The Fishing Pause Ends: Part 3

So this morning the fishing pause ends.

What is the fishing pause ? In Wisconsin the early season catch and release inland trout season ends a week before the regular season starts. Last week all fishing for trout was closed on the inland streams. This morning the regular season starts, and one might be sure that most of the catch and kill that occurs throughout the season will happen in the next couple of weeks across the states trout streams. If science mattered we would know that the continued selection of the largest classes of fish for harvest have destabilizing effects on the stream populations and ultimately are negatively selecting for large fish, as those are the ones that are generation after generation failing to reproduce. We can also know that across the board hatchery fish are no replacement for wild fish. Hatchery fish have smaller brains, and reproduce at a vastly lower rate in the wild. A recent study indicates that the Chinook salmon runs in California had as few as 10% wild fish, with the concomitant problems that comes both in putting a far weaker fish into the environment and masking the collapse of the wild fish population. Yesterday all fishing for salmon on the west coast was closed:

All salmon fishing banned on West Coast

Salmon fishing was banned along the West Coast for the first time in 160 years Thursday, a decision that is expected to have a devastating economic impact on fishermen, dozens of businesses, tourism and boating.

Commerce Secretary Carlos Gutierrez immediately declared a commercial fishery disaster, opening the door for Congress to appropriate money for anyone who will be economically harmed.

The closure of commercial and recreational fishing for chinook salmon in the ocean off California and most of Oregon was announced by the National Marine Fishery Service.

It followed the recommendation last month of the Pacific Fishery Management Council after the catastrophic disappearance of California's fabled fall run of the pink fish popularly known as king salmon.

It is the first total closure since commercial fishing started in the Bay Area in 1848.

It isn't as if this should be a surprise. We consistently pay no attention to the facts as they sit in front of us regarding management of these resources. These are not isolated scientific data sets. The recent article in National Geographic about the the collapse of the international fish stocks had this quote:

For reasons not fully understood, when areas are closed to fishing, snapper aggregate within them, forming large resident populations. Spiny rock lobsters ("crayfish" to New Zealanders) do the same. Their density inside the reserve is about 15 times higher than outside. Commercial crayfishermen have cashed in on the reserve's success because the outward migration of crayfish—a process marine biologists call spillover—brings the crustaceans to their pots, strategically placed just outside the boundary. These former skeptics are now some of the reserve's staunchest defenders. They refer to it as "our reserve" and act as marine minutemen, reporting poachers and boundary cheats.

S0 do these macro systems say anything about the rivers of the Midwest ? Our own history of the elimination of species, the Michigan Grayling, the Lake Superior Coaster and the Lake Michigan Lake trout all speak to the fact that all of these natural systems have been damaged and continue to be the wanton acts and policy of who and what we are as the alpha predator.

A curious thing happens when fish stocks decline: People who aren't aware of the old levels accept the new ones as normal. Over generations, societies adjust their expectations downward to match prevailing conditions. The concept of a healthy ocean drifts from greater to lesser abundance, richer to poorer biodiversity.

So today the fishing pause ends.

The Fishing pause: Part 2, more Damn Science

From the Science Daily


Fishing Throws Targeted Species Off Balance, Study Shows

ScienceDaily (Apr. 21, 2008) — Fishing activities can provoke volatile fluctuations in the populations they target, but it's not often clear why. A new study published in the journal Nature by scientists at Scripps Institution of Oceanography at UC San Diego and colleagues has identified the general underlying mechanism.

Research led at Scripps with a distinguished team of government and international experts (including two chief scientific advisors to the United Kingdom) demonstrates that fishing can throw targeted fish populations off kilter. Fishing can alter the "age pyramid" by lopping off the few large, older fish that make up the top of the pyramid, leaving a broad base of faster-growing small younglings. The team found that this rapidly growing and transitory base is dynamically unstable-a finding having profound implications for the ecosystem and the fishing industries built upon it.

"The data show that fished species appear to be significantly more nonlinear and less stable than unfished species," said Professor George Sugihara of Scripps. "We think the mechanism involves systematic alteration of the demographic parameters-and especially increases in growth rates that magnify destabilization in many ways-which can happen as fishing truncates the age structure."



How exploited and unexploited fish populations differ. (Credit: Image courtesy of University of California - San Diego)

Read the whole article here

The fishing pause: Part 1- Damn Science

From the Science Daily

Fewer Fish Eggs, Smaller Fish Result From Over-fishing

ScienceDaily (Jan. 24, 2006) — The practice of harvesting the largest individuals from a fish population introduces genetic changes that harm the overall fish population, a UC Riverside graduate student and colleagues have determined. Removing the large fish over several generations of fish causes the remaining fish in the populations to become progressively smaller, have fewer and smaller eggs with lower survival and growth, and have lower foraging and feeding rates, the researchers report.

The figure shows the decrease in body size in Atlantic silverside as found by a research team led by UCR graduate student Matthew Walsh. The silverside, having been reared for five generations in laboratory experiments, are all the same age. The fish shown here are from the fifth generation. The fish on the left are from populations from which large individuals were harvested over five generations; the fish in the middle are from populations from which fish were harvested at random over five generations; and the fish on the right are from populations from which only small fish were harvested over five generations. (Photo credit: M. Walsh)