Shark fisheries

Figure 1 : female porbeagle shark

female porbeagle shark

In Atlantic Canada there are only two directed shark fisheries. One is a recreational fishery for the blue shark which is primarily in the form of annual derbies. The other is a commercial fishery, currently inactive, aimed at the spiny dogfish. Blue sharks, porbeagles and shortfin mako are caught incidentally through other commercial fisheries.

Below is a table showing the recent catches of shark species by year. These are the reported Canadian landings only; the discarded bycatch from longline operations are not reported, nor are catches by foreign countries fishing within Canadian waters. For blue sharks in particular, the unreported catch is believed to be much greater than the landed catch ( blue shark FSR 2002). Recent calculations of shark discards across all fisheries are now available (Campana et al. 2011).

Shark Catch by Species per Year (weight in metric tons)
Year Landed Species
Porbeagle Blue Mako Spiny Dogfish Hammerhead Unspecified
1991 329 32 N/A 307 N/A 176
1992 814 101 N/A 868 N/A 161
1993 920 21 N/A 1435 N/A 168
1994 1573 122 131 1820 <1 105
1995 1348 112 103 956 <1 31
1996 1043 9 60 431 <1 9
1997 1317 3 80 446 N/A 19
1998 1054 4 71 1055 <1 37
1999 955 31 69 2091 N/A 8
2000 899 19 62 2741 <1 13
2001 499 <1 70 3820 <1 21
2002 230 5 79 3584 <1 14
2003 139 6 66 1302 <1 8
2004 218 <1 70 2362 <1 7
2005 203 <1 85 2270 <1 11
2006 190 <1 67 2439 <1 7
2007 94 <1 69 2384 0 8
2008 125 <1 44 1574 0 6
2009 62 <1 49 155 0 8
2010 83 <1 38 6 0 7
2011 30 <1 36 125 0 4
2012 34 1 29 65 0 3
2013 17 <1 35 6 0 1
2014 9 <1 55 54 0
2015 4 <1 83 1 0 0

The only directed commercial fisheries for shark in Atlantic Canada are for the porbeagle shark (which was discontinued in 2013) and the spiny dogfish. The porbeagle is usually harvested through longline fishery operations. Porbeagles are usually caught at a depth of 50 to 150 meters using squid as bait. The sea surface temperature generally ranges between 5 and 16 degrees Celsius. The main fishery is active in the spring and in the fall. Spiny dogfish are usually harvested by longline or handlines but gillnets and otter trawls have been used in the past. They are usually caught at a depth of 30 to 180 meters using either squid or herring as bait. The fishery generally begins in the late spring when dogfish schools begin to migrate northward and continues into the summer and early fall.

Canada started a directed fishery for the porbeagle shark in 1991, following on earlier successes by the Faroese and Norwegians. However it was not until 1992 that the first fisheries management plan was implemented. Prior to this, pelagic sharks were not covered by fisheries regulations. Finning, the act of removing the fins and disposing of the carcass at sea, was outlawed in June of 1994. Also in 1994, the Department of Fisheries and Oceans (DFO) began its analysis of porbeagle catches, and later that year, the first stock status report was produced. A preliminary stock assessment based on commercial catch rates was presented in 1996. The first detailed stock assessment was tabled in the fall of 1999. This assessment was updated and improved in the spring of 2001.

Management controls of the recreational shark fishery were initiated in 1994, when recreational shark fishing was limited to hook and release only: special regulations allow the catches to be landed in shark derbies.

The total allowable annual catch for porbeagle was 1500 tons per year until 1996. After the 1996 stock assessment was tabled, the total allowable catch was lowered to 1375 tons. In 1997 it was lowered again to 1000 tons where it remained until the end of 1999 as part of a 3-year management plan. Since detailed stock assessment information was not available at the time of release of the 1997-1999 management plan, these catch quotas were viewed as being precautionary in nature, rather than based on stock abundance information. The 2000-2001 management plan was based on the 1999 stock assessment, and limited catches to 850 tons per year. As a result of the 2001 porbeagle stock assessment (summarized in the 2001 Stock Status Report), a 2002-2006 management plan was set in place in which the catch quota was reduced to 250 tons per year, of which 200 tons per year is allocated to the directed fishery. This greatly reduced catch quota is needed to allow the population to recover from its current low level. A catch of 850-1000 tons per year should be sustainable once the population has recovered.

In 2004, by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) recommended that porbeagle sharks be designated as Endangered, based on the stock information summarized in Campana et al. (2003). To update and improve the available information on porbeagle, a comprehensive stock assessment was carried out in 2005 (Gibson and Campana 2005), concluding that the 2005 female spawner abundance is about 12% to 15% of its 1961 level, although population numbers have remained relatively stable since the reduction of catch quotas in 2002 ( Stock Assessment Report 2005). All analyses indicate that the population can recover, but that human-induced mortality needs to be kept below about 4% of vulnerable biomass (about 185 t per year) ( Recovery Assessment Report 2005). Since DFO is determined that the population recover, future management of this species will ensure that mortality is kept below the 4% level required for recovery. As such, the government has decided that porbeagle will not be listed as endangered under the Species At Risk Act (SARA). The most recent stock assessment indicates that population recovery has already begun ( Stock Assessment 2010) (Stock Assessment 2012).The directed fishery for porbeagle was closed in 2013.

For both the blue and shortfin mako, the total allowable catch was limited to 250 tons per year as a precautionary measure until scientifically-based sustainable catch quotas can be determined. Recent stock assessments for blue sharks ( 2008 Blue shark stock assessment) and shortfin makos ( 2008 Mako stock assessment) are now available. A  2006 Recovery Potential Assessment for makos concluded that Canadian catches should not increase over recent levels of about 100 tons per year (2006 Research Document).

Spiny dogfish have long been considered a nuisance by fishermen because they interfere with fishing operations for other species and sometimes cause damage to fishing gear. In some fisheries, spiny dogfish represent a large proportion of the bycatch. Since 1930, up to 24,000 mt per year have been landed by the U.S. and other foreign countries for food and as a source of vitamin A. Canadian landings were small before 1979, but averaged 1000-2000 mt annually until 2002. With declining fin fish stocks and a small foreign market for dogfish, a new directed fishery began in 2002. The first annual quota of 2500 tons was set provided that scientific data and samples would be collected with the fishery. With greater interest by Canadian fishermen in 2003, the total allowable catch was increased to 3200 tons and a 5 year research plan was established to collect scientific data. The quota was reduced to 2500 tons for 2004 and subsequent years, but the research plan was continued to address concerns that the population is in decline. One problem with the dogfish fishery in the U.S. is that most markets seek larger animals, which means that mature females are preferentially targeted. This practice has the potential to deplete the dogfish stocks because of the removal of reproductive females. The Canadian dogfish research program indicated that the Canadian fishery does not target mature females to the same extent, and that Canadian biomass levels are at least 300,000 mt ( 2007 Science Advisory Report). A detailed analysis of dogfish status in Canadian waters is now available as a Research Document. A comparison of Atlantic and Pacific Canadian dogfish stocks is presented in Wallace et al. (2009). More recently, a transboundary population model was developed to assess the status and health of the northwest Atlantic population (Canada and the U.S.), as well as determine sustainable catch levels (2014 Science Advisory Report). More information on the research program can be seen on the dogfish research page.

Below are figures of porbeagle catch rates by location in 1997. The first figure depicts the location of catches made by Canadian vessels greater than or equal to 100'. Figure Two is the location of catches for Canadian vessels less than 100'. Catch locations have not changed very much in recent years.

Figure 2 : Catch rates (kg/hook) for porbeagle sharks by Canadian vessels greater than or equal to 100' in 1997

Catch rates (kg/hook) for porbeagle sharks by Canadian vessels greater than or equal to 100' in 1997

Figure 3 : Catch rates (kg/hook) for porbeagle sharks by Canadian vessels less than 100' in 1997

Catch rates (kg/hook) for porbeagle sharks by Canadian vessels less than 100' in 1997