APPROACHES TO ITEMS BY STEELHEAD
AT BIG BEND POOL DURING 2010
In this piece, 2,309 approaches by steelhead to 1,092 items over a twelve-year period at Big Bend Pool are documented in a table and those approaches solely of 2010 are presented in another table. These 2,309 steelhead actions are a very small proportion of all of the generic rises seen every season just as the 1,092 items are clearly less than 0.0001% of the leaves, twigs, seeds, and other things drifting through the pool each season. In fact, these 1,092 items—only 21% of which are insects and crustaceans—make up less than 0.001% of simply the insects that drift over the pool during a season. I make this point because most rises are not for the purpose of approaching anything other than the surface and most approaches do not, in fact, make contact with the item approached.
The term approach is the general term used herein to identify any behavior that appears to be for the purpose of getting close to a specific item and includes, rises to items, mouthings or nudgings, swimming close to and turning away, and approaching and taking and expelling, or approaching, taking and keeping items. Thus a steelhead rise per se is not documented as an approach unless it appears to be for the purpose of approaching an item.
If feeding means purposely taking and swallowing nutritional items, less than 5%—perhaps considerably less than 5%—of these approaches represent feeding, or the approaching, taking, and keeping nutritional items. Our time on the pool suggests unambiguously that by far most of the actions documented represent curiosity on the part of the steelhead in question . . . whatever that means in steelhead terms. Finally, let me observe that, for the most part, these approach behaviors do not seem angry, fearful, or aggressive.
Do the steelhead in the pool approach items for the same reasons that the steelhead in the North Umpqua River fly zone approach flies? Who knows, probably even the steelhead don’t, but I expect so. I have watched as a friend rose a steelhead to a waking stick on the North Umpqua River and I have risen one to a pistachio shell on the same river.
After the 2010 table, the second table below, the text for each of this season’s approaches as documented in the natural history notes is given with a simplified row of data characterizing that information just above this text.
In the tables, the first four rows of data represent those items that could be construed as food (mayflies, caddis flies, crawdads, and other arthropods). The remaining rows represent non-food items and include: leaves, plant down (airborne seeds), miscellaneous items (these are listed below the table), and unknown items. Small fish chases are separated from these previously listed data because they seem different. The small fish are in the two to four-inch range and no steelhead pursuing one of these small fish has ever been seen to capture one; always, no matter how energetic the chase is at its start, the steelhead has appeared to turn away, giving up the pursuit.
Please note that my appreciation for what I was seeing the steelhead in the pool do has increased over the time that Sis and Maggie and I have been on the pool. Indeed, when first arrived in July of 1999, I thought that most of the rises and jumps observed were for the purpose of approaching items. It took quite a while to realize that most of the rises were for the purpose of getting air for their air bladder or simply to see above the surface. Virtually all of the jumps are to see above the surface. For these reasons, the approach data for 1999 is the most circumscribed and least comparable with the other seasons. For instance, 1999’s data shows that more food-like items were approached than non-food items. This is the only season for which this is true and probably represents the fact that I was not prepared to see steelhead rising to twigs and leaves and lichen, let alone see steelhead as they approached otters or mergansers.
Finally, some discussion of the Steamboat Creek temperatures and the numbers of steelhead present in the pool and incorporated into the tabulated data associated with the text of each entry from the notes is necessary. When entered in the individual text tables, the temperature is from Steamboat Creek above the much cooler Big Bend Creek, or about 150 yards above the pool. Because of the relatively cold tributary that enters Steamboat Creek about a 100 yards above the pool, the temperature of the pool itself is always cooler than this Steamboat Creek reading until around the middle of November when the two creeks seem to usually have dropped to the same temperature on most seasons, somewhere in the high thirties or low forties. The currents of the two creeks below their confluence are in a complex process of mixing throughout the pool and taking a temperature in the pool would be misleading and would also spook these highly aware creatures.
For anyone interested in frequency distributions, it is necessary to have some idea of how many times a particular fish behavior occurs, but it is also important to know how many steelhead are present and potentially capable of carrying out a particular behavior. For example, four approaches to items when there are ten steelhead present is a different circumstance than four approaches when there are two hundred fish in the pool.
The reader should also bear in mind the following things. Even when we are at the pool, much of our time is spent in the trailer or walking and, of the time that is spent at our perch overlooking the pool, some is spent napping, reading, or talking to visitors. So, season to season, what we see in the way of steelhead approaching items, varies in terms of how representative it is for a given season. These are real time data however. During the 2004 season for example, more time was spent at the pool than during the previous few seasons, however, I spent a lot more of this time writing in the trailer than ever before. With this in mind however, I am fascinated that the frequencies of fish rising to the different categories of items stays pretty much the same for each season. Go figure.
STEELHEAD APPROACHES
2010 through 1999 Common Era (CE)
note: when more than one fish approaches an item, that item is counted only once
ITEMS APPROACHED |
MAY |
JUNE |
JULY |
AUG |
SEP |
OCT |
NOV |
DEC |
TOTAL |
% |
Mayflies* |
|
|
|
|
8 |
21 |
26 |
5 |
60 |
5% |
Caddis Flies |
|
|
|
1 |
2 |
12 |
6 |
|
21 |
2% |
Crawdads |
|
1 |
|
8 |
5 |
4 |
|
|
18 |
2% |
Other Arthropods |
|
1 |
6 |
24 |
66 |
22# |
14 |
|
133 |
12% |
|
|
|
|
|
|
|
|
|
|
|
Leaves |
7 |
4 |
10 |
29 |
128 |
180 |
13 |
4 |
375 |
34% |
Plant Down |
|
|
|
14 |
15 |
1 |
|
|
30 |
3% |
Miscellaneous items |
4 |
5 |
9 |
49 |
127 |
93 |
6 |
1 |
294 |
27% |
Unknown items |
35 |
2 |
1 |
2 |
16 |
15 |
2 |
|
73 |
7% |
|
|
|
|
|
|
|
|
|
|
|
Subtotal |
46** |
13 |
26 |
127 |
367 |
348 |
67 |
10 |
|
|
|
|
|
|
|
|
|
|
|
|
|
Small 2 to 4-inch fish Chases*** |
|
|
|
11 |
23 |
52 |
1 |
1 |
88 |
8% |
|
|
|
|
|
|
|
|
|
|
|
TOTAL |
46 |
13 |
26 |
138 |
390 |
400 |
68 |
11 |
1,092 |
100% |
% |
4% |
1% |
2% |
13% |
36% |
37% |
6% |
1% |
100% |
|
|
|
|
|
|
|
|
|
|
|
|
No. of Steelhead observed Approaching Items |
46 |
15 |
44 |
289 |
960 |
854 |
85 |
16 |
2,309 |
|
— often more than one steelhead would approach the same item.
Miscellaneous items: feathers, area of a trout rise, otters, kingfisher, alder cones, mergansers, beavers, unknown plant parts, dead sticks, pieces of wood, bats, Styrofoam, bark, bubbles, fungus on a steelhead tail, fir needles, immature fir cones (reddish), sugar pine needle bundles, lichened sticks, cedar branchlets, lichens, leaf stems, blue-green algae, squirrel, stick with plant down attached, lichened bark, six-eight inch cutthroats, broad-leaved maple seeds, steelhead skin flap, parr with an autumn caddis, minnow carcass, six-inch ring-necked snake, racers and garter snakes, scales from a fir cone, alder catkins, large pink mushroom, spiders dragged by their airborne webs
* 22 of these approaches occurred during November of 2002
** 43 of these approaches occurred during May of 2002 and they were carried out by two winter steelhead
*** these are chases only and they were first counted during 2002. The mature steelhead in question always turn away before getting to the two to four-inch-long fish. No steelhead has yet been observed to take a small 2 to 4-inch fish .. Forty-eight of these small fish chases occurred during 2002 & 2009.
# 10/10/09 2:35 PM: the first and the only time I ever saw a steelhead jump to take a flying insect out of the air during my first eleven years at Big Bend Pool.
Take care and go well
Lee & Maggie