Pacific herring
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.)
Herring Spawn: nutritious fast food in danger?
A recent SeaDoc-funded project has revealed how important herring spawn can be for species like migratory waterfowl. Eric Anderson, Jim Lovvorn and others studying the role of herring spawn in the diet of surf and white-winged scoters found that these birds aggregate to feed on herring spawn whenever it is available.
Using predator distributions, diet, and condition to evaluate seasonal foraging sites: sea ducks and herring spawn
Species of concern within the Salish Sea Marine Ecosystem: changes between 2002 and 2008
Potential impacts of infectious diseases to populations of Pacific herring in Puget Sound
Abnormalities in larvae from the once-largest Pacific herring population in Washington State result primarily from factors independent of spawning location
Species of concern in the Puget Sound Georgia Basin: changes between 2002 and 2006
The value of herring spawning events to spring conditioning of scoters in the Puget Sound & Georgia Basin
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.