1 Fish Farm Wastes in the Ecosystem
27
fjord” because its greatest depth exceeds 30m. The adjacent loch Etive, receiving
much more freshwater, has been identified as a ‘transitional sea-loch’ (transitional
water type 5). Although there are some sea trout farms in Etive, the low mean and
strongly fluctuating salinities make it less good for farming the salmon than the
higher mean salinity of the coastal water fjords. In contrast, Etive has a good reputation for mussels, because the intermittently low salinities reduce fouling.
Table 1.2 illustrates the UK/ROI typology for the three fjordic types found in
Scotland, and gives details both of the physical conditions that define the type,
(UKTAG 2003) and of the proposed reference conditions (UKTAG 2004).
Protected areas in Creran include the serpulid reefs which are a SAC, and the
Shellfish Growing Waters that occupy the main basin of the loch. SEPA’s published
description of the shellfish waters (SEPA 2004) gives the following for “land use
and potential diffuse pollution sources”:
The predominant land use is coniferous forestry but there is some extensive livestock agriculture on the north and far western shores. The main freshwater inflow is the River
Creran, draining both forest and moorland. Loch Creran is remote from centres of population and is popular with visitors, particularly in the summer months.
Point-source discharges include those from about 50 private houses, and the consented, major discharges from a fish farm and a fish processing factory. Laurent et al.
(2006) used a mathematical model to show that the nutrients from the fish farm
could make a significant contribution during summer, when the concentrations in
the inflow from the Firth of Lorne are low. Nickell et al. (2003) found high organic
loading and oxygen demand immediately beneath the farm, falling off rapidly at
60 m distance and returning to normal background levels for shallow coastal waters
at 2 km from the farm. Only in the sediment immediately beneath the farm was the
benthic community composition grossly perturbed.
Creran’s waters are monitored for shellfish purposes from two sites, one near the
mouth and one near the head of the main basin. In addition the river Creran is
sometimes sampled for nutrients above its discharge into the upper basin: concentrations are typically low, as might be expected in runoff from granitic rocks and
unimproved acidic grassland.
SEPA (2004) reports that:
In 2002, all samples from both monitoring sites met all shellfish waters imperative and
guideline environmental quality standards. Biannual sampling is continuing for metals and
organochlorines in waters along with monthly sampling for T, Sal, DO and pH at South
Creagan and North Shian. Mussels will be sampled annually for organohalogens and metals at North Shian. This site will also be monitored quarterly for faecal coliforms in mussels and in addition, collection of mussels for TBT and PAH analysis will begin in 2004 as
part of a SEPA Environmental Improvement Plan…. SEPA will continue to pursue a policy
of no new discharges of sewage effluent to designated waters, to avoid incremental increase
in microbiological loading. In the event that discharges to the designated waters cannot be
avoided, they will be subject to appropriate treatment to ensure compliance with the
[Shellfish Waters] Directive’s standards.… All farms in catchment area will be inspected
according to the Scottish Executive’s… Plan to reduce point source farm discharges into
inland and coastal waters. SEPA intend to initiate an Environmental Improvement Plan of
agricultural inspections and improvement requirements, designed to reduce diffuse
pollution.
27
fjord” because its greatest depth exceeds 30m. The adjacent loch Etive, receiving
much more freshwater, has been identified as a ‘transitional sea-loch’ (transitional
water type 5). Although there are some sea trout farms in Etive, the low mean and
strongly fluctuating salinities make it less good for farming the salmon than the
higher mean salinity of the coastal water fjords. In contrast, Etive has a good reputation for mussels, because the intermittently low salinities reduce fouling.
Table 1.2 illustrates the UK/ROI typology for the three fjordic types found in
Scotland, and gives details both of the physical conditions that define the type,
(UKTAG 2003) and of the proposed reference conditions (UKTAG 2004).
Protected areas in Creran include the serpulid reefs which are a SAC, and the
Shellfish Growing Waters that occupy the main basin of the loch. SEPA’s published
description of the shellfish waters (SEPA 2004) gives the following for “land use
and potential diffuse pollution sources”:
The predominant land use is coniferous forestry but there is some extensive livestock agriculture on the north and far western shores. The main freshwater inflow is the River
Creran, draining both forest and moorland. Loch Creran is remote from centres of population and is popular with visitors, particularly in the summer months.
Point-source discharges include those from about 50 private houses, and the consented, major discharges from a fish farm and a fish processing factory. Laurent et al.
(2006) used a mathematical model to show that the nutrients from the fish farm
could make a significant contribution during summer, when the concentrations in
the inflow from the Firth of Lorne are low. Nickell et al. (2003) found high organic
loading and oxygen demand immediately beneath the farm, falling off rapidly at
60 m distance and returning to normal background levels for shallow coastal waters
at 2 km from the farm. Only in the sediment immediately beneath the farm was the
benthic community composition grossly perturbed.
Creran’s waters are monitored for shellfish purposes from two sites, one near the
mouth and one near the head of the main basin. In addition the river Creran is
sometimes sampled for nutrients above its discharge into the upper basin: concentrations are typically low, as might be expected in runoff from granitic rocks and
unimproved acidic grassland.
SEPA (2004) reports that:
In 2002, all samples from both monitoring sites met all shellfish waters imperative and
guideline environmental quality standards. Biannual sampling is continuing for metals and
organochlorines in waters along with monthly sampling for T, Sal, DO and pH at South
Creagan and North Shian. Mussels will be sampled annually for organohalogens and metals at North Shian. This site will also be monitored quarterly for faecal coliforms in mussels and in addition, collection of mussels for TBT and PAH analysis will begin in 2004 as
part of a SEPA Environmental Improvement Plan…. SEPA will continue to pursue a policy
of no new discharges of sewage effluent to designated waters, to avoid incremental increase
in microbiological loading. In the event that discharges to the designated waters cannot be
avoided, they will be subject to appropriate treatment to ensure compliance with the
[Shellfish Waters] Directive’s standards.… All farms in catchment area will be inspected
according to the Scottish Executive’s… Plan to reduce point source farm discharges into
inland and coastal waters. SEPA intend to initiate an Environmental Improvement Plan of
agricultural inspections and improvement requirements, designed to reduce diffuse
pollution.