unpalatable fish of the warm waters of the great valleys in the interior of the state”. Onespeciesthat has experienced lasting success is striped bass Morone saxitallis . In1879,about135Stripedbasswerebrought from the Navesink River in New Jersey, and planted in theCarquinezStraitsnearMartinez. Thiswasfollowed by an introduction in 1882 of 300 striped bass from theShrewsburyRiver,alsoinNewJersey. Thefish wereplantedintoSuisunBaynearArmyPoint. The introduction was successful and within ten years, a commercial gill net fishery flourished in the Sacramento- SanJoaquinrivers. Later,in1935thecommercialfishery was curtailed in favor of the sport fishery.
Another nonnative species that has gained popularity as a sport species is the largemouth bass Micropterus salmonids . Although there are no early records of largemouth bass being intentionally stocked in the Delta, “black bass”, most likely smallmouth bass Micropterus dolomieu , were introduced into the Feather River in 1891. Additional introductions followed and as early as 1910, many of the rivers and sloughs of the Sacramento and San Joaquin rivers were reported as “teeming” with largemouth bass M. salmoides . By the 1950’s, sport fishing for largemouth bass in the Delta was popular and by the 1970’s became even more so because of the popularity of black bass tournaments.
TheSacramento and San Joaquin rivershistorically providedspawningand nursery habitatsfor large runsofsalmonandsteelhead. Asearly as the 1860’s, the Sacramentoand San Joaquin riverssupported commercialsalmonfisheries. However,gold miningwith its dredgingandwater diversion in the second halfofthe 1800’s,followedbydam construction and development on all largeriversinthe mid-1900’s,blocked runs andeliminatedimportant spawning and nursery habitatsthatledtomajorreductionsofCentralValley anadromousfishruns.
With fewer numbers of salmon and steelhead coupled with the listing of certain species and runs as endangered, threatened, or as a species of special concern, along with our inability to correct environmental water management
Issue 1 April 2011
problems, more attention has been directed at non- water related topics. What was considered a minor problem in the past, an issue such as predation by nonnative fish on native species has today become the focus of attention and even lawsuits.
So what exactly do we mean when we talk about predator- prey relationships? Predation is a biological interaction where a predator (the one doing the eating) feeds on its prey (the one that is eaten) and the relationship between the two is referred to as the predator-prey relationship. So why is it important to understand predator- prey relationships? After all, most Delta anglers already know that a chartreuse spinnerbait is effective for black bass, and a hair- raiser or Hopkins jig will usually catch stripers.
A recent lawsuit brought by the Coalition for a Sustainable Delta, a nonprofit coalition made up of San Joaquin Valley water agencies, alleges that the enforcement of the sport fishing regulations enacted by the Fish and Game Commission maintains an elevated striped bass population. They contend that increased numbers of striped bass increase predation on fish species that are listed under the Endangered Species Act, such as winter-run Chinook salmon and Delta smelt. The Act prohibits any government agency, entity, or individual from "taking" a federally protected species without prior authorization. The plaintiffs contend that since Delta smelt and specific runs of salmon are listed by the Federal Government, the Commission’s action in setting bag and size limits and allowing striped bass to prey on listed species (e.g., take) is a violation of the Act. The Coalition claims on their website, “Predation by non-native striped bass is the leading cause of
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