POPULATION DYNAMICS
|
Information on the maximum size and age of fish, on their length-weight relationships and estimates of their growth parameters, natural mortality and recruitment variability are crucial for fisheries management purposes.
While maximum age and size, and length-weight relationships are relatively easy to obtain for most fish species, making sure that such information is available wherever and whenever needed¾ and in the appropriate format¾ is rather more difficult. |
||
| Growth parameters are hard to obtain |
This problem is magnified for growth parameters, which are harder to obtain: one set typically corresponds to the work embodied in an MS thesis, or short scientific paper. As for recruitment time series, many years are required for patterns to emerge. Thus, stock assessment research can be considerably accelerated by making available to practitioners growth parameters that have already been estimated, both to replace stock-specific estimates by values from neighboring stocks, and to provide data for reliability checks of one’s estimates. Similar considerations apply to natural mortality estimates, and to recruitment time series.
These points are so compelling for tropical fisheries research that they provided, in 1987, the reason for proposing the creation of the database that eventually became FishBase, and which was to include "a summary of growth and mortality information for each species [.....] with the ultimate goal of covering 2,500 species" (Pauly 1988).
|
|
| We have identified growth parameters for about 1,300 species |
This vision underestimated the number of species to be included in FishBase (now ten times more than initially anticipated), but overestimated the number of species for which growth parameters and related information exist: we have now identified published sets of growth parameters for about 1,300 species and there is little prospect that this figure will increase by more than 10-20% in the next years. However, the species presently covered sustain over 95% of the world’s fisheries catches, ensuring the relevance of the entries in the tables presented below.
Similarly, the stocks for which over 750 time series of recruitment are included belong to the best-studied, and most important single-species stocks in the world.
A number of precautions were taken to ensure the highest possible accuracy for the entries in the above tables. This included, among other things, rejecting parameter estimates not compatible with related estimates in the same, or closely allied species. However, we are aware that these and related procedures cannot identify all errors, whether in the original papers or as a result of faulty data entry, and all we can hope for is that you will contact us when you find errors or inconsistencies, so that they can be repaired for the next release of the database. Notably, we will investigate cases labeled ‘out-of-range’ in the Remarks field, which refer to studies conducted at sites located outside of a given species range, and which thus imply a misidentification.
|
|
| References |
Pauly, D. 1988. Resource assessment and management program, p. 47-66. In ICLARM five-year plan (1988-1992), Part 1. directions and opportunities. International Center for Living Aquatic Resources Management (ICLARM), Manila.
Daniel Pauly and Crispina Binohlan | |