Wanless,R,Ross,Mr,ADU wrote:
>
> I am researching the global impact of longline fisheries on seabirds.
> At present I am simply gathering data on all the longline fisheries
> around the world. I would like the following information, preferably
> broken down by fishery (target species) and by year:
>
> 1. Region of fishing activity
> 2. Number of countries and vessels actively fishing
> 3. Annual total fishing effort (i.e. number of hooks)
> 4. A measure of the total annual bycatch of birds (by species if
> possible)
Don McAllister has mentioned the groundfish longlining in the
northwest Atlantic in this context. I carried out an extensive
interview survey of Nova Scotian groundfish longline fishermen in
1990-91. The topic of birds caught on the line was mentioned by a few
interviewees but in the context of the fishermen having to avoid the
problem: Setting the gear in daylight could sometimes result in birds
being caught. Their bodies are bouyant, which prevents the hooks
sinking to the bottom and thus stops them from fishing. For this
reason, among others, the fishermen almost always set at night, when
the bird kill is virtually zero.
The region in question was the northwest Atlantic from the
international boundary on Georges Bank to the Flemish Cap. All of the
_groundfish_ longlining in that area is by Canadian boats (except
possibly on Flemish Cap and the Nose of Grand Bank, though foreign
activity must be minimal even there). In 1990, there were some 750
active boats based on the Atlantic coast of Nova Scotia or in the Bay
of Fundy, plus others out of Newfoundland. This number has since been
reduced by fishery closures.
The total number of hook-sets in a year is unknown, though the average
number of hooks set per boat-day of fishing was around 6500. The total
bird kill is also unknown but certainly much less than one per
boat-day (perhaps not even one per boat per year, though I do not have
the data to support such a "precise" estimate). The commonest species
around longline boats off Nova Scotia is the sooty shearwater,
Puffinus griseus, and that may well be the one most frequently ("least
infrequently"?) killed.
While the data for a proper evaluation of the problem do not exist, I
hope this helps to put it in perspective.
Trevor Kenchington
--
Trevor J. Kenchington PhD [log in to unmask]
Gadus Associates, Office(902) 889-9250
R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251
Nova Scotia B0J 2L0, CANADA Home (902) 889-3555
Science Serving the Fisheries
http://home.istar.ca/~gadus
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