Problems set 1

You have collected a 5 ml plasma samples from 27 anadromous sturgeon at the lower section of a freshwater river, just about 1 km above the rivers delta with the Pacific ocean. You analyzed the osmotic concentration of plasma and found the following data.

Fish ID....................mOsm
1.............................. 304
2.............................. 318
3.............................. 351
4.............................. 325
5.............................. 305
6.............................. 302
7.............................. 314
8.............................. 307
9.............................. 318
10............................ 336
11............................ 321
12............................ 301
13 ............................333
14............................ 306
15............................ 322
16............................ 320
17 ............................355
18.............................322
19............................ 299
20............................ 339
21 ............................319
22............................ 316
23............................ 355
24............................ 339
25 ............................343
26............................ 326
27 ............................305

A series of previous studies have reported that the entire sturgeon population at that locality had a mean osmotic concentration of 315mOsm and those specimens were known to be in their full freshwater stage. You do not know if the samples you collected this time are from sturgeon in their freshwater stage or are specimens returning from the ocean, which should have higher blood osmolarity. What do you conclude (show all work).

You know have subdivided your samples into two major age classes and wish to determine if there is an age-effect on osmoregulation as measured by the osmotic content (mOsm). Do your data (below) support this age-specific mechanism? (show work).

Sexually mature Sexually immature
304........................... 322
318........................... 320
351........................... 355
325........................... 322
305........................... 299
302........................... 339
314........................... 319
307........................... 316
318........................... 355
336........................... 339
321........................... 343
301........................... 326
333........................... 305
306

You wanted to know if the sexually immature sturgeon altered their blood plasma osmolarity if exposed to full strength seawater for 1 day. Using the data below what do you conclude (show all work)

Day1........................Day 2
322........................... 335
320........................... 329
355........................... 356
322........................... 331
299........................... 305
339........................... 342
319........................... 316
316........................... 315
355........................... 365
339........................... 341
343........................... 351
326........................... 329
305........................... 310

Finally, you wanted to determine if there is a decrease in the blood plasma osmolarity as mature sturgeon swim upriver. You collected data for mature specimens at three sites. Is there a difference among sites, if so, which one. (Show work)).

1 km...............2 km..................3 km
304................... 297................... 256
318................... 260................... 243
351................... 288................... 261
325................... 258................... 269
305................... 265................... 269
302................... 306................... 278
314................... 295................... 265
307................... 313................... 248
318................... 297................... 254
336................... 260................... 271
321................... 312................... 242
301................... 251
333................... 260
306

What is your overall conclusion from the series of experiments. Make a concise and precise statement that summarizes all the findings on your sturgeon study.