The model (Fig. 1) is composed of five levels of review and five corresponding “Decision Boxes”. Components of the model are described below, with decisions being based on scale values obtained from an “opinionnaire” (Table 1).
Note - A simplified model has been enclosed as Figure 2.
(a) Proposal for introduction of aquatic organisms
An entity desiring to realize an introduction would prepare a proposal that includes the answers to the following questions:
What is the current state of knowledge concerning the acclimatization
potential of the organism?
e.g., (a) Thermal requirements: tropical, temperate, Arctic; (b)
Habitat requirements: stream, river, lake, pond, etc., (c)
Reproduction: describe the spawning habitat and reproductive strategy
of the organisms.
A bibliography of pertinent literature should be appended to the proposal.
(b) Level of Review I
Purpose of introduction
Does the proposing entity have valid reasons for introducing the aquatic
organism? Could no native species serve the same function?
Abundance in native range
Knowledge of the population abundance of the organism in its native
range is an important aspect of the evaluation. Is it endangered,
threatened or rare? Is it exploited from the wild or under culture?
Communicable pathogenic organisms and parasites
The evaluation would include assessing the safeguards for avoiding
transmission of communicable pathogenic organisms or parasites to the
proposed receiving system(s).
Site of introduction
It is important to discern from the outset whether the organism would be
stocked in an open or closed system. Would it be stocked in or have
potential access to a major drainage? If it is to be maintained in a
closed system, the proposing entity must identify steps it would take to
guard against accidental escape.
Figure 1. Review and Decision Model for evaluating proposed introductions of aquatic organisms. Mean “opinionnaire” values (see Table 1) are used at decision-making points (Kohler and Stanley, 1984)
Table 1. Opinionnaire for appraisal of introductions of aquatic organisms.
Each member of an evaluation board or panel of experts circles the number most
nearly matching his/her opinion about the probability for the occurrence of the ev
| Response | |||||||
| No | Unlikely | Possibly | Probably | Yes | D k | ||
| 1. | Is the need valid and are no native species available that could serve the stated need? | 1 | 2 | 3 | 4 | 5 | |
| 2. | Is the organism safe from over-exploitation in its native range? | 1 | 2 | 3 | 4 | 5 | |
| 3. | Are safeguards adequate to guard against importation of disease/parasites? | 1 | 2 | 3 | 4 | 5 | |
| 4. | Would the introduction be limited to closed system? | 1 | 2 | 3 | 4 | 5 | |
| 5. | Would the organism be un able to establish a self-sustaining population in the range of habitats that would be available? | 1 | 2 | 3 | 4 | 5 | |
| 6. | Would the organism have mostly positive ecological impacts? | 1 | 2 | 3 | 4 | 5 | |
| 7. | Would most consequences of the introduction be beneficial to humans? | 1 | 2 | 3 | 4 | 5 | |
| 8. | Is data base adequate to develop a complete species synopsis? | 1 | 2 | 3 | 4 | 5 | |
| 9. | Does data base indicate desirability for introduction? | 1 | 2 | 3 | 4 | 5 | |
| 10. | Based on all available information, do the benefits of the exotic fish introduction outweigh the risks? | 1 | 2 | 3 | 4 | 5 | |
Figure 2. Review and Decision Model for evaluating proposed introductions of aquatic organisms (Kohler and Stanley, 1984) (Simplified by B. Steinmetz, unpublished correspondence).
| Review level | Opinionnaire value* | Decision | |||
| I | |||||
| 1. | Is the need valid and are no native species available that could serve the stated need? | ≤ 2 | - reject | ||
| > 2 | - to next question | ||||
| 2. | Is the organism safe from over-exploitation in its native range? | ≤ 2 | - reject | ||
| > 2 | - to next question | ||||
| 3. | Are safeguards adequate to guard against importation of disease/parasites? | ≤ 2 | - reject | ||
| > 2 | - to next question | ||||
| 4. | Would the introduction be limited to closed system? | ≥ 3 | - approve | ||
| < 3 | - to review level II | ||||
| II | |||||
| 5. | Would the organism be unable to establish a selfsustaining population in the range of habitats that would be available? | ≥ 3 | - approve | ||
| < 3 | - to review level III | ||||
| III | |||||
| 6. | Would the organism have mostly positive ecological impacts? | ≤ 2 | - reject | ||
| < 3 >2 | - to review level IV | ||||
| ≥ 3 | - to next question | ||||
| 7. | Would most consequences of the introduction be beneficial to humans? | ≤ 2 | - reject | ||
| < 3 >2 | - to review level IV | ||||
| > 3 | - approve | ||||
| IV | |||||
| 8. | Is data base adequate to develop complete species synopsis? | < 3 | - conduct detailed lit. rev. 1) | ||
| ≥ 3 | - to next question | ||||
| 9. | Does data base indicate desirability for introduction? | ≤ 2 | - reject | ||
| < 3 > 2 | - conduct research 2) | ||||
| ≥ 3 | - approve | ||||
| 10. | Would benefits exceed risks? | ≤ 2 | - reject | ||
| ≥ 3 | -approve | ||||
| 1) thereafter next step question 9. | |||||
| 2) research focused on potential impact on indigenous species and habitats. thereafter question 10. Value < 3 > 2 restart research. | |||||
* see Table 1 of Kohler and Stanley.
(c) Decision Box I
A proposal for an introduction would be rejected if:
reasons for introduction were not deemed valid;
the introduction is for reasons other than conservation where the organism is endangered, threatened, or rare in its native range; or
the proposing entity has not established that adequate safeguards would be taken to avoid introduction of communicable pathogenic organisms and parasites. The proposal would be approved at this stage when the above criteria are met and provided that the introduction is perceived as being limited to a closed system. When this last condition is not fully met, the evaluation process would proceed to the next level of review.
(d) Level of Review II
This and subsequent levels of review are directed to experts selected by the Working Group. In Level II, the acclimation potential is assessed (Question 5 of the “opinionnaire”, Table 1). Should pertinent information be insufficient, as evidenced by more than 50 percent of the experts marking “don't know” on the “opnionnaire”, the Working Group might suggest that the proposing entity conduct research with a limited number of specimens under confined conditions for the purpose of obtaining the required data. The Working Group may suggest that all research be conducted within the organism's native range.
(e) Decision Box II
The proposal for the introduction would be approved when there is a strong chance that the organism would not establish a self-sustaining population (average value 3 for Question 5 in Table 1). Alternatively, further evaluation would be mandated for those organisms that would likely produce self-sustaining populations, or when evidence is insufficient for making a seasonable prediction.
(f) Level of Review III
This level of review is based on predicting the potential impact of the organism on the ecological integrity of the system(s) where it is proposed for introduction. In addition, the analysis of benefit and risk would include assessing the array of potential impacts on man. Review at this level requires detailed knowledge on the ecological relations of the organism in its native habitat, as well as considerable information on the community structure of the proposed receiving system(s).
(g) Decision Box III
The introduction would be rejected if the available information suggests (average “opinionnaire” values 2) that the organism would exert a major adverse impact on the receiving system(s) or on man. The proposal would be approved when indications are for the opposite outcomes. If the available information is not considered conclusive, the evaluation should proceed to level at Review IV.
(h) Level of Review IV
Level of Review IV requires development of a detailed literature review based on the format for a Food and Agriculture Organization (United Nations) Species Synopsis. However, additional sections concerning impacts of introduction (documented or potential) would also be required. Once the synopsis is prepared, this information will be sent again to the experts so they can attempt to arrive at a recommendation.
(i) Decision Box IV
On the basis of an analysis of the second round of “opinionnaire” data, the
Working Group would either approve or reject the proposed introduction.
Additional review (Level V) would be necessary whenever the current data base is
not considered sufficient, or if it is unclear whether the introduction is
desirable.
(j) Level of Review V
This level of review requires that research be conducted to complete the species synopsis or to assess the potential impact of the introduction on the indigenous flora and fauna and habitats. It might be suggested that research be conducted under controlled conditions near the site where the introduction is contemplated or the Working Group may suggest that all studies be carried out within the organism's native range.
(k) Decision Box V
Using all information collected at this stage, the Working Group should be able to make an informed recommendation regarding the proposed introduction. However, the Working Group may find it necessary to suggest additional research if important questions remain to be resolved. In such a situation, the fifth and final evaluation stage would become a loop of the “Review” and “Decision” models until a recommendation could be made.
