Can catch share fisheries better track management targets?

Published source details Melnychuk M.C., Essington T.E., Branch T.A., Heppell S.S., Jensen O.P., Link J.S., Martell S.J.D., Parma A.M., Pope J.G. & Smith A.D.M. (2012) Can catch share fisheries better track management targets?. Fish and Fisheries, 13, 267-290.
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This study is summarised as evidence for the following.

	Action	Category
	Introduce catch shares Action Link
	Introduce an overall catch limit (quota cap or total allowable catch) by fishery or fleet Action Link

Introduce catch shares

A systematic review in 2000–2004 of 11 marine regions worldwide (Melnychuk et al. 2012, same data sources as Melnychuk et al. 2016) found that fisheries that introduced catch shares (divisions of annual fleet-wide quotas among individuals or groups) did not have improved management performance based on biomass targets compared to fisheries managed only by fleet-wide quota caps or fishing effort controls (non-catch share fisheries) but did result in lower rates of over-exploitation than non-catch share fisheries. Across stocks (mainly fish but including some invertebrate fisheries), there were no differences in ratios of current stock biomass to target management biomass between catch share, fleet-wide quota caps and non-catch share fisheries (data reported as statistical results). In addition, there was no difference in the proportion of stocks subject to over-exploitation (measured as current exploitation rate - fishing mortality - relative to target exploitation rate) between stocks under catch shares, both full and partial (9–17%), and fleet-wide quota limits (13%). However, over‐exploitation was higher (41%) in stocks under effort controls (like days-at sea limits or size-based limits). Data for 2000–2004 were extracted from a fisheries stock assessment database (‘RAM Legacy’ - see original paper for details) and from other sources including stock assessment documents and fishery management plans. A global meta-analysis examining trends in biomass and exploitation rates was performed for 345 stocks of 158 species from 11 regions. See original paper for full details of assessment methods and metrics used.

(Summarised by: Natasha Taylor)
Introduce an overall catch limit (quota cap or total allowable catch) by fishery or fleet

A systematic review in 2000–2004 of 11 marine regions worldwide (Melnychuk et al. 2012) found that fisheries that introduced fleet-wide catch limits (quota caps) did not have improved biomass-based performance targets compared to fisheries managed by catch shares (divisions of annual fleet-wide quotas among individuals or groups) or fishing effort controls but, along with catch share fisheries, had lower rates of over-exploitation than fishing effort controls. Across stocks, there was no difference in the ratios of fish stock biomass relative to the target management biomass between catch share and non-catch share fisheries (data presented as statistical results). In addition, there was no difference in the proportion of stocks subject to over-exploitation (measured as current exploitation rate to target exploitation rate) between stocks under catch shares (9%) and fleet-wide quota limits (13%). However, over‐exploitation was higher (41%) in stocks under effort controls (like days-at sea limits or size-based limits). Data for 2000–2004 were extracted from a global fisheries stock assessment database (see original paper for details) and compiled from other sources including stock assessment documents and fishery management plans. A global meta-analysis examining trends in biomass and exploitation rates was performed for 345 stocks of 158 species from 11 regions. See original paper for full details of assessment methods and metrics used.

(Summarised by: Natasha Taylor)