The recent opinion piece in the journal Nature by Pauly from one

The recent opinion piece in the journal Nature by Pauly from one perspective, by Hilborn and Branch from another [4], captures very well the issues facing fishery scientists as they grapple with the challenge of determining stock status and sustainable management approaches for the world’s

fisheries. However, the particular point at issue is not whether catch data are unimportant; rather it is that on their own, catch data are not a reliable indicator of stock status. To understand why this is so one must first examine under what circumstances catch data are ever likely, on their own, to be a useful indicator of stock status. This is the case where fishing activity is unconstrained by management,

where this activity is unaffected by dynamic fishery economics (the cost of extraction and the value of fish) and particularly SGI-1776 order the world trade in fish, and where fish population dynamics EPZ015666 can be expected to be more or less predictable. Whilst these may have been appropriate simplifying assumptions when FAO scientists developed the approach which they used in 1996 to infer stock status [5], this is no longer so given the further information available now almost 20 years later. The failure of stock status determination methods based solely on catch data has been repeatedly demonstrated ([6], [7], [8] and [9] and figure 2 in Ref. [4]), but still some scientists seek to continue to promulgate their use [4] and [5]. Even when corrected for recent management intervention [10], such methods cannot accurately determine

stock recovery and rarely predict anything other than a continuing decline in world fish stock status that leads to a conveniently simple (see figure 1 in Ref. [4]) but misleading message. The inconvenient about truth is that determining stock status is not simple, and requires the use of multiple data sources in addition to catch data to avoid misinterpretations and confusion within managers, policy makers and the general public. While Hilborn and Branch [4] suggest use of data from surveys conducted from research vessels, age and size distributions of fish, and catch per unit of effort, Pauly [4] argues that this information is not readily available in developing countries nor there is the capacity to build such databases. However, none of the authors proceeds to suggest alternative solutions to this problem. Traditional stock assessment methods are costly and demand large quantities of time and information. However, simple assessment methods that use historical catches and size-composition information could potentially be applied to many data-poor stocks.

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