Saturday, June 16, 2012

The Rate of Growth of Flathead Catfish

 I found a great resource online recently that has a lot of material from Oklahoma state biologists dating back to 1921. Over the next few blogs, we'll be posting up some information from those resources. All rights reserved and credit goes to those Biologists who did the work.


The Rate of Growth of Flathead Catfish
in Twenty-one Oklahoma Lakes
H. A. McCOY, Oklahoma Game and FIsh Department, Norman, 1953



In the computation of average lengths in individual waters, fish were grouped into year-classes and a weighted average was obtained. The simple average of the weighted means for each lake was computed 'to establish the average length at the end of each year of life for the entire sample. On the basis of this sample, flathead catfish average about 4.6 inches at the end of the first year of life, and during the succeeding 13 years attain average lengths of 9.7, 15.2, 20.0, 23.4, 25.9, 28.9, 32.4 35.1, 38.3, 39.0, 41.5, 42.8, and 43.3 inches. Corresponding average weights at these lengths (calculated from length-weight formula in later section are approximately 0.03, 0.31, 1.34, 3.28, 5.47, 7.61, 10.88, 15.77,20.48, 27.20, 28.87, 36.32, 39.06, and 40.67 pounds, respectively. The average annual increment of growth in length is approximately flve inches tor the tirst four years of Ufe, three inches during the following six. years, and decreases to about one inch per year by the fourteenth year (Table II, Figure 1). The average annual increment of growth in weight ae~leratea sharply to about five pounds per year by the ninth year of life (Figure 1). On the basis of three-year moving averages the rate of weight increase declines slighUy after the tenth year of Ufe. However, this phenomenon is not typical of large reservoir populations




AGE-GROUP     NUMBER OF FISH     AVERAGE LENGTH    LENGTH RANGE
III                                   4                                      18.4                       16.9-20.0
IV                                   3                                      22.9                       21.7-23.5
V                                    17                                    27.45                     25.6-28.7
VI                                   4                                      32.2                       30.6-34.3
VII                                  4                                      36.2                       31.6-38.5
VIII                                 -                                       -                            -
IX                                   2                                      40.5                       39.8-41.1
X                                    3                                      38.0                       33.5-39.0
XI                                   6                                      39.5                       36.0-46.0
XII                                  4                                      45.7                       43.0-48.0
XIII                                 9                                      44.2                       41.2-54.5
XIV                                 6                                      44.6                       43.1-46.7
XV                                  5                                      46.3                       41.2-55.5
XVI                                 4                                      43.7                       37.2-50.5
XVII                                1                                      43.1
XVIII                               2                                      43.2                       42.0-44.5
XIX                                 1                                       42.0


A 42.0-inch, 19-year-old flathead catfish taken from Boomer Lake was
the oldest individual in the entire sample, and is the oldest individual of
any Oklahoma species on record at the Fisheries Research Laboratory.

The largest flathead catfish represented in the entire sample was 55.5 inches
long and weighed 95 pounds. This 15-year-old individual, taken from
Boomer Lake, has a calculated weight of 91 pounds.

The Length-Weight Relationship of Flathead Catfish in Oklahoma Water.
SIZE INTERVAL     No. of      AVERAGE TOTAL     AVERAGE WEIGHT     CALCULATED
(INCHE8)                FISH       LENGTH (INCHES)         (POUNDS)             WEIGHT (POUND8)
------
3.0- 4.9                    12                    4.2                                 0.03                             0.02
5.0- 6.9                    20                    5.9                                 0.08                             0.06
7.0- 8.9                    37                    7.9                                 0.18                             0.16
9.0-10.9                   33                    10.0                               0.36                             0.34
1l.0-12.9                  27                    11.9                               0.69                              0.60
13.0-14.9                 36                    13.8                               0.91                             0.98
16.0-16.9                 20                    15.8                               1.37                             1.51
17.0-18.9                 26                    17.9                               2.15                             2.29
19.0-20.9                 17                    19.9                               3.14                             3.23
21.0-22.9                 12                    22.0                               4.25                             4.47
23.0-24.9                 22                    23.8                               5.93                             5.82
26.0-26.9                 26                    26.1                               7.80                             7.77
27.0-28.9                 32                    27.8                               10.16                           9.58
29.0-30.9                 19                    29.9                               12.21                           12.12
31.0-32.9                 14                    31.9                               15.67                           15.05
33.0-34.9                 13                    33.6                               18.26                           17.76
35.0-36.9                 14                    36.1                               23.50                           22.44
37.0-38.9                 14                    37.6                               25.94                           25.60
39.0-40.9                 8                      39.6                               30.07                           30.46
41.0-42.9                 7                      41.7                               35.24                           35.87
43.0-44.9                 11                    43.6                               40.35                           41.43
45.0-46.9                 1                      45.7                               50.00                           48.35
Total Number of Fish - 421

2 comments:

  1. That is interesting. Do you know if age affects taste?

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    1. I don't have any specifics or scientific data on that. I do, however, prefer to keep catfish between 2-10 pounds for eating. They tend to not be as grainy or taste like dirt/mud. Also, when cleaning the fish, skip the belly meat, that is where most of the taste comes from. Any meat that has a yellow tint to it, cut it out. That is usually where you'll get the undesirable taste.

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