><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
If you reply to this message, it will go to all FISH-SCI members.
><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>

Rom Lipcius wrote:

> Yes, exploitation rate or fishing mortality rate increases at  
> decreased stock/population levels, for instance when fishers  
> attempt to catch the same number of animals annually, irrespective  
> of stock size.
>
>>> I am investigating depensatory exploitation of the Chesapeake Bay  
>>> blue crab population, and have been searching for published  
>>> examples of depensatory exploitation, particularly in marine  
>>> invertebrates. I have found some examples for fish, but none yet  
>>> for marine invertebrates. Does anyone know of any published  
>>> examples of depensatory exploitation in marine (or estuarine)  
>>> invertebrates?

Thus defined, I would expect some degree of "depensatory  
exploitation" to be a normal feature of all fisheries (though, as  
ever, there will be specific exceptions), at least across some ranges  
of biomass and subject to masking by other  factors (e.g. a collapse  
in market prices as biomass declines).

Most stock assessments that document time series of biomass and  
fishing mortality should provide examples.


Trevor Kenchington

><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
       To leave the Fish-Sci list, Send blank message to:
        mailto:[log in to unmask]
   Web page at http://segate.sunet.se/archives/fish-sci.html
><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>