Ref. Ares(2018)3458435 - 29/06/2018
Ref. Ares(2019)2387732 - 04/04/2019
High survival exemption for plaice caught by TR2 vessels
using Otter Trawls in ICES areas VIIf and VIIg
Request under Article 15.4(b) of Regulation (EU) 1380/2013 to exempt from the landing
obligation plaice caught by Otter trawls in ICES areas VIIf and VIIg.
Summary
Article 15.4(b) of Regulation (EU) 1380/2013 on the Common Fisheries Policy states that
the landing obligation shall not apply to:
“species for which scientific evidence demonstrates high survival rates, taking into
account the characteristics of the gear, of the fishing practises and of the
ecosystem;”
In response to industry’s view that Plaice has a high rate of survival, the Centre for
Environment, Fisheries and Aquaculture Science (Cefas) was commissioned to carry out a
number studies on high survivability of Plaice. The sea trials were carried out in Bideford
Bay off the coast of North Devon (ICES area 7f) on a vessel representative of normal
fishing activity targeting Rays, Plaice and Dover sole using TR2 Otter trawls.
The North Western Waters regional group notes that scientific evidence demonstrates a
survivability rate of 78% for plaice (Pleuronectes platessa) caught by TR2 vessels using
Otter Trawls in area VIIf and recommends that catches of Plaice caught in areas VIIf and g
should be exempt from the landing obligation on grounds of high survival rates, as
provided for by Article 15.4(b) Regulation (EU) 1380/2013. This will reduce the risk of
vessels being prevented from continuing to fish at sea due to their low Plaice quota.
Key Information
Exemption target:
Plaice (Pleuronectes platessa)
Exemption grounds:
High survivability.
Survivability rates:
78%
Vessels affected:
49 (UK)
Discard rate:
73%
2018 UK TAC:
77
Fishery
1
In 2017, 49 vessels registered in the UK caught plaice with Otter trawls in area VIIf and
VIIg, landing 13 tonnes.
The discard rate for plaice in area VIIf and VIIg is 73%. An estimated 17.85 tonnes will be
discarded in 2018. The survival rate in the study is a minimum of 78%, which would
indicate that at around 13.92 tonnes of the discarded Plaice will survive. The survival rate
is discussed further below.
Study
Sea trials were carried out in Bideford Bay (ICES rectangle 31E5 in ICES 7f), off the coast
of North Devon (see Figure 1) on a vessel which is a fibre-gall hulled trawler of 9.95 m
overall length with a 148kw engine. In total 10 hauls were made during three days in
March 2015. The fishing activity of the vessel was representative of normal practice and
was considered to be comparable to that pf the South Wales trawler fleet. All fishing was
carried out during March 2015, on typical fishing grounds for this vessel at this time of the
year. Rays were the main target species.
Figure 1. Map of Bideford Bay, North Devon.
Fishing activity at sea
At sea the trawl gear was deployed, towed, and hauled as per normal commercial fishing
practice. The cod ends were emptied into the aft pounds and the nets were fully re-
deployed prior to catch sorting. The crew sorted the catch by hand, and any small,
unwanted rays present were thrown back to the sea immediately. The unwanted plaice
and other unwanted species were left in the pond and, at the point of normal discarding
were collected from the deck by the observer and placed into a 5-stone fish basket.
Data collection
2
Each plaice caught was measured and recorded by length, then assess for vitality. Each
individual fish was measured and scored using a predefined assessment protocol
developed methods described in the ICES WKMEDS 2014 report and refined in the Cefas
laboratory using aquarium kept plaice. Vitality was assess using a semi-quantitative
assessment of activity and a quantitative reflex and injury scoring method.
Catch composition
The catch composition was dominated by Lesser Spotted Dogfish, rays and plaice. All sole
and plaice caught were recorded. The length distribution is shown in Figure 3. A total of
572 plaice was caught and assessed for vitality. In total, 18 plaice was assessed as being
dead at the point that they would be discarded. The remaining fish were scored and a
proportion of fish was selected for the on-board observation tanks. Table 1 sets out the
vitality assessment and survivability probability of Plaice from the hauls used in the study.
Estimate of survival
To generate an estimate of survival for this fishery required the application of survival rates
from another source. Using the same method, during the same period, survival estimates
by vitality category were generated from an otter trawl working in the neighbouring ICES
sub division. The estimate generated inferred that survival was the same for each vitality,
as was observed in a closely related otter trawl fishery. This assumed that the stresses
endured by the fish in one fishery were the same as those of the other and that health
vitality assessments were consistent across both studies.
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Table 1: Survivability and catch profile of study by vitality assessment for plaice.
Proportion of fish at
Survivability
Vitality assessment
each vitality
probability (%)
Excellent
0.57
73
Good
0.14
10
Poor
0.26
7
Dead
0.03
-
Figure 2. Length frequencies of plaice caught by a Bristol Channel otter trawler
4
Results
The estimated survival for otter trawl caught plaice, 78% (75-88%).
The study identified a number of potential stressors on the captive fish associated with the
methodology in this study, which are likely to have resulted in experimental induced
mortality and therefore underestimated survival. Specifically these stressors included:
Handling fish to conduct the vitality assessments, length measurements and to put
fish into the on-board tanks
Captivity in the on-board tanks (movement caused by vessel movement; proximity
with other fish; serial flow of water from top to bottom tank)
Stopping water flow to on-board tanks on approach to port until docked (reducing
dO2)
Transfer of fish into tubs (handling of fish)
Carrying tubs off the vessel and transporting, by van, to onshore holding tanks
(increased temperature, reduced dO2, movement)
Handling the fish to transfer into onshore tanks
Adjusting to salinity and temperature
Constructing survival studies on small commercial vessels in remote ports is technical and
logistical challenging. Due to restricted deck space the vessels could only hold small
number of fish in suitable tanks, and these must be transferred to shore when fishing for
less than one day, this meant that the use of controls had to be limited and there were
unavoidable additional stressors exerted on the fish. The survival estimates should,
therefore, be interpreted as minimum discard survival estimates.
Conclusion
The UK believes that the fishing practices in Bideford Bay resulting in survival rates of 73%
for bycatches of Plaice are representative of general fishing practices by the vessels using
otter trawls in ICES areas VIIf & g. On this basis we would like to request a high survival
exemption for plaice caught by TR2 Otter trawls in ICES Areas VIIf & g.
Further information on the study can be found in Annex C, under the Otter Trawl study.
5
Table 5: Completed STECF table for high survivability proposal
Country
Exemption
Species as
Number of
Landings
Estimated
Estimated
Discard Rate
Estimated
applied for
bycatch or
vessels
(by landing
Discards
Catch
discard
(species, area,
target
subject to
obligation
survival
gear type)
the landing
subject
rate from
obligation
vessels)
provided
studies
UK
Plaice
Bycatch
49
13t
17.85t based 30.85t
73% for stock
78%
on area
in VIIf, g
VIIf, g
discard rate
Otter Trawls
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Document Outline