Sea lice treatment increased in Norwegian fish breeding in 2009

Published 16.03.2010 , updated: 16.03.2010, 13:44
Stikkord:Fish, Wholesale based drug statistics

A large increase in sales of agents used in sea lice infestations was seen in 2009. There was also a smaller increase in the use of antibacterials and anaesthetics for fish. Sales of anthelmintics and fungicides were lower than in 2008. Increasing resistance to sea lice treatment has led to the reintroduction of many older drugs that have not been used for many years.

Last year, increased resistance to sea lice treatments such as the pyrethroids cypermethrin and deltamethrin, as well as emamectine, was observed. Pyrethroid use still increased from 2008 to 2009, although use of emamectine reduced significantly. Older sea lice treatments are being used again due to resistance problems, e.g. azametiphos, diflubenzuron and teflubenzuron. Hydrogen peroxide, which has not been used since 1997, was also used again in 2009, mainly under controlled conditions in wellboats.

The increase in antibacterial sales from 2008-2009 was marginal and, when seen in relation to the biomass of bred fish, the usage is very low. Prescription-based statistics from the Norwegian Food Safety Authority for 2000-2008 show that antibacterials have been increasingly used in the treatment of newer breeding fish species, especially cod. For this period, the increase in the use in cod was positively correlated to the increase in biomass of cod produced. Data for sales per fish species for 2009 are not yet available.

Anthelmintics have shown an annual reduction in sales since 2004 and fungicides are back to 2008 levels.

The tables below show an overview of sales of antibacterials, sea lice treatment, anthelmintics and fungicides, as well as anaesthetics used in Norwegian fish breeding in the period 2001-2009. The figures are based on sales from wholesalers to pharmacies and from feed mills to breeders.

Table 1. Antibacterials (per kg active ingredient)

	2001	2002	2003	2004	2005	2006	2007	2008	2009
Florfenicol	109	205	154	111	202	302	139	166	303
Flumequin	7	5	60	4	28	7	18	1	1
Lincomycin/ Spectinomycin (1:2)						50	66	70	43
Oxolinic acid	517	998	546	1035	977	1119	406	681	926
Oxytetracycline	12	11	45	5	8	0	19	23	40
Total	645	1219	805	1159	1215	1478	648	941	1313

Table 2. Sea lice treatment (per kg active ingredient)

	2001	2002	2003	2004	2005	2006	2007	2008	2009
Azametiphos								66	1460
Cypermethrin	69	62	59	55	45	49	30	32	88
Deltamethrin	19	23	16	17	16	23	29	39	62
Diflubenzuron	-	-	-	-	-	-	-	-	1413
Emamectine	12	20	23	32	39	60	73	81	41
Hydrogen peroxide									308 metric tons
Teflubenzuron	28	-	-	-	-	-	-	-	2028
Total	128	105	98	104	100	132	132	218	5092¹

¹Hydrogen peroxide not included

Table 3. Anthelmintics (per kg active ingredient)

	2001	2002	2003	2004	2005	2006	2007	2008	2009
Fenbendazole	21	8	2	23	78	27	1	0	0
Praziquantel	100	152	232	412	122	145	94	91	29
Total	121	160	234	435	200	172	95	91	29

Table 4. Fungicides (per kg active ingredient)

	2001	2002	2003	2004	2005	2006	2007	2008	2009
Bronopol	392	396	422	314	377	492	493	751	508
Malachite green	7	8	4.5²⁾	0.7²⁾	0.9²⁾	0.9²⁾	0.8²⁾	0.6²⁾	0
Total	399	404	427	315	378	493	494	752	508

²Not used in production of fish for human consumption.

Table 5. Anaesthetics (per kg active ingredient)

	2001	2002	2003	2004	2005	2006	2007	2008	2009
Benzocaine³	ca 500	ca 500	ca 500	ca 500	ca 400	ca 400	ca 700	ca 800	ca 800
Isoeugenol⁴	3	1	1.5	2.5	-	6.5	5	25	65
Chlorbutanol	1	-	-	-	-	-	-	-	-
Tricaine mesilate (metacaine)	440	827	699	737	960	1248	1269	2164⁵	2379

³Calculated sales for fish breeding. Benzocaine is also used in human medicine.

⁴Isoeugenol is only used in research.

⁵Figures are corrected from last year’s ”Pharmaceutical use in Norwegian fish breeding"

Source statement

Wholesaler-based Drug Statistics, Norwegian Institute of Public Health, 2009. Data from this source can be freely stored electronically, printed, reproduced and further processed as long as the original source is quoted in every report, table or figure.