Isles of Scilly Fish and Fisheries - Cornwall Wildlife Trust

11.2) Crustacean fisheries
11.2.1) Crab and Lobster
Robson (1996a) wrote “To keep this fishery economically viable, fishermen have
steadily increased the number of pots set per boat, as catch rates and market prices
have fallen.” There is some hearsay that this still the case; it cannot be known without
a full directed study of this fishery with detailed statistical analysis of data that may not
be available.
The measures adopted for the management of the lobster stocks include the increase
of the Minimum Landing Size (MLS) from 87 mm carapace length to 90 mm, and a
voluntary V-notching scheme. In a V-notching scheme, the fisherman who catches a
lobster just under the MLS or an ovigerous (berried) female will cut a V in its “tail”
(Uropods or telson). This will remain until the lobster grows and moults. A V-notched
lobster should not be landed and will not be accepted by the Cornish wholesalers.
These actions may help the lobster population.
11.2.2) Crawfish
There is a lot of anecdotal evidence that the population of P. elephas has declined
dramatically. Indeed Pawson and Robson (1996a) commented “It is thought that
overfishing has had a serious impact on stocks of migratory species, such as crawfish.
Some fishermen also attribute the decline of crawfish stocks to the over-use of tangle
nets.” However, it is known that the recruitment of young crawfish can be extremely
variable and dependent on environmental conditions, and the effects of these cannot
be completely ruled out. It is hopeful that in 2010 higher than usual numbers of young
crawfish have been seen.
11.3 Fish
At present there are no obvious signs of problems, but tales of smaller fish and lower
catch rates – “Never the same after the “Mackerel Bonanza” of the late 1970s and
early 1980s”, suggest there could be a problem.
An interesting comparison can be made of the angling catches of the Reverend Smart
in the 1880s, and the largest fish reported by anglers in 2008, as recorded by David
Townend in the 2009 Isles of Scilly Tide Tables (Table 1).
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