menu icon


SCRFA Main Logo

Database Field Descriptions (parameters)

Lunar phase : The timing of many spawning aggregations is linked to the cycle of the moon. Lunar phase refers to the 4 phases of the moon that occur each month for approximately 7 days each. These are, in order, New Moon, First Quarter, Full Moon and Third Quarter and appear in the search results as New, First, Full and Third, respectively. Some aggregations may only last for a short period of the Lunar Phase indicated, others may last for weeks in which case all the Lunar phases covered will be indicated. If all Lunar phases are indicated this suggests that the timing of the aggregation is not linked to the moon cycle but can occur in any phase.

Geomorphological type : Physical characteristic of the spawning site such as reef channel or pass.

Habitat : Habitat associated with the spawning site, such as seagrass, artificial reef, sand channel, etc.

Aggregation type : An aggregation refers to a group of fish of the same species gathered together, as indicated by fish densities being significantly higher than those found during the non-reproductive period; there are two types of aggregation recognized, depending on the distance traveled from the area of typical residence to the aggregation site, and the frequency with which they form each year.

Resident aggregations: Individuals travel a short distance, from their typical site of residence, to the aggregation site taking a few hours or less. Spawning may occur many times a year.

Transient aggregations: Individuals migrate long distances over days or weeks to the aggregation site during a very specific portion of just a few months of the year.

Months of spawning: The months of the year during which the spawning aggregation forms. Note that this may include all the months the aggregation has formed over several years and that the aggregation may not form in exactly the same months each year (i.e., there may be some year to year variability in the spawning months).

Sign of spawning : It is important to confirm that the aggregation observed has formed for the purpose of spawning (it is not uncommon, for example, to observe a non-spawning aggregation such as for feeding). Both direct and indirect indications are used. Direct signs provide unequivocal evidence for spawning, indirect signs are other indications of spawning that need to be accompanied by supporting information.

Direct Evidence: The following spawning signs have been observed: actual spawning with release of sperm and eggs, hydrated eggs, and postovulatory follicles. Eggs become hydrated just a few hours before spawning while postovulatory follicles are structures left in the ovary following the release of eggs and that degenerate shortly after spawning. Therefore the presence of these two features (post-ovulatory follicles and hydrated eggs) are signs of very recent, or imminent, spawning, respectively .

Indirect Evidence: If none of the direct signs have been observed, detailed information to support the likelihood that the aggregations have formed for the purpose of spawning should have been provided. This may include literature to indicate that behaviours or colour patterns observed are exclusively associated with reproduction. GSI (Gonado-Somatic Index=[gonad weight/body weight minus gonad weight] x 100) data, heavily swollen abdomen in many fish and other indications of spawning can be used as supportive evidence. Note, however, that in some species, such as some snappers (lutjanids), large fat bodies can form within the abdomen outside of the spawning season, as well as in immature fish, or in some cases a hefty meal can produce a swollen abdomen in species like groupers. Examination of the swollen abdomen in a small sub-sample of fish is advised.

Note that some spawning aggregations in the SCRFA database have neither direct nor indirect evidence of spawning. Such cases are indicated in the output (i.e. both direct and indirect columns will be "unspecified") and occur almost entirely where the presence of spawning aggregations has been reported in old literature, or as traditional knowledge from fishers during interviews, where the interviewees have not indicated why they report a spawning aggregation. In these cases it is often not known how the presence of a spawning aggregation was determined. It is important, therefore, that interviews of fishers establish the basis (i.e. which direct or indirect character) on which a fisher identifies a spawning aggregation.

Current Status: This is an opinion regarding the current status of the aggregation relative to the past. The following categories are used: Same (i.e. no change); Increasing; Decreasing; Gone. The reason why a certain category was chosen is provided in the Current Status notes.

Questionnaires used for interviews are available on the SCRFA website (under field surveys).

Current Status Notes: There are a number of types of data, and combinations of them, that can be used to judge the status of an aggregation. For instance, decreases in the number of fish at the aggregation site observed by divers, decreases in fish size caught by fishers over time, and decreases in CPUE (Catch Per Unit Effort) could be used to indicate the aggregation is Decreasing in status. CPUE is a way of standardizing catches in order to make useful comparisons, e.g. 4 kg fish/fisher/day. The notes should indicate any changes in fishing practices that could have caused, at least in part, any changes to occur (e.g. changes in gear type used, introduction of fishery management, etc.).

Management/Protection : This indicates whether the aggregation is managed or if the aggregating species is protected in any way during the time that the aggregation forms. Examples include a ban of sales during the spawning season, designation of a marine protected area (with restrictions that prevent uncontrolled fishing on the aggregation), time/area closures, size limits, landing quota, limited entry to the fishery, etc. The management/protection in the database reflects that at the time of data entry. Updates will be made as new information is received.

Reference: This indicates the source, published literature, fishery report, etc., direct information from somebody familiar with the aggregation (noted as pers. comm. = personal communication), or standardized fisher interviews conducted by SCRFA.