How can you "manage" the fish you can't see?
Lavern Weber once said "when you pull thousands of tons of fish out of the water, you aren't sure what it does to the other species left behind." So, this is where fisheries management becomes critical - for today, and for the future.
Fish are an important source of protein, and Oregon’s many fisheries (including crab, shrimp, salmon, flatfish, rockfish, sablefish, lingcod, and whiting) provide employment for many of Oregon’s coastal communities. These fisheries also provide recreational opportunities for our coastal residents and visitors. Ensuring that Oregon’s fisheries remain sustainable and productive is an important aspect of some of the research conducted by David Sampson and other COMES faculty.
When fisheries are managed on a sustainable basis – which allows the stocks to continue to be productive year after year – the harvest levels will be below the level that jeopardizes the fisheries’ long-term health.
The biological characteristics of a particular fish stock help determine how that fishery might be managed. Seasonal closures, which would allow no harvesting of that species during that time period, and closing areas known to be habitats of the species are two of the methods that may be used. Others include restrictions on fishing gear and limits on the sizes of the fish that can be landed. A combination of any of these techniques may also be used. Size limits are important because the taking of too many young fish wastes their growth potential and their contribution to the future breeding pool. Taking too many of breeding age and size will also reduce the future population of the species.
One common approach to limiting the commercial fish harvests is for the fishery management authorities to impose quotas on the catch. When the quota has been reached, the authorities close the fishery for the remainder of the fishing season. Although fishing quotas can cause disruptions to the supply of these seafood products, and may be viewed by some as unwanted government intervention, they provide important safeguards that prevent fish stocks from becoming badly depleted.
Managing a fishery is a complicated and challenging process that must try to balance competing needs – today’s need for seafood and the fisherman’s ability to earn his living, versus tomorrow’s need for a healthy, abundant, and economically sustainable fishery.
Stock assessments provide basic information on the status of the fish stocks by providing fishery management authorities with information about whether the stocks are increasing or decreasing, and why. When stock assessments under-estimate the health or productivity of a fishery, management authorities may reduce the number of fish caught by setting catch quotas that are too small, which can result in lost fishing opportunities. In turn, this reduces the supply of seafood and the economic opportunity for the fisherman.
When stock assessments are overly optimistic – indicating the fishery is healthier or more abundant than it actually is – harvests can be unsustainably large. When too many fish are taken, as a result of a misleading stock assessment, future reproduction rates will be too low to replace those fish already taken. When long-term productivity is reduced, the fishery will decline, and may no longer be sustainable.
A stock assessment is a specialized form of statistical analysis, which reconstructs the history of the stock from data collected from the fisheries on the annual catches and their age- and size compositions. For many stocks there are also research surveys that provide information, independently from the fisheries, concerning a stock’s biological characteristics. Making sense of the available information is often a very difficult task. The patchiness and inaccessibility of most fishes, coupled with natural variability and an uncontrolled environment, make it difficult to measure, let alone predict changes in fish stocks and fisheries.
The fisheries within Oregon’s marine territorial waters are managed by the Oregon Department of Fisheries and Wildlife (ODFW). The fisheries off Oregon that operate outside of Oregon’s waters are managed by the Pacific Fishery Management Council (PFMC) in collaboration with the ODFW, the US National Marine Fisheries Service, and the fisheries agencies of Washington and California. Faculty from COMES have been active in providing ODFW and the PFMC with technical expertise and advice on stock assessments and fishery management issues.
Agencies providing additional information include:
Oregon Department of Fisheries and Wildlife – Marine Program
Pacific Fishery Management Council - PFMC
SeaGrant/University of New Hampshire Guide to Fisheries Stock Assessment