Application of a bioeconomics model to examine sustainability of fishery resources in the global market: the case of octopus resource in Morocco

Abstract

A study was conducted to examine the longterm relationship among price of fish, harvest level, and resource condition using a bioeconomics model. Data on the annual amount of production and prices of octopus (Octopus vulgaris) in Morocco from 1970 to 2006 are plotted on a diagram to trace annual changes of price and production. The plotted pattern suggests a long-term movement of the yield-price equilibrium along the line of a theoretical long-term supply function curve of the bioeconomics model. The plotted data also suggests that there are four stages of resource exploitation for octopus in Morocco: (1) the underexploited stage from 1970 to 1987 which is characterized by small catch and low prices, (2) the maximum sustainable yield (MSY) stage from 1988 to 1998 which is characterized by moderate catch and intermediate prices, (3) the overexploited stage from 1999 to 2001 which is characterized by large catch and intermediate prices, and (4) the reduced stock stage after 2002 which is characterized by small catch and high prices. This result is consistent with the independent scientific research information on octopus harvested in Morocco. Our study indicates that an analysis of market information (i.e., amount of production and price) could be an effective tool in identifying approximate status of fishery resources.

Effect of a nonlinear demand function on the dynamics of a fishery

“…when the price becomes very high the demand decrease. We believe that our function could show an illustration of the actual case of the "Octopus" in Morocco as reported by [13][14][15][16]. Some resellers store a large portion of the octopus catch.…”

“…where Q = q (1−γ) L is the total catchability parameter. We substitute the fast equilibrium for the price (13), fish (9,10,11), and boat movement (12) into the complete model (8) and by adding the equations for L + 1 fishes and L boats, we obtain the aggregated model:…”

Ex-vessel price formation of fish species with low and irregular harvests: The case for John dory in Mie Prefecture, Japan

“…We discuss several possibilities that drive this empirical result. 18,19) 市場間の価格連動に注目した研究， 20 26) 漁獲物の品質が 価格に与える影響を考慮している研究 27 29)    ,   , and denote statistical signiˆcance at the 1, 5, and 10 levels, respectively. All the speciˆcations include market-size-method-and day-ˆxed eŠects, and climate variables as controls.…”