I am currently analysing two years of data from a fisheries monitoring
programme that was originally conducted to try to assess the potential
negative (or positive) effects of mud dumping in the Pearl River estuary
(south China/Hong Kong). My objective is to look at the sampling methodology
with a view to calculating the optimal sample size required in order to be
able to conduct valid statistical analyses of changes in demersal fish and
invertebrate communities in future monitoring programmes.
The original sampling methodology utilised a local commercial shrimp trawler
deploying beam trawls (5m length x 2 m mouth) for 10 minutes at six
stations. Replicate trawls were conducted. Initially, only two nets were
used per trawl but the low catch resulted in this being increased to 6 nets.
I have a total of 1047 sample sets to work with from the two year programme.
Data from each sample set has been split into fish and invertebrates.
Now, I am familiar with the mathematics for calculating the optimum number
of nets required to obtain a representative sample of the population and
this, in itself, answers the question I have been posed. However, I would
like to broaden the scope a little and look at this from a more regional
perspective rather than looking at an isolated case. To this end, I am
trying to locate people who have been involved in setting up/running
demersal fish/invertebrate sampling programmes using beam trawls and/or
papers relating to this particular 'problem'. Not being in an academic
environment, my access to scientific literature is limited and so far, I
have not been very successful.
While I appreciate that open requests for references are often frowned upon,
I ask for a little indulgence by FE members on this occasion. I'm not so
much seeking lists of references per se, rather I am hoping that someone
might be able to point me in the right direction for finding further
Please reply to me personally unless it is felt this topic is worthy of
'public' discussion on the list.
Many thanks in advance.
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