded as part of the SeaDoc Society's competitive grants program.
Two main observations were made. First, nearly 100% of the contaminants in chinook salmon were acquired while they lived in the ocean. Second, southern killer whales are contaminated with higher concentrations of chemicals because 1) they eat more salmon than their northern counterparts and 2) southern salmon have higher levels of contaminants than northern salmon because the southern waters are more contaminated than the northern waters. In fact, PCB concentrations in southern salmon were almost four times those in northern salmon.
It is known that salmon can lose as much as 80% of their lipid (fat) stores as they journey back to their natal streams. Salmon stop eating during this time and draw energy from their lipid stores. Thus, they are less nutritious to whales than they would be otherwise. Furthermore, southern salmon were found to have lower lipid content than northern salmon. Whales therefore eat larger amounts of salmon and consequently are exposed to larger amounts of chemicals in the salmon. Southern whales, in particular, consume as much as 50% more salmon to compensate for the fact that their food is, per unit, less nutritious.
Salmon paradoxically help killer whales (food) and harm them (contamination). This study is important because it illustrates the increasing amount of damage to fragile ecosystems that occurs as industries continue to dump waste into rivers and oceans.
To read the entire review, Persistent Organic Pollutants in Chinook Salmon (Oncorhynchus tshawytscha): Implications for Resident Killer Whales of British Columbia and Adjacent Waters (Vol. 28(1):148–161), visit http://www.allenpress.com/pdf/ENTC_28.1_148.pdf
Scientists try to uncover the dangers to Killer Whales
When seven resident killer whales that frequent inland waters of Washington went missing this year, there was no shortage of suspects.
SeaDoc Society convenes meeting to discuss Orca deaths
Read more about the meeting in a Kitsap Sun article by Christopher Dunagan.
Species of concern in the Puget Sound Georgia Basin: changes between 2002 and 2006
Salish Sea Facts
What is the Salish Sea?
The Salish Sea is one of the world’s largest and biologically rich inland seas.
The Salish Sea is the unified bi-national ecosystem that includes Washington State’s Puget Sound, the Strait of Juan de Fuca and the San Juan Islands as well as British Columbia’s Gulf Islands and the Strait of Georgia. The name recognizes and pays tribute to the first inhabitants of the region, the Coast Salish.
The name Salish Sea has been approved by naming boards in both British Columbia and Washington State as well as by the United States and Canadian naming boards.
Politically the Salish Sea is governed by the USA and Canada, but the international boundary separating the Puget Sound Basin (USA) from the Georgia Basin (Canada) corresponds to no natural barrier or transition. The border is invisible to marine fish and wildlife. Species listed as threatened or endangered under the US Endangered Species Act or the Canadian Species at Risk Act, including Southern Resident killer whales (Orcinus orca), marbled murrelets (Brachyramphus marmoratus), and some ecologically significant units or species of Pacific salmon (Onchorynchus spp.), traverse the boundary daily. Oceanographic processes such as freshwater inflows and wind driven surface currents exchange biota, sediments and nutrients throughout the larger ecosystem.
Salish Sea Facts:
- Coastline length, including islands: 7,470 km (1:250,000 scale World vector Shoreline and TEOPO2 topographic/bathymetric GIS grid)
- Total number of islands: 419 (1:250,000 scale World vector Shoreline and TEOPO2 topographic/bathymetric GIS grid)
- Total land area of islands: 3,660 square kilometers (1:250,000 scale World vector Shoreline and TEOPO2 topographic/bathymetric GIS grid)
- Sea surface area: 16,925 square kilometers (1:250,000 scale World vector Shoreline and TEOPO2 topographic/bathymetric GIS grid)
- Maximum depth: 650 meters (Bute Inlet, BC; 1:250,000 scale World vector Shoreline and TEOPO2 topographic/bathymetric GIS grid)
- Number of different marine animals species estimated: 20 species of mammals, 128 species of birds, 219 species of fish, and over 3000 species of invertebrates (Brown and Gaydos, 2007) http://www.vetmed.ucdavis.edu/whc/seadoc/pdfs/brown-gaydos07.pdf
- Number of species listed as threatened, endangered or are candidates for listing: 64 (Brown and Gaydos, 2007) http://www.vetmed.ucdavis.edu/whc/seadoc/pdfs/brown-gaydos07.pdf
Population Map of the Salish Sea
Why do we need marine fish and wildlife research?
Well the first reason is that scientific information excites us and makes us care; it gives us the information we need to get people excited about marine conservation. American’s love naming. Maybe it goes back to Adam’s task of naming the animals. Anyway, we feel that if you can name an animal, you know it. But is that really true? You recognize and can name a harbor seal, but how deep does it dive? How many do we have in San Juan County? What percentage of the harbor seals are estimated to be hauled out at any one time on a very low tide in the summer time? How long can they live? Why has the population rebounded? Harbor seals can dive to 600 feet with no trouble; then can utilize every foot of our Salish Sea marine ecosystem. We have about 7,000 in San Juan County. We know this because Washington State Fish and Wildlife does aerial surveys in the summer time when we know that about 60% of the seals are hauled out at any one time. Multiply the number counted by a correction factor of 1.6 and you have an estimate for the number of seals. The oldest reported harbor seal was 34 years old. The population has rebounded because of the enactment and enforcement of the Marine Mammal Protection Act. Facts like these make an animal much more interesting than its name alone!
It is the same thing with the Southern Resident Killer whales. Why do we care about saving killer whales? There are 3 reasons, the first of which is because we are emotionally tied to them. It is facts like they are a matrilineal society with pod leaders that can live to be 90 years old that makes us care. Just as information like that a female transient killer whale’s first born son will stay with her for her entire life makes us care.
The second reason we care about saving killer whales is because our health is intimately tied to their health and the health of the ecosystem. Southern resident killer whales have some of the highest levels of contaminants in their blubber of any marine mammal in the world. What do they eat? Salmon. How many of us eat salmon? Does that give you cause for concern? It should. Two porpoise species that frequent the Salish Sea provide us with another good example of how human health and well being is intimately tied to the health and well being of fish and wildlife. By studying wildlife and wildlife health, we can learn more about human health. Have you have heard about Cryptococcus gatii, the fungus that is killing people in Washington and BC? This fungus also has killed about 25 porpoise in the region and disease in porpoise has acted as an early warning for human and domestic animal health. We had dead porpoise in Washington before we this disease was killing people or cats.
The third reason we care about healthy fish and wildlife populations is economics. These Steller’s sea lions frequently seen in the Salish Sea during the winter each weigh about 2,000 pounds. How much salmon do you think one Steller sea lion can eat? What is the impact on endangered salmon stocks? What is the economic tradeoff between having sea lions for ecotourism and having salmon for fishing? I tell you: both salmon and Steller sea lions are important. The importance of salmon is obvious. What about of Steller’s Sea lions. People talk about whale watching, but let’s just talk about watchable wildlife in general rather than focusing on one species. In 2001, over 47% of Washington’s residents participated in wildlife watching. In doing so, Washington residents spent $979 million resulting in a total economic output of $1.78 billion, generating and or maintaining 22,000 jobs. Guess where most wildlife watching occurs” In Washington’s Rural Counties like San Juan County.
Let’s go from a 2,000 pound Steller sea lion, which by the way is larger than a grizzly bear, down to an invertebrate that lives of microscopic plankton. Let’s talk anemones. Let’s talk any of the over 3000 invertebrates we have in the region; take the white-lined dirona, which is just a type of sea slug. It is a beautiful sea slug and it is creatures like these that bring people from all over the world to San Juan County to SCUBA dive. The Washington SCUBA alliance reports that more than 15,000 divers are certified to dive here in the Pacific Northwest yearly.
That’s right, despite the cold water the world’s best known underwater explorer and original SeaDoc Jacques Cousteau rated diving in the Puget Sound as second in the world only to the red sea! More than 1,000 dive related businesses exist in the state.
Let’s move up the food chain a bit. We have over 225 species of fish in the region. In the 1970’s lingcod populations in Puget Sound proper were low, prompting an almost complete moratorium on fishing from 1978 to 1982. The same thing happened in the San Juans in the 80s and 90’s. Good science let us know what was happening with the population and good science gave us a simple solution to solve the problem. Shorten the season. A nine-month fishery with a daily bag limit of 2 was restricted to a 6-week fishery with a daily bag limit of 1. Since 2000, ling cod fishing has substantially improved in the San Juans. This is an example of economics and human health and well being; the ability to harvest local nutritious food.
And just like with marine mammals, fish research allows us to learn how cool fish are. Take a tiger rockfish. We have over 26 species of Rockfish in the Puget Sound area. Science gives us information that excites us about these fish. They are all members of the Scorpionfish family and have poisonous spines. Did you know that? Some are schooling, some are loners, some move, some stay on the same rock their entire adult life. Even if you capture them, take them up into a boat and move them several miles away and release them, they’ll be back at that same rock in a day or two. Science also is helping us to recover rockfish. When were buying out salmon licenses in the 1980’s people thought, hey, we can get these people to fish rockfish – hence the big spike in harvest in 1987 and 1989. Only, there was a little problem. We thought rockfish might live 30 years. Some species like the yellow-eye actually can live 118 years! You see, there is a reason for good science beyond interest, it is called economics.
This is a red- urchin. How old do you think it can live? In Washington State we harvest about 475,000 pounds or about ½ million dollars worth of red urchins annually. I think it is important that we know how long they can live so we can design harvest strategies to sustain the fishery for eternity. Red urchins, by the way, can live to be over 100 years old.
And don’t think I’ve forgotten birds. I have not. We have about 160 species of birds that depend on our marine environment and they embody everything I’ve told you today about why we need research. Take surf scoters as an example. Because the population has declined 50% over the last 25 years we needed to figure out where they went when they were not in Puget Sound. We implanted satellite transmitters and watched these bird - Wow - fly all the way to the Northwest Territories and Ninavut to breed, then back to Puget Sound; maybe some went down to Humboldt Bay to molt and then back here again! The satellite track on one animals shows it flew to the Northwest Territories, across the Beaufort Sea to Alaska then back down to BC and then Washington. Amazing! Science will amaze you and increase your respect for and appreciation of wildlife.
Science also tells us about diseases that birds can carry that can impact human health –diseases like HPAI H5N1, Salmonella, and others.
And of course, there is economics of bird recovery and having sustainable populations of wild birds. Bird watching is one of the most popular wildlife viewing activities for Washingtonians, who have the fourth-highest participation rating in the country. Did you realize that 36% of Washington residents regularly participate in bird watching activities? As a side note, only 16% fish recreationally.
So when you see or think about amazing fish and wildlife, think about how much science has helped us. It helps use appreciate how magnificent they are; It helps us understand how their health and the health of the ecosystem is intimately linked to our health; and it helps us economically, whether it was through harvest or through tourism and watchable wildlife.
Bald Eagle De-Listing
On June 28, 2007, the bald eagle was removed from the U.S. list of threatened and endangered species. After nearly disappearing from most of the United States decades ago, wildlife enthusiasts are celebrating the eagle’s recovery. Now that this keystone predator has been restored to historical levels, it will be important to monitor the eagle’s impact on marine birds.
Are Seals Causing Bottomfish Declines?
Many people have been concerned that a burgeoning harbor seal population is responsible for the declines in bottomfish like rockfish, lingcod and greenlings, but nobody has the data to show if this is true or not. If seals are eating large numbers of bottomfish, it’s important to know so we can make good decisions about where to locate bottomfish protection areas.