August 1999

DFO SciencePacific Region Stock Status Report C6-07 (1999)

Background

Prawns (Pandalus platyceros), are the largest of theseven commercial species of shrimp in British Columbiawaters, all belonging to the family Pandalidae. Prawnsgenerally live for four years. They start their lives asmales and mature at age 1. They function as maturemales for two seasons and then transform into femalesin the final year of life. This condition is known asprotandric hermaphrodism.

Prawns live in rocky habitats from the intertidal zoneto a depth of 487 metres, but normal adult habitat isbetween 70 and 90 metres. They are distributedthroughout the northeastern Pacific from San Diego,California, to Unalaska Island, Alaska, and in thenorthwestern Pacific from the Sea of Japan to KoreaStrait.

Mature prawns breed in the autumn. The female carriesfertilized eggs on small appendages of the abdomenknown as pleopods or swimmerettes, from October toApril, at which time the larvae hatch and spend up to 3months in the water column before settling on thebottom.

Figure 1: Pacific Fishery Management Areas (PFMA)and Divisional Areas

Summary

• This is a fully competitive limited-entryfishery, with 253 licence holders managedwith a variety of input controls, includinggear limits and gear and vesselspecifications.

• The fishery is managed to a biologicalreference point, the mean monthly index,which is the number of remaining femalesavailable for spawning.

• The fishery is meeting conservation goals,assisted by industry funding for the costsof in-season assessment and management.

• Fishermen express concern for thesustainability of the fishery.

• This is a coastal community-based fishery.

Prawn, Pandalus platyceros, offthe West Coast of Canada

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Pacific Region Prawn, Pandalus platyceros, off the west coast of Canada

The Fishery

Prawns in the commercial fishery are caught intraps deployed on long-lines, commonly from55 to 90 metres on rocky bottoms. The annualprawn catch has been generally increasing since1980, and in 1996 and 1997 exceeded 1,700tonnes. In 1998, recorded catch fell to 1,675tonnes, but was still the third-highest catch onrecord.

The commercial prawn fishery occurs throughoutthe B.C. coast. In 1998, 23 % of the total catchwas reported from northern coastal waters inPacific Fisheries Management Areas (PFMA) 1to 10 (North Coast Division) and 77 % fromsouthern coastal waters in PFMA 11 to 29 (SouthCoast and Fraser River Divisions). All inshoreareas are now considered to be fully subscribed.Opportunity remains to expand the fishery intooffshore waters (PFMA 101 to 130).

Figure 2: Recorded prawn catch (tonnes), 1980-1998.

Most prawns are either landed as whole frozen-at-sea (FAS) product, or as fresh, and thenconverted to whole frozen product in shore-sideprocessing plants. Frozen product is destined forthe Japanese market and has accounted for 90 to95 % of the total landings in the last 3 years. Liveand fresh product is landed from day vesselsoperating in southern coastal areas which are closeto local markets.

Historically, the live and fresh product was ofhigher value, but in 1995, the price paid to

fisherman for FAS prawns increased, and theirlanded value exceeded live and fresh productlanded value. By 1997, the whole landed valueof FAS prawns product reached a high of $19.80/kg for large FAS prawns. In 1998, however,instability in the Asian market resulted in a pricereduction for FAS product and the value of directpublic sales of live and fresh prawns againexceeded FAS product

The total landed value of the prawn fisheryexceeded $26 million in 1996 and 1997 (Figure3). In 1998, the landed value fell to $18 milliondue to the weakened Japanese market.

Recreational fishing occurs near coastalcommunities. Effort in recreational prawn fishingis growing. First Nations fishermen participateas licence holders in the commercial fishery, aswell as occasionally harvesting prawns for food,social, and ceremonial purposes. There is a minorbycatch of prawns in the shrimp trawl fishery.

Figure 3: Reported Landed value of the commercialprawn fishery, in millions of dollars.

Licence limitation came into effect for this fisheryin 1990. By 1998, there were 253 licences eligibleto participate in this fishery. Most licences arenow fished every year, either individually or incombination with a second licence. This practiceis known as “stacking,” an option that wasintroduced with trap limitation in 1995. Inaddition to the licence limitation program, a traplimitation program was introduced in 1995,allocating 300 traps per licence. Additionalmanagement fees collected as part of this program

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Pacific Region Prawn, Pandalus platyceros, off the west coast of Canada

are used to contract at-sea prawn charterobservers, who carry out in-season monitoring ofcompliance to the trap restrictions. The observersalso carry out the in-season monitoring of thecatch composition and effort in the fishery. Thisinformation is reviewed weekly and analysed todetermine necessary closures based on femaleescapement targets

The protection of smaller-sized prawns ismaintained in the commercial fishery with size-limits and the specification of fishery openingdate. The size limit was initially set at a 30-mmcarapace length in 1988, and was increased to 33mm in 1997.

Since 1979, the commercial prawn fishery hasbeen monitored, using a biological reference pointknown as the mean monthly index, to ensure thatfemale spawning stock is protected. The fisheryis closed in an area when the number of spawnersfalls below a predefined level.

Resource Status

Adult prawns do not migrate to any significantextent and therefore there may be hundreds oflocalized adult stocks. Since trap limitation in1995, improvements have been made in thegeographic coverage of in-season biologicalsampling, the mean monthly index is beingapplied in a more conservative fashion, and moretimely closures have been implemented inresponse to recommendations from the StockAssessment Division. This management regimeis intended to move fishing effort in a timelyfashion to prevent localized overfishing. Stocksare believed to be healthy in most coastal areas.

Management Considerations

Since trap limitation in 1995, fishermen haveincreased effort and invested capital in vesselupgrades and vessel replacements to achievegreater speed and carrying capacity. Manyfishermen are now setting their traps several timeseach day, particularly at the beginning of theseason when stocks are strongest. Fortunately,observer sampling has been able to keep pace with

this increase. The increasing effort and improvedin-season assessment resulted in the fishingseason being reduced from 230 days in 1994 to93 days in 1998. Although managers and stockassessment personnel are confident that they areachieving conservation goals, fishermen areconcerned that their effort in future mayoverwhelm the response time of the currentmanagement system. They are also concerned forthe sustainability of the commercial fishery, buthave widely divergent views on the managementactions that should be considered.

The sports fishery in recent years has grown solarge in some areas that the effort possibly exceedsthe commercial effort in areas close to majorpopulation centers. The sports fishery presentlyis not subject to any management closures,however, with this kind of effort severeoverfishing can occur and a management strategyneeds to be implemented to address the issue ofthe sports fishery impact on conservation of theseanimals.

Outlook

The commercial prawn fishery has a strongdependence on the Asian market. Instability inthis market in 1998 led to a 30 % decline in thelanded value of prawns in B.C. In addition, theshort seasons of the past few years are generallyunsuitable for live and fresh markets, as bothmarkets are easily glutted by short, intensefisheries.

The sports fishery is expected to grow in morelocations as people become more familiar withthe fishing techniques.

The continuing illegal harvest of prawns is ofconcern, particularly in areas closed tocommercial harvest for conservation purposes.

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Pacific Region Prawn, Pandalus platyceros, off the west coast of Canada

This report is available:

PSARC SecretariatPacific Biological StationNanaimo, BC V9R 5K6Phone: (250) 756-7208Fax: (250) 756-7209E-Mail: psarc@pac.dfo-mpo.gc.caInternet Address: (www.dfo-mpo.gc.ca/csas)

ISSN 1480-4913 (for English series)ISSN 1480-4921 (for French series)

La version française est disponible àl’adresse ci-dessus.

Correct Citation for this publication

DFO, 1999. Prawn, Pandalus platyceros, off thewest coast of Canada. DFO Science Stock StatusReport C6-07 (1999).

For more Information

Contact:J.A. BoutillierShellfish SectionStock Assessment DivisionPacific Biological StationNanaimo, B.C. V9R 5K6Tel: (250) 756-7000Fax: (250) 756-7138E-Mail:Boutillierj@pac.dfo-mpo.gc.ca

References

Boutillier, J.A. 1993. 1993 Review ofExperimental Prawn Fishing in Howe Sound.In Hand, C.M. and B.J. Waddell [eds.]. 1996.Invertebrate Working Papers Reviewed by thePacific Stock Assessment Review Committee(PSARC) in 1993 and 1994. Can. Tech. Rep.Fish. Aquat. Sci. 2089: 303 p.

Boutillier, J.A. and J.A..Bond. 1999. Implicationson Assessment of the British Columbia PrawnPopulations with the Adoption of a QuotaManagement System. Invertebrate WorkingPaper I99-08 reviewed by the Pacific StockAssessment Review Committee.

Butler, T.H. 1980. Shrimps of the Pacific coastof Canada. Can. Bull. Fish. Aquat. Sci. 202:280 p.

Morrison, J., M. Kattilakoski, I. Winther and J.Boutillier. 1998. Prawn and Shrimp by TrapFishery – 1996, 1997. PSARC FisheryUpdate. http://www.pac.dfo-mpo.gc.ca/ops/fm/shellfish/prawn/prawn.htm