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An International Survey of Reef aquaristics

How many of you readers have ever wondered: "How do other aquarists in other countries solve this problem ?" or "Am I doing things right ?...... I wish I knew what fellow aquarists would do in this situation !" ?.

During spring 1997 we wondered if it would be possible to log the status of the reef aquarists on an international basis? It would obviously be most interesting to compare statistically the status of the hobby from different parts of the world. Are there, for instance, major differences in the use of technique in German reef tanks versus American reef tanks? Or, what are the biggest difficulties encountered by European aquarists, and are these the same as those which are troubling aquarists elsewhere in the world? We had never seen any surveys previously done on this subject, at least not extensive ones, nor on an international basis. We had no doubt that it would be worth the effort to carry out such a survey on our own; - so we decided to give the international survey a chance !

The rapidly growing use of Internet world-wide gave us the possibility to, in a simple way, spread a survey to many countries, while - at the same time - aquarists could respond without using stamps and envelopes. Furthermore, on order to get reasonable coverage also in countries where the use of Internet is less common, we distributed copies of the survey form per snail mail to aquarists societies and shops for them to distribute among their members/customers.

When reaching the end of August, the deadline for participating in the survey, we had got a total of 683 answers from 33 countries. See details below.

Statistic material can be treated in different ways. In all surveys some answers tell you a lot while others are of little value. When the survey is done and the results are counted, you are bound to discover that some questions should have been phrased in another way, or that you rather should have ask about other, more or less related, topics. Still you have to do the best out of the material you actually have, and in our case we believe we have uncovered highly interesting trends and tendencies, indeed. In order to cover the few aspects where we should have asked differently to get clearer results, we'll have to get back to you all on another occasion.

We used Microsoft Office-97 EXCEL spreadsheet for treating the answers and estimating the relative frequencies of each question. The number of answers is named "n", meaning that if we look on all answers world-wide as one, single group, where n is equal to 683. If we, however, look at answers from Germany only, then n equals 155. See further details below.

In many of the questions one and the same aquarist marks several alternative answers. We have chosen what is normal in such cases, to look at each single answer-alternative as a separate question. Let us look at question #22 in section C as an example. The question sounds:

For adding calcium I use:.....

......and has the following answer-alternatives:

ß no adding
ß "kalkwasser"
ß "kalkwasser" and CO2
ß "kalkwasser", CO2 and pH-control.
ß Carbon reactor with calcareous material and CO2 adding.
ß Carbon reactor with calcareous material, CO2 and pH-control
ß other type of calcium adding.

From Germany, where we got 155 forms back, question #22 gave 189 markings. Some aquarists use more than one way of adding calcium and have, of course, checked more than one alternative when they answered this question. Consequently, when we estimate the relative frequency (in %), and look upon each alternative answer in question 22 as a separate question, we get a sum higher than 100%. Those aquarists that have checked more than one alternative, count for two or more aquarists, depending on how many alternatives they actually checked. Table 1 shows the result:

         TABLE 1:

Alternatives Number % (n=155)
No adding 11 7.1
Kalkwasser 79 51
Kalkwasser + CO2 5 3.2
Kalkwasser + CO2 + pH control 3 1.9
Kalkreactor + CO2 36 23.2
Kalkreactor + CO2 + pH-control 33 21.3
Other type of adding 22 14.2
SUM 189 121.9

In this case there are 34 aquarists or 21,9% that have checked for more than one alternative in question #22. We can call this group "multiple answers". Potentially there will also be a group of responders who have not answered the question, either because they cannot, or because they will not answer to that particular problem. We call this group "refusers". With respect to the example above the group of "refusers" in fact counts zero as all the 155 responders had answered question #22, but so is not the case for all questions.

The divergence in the sum of the relative frequency above or below 100% indicates how many "multiple answers" and "refusers" there are. It will not be totally precise to compare the results of questions where the number of "refusers" are high with the results of questions that have a low number of "refusers".

It will, however, be correct to compare two or more questions which all have low numbers of "refusers". In any case the different alternatives in each question can be compared with one another. For instance the frequency for question #22 from Germany clearly tells us that about half of the aquarists use "Kalkwasser" while only a very small number use "Kalkwasser" combined with CO2. This finding can in turn be compared with the results for the same question in other countries or regions.

Alternatively we could have used n = 189 for question #22 and used different "n"-values for each question where "n" was equal to the number of markings in each question. This, however, would make it even more difficult to compare the results. The number of respondent world wide is shown in table 2:

Countries Number of responders
USA 297
Rest America 9
Rest Europe 22
Rest World 17
Total 683

The results are grouped in 6 different files to download:

R1:        WORLD (n=683)
R2:        USA (n=297) vs. GERMANY (n=155) vs. REST WORLD (n=231)
R3:        GERMANY (n=155) vs. REST WORLD (n=528)
R4:        USA (n=297) vs. REST WORLD (n=386)
R5:        EUROPE (n=325) vs. REST WORLD (n=358)
R6:        GERMANY (n=155) vs. REST EUROPE (n=170) vs. REST WORLD (n=358)

The results are official and you are welcome to use them for your own purposes. We would be happy if your local aquarium club would discuss the findings. If you use it in your club magazine or equal publications, we would, however, greatly appreciate receiving two (2) copies of the publications for our files. Please mail to: Alf Jacob Nilsen, P.O.Boks 142, N-4401 Flekkefjord, Norway

Created by liquid
Last modified 2005-02-03 06:17