The last few years have seen a major proliferation of action on the formulation of reference points to achieve precautionary fishery management goals, following the technical Working Group of the Conference on Straddling Fish Stocks and Highly Migratory Fish Stocks that met in 1994-95 (Annex 2 of that Report describes this requirement; UN 1995). This working group based its efforts on two FAO Fisheries Circulars: one on precaution, the other on reference points (FAO, 1995a,
b). The latter document, later revised and extended (Caddy and Mahon, 1995), put forward the concept of Limit Reference Points (LRPs) as one practical way of defining the limits to exploitation of a stock. Following this, recent work has distinguished Target Reference Points (TRPs) from Limit Reference Points (LRPs), but their relative role in the management process still remains somewhat unclear, and divergences of approach are evident, in which more than two types of reference points appear to be emerging.
What is most of concern with respect to the way the LRP concept has developed since the UN Conference and its base documents is that most current work on LRPs is aimed at the definition of reference points, with relatively less emphasis or experience on how efficiently they will perform in a functioning management system. As noted in an earlier communication (Caddy, 1997), this may require significant changes in the way that management bodies function but will also require a systems approach in which industry, managers and scientists discuss their respective roles, particularly in defining the risk to the resource of implementing a given management measure.
It may be worth recalling here that previous management approaches based on target reference points alone had proved vulnerable to overfishing once a TRP had been overshot. This was partly because of the high degree of uncertainty in locating the current position of the fishery in relation to the TRP but also because recovery times after effort overshoots were often long and because mechanisms for integrating the efforts of scientists, managers and fishermen into a single responsive fisheries management system had been neglected. Often adversarial positions were adopted in the course of management decision-making that required long negotiations and inconclusive management responses before the 'fishery system' could react to downturns in resource abundance due to fishing or natural causes. In the interim, the fishery continued to overfish the stock in absence of a prenegotiated, precautionary approach to management which is integral to the new legal instruments. We may expect similar anomalies with the application of LRP-based management systems (Fig. 1), unless a systems approach is agreed to by all parties.
The new paradigm whereby LRPs are defined was incorporated into the UN Agreement and is also part of the FAO Code of Conduct for Responsible Fisheries (FAO, 1995c). Integral to this LRP approach is the concept that the fishery as a 'system' will react to the approach of the fishery to an LRP by adopting a prenegotiated response to unfavourable events. This will necessarily involve sharp reductions in fishing effort over a period sufficiently sustained for the stock to return to a healthy condition, i.e. a stock recovery strategy will have to be applied to bring it back to a spawning biomass significantly higher than that at which the LRP is established.
Defining such a recovery target involves setting a distinct biomass-based management RP. This is defined by recent international instruments as that at which "the stock can support the harvesting of an MSY without adverse impacts". This is not to imply, of course, that the MSY conditions should be the target for harvesting; to the contrary, both the FAO Code of Conduct and the UN Agreement on Straddling Fish Stocks and Highly Migratory Fish Stocks indicate that MSY conditions should be regarded as representing a limiting condition that should not be exceeded (for FMSY) or allowed to fall below (for BMSY), and MSY conditions now constitute minimum conditions for stock recovery.
Questions relating to the definition of RPs have been the source of major discussion in a number of fora, for two of which a summary of the current position is given here, mainly based on the reports of Serchuck et al. (1997) for NAFO and ICES (1998).
Figure 1. Illustrating the necessary linkage between precision of definition of reference points, acceptable level of overshoot and management rigour in enforcing a fishery control law based upon them.
Figure 2. Example of a simple approach to 'zoning' safe and risky fishing conditions using peak or mean historical landings and percent mature fish in the catch.