Evidence of by-catch in these
fisheries
93. There is some evidence that other pelagic fisheries
may also be responsible for some by-catch of common dolphins,
although few observer studies of by-catch in these fisheries appear
to have been carried out. The Whale and Dolphin Conservation Society
(WDCS) and Nick Tregenza both note that, during the 1990s, observer
studies of by-catch in pelagic trawl fisheries recorded dolphin
catches in three other fisheries, those for mackerel, horse mackerel,
hake and tuna:
- the WDCS refers to a Dutch
observer study of by-catch in the pelagic trawl fishery for mackerel
and horse mackerel that was conducted in the early 1990s, which
recorded by-catch of a wide range of cetaceans. In 1994, a total
catch of 172 dolphins was recorded by 12 Dutch and two English
vessels in this fishery.[112]
- Nick Tregenza states that, in an observer study
published in 1995, dolphin by-catch was seen in tows catching
mackerel. He suggests that dolphin by-catch may often be overlooked
by the mackerel boats, because they tend to pump their catch aboard:
dolphins are too big to come through the pump and are hard or
impossible to see in the net. They are finally discharged well
astern of the boat, still unseen.[113]
Defra itself cites an example of an experimental
fishery involving pair trawling for tuna which was conducted by
the Republic of Ireland in 1998 and 1999, during which period
it recorded a total catch of 180 cetaceans.[114]
94. The WDCS also pointed out that a number of other
pelagic fisheries share common characteristics with the pelagic
sea bass fishery: other fisheries also use trawling and pair trawling
gear and operate in the Celtic Sea/Bay of Biscay area during the
winter months, when dolphin strandings occur on the south-west
coast. In addition to the fisheries named above, they also cited
the herring, blue whiting, pilchard, sardine and anchovy fisheries,
and the albacore tuna fishery, which operates during the summer
months but uses pair trawling gear.[115]
The WDCS considers that, until these fisheries are properly monitored,
it is reasonable to assume that some, if not all, may be responsible
for some cetacean by-catch.
95. We acknowledge the evidence of the SMRU, which
considers that any by-catch in other pelagic fisheries is unlikely
to be very high. On the basis of what it has so far observed in
other pelagic fisheries, the SMRU calculates that cetacean by-catch
rates in the UK pelagic trawl fisheries for mackerel, herring,
sprat, horse-mackerel and pilchard "are very unlikely to
exceed 457 dolphins per year in total".[116]
Need for monitoring in other
pelagic fisheries
96. We are concerned that Defra has not properly
taken into account the consideration, neatly summarised by Nick
Tregenza, that "the current generalisation, from a small
data set, that it is only the bass fishery [that is responsible
for cetacean by-catch] is unreliable … because of the variable
and clumped distribution of the fish and the cetaceans it is to
be expected that years will differ greatly in their catch rates
in different fisheries."[117]
From the evidence we have received, it seems clear to us that
a "steady flow" of by-catch cannot be expected, and
that rates of by-catch are likely to vary between fisheries and
between years. For example, we have received evidence suggesting
that, because common dolphins tend to travel in groups, they also
tend to be caught in groups—a single trawl tends to catch
either no dolphins, or a significant number of dolphins.[118]
In 1999, the Irish study referred to by Defra recorded 145 cetaceans
caught in 313 observed hauls, of which only 31 hauls had a cetacean
by-catch. Of the 145 cetaceans caught, 98 were taken in just ten
hauls.[119]
97. Consequently, we recommend that, in implementing
its strategy document, the Government places much greater emphasis
on moving quickly to set up long-term observer monitoring programmes
for other pelagic fisheries that take place off south-west England,
particularly in the winter months, such as those for mackerel,
horse mackerel and tuna. It would be most unfortunate if,
on the basis of fairly recent evidence only, the Government were
to conclude that the trawl fishery for sea bass is the only pelagic
fishery requiring immediate attention. Bearing in mind that rates
of by-catch are likely to vary between fisheries and between years,
we urge the Government to focus on gathering more conclusive evidence
about rates of cetacean by-catch in these other fisheries.
95 Defra strategy, para 112 Back
96
Defra strategy, para 114 Back
97
Defra strategy, para 36 Back
98
See page 18 of Defra's strategy document for a diagram showing
the operation of a separator grid. Back
99
Defra strategy, paras 60 and 61 Back
100
Defra strategy, para 62 Back
101
The 2002-03 trial ran from 14 March to 25 March 2003. The first
stage of the trial was originally scheduled to commence in December
2002, but had to be postponed to March because one of the trial
boats was involved in a collision. Following the "official"
end of the trial, in March, the skippers concerned voluntarily
continued using the selection grid system, until 8 May when they
ceased prosecuting the fishery. Back
102
Defra final project report, "Further development of a dolphin
exclusion device", 25 November 2002 to 31 March 2003 Back
103
Q 252 [Ben Bradshaw MP] Back
104
Defra strategy, para 91 Back
105
Ev 49 [Linda Hingley] Back
106
Q 81 [Nick Tregenza] Back
107
Although there were no camera images available for three nights
(but not days) during the trial, due to defective cameras; unfortunately,
it was during one of these nights that the two dolphins were caught
in the net and died: Defra final project report, "Further
development of a dolphin exclusion device", 25 November 2002
to 31 March 2003, p 7 Back
108
Qq 143-47 [National Federation of Fishermen's Organisations] Back
109
Q 205 [Linda Hingley] Back
110
Q 213 [Ben Bradshaw MP] Back
111
Q 143 [National Federation of Fishermen's Organisations] Back
112
Ev 26 [Whale and Dolphin Conservation Society] Back
113
Ev 11 [Nick Tregenza] Back
114
Defra strategy, para 44 Back
115
Q 90 [Whale and Dolphin Conservation Society] Back
116
Ev 77 [Natural Environment Research Council] Back
117
Ev 11 [Nick Tregenza] Back
118
Q 205 [Linda Hingley] Back
119
Defra strategy, para 44 Back
