Assessment of two octopus stocks with fluctuating dynamics in Yucatán, Mexico
The total latent productivity surplus production model can be used in multilateral and national fisheries management policies to avoid overfishing stocks.
In fluctuating populations of fished stocks – typically in tropical and sub-tropical regions and characterized by having an unstable equilibrium point where any small disturbance from the equilibrium point may bring the stock to oscillating or irregular shifts – the conditions are not present for the existence of the maximum sustainable yield (MSY, the theoretically largest yield or catch that can be taken from a species’ stock over an indefinite period, and a key concept in the generation of biological reference points to harvest fish stocks sustainably).
This is because the population growth rate is constantly switching from positive to negative at regular or irregular intervals so that surplus production is followed by deficit production in a persistent cycle, and MSY requires stable zero growth rates.
A more general surplus production concept is the total latent productivity (TLP). TLP averaged over years of negative and positive productivity has been considered as a sustainable annual harvest rate for fluctuating stocks. Roa-Ureta et al. proposed to use the total latent productivity (TLP), averaged over positive and negative growth rate periods, as limit harvest rate. Because unlike the MSY, the TLP is not a constant, varying year to year following the fluctuations of stock biomass, it was proposed as a novel solution to the well-known challenges that fluctuating stocks present when trying to determine their status with reference to MSY.
Click here to read the full assessment by Dr. Alicia Poot-Salazar Dr. Iván Velázquez-Abunader Otilio Avendaño, Ph.D. Polo Barajas-Girón Dr. Ramon Isaac Rojas-González Saul Pensamiento-Villarauz, M.C. Jesús M. Soto-Vázquez, M.C. Dr. José F. Chávez-Villegas Dr. Rubén H. Roa-Ureta on Global Seafood Alliance.
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