We have spent the last several weeks introducing and defining a variety of terms used in steelhead management. This week, we shift to looking at terms related to steelhead biology, specifically terms used to describe different life stages of juvenile steelhead. Let’s start with eggs. These are the little round suckers that produce the fish. Seriously, everyone understands the …
Science Friday: What is PNI about and why is it important?
Another week, another Science Friday post from Wild Steelheaders United. Last week we discussed the acronyms used in hatchery literature and management plans. Now we narrow the focus a bit to understand how these acronyms are used with one another to evaluate genetic risks associated with hatchery programs — we even offer some formulas for you to geek out on. …
Science Friday: What the heck do all those acronyms mean?
Science Friday! Another chance to dive into the weeds and define some of the jargon used when discussing, studying and evaluating hatchery steelhead. This week we focus on acronyms commonly used in hatchery management plans. Anyone who has read through a Hatchery Scientific Review Group plan or review, or most any resource management plan for that matter, has probably …
Science Friday: What is introgression?
For this edition of Science Friday, we continue to define terms used in studies that evaluate hatchery steelhead (and often other species of salmon and trout). Last week we defined fitness and discussed how it is measured and why it is important to understanding the biology of steelhead. This week we take another step into the deeper end of the …
Steelhead 101: Defining types of steelhead hatcheries
Every steelhead angler is probably somewhat familiar with hatcheries. As we discussed last week, deciphering the jargon associated with hatcheries is important, but can also be difficult. This week’s terminology is more common-place, and many of you may be familiar with it already. But, just in case, let’s look at the terms used to broadly classify hatchery programs: segregated and …
Steelhead 101: Defining native, wild, hatchery and natural-origin
In recent posts we covered the basics of defining escapement and run size, and the ways these are measured by resource managers. Today, we turn our focus to the complex terminology used for describing and comparing hatchery and wild steelhead. Steelhead are typically referred to as either being “wild” or “hatchery,” but they may also be defined as being “native” …
Steelhead 101: Estimating steelhead run size
Recently we have described the various methods used by biologists and resource managers to estimate steelhead escapement, which is the number of fish that escape and survive fisheries (all forms of angling) to actually spawn in a watershed. Run size is the total number of steelhead that return to a watershed each year. In order to estimate run size …
Steelhead 101: Using weirs to estimate adult steelhead escapement
Recently we have described how scientists use redd counts and snorkel surveys to estimate steelhead escapement. This week we focus on weirs, a totally different way of counting steelhead. Rather than sending out surveyors to sample stretches of stream where they count redds or fish, the operation of a weir is much simpler. A weir basically blocks the river and …
Steelhead 101: Using snorkel surveys to estimate adult steelhead escapement
Another week, another post on how scientists and fisheries managers measure steelhead escapement. Last week, we described redd counts and why they are an important tool. This week, we review snorkel surveys. Snorkel surveys entail divers swimming in the river and visually counting adult steelhead. Like redd counts, snorkel surveys do not cover an entire river, but rather break …
Steelhead 101: Using redd counts to estimate escapement of steelhead
Last week we defined the terms run size and escapement. If you didn’t see the post, check it out. This week we will discuss how fisheries managers actually measure escapement for wild steelhead using redd counts, and some of the challenges they face in doing so. We begin with escapement because it is usually measured first, and …