2 Monitoring of Marine Aquaculture
81
values of the index for uneaten feed-fish (Table 2.8) recorded in 2005 averaged 1,
compared to values of between 3 and 4 recorded in 2001–2003. Furthermore, it
should be emphasised that all tuna farmers have, in general, adhered to the environmental monitoring requirements, while one particular operator has even taken the
initiative of including details of the monitoring and results obtained on their web site
(e.g., http://www.ajdtuna.com/). The possibility of developing an alternative feed
source for tuna should be explored, as this could potentially reduce adverse impacts
on the seabed, while alleviating fishing pressure on wild stocks of feed fish.
While the accumulation of decomposing organic matter on the seabed is the key
source of marine benthic impact of the Maltese tuna farming operations, it is not
the only potential adverse factor. Mass deaths of tuna have occurred at least on two
separate occasions, however, it seems that the farm operators have taken remedial
action and recovered the carcasses from the seabed at the earliest opportunity; thus
during the 6 years of monitoring, tuna carcasses were only encountered near the
cages on two or three occasions, and then as single dead fish. The accidental introduction of anthropogenic items, most of which are related to the tuna-penning
activities, is also of concern. This can be mitigated relatively easily by enforcing a
strict policy of not throwing anything into the sea and by implementing periodic
“clean-ups” of the seabed. Additional impacts result during feeding and harvesting
of the tuna, when entrails and oily slicks transported by surface currents have been
reported. These observations highlight the importance of guidelines for operational
procedures and mitigation measures to reduce adverse environmental effects on the
marine environment.
Acknowledgement We are grateful to Barry Hargrave and Patrick White for providing data on the
regulations and monitoring of aquaculture operations, and to Marie B. Lauridsen for Fig. 2.1. We
also thank Mr Michael Sant (Malta Environment and Planning Authority, Malta) and Prof Carmelo
Agius (University of Malta, Malta) for supplying us with useful information.
References
Axiak V, Gauci V, Mallia A, Mallia E, Schembri PJ, Vella AJ (1999) State of the environment
(summary) report for Malta 1998. Floriana, Malta: Environment Protection Department,
Ministry for the Environment; 130 pp
Anonymous (1981) Act of 13 March 1981 No.6 concerning protection against pollution and concerning waste (the Pollution Control Act), most recently amended by Act of 20 June 2003
No.45. LOV-1981-03-13-6, Lovdata, Oslo, Norway
Anonymous (1990) Ministerial Declaration of the Third International Conference on the
Protection of the North Sea, The Hague, 8 March 1990
Anonymous (2000) Forskrift om bekjempelse av lakselus (Act for combat of sea lice). FOR 200002-01 nr 70, Lovdata, Oslo, Norway (In Norwegian)
Anonymous (2003) Forskrift om krav til teknisk standard for installasjoner som nyttes til akvakultur (Regulations relating to technical standard for installations used in aquaculture). FOR2003-12-11-1490, Oslo, Norway (In Norwegian)
Anonymous (2004) Regulations relating to operation of aquaculture establishments (Aquaculture
Operation Regulations). FOR 2004-12-22 no. 1785, Lovdata, Oslo, Norway
81
values of the index for uneaten feed-fish (Table 2.8) recorded in 2005 averaged 1,
compared to values of between 3 and 4 recorded in 2001–2003. Furthermore, it
should be emphasised that all tuna farmers have, in general, adhered to the environmental monitoring requirements, while one particular operator has even taken the
initiative of including details of the monitoring and results obtained on their web site
(e.g., http://www.ajdtuna.com/). The possibility of developing an alternative feed
source for tuna should be explored, as this could potentially reduce adverse impacts
on the seabed, while alleviating fishing pressure on wild stocks of feed fish.
While the accumulation of decomposing organic matter on the seabed is the key
source of marine benthic impact of the Maltese tuna farming operations, it is not
the only potential adverse factor. Mass deaths of tuna have occurred at least on two
separate occasions, however, it seems that the farm operators have taken remedial
action and recovered the carcasses from the seabed at the earliest opportunity; thus
during the 6 years of monitoring, tuna carcasses were only encountered near the
cages on two or three occasions, and then as single dead fish. The accidental introduction of anthropogenic items, most of which are related to the tuna-penning
activities, is also of concern. This can be mitigated relatively easily by enforcing a
strict policy of not throwing anything into the sea and by implementing periodic
“clean-ups” of the seabed. Additional impacts result during feeding and harvesting
of the tuna, when entrails and oily slicks transported by surface currents have been
reported. These observations highlight the importance of guidelines for operational
procedures and mitigation measures to reduce adverse environmental effects on the
marine environment.
Acknowledgement We are grateful to Barry Hargrave and Patrick White for providing data on the
regulations and monitoring of aquaculture operations, and to Marie B. Lauridsen for Fig. 2.1. We
also thank Mr Michael Sant (Malta Environment and Planning Authority, Malta) and Prof Carmelo
Agius (University of Malta, Malta) for supplying us with useful information.
References
Axiak V, Gauci V, Mallia A, Mallia E, Schembri PJ, Vella AJ (1999) State of the environment
(summary) report for Malta 1998. Floriana, Malta: Environment Protection Department,
Ministry for the Environment; 130 pp
Anonymous (1981) Act of 13 March 1981 No.6 concerning protection against pollution and concerning waste (the Pollution Control Act), most recently amended by Act of 20 June 2003
No.45. LOV-1981-03-13-6, Lovdata, Oslo, Norway
Anonymous (1990) Ministerial Declaration of the Third International Conference on the
Protection of the North Sea, The Hague, 8 March 1990
Anonymous (2000) Forskrift om bekjempelse av lakselus (Act for combat of sea lice). FOR 200002-01 nr 70, Lovdata, Oslo, Norway (In Norwegian)
Anonymous (2003) Forskrift om krav til teknisk standard for installasjoner som nyttes til akvakultur (Regulations relating to technical standard for installations used in aquaculture). FOR2003-12-11-1490, Oslo, Norway (In Norwegian)
Anonymous (2004) Regulations relating to operation of aquaculture establishments (Aquaculture
Operation Regulations). FOR 2004-12-22 no. 1785, Lovdata, Oslo, Norway