• FISHERIES RESEARCH BOARD OF CANADA l llJR~~ ,

FI HfIUr:'S IIES£ARClf BO~R D 01: u.lW.II'., ,IOLlXi ICAl. STAT ION, fT. JOHN'S, NEWfOUNDLAND, CAHADA. MANUSCRIPT REPORT SERIES

No.120l

TITLE

The St. Lawrence rough whelk fishery and its paralytic shellfish poison problems

AUTHORSHIP

J. C. Medca-L t: I

Establishment Biological Station St. Andrews, N. B.

Dated September 1972

This seiies includes unpublished preliminary reports and data records not intended fOf general distribution. They should not be referred to .in publication5 without clearance from the i55u ing Board establishment and without clear indication of their manuscript statuI. CONTENTS Paqe I~ • I" - . Abstract ...... Introduction...... 2

The rough whelk...... 2 Whe 1 k fi shery in eas tern Canada ...... 3 Commercial fishery...... 3

Domestic fishery 3 Commercial processing and domestic cooking ...... 3 Commercial processing...... 4 Domestic cooking...... 4

Wholesomeness as a seafood ...... 4 Good repu ta t ion· . . • . • ...... 4 Unwholesome sometimes...... :) Paralytic shellfish poison in whelks ...... , 5

Public health precautions ...... 6 Monitoring processed whelks ...... 6 Restriction of fishery...... 6 Control does not eliminate poisonings...... 6 Cap Chat poisonings...... 7 True cases of psr ...... 7 Whelk sampling ...... 7 Local enquiries and interpretations...... 8

Features of whelk toxicity 9

Toxicity changes with season 9 - 2 -

Year-to-year variation in whelk toxicity and winter carry-over of poison by bivalves 1 ()

• Poison accumulation and excretion by bivalves and whelks ...... 12

uifferential variations in bivalve and whelk scores...... 13

Commercial processing and domestic cooking reduce toxicity...... 14

H0 \'1 t 0 x i c d 0 'vI h elk s get?...... 1 6

Tile danger level 1 7

The road to efficient control ...... 18

Public health interests ...... 19

Commercial fisheries interes t ...... 19

Needs for research ...•...... •...... 20

Acknowledgments ...... 23

References 24

Appendices I and II ..

ABSTRACT • The rough whelk (Buccinum undatum) is a carnivorous snail abundant in cool-water area s of the Canadian Atlantic coast and a popular seafood i n parts of the province of Quebec and northern New Brunswick. I t is fished commercially in the estuary of the St. Lawrence River. The whelk is not a plankton feeder, nevertheless, in nature it sometimes contains paralytic shellfish poison which . is derived from a planktonic dinoflagellate, GOnaaulax tamarensis. The whelk is believed to obtain its poison secon -hand from . bivalves and other plankton feeders on which it preys. Extensive sampling shows that raw whelk toxicity scores (~g of poison/100 g of whelk meat) are generally low (maximum recorded 608) indica­ ting that the whelk is not usually a dangerous seafood. In spite of this there have been 16 documented cases (one fatal) of whelk poisoning of humans. The latest poisonings occurred in March 1970 following unprecedentedly high toxicity scores for . bivalves during the autumn of 1969. From this and other informa­ I tions it is deduced that under special, rare conditions, scores ,t a of raw whelks may exceed 1000-2000. Scanty data indicate that cooking, shucking and trimmin g reduce whelk scores 80-90% and that cooking and shucking wi t hout trimming reduces scores 70%. All the 16 poisonings are attributed to consumption of whelks taken by the domestic fishe r y which is difficult to control. It is easy to control the co mmercial whelk fishery and processing industry and controls aimed to reduce risks of poisoning are justified. However, present control measures seem unnecessarily hampering to t he fi s hery. Possible ways of improving controls of both the do me stic and commercial whelk fisheries are discussed. - 2 -

INTRODUCTION There is a traditional rough whelk fishery in the estuary of the St. Lawrence River (Fig. 1). This is the only stable Canadian Atlantic commercial fishery for the species. although small landings are sometimes reported for the Magdalen Islands and experime ntal fishing has been done in Prince Edward Island (Younker a nd MacWilliams 1971). Nobody seems to know when or how the Quebec fishery began. Possibly the first settlers brought it with them 300 years ago from their native France where it is no longer carried on (Hancock 1967). Or perhaps the settlers learned how to catch and eat whelks from the Indians. Whelk shells are abundant in their middens in eastern Canada (personal observa- t ion) . The fishery is described here partly because of its intrinsic interest as a fishery but mainly because of its implication in a public hea lth problem - paralytic shellfish poisoning (PSP) . . Appreciation of t hi s implication is recent and still incomplete. Our stud y has clarified some of its puzzling aspects but many are still unsolved and deserve in­ vestigation. THE ROUGH WHELK The rough whelk is a marine snail with many other common names (waved whelk, edible whelk, common northern whelk. buckie, gros bigorneau, bourgeau, vignot and buccin) but it has only one scientific name, Buccinum undatum L. The limy shell is heavy and variable in colour, being greyish-green, yellowish-brown, or mottled yellow and brown (F i g . 2). The commonest specimens seen are 2-4 inches long, but whelks up to 6 inches are reported (Ganong 1889) The species is widely distributed from Labrador to New Jersey in the western Atlantic and most abundant in the cooler waters of eastern Canada, such as the estuary of the St. Lawrence River and the Bay of Fundy. It is also common on the Atlantic coast of Europe. It may be found from just above low-water mark on intertidal beaches to depths approach­ ing 100 fathoms. It is mainly carnivorous, feeding on living or newly dead animals, including fish caught in nets set at the bottom (Dakin 1912) and crabs and molluscs such as mussels (Ingham et al.1968). Chiasson (MS 1952) reports that it does not I ' attack sea scallops in mid-summer, but Caddy and Chandler (1968) found that, when kept in aquaria, it will eat scallop I.' "livers". It is able to bore through the thin shells of some I , species and feed on them with its protrus;ble rasping tongue , - I .- - 3 - (Dakin 1912). • The whelk travels slowly and is presumed to move only short distances. Apparently it is active the year round (Roy personal communication 1970) . WHELK FISHER Y IN EA STERN CANADA The whelk abounds on bo th the north and south shores of the estuary of the St. Lawrenc e River and is fished both commercially and for domestic us e during the open water season. Commercial fishery The commercial fishery centers at Matane on the south shore of the estuary and at Godbout and Baie des Homards on the north shore (Fig. 1). Whelks are caught in baited hoop traps that are set in strings beyond l ow- water mark from oared boats or small motor boats (Figs. 3 and 4). A boat fishing thirty · trap~, lifted twice a day, will land 50-60 ten-quart buckets of whelks per day in mid-summer. A buc ketful weighs about 20 ! : pounds. ! In 1971 this fishery landed approximately 368,000 1b of whelks with a landed value of $19,000 (Quebec Bureau of Statistics,197l ). Domestic fishery Whelks are fished for home consumption either by hand picking them on intertidal beaches, or by hoop-trapping beyond low-water mark (La Cote-Nord 1960). Nowadays the domestic fishe ry is lim i t ed almost exclusively to the open-water season. But according to ~r. Andr~ Roy. a fishman of Cap Chat (Personal communication 1970), hoop-trapping throuqh holes in the ice was a common practice in earlier times in ~ome localities. This fishery was usually carried on during early winter "before the ice got too thick for easy chopping . We have no estimate of quantities landed by the domestic fishery. COMMERCIAL PROCESSING AND DOMESTIC COOKING Commercial processing On 5 July 1966, I visited Mr. Philippe Lejeune's whelk packing plant at Godbout, P.Q. Here the fishermen's catches were washed, steamed, and shucked (meats removed from the shells). - 4 - In the shucking process, the smal l est whorls of the coiled meats, the gill and the loose fold of the mantel were trimmed .. away, leaving only the firm lower muscular parts of the body . The trimmings contain the digestive gland that gives the small whorls their brown or greenish-brown colour. During shucking, the operculum, a flex ible oval door that closes the shell aperture, was also removed if it had not already separated from the meat during the stea mi ng process. The trimmed, steamed meats (creamy white with small black flecks) were packed in sma l l glass bottles with a marinade of sugar and spiced or plain vinegar. Or they were canned in brine and heat-treated to produce a pack with a longer she l f life and with other advantages described in the section, "Com­ mercial processing and domestic cooking reduce toxicity". These products found a ready market in the Province of Quebec and in New Brunswick communities bordering the Bay of Chaleur. Domestic cooking i :Ii According to Mr. Roy (Personal communication, 1970) the usual method of cooking whelks for home consumption is steaming. Whole, live whelks are placed in a covered pot with a small amount of water on a hot stove and cooked until the operculum (lithe part like a fingernail") separates .from the meat. Whelks are served piping hot from the pot; the diner thrusts a fork into the part of the body that protrudes from the shell, gives the shell a dexterous twirl and the meat comes out either entire (which happens about half the time) or minus the dark, upper whorls that often fail to separate from the shell. Some diners prefer to remove the da rk whorls (if they come out) before eating but Mr. Roy assu red me that whatever comes from the shell is "all good".

A domestic processing (bottlin~) of trimmed meats in vineqar is also practised in some areas (La Cote-Nord 1960). WHOLESOMENESS AS A SEAFOOD Good reputation Whelks are a popular seafood, especially in Quebec, and consumers rate them as tasty, nutritious and wholesome. Some say that a feed of whelks is asstrengthening as a steak dinner (Dakin 1912). In Quebec they are said to be tastier in the cold months than in summer (La Cote-Nord 1960; Roy perso~al I • communication 1970). . - 5 - ~ Unwholesome sometimes In 1936 twelve persons were poisoned (none fatally) by eating whelks at Godbout, P.Q. The illnesses were attributed to pollution of the whelk bed by the outfall of an adjacent pond that was full of shavin gs f ro m pulp-barking operations (i~edcof et al. ~1S 1966). Th irty ye a rs later, four more illnesses were reported (one fatal) foll ow ing consumption of whelks fished at Cap Chat (The Gazett e 1970; Litalien Personal communication 1970; Boyd and Tur ge on MS 1971; CBC 1970). Paralytic shellfish poison in whe lk s There is ample evidence that the whelk accumulates paralytic shellfish poison if its prey is toxic (Medcof MS 1952 and MS 1971A; Bond MS 1955; Boyd and Lachance MS 1962-MS 1970; Medcof et al. MS 1966 ; Cad dy and Chandler 1968; Ingham et al. 1968; Boyd and Turge on MS 1971 ). The poison content (re ferred to herein as "toxicity score" or uscore") is the numbe r of mi c rograms {pg} of poison i : . present in a representative sample of 100 grams of whelk meats. Scores are determined by bioassay (Tennant, in Prakash, Medcof and Tennant 1971). All the scores listed in this report are quoted exactly as they appear in documents referred to. In many cases these are represented as having three-figure or even four-figure accuracy. Dr. Tennant points out (see above reference) that bioassay res ults have wide variance and he suggests (personal communication 1972) that they should be considered as having no more than two-figure accuracy. Raw whelks are se ld om assayed for pO ison partly because this ;s such a laborious process. It requ ires careful cracking of the shell to avoid crushing or fr a gm enting the meat. The smallest whorls of the coiled meat are difficult to remove from the shell. Sometimes they break off and cannot be recovered. If the poison were evenly distributed throughout the body, this loss would be inconsequential. But the poison is concentrated in the brown digestive gland which is located in the smaller body coils (Medcof et al. MS 1966; Caddy and Chandler 1968). The result is that, unless the living meats are removed with extreme care, the bioassay scores for whole whelks are likely to be falsely low. The most toxic raw samples of whelks tested to date are described by Nadeau and Lachance (Medcof et al. MS 1966). These were taken from Godbout t P.Q., 29 June 1964. Thei r whol e

>. bodies scored 608 and their digestive glands 1600. I i - 6 - '[ : Commercially processed whelks sometimes contain poison ! " too. This was discovered in 1954 (Bond MS 1955) after this • product became suspect following a 1951 demonstration that raw Bay of Fundy whelks may be toxic (Medcof MS 1952). t PUBLIC HEALTH PRECAUTIONS Government has r e spons ibi li ty for insuring that food processors, operating under government licence, offer the public wholesome products. Monitoring processed whelks A program of government monitoring of commercially processed whelks was begun in 1954 (Bond MS 1955), dropped after 1955, then reinstated in 1964 and continued since. The monitoring resul ts are reported annually by the federal fisheries service in manuscript reports, "Shellfish Toxicity Records", and apply largely to the St. Lawrence estuary. Altogether 202 as says of rough whelks were reported .. up to the end of 1970. There have been few positive scores and most of them have been well below the danger level of 80. Only four scores have exceeded 80. They were 93 and 83 at Godbout in 1964 (Boyd and Lachance MS 1965); 396 at Baie des Homards in 1969 (Boyd and Lachance MS 1970) and 150 at Riviere i1adeleine in 1970 (Boyd and Turgeon MS 1971). Restriction of fishery Government precautioris in the interest of public health have gone further than monitoring the comme rcial product. In some areas the whelk fishery has been closed down at times when those areas were quarantined to fishing of musse l s and clams on account of their high poison scores. This precaution was taken partly for administrative convenience, even though commercially processed whelk meats from these areas were still testing poison-free. This has had a severely adverse effect on the whelk fishery and the processing industry it supports. Control does not eliminate poisonings Controls of the commercial shellfish fisheries and shellfish processing plants are simple and effective and without doubt have prevented some cases of PSP, for example from soft­ shell clams. However, they have not eliminated poisonings from either bivalves or whelks. In 1936 there were 12 poisonings from whelks. These ", were not recognized as cases of PSP until case histories were - 7 - compiled thirty years later (r1edcof et al. MS 1966). These occurred before government controls were instituted but there f : have been four poisonings since controls were instituted . f All the 16 recorded poisonings are attributed to whelks taken by the domestic fishery and government agencies frankly admit that they cannot control the domestic fishery directly as they do the commerc ial fishery. That would require strict patrol of hundreds of miles of affected coastline . The only protection government can provide for those who fish their own shellfish is indirect. It can only warn them of risks of PSP when shellfish are toxic. This is regularly done by posting warning signs in affected areas and by issuing warnings in newspapers and on the radio and TV. CAP CHAT POIS ONINGS On 30 March 1970, there were fo ur poisonings from whelks (one fatal) at Cap Chat, P.Q. Television (CBC National ! . News 1970) and newspaper (e. g . The Gazette 1970) reports gave these poisonings wide publi ci ty. No clear indication of the nature of these illnesses was indicated by the public an nouncements. March seemed to be "off season" (too early) for PS P which is generally considered to be a summer malady (Medcof, Fig. 4 in Prakash, Medcof and Tennant 1971). As a result there was much speculation as to the cause of the illnesses until clinical case history reports were received from Ste.Anne des Monts (Litalien personal communication 1970). True cases of PSP Dr. Litalien1s long clinical experi ence with PSP, his case history reports (Litalien MS 1970) and his firm diagnoses based on symptomatology of the four Cap Chat illnesses as true cases of PSP, are convincing. Whelks seemed to be the only food taken, by all four poisoned people,that might have carried poison. A search was made for direct evidence as to whether the whelks were toxic enough to cause severe illness and death. This was the first time that such an opportunity had presented itself. There were no recent toxicity monitoring data for Cap Chat whelks, either processed or raw, so sampling of the whelk population was undertaken (Boyd and Turgeon 1971). , .-. Whelk sampling Whelk samples taken from unspecified sites at Cap Chat on 9 and 27 April,gave cooked meat scores of <44 and 45 - 8 - (A cooked score of 45 is equivalent to a raw score of 150). A sample of blue mussels taken 9 April from Ste . Anne des Monts gave a raw score of 90. These records are inadequate in explaining the poisonings. It is inconceivable that whelks with raw scores of only 150 could cause illnesses of the severity described in Dr. Litalien's case history reports. And it is hard to believe that whelk scores could have de cr eased from dangerous levels on 30 March to<.44 in only 10 days. Local enquiries and interpretations To learn more about the poisonings, a visit was made to Cap Chat on 8 June 1970 and interviews were held with Mr. Andre Roy, fisherman of Cap Ch a t, and with six other residents of that community. The interv i ew s showed that the ice had left the river in late February; that Mr . Roy was the only person in the neighbourhood who fished whelks in late March 1970; that he caught them in hoop traps set on bottom in 10 fathoms of water directly off from the Cap Chat government wharf; that he was ." fishing for his own domestic use but that his catch from one day's set (30 March) was so large that he shared it with two neighbouring families, the Va11~es and the Pe1tiers.

None of the Va11~e family were interviewed on 8 June. They had recently moved from Cap Chat to Levis, P.Q. Interviews were held, however, with the Roy and Peltier families and with Camille Morin who had shared the whelk dinner with the Roys. The interviews established that all three families cooked the whelks by steaming; that nobody drank any of the bouillon from the cooking pot; that 14 persons shared whelk dinners; that 5 persons became ill and were taken to hospital an d that 9 persons (4 adults and 5 young children) suffered no i l l e f fects. None of the diners could recall very clearly how many whelks they had eaten. Estimates ranged 2-6 for the children and up to 2 dozen for the adults. Some ate the meats whole, as they came from the shells, while others trimmed them before eating. These interviews confirmed and amplified earlier accounts obtained through the local fisheries officer and throuqh telephoned and written accounts (Appendix II) from Or. Litalien. One would expect that at least the adult and the teenage victims would have had some tolerance for paralytic poison because they were residents of a shore community and accustomed to eating molluscan shellfish that are sometimes ", t 0 x i c U1 e d c 0 fin Pr a k ash, i~ e d c 0 fan d Ten nan t 1 9 7 1 ) . The fa c t - 9 - i that the teenager (Appendix II, Case 4) claimed to have eaten only three whelks and that she and the adult (Case 1) suffered • mild-to-severe illnesses suggests, but does not prove, that they ingested heavy poison dosages.

1ft hey ~l a d bee n a v era g e, poi son - sen sit i ve, non­ residents of shore communities their dosages would likely have been between 1,000 and 2,000 microgr ams. 1\ whole (untrimmed) steamed meat from a whelk 63 mm (2.5 inches) high weighs 13- 14 grams and a meal of 2 dozen untrimmed, steamed whelk meats (320 g) would not contain 1,000-2,000 micrograms of poison unless the cooked scores ranged from 300 to 600. It maybe assumed that cooking reduces raw whelk scores by 70% as it does raw scores of soft-shell clams and blue mussels (Medcof i n P r a k ash, f1 e d c 0 fan d Ten nan t 1 97 1 ) . 0 nth i s bas is, whe 1 k s that still scored 300 to 600 after cooking must have had raw scores of 1,000 to 2,000. These estimates are far in excess of 150, the equiva­ lent raw score for whelks sampled in April 1970. This deduction strengthened the view that the April samplings were not repres~ntative of the whelk stock that was responsible for the Cap Chat poisonings on 30 March. It also prompted a study of features of whelk toxicity that might clarify these anomalies and explain the melancholy events at Cap Chat. FEATURES OF WHELK TOXICITY Much is known about physiology, behaviour and toxciology of bivalve molluscs such as mussels and soft-shell clams. Whelks differ from bivalves but, since both are molluscs, many priciples derived from mussel and soft-shell clam studies are helpful in discovering features of whelk toxicity and how it may interact with toxicities of bivalves. Such interactions could have affected the poison dosages of the Cap Chat victims of whelk poisoning. Toxicity changes with season Seasonal chanqes are illustrated by records for 1964 (Uoyd and Lachance 1965) plotted in Figure 5. These show that in June and July the scores for commercially processed meats of whelks from Godbout, P.O., were usually less than those fot raw soft-shell clams from Franquelin which is 15 miles to the west (Fig, 1) and that changes in whelk scores parallelled changes in clam scores. Figure 5 also shows a similar but vaguer relationship between whelk scores and scores for blue mussels from Mistassini which is 20 miles to the west. In

' . August when, judging from bivalve scores, the highest whelk scores would have been expected (Fig. 5) no whelk samples were - 1 0 - taken. At that time, shellfish areas were quarantined and .. the whelk fishery and whelk processing plants were closed down . Scores for 1968 samples of processed meats of whelks from Matane on the south shore of the St. Lawrence show similar relationships. The whelks were poison-free from 15 May to 4 September except on 16 July when they scored 51 (Boyd and Lachance MS 1969). During this period, scores for blue mussels from Les M~chins (30 miles to the east of Matane) rose suddenly from 86 on 17 June to 3,080 on 2 July. They were still 2,400 on 16 July, then fell quickly to 176 on 20 Auqust on which date the whelk meats again tested poison-free . These demonstrations of whelk and other shellfish score changes in the Godbout and Matane areas are important for hlo reasons: (1) They show that cooked whelks contain most poison when filter feeders are most poisonous. (2) They suggest that scores for whole raw whelks may reach .' levels far above those recorded to date as was deduced from analysis of Dr. Litalien's case history records and from local enquiries on 8 June 1970. Year-to-year variation in whelk toxicity and winter carry-over of poison by bivalves The two highest monitoring scores for processed whelks were from opposite sides of the estuary of the St. Lawrence and in different years but they seem to be related. The highest score. 396 at Baie des Homards, 29 September 1969, came in a year of record high bivalve scores and at a time in that year, when scores for blue mussels and soft-shell clams in Baie des Homards were at or close to their annual maximum. At that same time mussel scores on the south side of the estuary reached all-time highs - 23,000 at St. Johachim de Tourelle and 10,000 at Cap Chat (~oyd and Lachance MS 1970). The second highest score for processed whelks was 150 at Riviere Madeleine on 18 May 1970. That was during the spring following the 1969 autumn of record-high bivalve scores - the spring when bivalves retained record hiqh amounts of poison that they had accumulated durinq the precedinq autumn. For example, on 23 March 1970 mussels at Les M~chins and soft-shell clams at ~aie des Capucins were both scoring 1,012 (Table 1 and~oyd and Tu r 9 eon [·1S 1 9 71 ) . '. - 1 1 -

Table 1. Scores of soft-shell clams (~) and blue mussels (Mytilus) in late autumn and ln early spring of the year following indicate frequent winter carry-overs of poison in the St. Lawrence region. (Data from Shellfish Toxicity Records 1964-1970.) Autumn and Reduction Loss of spring in score poison Years Species Place scores % pg/day

1964(23 rlov.) ~ Baie des 352 Capucins 1965(12 Apr.) 158 55. 1 1 • 4

1966(26 i~ov.) II " 726 1967(lG Apr.) 52 8 27.3 1 . 5

1966 LC s 1,1 echi n s

.. 1967(10 Apr.) II 484

1967(14 i ~ov.) ~~ l3aie des 352 capucins

196 3 (7 Hay) II " 374 +6.3 +0. 1

1968(19 Nov.) Nytilus 53

1 9 6 9 ( 1 4 1\ P r . ) II 45 1 5 . 1 o , 1

1969(10 Nov.) " " 1804 1970(23 r1ar.) I I II 101 2 43.9 6.0 1969 Baie des Capucins 1 970 ( 23 :-1a r . ) " 1 01 2 1)69(15 Uec.) " Betsiamites 484

1 9 7 0 ( 1 8 i~ a r . ) " " 418 1 3.6 0.7

., .- - 12 - Winter carry-over of poison was first observed at Lepreau ~asin, N.~., and later in other inlets (e.g. Crow Harbour) in the ~ay of Fundy region (Medcof MS 1949 and MS 1971B). In that region, winter carry-over is considered an unusual phenomenon and winter scores are usually low, but Table 1 shows that carry-overs are common in the estuary of the St. Lawrenc~. The explanation of carry-overs based on field experimentation (Medcof MS 1949) is that after the poison-bearing organism, Gonyaulax tamarensis, disappears . from the plankton, bivalves can no longer accumulate poison and begin to excrete it at rates that are requ1ated by decreasing autumn water temperatures. This is illustrated by toxicity graphs (Fig. 6) drawn by inspection and inter­ pretation to fit data from Boyd and Lachance (MS 1970) and fro m Boy dan d Tu r 9 eon (i'l S 1 971) and by ate mper at u reg rap h . There are no data on water temperatures under the ice in the St. Lawrence. So the temperature qraph in Figure 6 is based on ~ay of Fundy data with modifications suggested by Dr. L. M. Lauzier, Oceanograrher, Department of the Environment, Ottawa, from his wide general knowledge of the St. Lawrence estuary. It seems that at temperatures below 2.0-2.5°C blue mussels and soft-shell clams are unable to excrete poison at appreciable rates and that during the winter of 1969-1970 water temperatures dropped below that level before the bivalves had excreted all their poison. This concept is implied by the plateau sections in the toxicity graphs during the coldest part of the wi nter. Th is is the "ca rry-over II descri bed above. The end of the carry-over is heralded by the spring rise in water temperatures and an increase in the rate of poison excretion as demonstrated by the downward inflections of the toxicity graphs in March and April 1970 (Fig. 6). At that time the slopes of the toxicity grarhs approximated those observed in December 1969 when water temperatures are believed to have been at about the same levels. The presence of toxic bivalves throughout the winter provides a ready source of poison for predators like whelks long after Gonyaula~_ has disappeared from the plankton.

~~~~n__ a-.£c _ ~_inu 1 ~~i_on and . ~x_~J:..e t ion by b iva 1 v~_s_ _~~~l~_ As long as the poison-source organism ()onfaulax) is pre sen tin the p 1 a n k ton the poi son con ten t (s cor e 0 any- - bivdlve is a function of rate of poison accumulation and rate of poison excretion. GOnfaulax does not seem to thrive at water temperatures below O°C and disappears from the plankton when decreasing water temperatures reach that level (Prakash, -. in Prakash, Medcof and Tennant 1971). Thereafter, the poison contcnt of bivalves is assumed to be a function only of their rates - 1 3 - of poison excretion with water temperature as a controlling factor (Fig. 6). In years when plankton feeders become poison-free before cold weather sets in, whelks that are presumed to behave like their plankton-feeding prey and become less toxic or poison-free. Little is known about rates of poison excretion by whelks. At 12°C scores of mildly toxic whelks on a poison­ free diet decrease at a rate of 6 pg(=5%) per day (Caddy and Chandler 1968). Figure 5 indicates that in June and July the scores of mildly toxic whelks decrease at about this same rate even when bivalves in neighbouring areas are mildly toxic. It is not known whether there is a temperature threshold below which whelks are unable to excrete poison but Figure 6 strongly indicates that this is the case. However, according to Mr. Roy (personal communication 1970) they are attracted to food at water temperatures close to freezing and presumably feed at those temperatures and could accumulate poison if it were present in their food .

." In years when plankton-feeding prey of whelks are toxic throughout the winter, the behaviour of whelk scores may be highly complex. Depending on water temperatures, whelks could accumulate poison faster than they excrete it or could even accumulate it without excreting any and thereby build up higher and higher scores that might increase steadily until early spring when water temperatures begin their annual increase and permit excretion at faster and faster rates. There is evidence that bivalves sometimes accumulate sufficient poison to kill themselves (Adams et al. 1963). It is conceivable that in winter whelks could accumulate similar vast amounts of poison although there is no evidence of mortalities. Nevertheless, there are good grounds for believing that scores of Cap Chat whelks were sufficiently high in late March 1970 to have caused the poisonings described by Dr. Litalien. Differential variations in bivalve and whelk scores Bivalves derive their poison from Gonyaulax which ;s a component of the summer-autumn plankton of parts of the estuary of the St. Lawrence. The water then is like a well stirred soup with the poison-bearing plankter more or less evenly distributed through it. As a result, all plankton feeders, like mussels and soft-shell clams in an affected area have opportunity to feed on Gonyaulax and to become toxic to about the same extent. There are likely to be within-area variations in the amount of poison they accumulate, depending ". on beach level of intertidal species and positions in harbours - 14 - (Medcof, in Prakash, Medcof and Tennant 1971) but these varia­ tions are usually minor where plankton feeders are concerned. Within-area variations in toxicity of carnivorous species like whelks have never been studied but general know­ ledge of whelk biology permits conjectures about their place­ to-place variations. Within any affected area, the food of whelks may be expected to vary greatly with micro-habitats because their feeding range is believed to be limited and because the distribution of their associated organisms (;nclud­ ingtheir prey) is much influenced by such factors as bottom type that may vary greatly over short distances. For example, ~r. Roy (personal communication 1970) stated that it is easy to distinguish between Cap Chat whelks that are taken from hard bottom and soft bottom because whelks from rocky bottom usually have barnacles growing on their shells whereas whelks taken from muddy bottom have none. He also stated that hard bottoms and soft bottoms are often separated by only short distances in the Cap Chat area. We have no evidence that whelks feed on barnacles but we do know that they feed on blue mussels and that blue mussels require firm substrates, that soft-shell clams thrive on sand-mud bottom, that elongate nut clams (Yoldia) are most abundant on soft mud and that each species of bivalve has its own characteristic capacity for poison accumulation (Medcof, in Prakash, Medcof and Tennant 1971). Consequently, at any particular time, the toxicity of whelk food (be it mussels, nut clams or some non-filter feeders) and the whelks' opportunities for accumulating shell­ fish poison is likely to vary greatly over short distances. This means that scores of whelks hand-picked from a muddy inter­ tidal beach may be very different from scores of whelks like those fished by Mr. Roy on 30 March 1970 from hard bottom at 10 fathoms off Cap Chat wharf. It would be misleading, therefore, to estimate the scores of the whelks that caused the 1970 poisonings from the scores of whelks sampled at Cap Chat on 9 and 27 April from unspecified collection sites. Lacking samples of the whelks that were consumed or of whelks collected from the area fished by ~r. Roy, we cannot calculate the poison intake of persons who were poisoned on31 March 1970. Commercial processing and domestic cooking reduce toxicity It has been well demonstrated that commercial process­ ing and home cooking reduce the scores of bivalves (Medcof, in Prakash, Medcof and Tennant 1971 ).Nadeau and Lachance reported - 15 - scores of two samples of whole raw whelks taken in June 1964 at Godbout, P.Q. (Medcof et al. MS 1966) and Boyd and Lachance (MS 1965) reported scores of samples of commercially processed (steamed and trimmed) meats of whelks that were fished and processed at Godbout on the same dates.

Scores of Raw Commercially Decrease in Godbout whole processed score caused by whelks meats meats processing 1964

22 June 430 69 84 %

2g " 6013 93 85 %

The tabulated records indicate that commercial processing (steaming and trimming) destroys or removes about 85% of the poison present in raw whelks . . ' Tennant (MS 1971) has shown that marination in vinegar reduces the p6ison content of mussel meats that are still toxic after steaming. We may safely assume that it has similar effects on marinated whelk meats. Thus it appears that commercial processing provides whelk consumers a very high level of protection from risks of PSP. In one respect commercial processing of toxic whelks may be a safer treatment than canning of toxic soft-shell clams because trimming cooked meats reduces the toxicity of whelks but tends to increase the toxicity of soft-shell clams (Medcof, in Prakash, Medcof and Tennant 1971). The data listed above provide no estimate of the relative importance of the two processing treatments, steaming and trimming, in reducing whelk scores. rladeau and Lachance, working with raw meats, showed that processing reduces toxicity (i1edcof et ale :'15 1966) because it removes digestive glands that may be 8-24 times as toxic as the trimmed meats. Even without trimming, it is reasonable to expect that steaming would reduce raw \'/helk scores by 70 % as it does raw bivalve scores U"ledcof, in Prakash, r·1edcof and Tennant 1971),

ilo direct study has been made to discover effects of domestic cooking on whelk scores, They are assumed to be similar to but less consistent than those of commercial process­ ing - similar, because the heat treatment is essentially the '. same in both processes; less consistent, because home-cooked whelks mayor may not be trimmed before consumption, whereas commercially processed whelks are always trimmed. However, ·. - 16 - there is good reason to expect that home-cooked whelks would be as wholesome as the commercially processed whelks provided that: (1) They are cooked until their opercula separate from their meats and their meats separate readily from their shells. (2) Their meats are carefully trimmed. How toxic do whelks get? This question cannot be answered directly because there are so few toxicity records for whole raw whelks. The answer can be deduced only fro~ scanty records that were gathered without this purpose in mind. The highest score recorded for commercially processed whelks was 396 at Baie des Homards on 29 September 1969. Pre­ sumably 85% of the poison they contained was removed or destroyed in processing. So their raw score was probably about 2,200. A similar deduction based on the Riviere Madeleine score of 150 for processed whelks indicates a raw score of 850 for these animals on 18 May 1970. Judginq from Figure 6, the raw score must have been substantially higher on 30 March of that year because water temperatures during April -May would favour rapid excretion of poison. The highest score recorded for raw whelks was 608 at Godbout on 29 June 1964. No further raw samples were taken there that year so the mid-summer scores for raw whelks are unknown. However, they can be deduced on the assumption ~ig. 5) that increases in whelk scores were proportional to increases in bivalve scores in neighbouring areas, for example, from increases in scores of mussels at Mistassini and from increases in scores of clams at Franquelin. In early July 1964, the scores of raw mussels and clams and of processed whelks were all about 50 (Fig~ 5). By early August the mussels scored 1,370 (a 27-fold increase) and the clams scored 560 (an 11-fo1d increase). Using these ratios, we deduce that in early August 1964 the scores of processed whelks may have reached 1,370 or 560 (equivalent to raw scores of 9,100 or 3,700). The 1964 scores of most shellfish were well below the peak levels reached in 1969 when mussels at Mistassini scored 14,660 and clams at Franque1in scored 5,060 (Boyd and

'. Lachance MS 1970). From this it would seem that under extreme conditions like those in 1969, raw whelk scores might be even I • higher than 1,000-2,000 levels deduced above. - 17 -

The bas i s for de d u ( i n 9 3 () r1 a r (h 1 970 s (0 res for Cap Chat whelks is less substantial. In the autumn of 1069 Cap Chat In u sse 1 s s cor e d 1 0 , 0 0 0 ([3 0 y tI and La ( han c e ~~ S 1 9 7 0 ) and there was a high winter carry-over of poison in neiqhbouring areas (Table 1). This indicates that scores of those Cap Chat whelks that were preying on filter feeders were high in the spring of 1970. There are no whelk toxicity reco~ds that are considered pertinent in appraising this con­ cluslon. The only supporting evidence is that four poisonings occurred there on 31 March from whelks fished at 10 fathoms in line with the government wharf. Thus we have a great body of evidence suggestinq that under special and rare occasions whelk scores may far exceed the highest levels recorded to date. That is not a satisfactory answer to the question posed here. However, it seems safe to say that the Cap Chat ~Jhelks were dangerous food with scores well above 1,000-2,000 in late ~arch and that the April 1970 whelk samplings were certainly not representative of the stocks that caused the poisonings on 30 March. The danger level .' Studies of the 1945 and 1957 PSP epidemics in the Bay of Fundy region showed tnat all the 59 poisonings resulted from consumption of highly toxic shellfish, mostly soft-shell clams. These are eaten without trimming away any toxic parts of the meats. In 1945 the raw score of the least toxic of the offend­ ing shellfish \'Jas 1,000 01edcof et al. 1947) anti in 1957 it was 1,600 (Bond and Medcof 1958). It is generally agreed that it is the amount of poison ingested (dosage) that determines whether a consumer is .poisoned. In other words, he may become just as ill from eating larqe numbers of mildly toxic shellfish as from eating small numbers of highly toxic shellfish. This assumption mayor may not be sound. It has not been tested, so it may be best to work from the direct observations of 1945 anti 1957 that bivalves are dangerous when their raw scores range above 1,080 and use the same rule where it aoplies to toxic \'/helk meats, i.e. wilen the cooked meats are eaten without trimming. Applying this rule suggests that none of the raw whelks tested to date (maximum score 608) were dangerous. However, deductions made in the preceding section indicate that dangerous scores probably occurred in the Baie des Homardsarea in the autumn of 1969 and at Riviere Madeleine and at Cap Chat in the spring of 1970. No doubt they were equally dangerous in other areas at both these times.

'. [ v ide n c e inti i cat est hat \"/ h elk s (] res e 1 d 0 m dan fj e r 0 us. Tile only recorded poisonings were in 1936 and 1970. So (asp. his tor y r e cor d s s u q 9 est t II a t VI h elk s are tI a n 9 e r 0 u son 1 yon c e every 34 years. - 18 - ,Shellfish toxicity records compiled for the St. Lav'/rence estuary since 1949 suggest that whelks are dangerou s only once or twice in 23 years and that high whelk toxicities are heralded by unusually high scores of filter feeders such as clams and mussels. Toxicities of these species are regularly monitored in the St. Lawrence estuary. So it should be possible to determine, year-by-year, whether whelks are dangerous and to warn the public of risks of eating whelks. It seems that this step will seldom be necessary. From results of bivalve monitoring, it should also be possible to determine when it is necessary to close down commercial whelk fisheries and whelk processing plants in the interests of public health. (This is something quite different from the need for warning people who may eat untrimmed whelks.) All evidence suggests that need for this drastic step is very rare indeed. Givalve toxicity records indicate that it was needed only once in the 23-year period during which summer monitoring has been conducted. This conclusion may have to be altered if and when data on winter toxicity of whelks become available. Data preSented above show 85 % removal of poison by commercial processing. This means that poison-free packs (scores <44) should be regularly obtainable from whelks with raw scores up to about 300. If packs scoring <80 were marketable they might be obtained from whelks with raw scores up to 530. If advantage could be taken of score reductions by marination it might be possible to prepare safe packs from even higher-scoring whelks. THE ROAD TO EFFICIENT CONTROL Efficient control of the whelk fishery involves the principle of fullest possible use of resources with least risk to public health. We say "least risk" because, no matter how diligent controllers may be, some people who gather their own s 11 ell f ish, wit tin g 1y 0 run wit tin 9 1y, \'/ ill not a 1 way s f 01 low advice and regulations. For the control agencies, these are the problem people. It is they who are involved in most poisonings. Only 1% of the more than 200 recorded cases of PSP in eastern Canada are attributed to shellfish that were com mer cia 1 1 y f ish e dan d pro c e sse d (r~ e d c 0 f, i n Pr a k ash, i~ e d c 0 f and Tennant 1971) and none of that 1% is attributed to processed whelks. The principle of fullest use with least risk places t heavy burdens on government agencies. To begin with, they I' must maintain vigils that provide reliable, current information on toxicities of shellfish and on industrial operations in the areas for which they are responsible. They must engage in research, keep abreast of results of research by other agencies - 1 9 - and be thoroughly conversant with requlations. They must impose quarantines when necessary according to regulations and modify regulations when this is consistent with the principles of efficient control. This presumes a clear policy that recoqnizes priorities of interests of the many qroups affected. Public health interests There is general agreement that public health interests have first priority and commercial fisheries in the estuary for clams, mussels and whelks have been closed down when monitoring scores indicated that there were risks of PSP from bivalves. Thereupon public notices have been issued advising of hazards of domestic use of molluscan shellfish at specified times and places. It seems fair to say that public health interests have been well served. Commercial fisheries interests Second priority has always been given to interests of ttle commercial fisheries and the processing industries they support and to interests of the domestic fisheries. This has advantages to commercial processors but it also has dis­ advantages. Commercial whelk fishermen and processors do not want to market unwholesome products. It would be bad for consumers and what is bad for consumers is bad for business. But in 1966 processors complained about the comprehensiveness of temporary closures of shellfish fisheries in the interests of public health. They maintained that processed whelks were always safe because steaming and trimming remove poison. Since then, Tennant (MS 1971) has shown that scores of processed shellfish are further reduced by marination which makes some packs of whelks doubly safe. Processors aqree with qovernment closures of fisheries for mussels and clams, because in many inlets their scores regularly reach dangerously high levels. But they did not agree with closures of whelk fisheries. One whelk processor suggested that control agencies could be of great service to his industry if they were to study industri~l problems as thoroughly as they study public health problems. The suggestion has merit and deserves sympathetic consideration because the whelk industry has suffered severe restrictions. Results of monitoring processed whelks since 1964 demonstrate that what the whelk processors said about their product is almost true. Positive scores are seldom recorded and scores that exceed the danger level are real rarities. This new light on features of whelk toxicity, the ever-present - 20 - need for employment in the fisheries and the legitimate demands of consumers for a favorite seafood all indicate the value of prompt reassessment of policies and practices in the control of the commercial whelk fishery. The question to be dealt \'litll is: Can controls be made more efficient in line with the principle of fullest use with least risk and thus encourage small but locally important whelk fisheries and markets? The answer would seem to be "Yes". Based on available records, some improvements in control could be made now. For example, in most years the commercial fishery, which supplies whelks only to processors, could continue even when the whelk fishery for domestic use is closed. There is a long-standinq precedent for this type of control. For more than 25 years, Bay of Fundy soft-shell clam areas have remained open to fishing for canning after they are closed to fishing for domestic use and to fishing for another kind of processing - raw shucking. In the Fundy area, complete closure to fishing (including fish­ ing for canning) is imposed only when scores of raw clams reach specified levels beyond which scores of the canned product fail to meet control standards (Hedcof, in Prakash, 1'1edcof and Tennant 1971). It therefore seems wrong to close down commercial .' whelk fisheries before monitoring proqrams show that their products fail to meet prescribed standards. That kind of control is not "efficient" in the sense in which that term is used in this report.

j~eeds for research Keeping the commercial fishery open until its rroducts fail to meet marketing standards seems to be tile only important improvement in control that can be made without better under­ standing of the problems confronting control agencies. Better understanding depends on well planned and carefully conducted research and there are three main problem areas that deserve research. Each has many facets. Whelk biology in relation to PSP problems is only vaguely understood. Right now the greatest need is for year­ round studies of toxicities of raw whelks. Winter observations through the ice are specially needed in places like Baie des Homards. Riviere Madeleine and Cap Chat during years when bivalves show high winter carry­ overs of poison. There are many questions to be answered. For example: Do w~lClk scores increase in winter? How do low temperatures affect poison accumulation and excretion?

Til ere i sal son e e d for i n ten s i ve, wit h i n - are a sur v e .y s ". in summer when scores are at their seasonal maxima, to discover patterns of toxicity variation. How, for example, does toxicity .. - 21 - vary with depth of water, and from hard bottom to soft bottom and what animals are associated with whelks in these vario~s habitats? More information is needed on the whelk's food habits at all seasons. What are its prey species and how does their abundance vary with depth and bottom type? To what extent is the whelk dependent on plankton-feeding species? What are the capacities of the these species for accumulating poison and how quickly do they excrete their accumulated poison after Gonyaulax has disappeared from the plankton? Does the whelk mlgrate from shallow to deep water in autumn and from deep to shallow water in spring? How rapidly does it excrete poison when it is starved and when its diet changes from toxic to non­ toxic prey? If answers to questions like these had been available in 1969, it might have been possible to forecast whelk toxicit­ ies in the spring of 1970 and to prevent the illnesses and the fatality at Cap Chat. Finding answers to these questions is difficult and time-consuming. It may be impossible for control agencies to carry out this kind and amount of research as well as their many other tasks. Perhaps this work should be done by univer­ sity researchers. The same might be said of research needed in two other areas mentioned below. food processing research is vital to the understanding of PSP risks as indicated earlier in this report. Effects of commercial processing on whelk toxicity have never been explored by experiments in which cooking time and cooking temperatures were controlled. The relative importance of cooking and trimming of cooked meats in reducing scores of the final product has not been measured. What happens to the poison in raw toxic whelks w11 e n t 11 e y are coo ked? lsi t des t roy e d 0 r i sit car r i e din to the bouillon (body juices lost during cooking) as it is in processing bivalves (r1edcof, in Prakash, ~ledcof and Tennant 1971)? What is the maximum score of raw whelks that will still yield processed packs that meet market standards? How does domestic cookinq affect scores of whelks that are eaten whole (digestive glands included)? What are the characteristics of whelks that make them more appetizing in cold-water seasons than in summer? Arc tlH~rc ways of processi ng wlle1 ks that wi 11 make them more appealing to consumers?

Resear~h on publicity techniques used in PSP warning programs is needed. Great effort is expended in monitoring

'. shellfish toxicities, in preparing and posting warning signs and in issuing warnings in newspapers and on radio and TV. In spite of all this effort, poisonings continue to occur, usually - 22 - from bivalve shellfish. What is the eXplanation of this paradox? The publicity is designed mostly for the control of PSP risks to picnickers, tourist~ and domestic users and these continue to be the victims. The control of commercial fishin9 and processing is more effective, involves less effort and is accomplished without fanfare. Some commercial operators object to the wide publicity given to risks of poisoning. They admit that it may help protect "do-it-yourself" seafood gatherers but they claim that it gives shellfish a bad name and damages all shellfish industries at all seasons - even the lobster and shrimp industry are said to be affected. There is some evidence on record to support this claim. Some processors advocate reduction in publicity. This could be interpreted as nothing more than direct opposition to the principle of fullest use with least risk, but it does raise important questions that apply to the Bay of Fundy region as well as to the estuary of the St. Lawrence. Does the publicity reduce the frequency of poisonings? Does it damage the shellfish industry? Is the publicity well designed for the job it attempts to do? . In answer to this last question some say "No". They feel that it over-emphasizes temporary emergency cbnditions, and that it creates blind fear of all shellfish. Those who have thought about it agree that PSP publicity should be carefully designed to encourage sober understanding of the problems we must live with indefinitely and to avoid frightening the public. Criticisms from industry seem justified, at least in part, but how can the situation be improved? I have discussed this question many times with staffs of control agencies and with industrial operators. Most of them agreed that effective controls must comprise both warnings and education but that, in the long run, education is the more imp 0 r tan t (M e d c 0 f, i n P r a kash, t~ e d c 0 fan d Ten nan t 1 9 7 1 ) . T0 date these two elements have usually been combined in PSP publicity through the media mentioned above. A review of examples of these "package deals" shows that the warnings of emerqency conditions do indeed get priority, as whelk processors claim, and that the educational part is frequently subordinated or obscured or even omitted altogether. A new approach is needed. Controls might be improved (not overnight but within a few years) if educational messages and warnings were presented separately. Warnings could continue to be released throuqh regular channels. A new channel probably should be found for - 23 - educational releases. This approach has been taken in British Columbia where an inexpensive brochure (Quayle 1966) of the "hand-out" type is distributed gratis. It is not clear whether this is or is not good enough for today. Brochures of this sort are steadily losing their appeal and effectiveness because they have such a powerful competitor - the motion picture documentary film. The documentary is adaptable to TV as well as to regular screening and is unrivalled in its efficiency in the field of mass education. There is a strong case for making a documentary film on PSP, perhaps in cooperation with the National Film Board. It could cover each ch~pter of the PSP story from Gonyaulax to: (a) The man on the beach who reads a warning sign and decides on roasting hot dogs with his family instead of boiling toxic clams for their picnic lunch; (b) The man who disregards warnings and ends up in hospital as a victim of PSP. When properly presented, this story is intensely interesting because it concerns food. This ne\>/ approach to public education, the basic need now facing control agencies, deserves examination with competent advisers to determine its likely advantages and disadvantages to the public and to industry; its likely costs over a period of years and whether it is justified.

ACKNOWLEDGi·tENTS I wish to thank those who have assisted in this study and r> art i c u 1 a r 1y the f 0 1 low i n g: [) r. A1 anD. Ten nan t 0 f til e Department of the Environment and formerly of the Department of; ~ a t ion a 1 He a 1 t han d Welf are, 0t taw a; Dr. L. r~. La u z i e r 0 f the Department of the Environment, Ottawa; Dr. A. Nadeau and ~essrs. Armand Lachance, H. Paul Dussault, and Claude Turgeon, Ministry of Industry and Commerce, Quebec, P.O.; Dr. Albert Lit ali en, pity sic ian, 0 f S t e. Ann e des [~o n t s, P.I/.; r~ r. And r~ Roy, fisherman, of Cap Chat, P.Q. I also thank my Fisheries Research Board, St. Andrews, [LB., colleagues, Or. D. G. Wilder for helpful criticisms of this manuscript and Mrs. Warner (St-Pierre) Parker for assistance in French correspondence.

'. ·. - 24 -

REFERENCES

1\ dam s, J. II., [). [). Sea ton, J. B. Bu c han a nan d 1-1. R. Lon 9 bot tom . 19G 8 . Biological observations associated with the toxic phytoplankton bloom off the east coast. Nature 220 (5162): 24-25.

Bond, R. i1. j·1S 1955. Toxicity Records 1954. Dept. Fish. Canada Fish. Insp. Lab., St. Andrews, N.I3., 68 p. (Unpublished MS).

Bond, R. i~. and J. C. 1'ledcof. 1958. Epidemic shellfish poisoning in flew I3runswick, 1957. Canad. fled. Assoc. J. 79: 19-24.

Boyd, H. L. and A. Lachance. (Nine reports) ['lS 1962-I-IS 1970. Shellfish Toxicity Records 1961-1969. Dept. Fish. Canada Fish. Insp. Lab., St. Andrews and Black1s Harbour, iLB. ( Un pub 1 ish e d ;,1S S ) . .

Boyd, H. L. and C. Turgeon. flS 1971. Shellfish Toxicity Records, 1970. Dept. Fish. and Forestry Canada. (Un- p u bl ish e d i' l S ) . -. Cad d y, J. F. and i< . A. Chan d 1 e r . 1 96 8 . Ac cum u 1 at ion 0 f paralytic shellfish poison by the rough whelk (l3uccinum undatum L.). Proc. National Shellfisheries Assoc. 58 : 16-50.

CBC (Canadian I3roadcasting Corporation). 1970. TV National News (carried on Station CHSJ, Saint John, New Brunswick, 2 April 1970).

Chiasson, L. P. MS 1952. Starfish and rough whelk as possible predators of sea scallops. Fish. Res. Bd. Canada Biol. S tn., S t. And r e ws, fL B • 0 rig. ;1 S Re f1 t. rJ o. 921, B p. (Unpublished MS).

La Cote-Nord. 1960. La peche aux bigorneaux ~ Baie-Comeau. 13 January issue (weekly newspaper), 3(51-52): 1 & 3. (Published at St. Joseph (Beauce), P.Q.).

/'0a kin, ~J. J. 1 91 2. Bu c c i n u m, the \,1 h elk. L i ve r p 001 i" a r. Ecol. Committee. t-'emoir 20, 115 pages.

Ganong, W. F. 1889 . The economic mollusca of Acadia. Natural Hist. Soc. New Brunswick, Bull. 8, 116 paqeS. -. The Gazette. 1970. Girl, 12, dies after eating poison snail. 21\pril issue, ilontreal, P.Q. (I\ppendix I). , f f ,..I r - 25 - , '. Hancock, D. 1967. Whelks. U.K. Min. Agric. Fish. and Food. Fish. Lab. Burnham on Crouch. Lab. Leaflet No. 15, 14 p. Ingham, H. R., J. Mason and P. C. Wood. 1968. Distribution of toxin in molluscan shellfish following the occurrence of mussel toxicity in northeast England. Nature, 220 (5162): 25-27. Litalien, A. MS 1970. Personal communications. See Appendix II.

r1edcof, J. C. ["lS 1949. Toxi ci ty Records, 1948. Fi sh. Res. Bd. Canada. Biological Station, St. Andrews, N.B., Oriq. ns Rept. No. 756,57 p. (Unpublished ~1S). MS 1952. Shellfish Toxicity Records, 1951. Ibid. No. 801, 36 p. (Unpublished r~s). MS 1966. The rough whelk fishery at Godbout, P.Q. Ibid. No. 1038, 4 p. (Unpublished MS). MS 1971A. Rough whelks can be dangerous (In Boyd and Turgeon. NS 1971, see above). j'lS 1971B. Winter variability in paralytic shellfish poison scores for Crow Harbour, New Brunswick. Fish. Res. Bd. Canada, MS Rept. 1163, 17 p. (Unpublished MS).

t'ledcof, J. C., A. H. Leim, A. B. Needler, A. W. H. Needler, J. Gibbard and J. Naubert. 1947. Paraiytic shellfish poisoning on the Canadian Atlantic coast. Fish. Res. Bd. Canada Bull. 75: 32 p.

i~edcof, J. C., N. Morin, A. Nadeau and A. Lachance. r~s 1966. Survey of incidence and risks of paralytic shellfish poisoning in the province of Quebec. Fish. Res. Bd. Can a d a . r,1S Rep t. S e r. (B i 0 log i cal ), No. 886, 1 3 1 p age s (Unpublished MS).

Prakash, A., J. C. Medcofand A. D. Tennant. 1971. Paralytic shellfish poisoning in eastern Canada . Fish. Res. Bd. Canada, Bull. 177,87 p. Quayle, U. B. 1966. Paralytic shellfish poisoning - safe shellfish. Fish. Hes. Bd. Canada, Biol. Stn.~ Nanaimo, B.C., Circa No. 75, 11 D. (Mimeoqraphed). Quebec Bureau of Statistics. 1970. Commercial fisheries 1969. '. .. - 26 - Roy, Andr'. 1970. Personal communication 8 June 1970 re domestic fishery for whelks and March 1970 poisonings at Cap Chat, P.Q. Tennant, A. D. r1S 1971. Detoxification of mussels by marination in vinegar. Dept. Fish and Forestry, Ottawa. Minutes Interdepartmental Shellfish Committee, 3-4 March, 1971. Appendix 10, 3 pages (Unpublished I-1S). 1972. Personal communication, 9 June 1972. / Vounker, D. and K. l'1acWi11iams. MS 1971. Whelk Survey: final report. MS1971 . Prince Edward Island , Dept. Fish., 36 p. (Unpublished MS). o 10 30 50 Miles 'L...-...L'_ ' -'-_..L'_.1---1'

Quebec

51 Lawrence River

-'

Gaspe Peni nsula

I I I I I New Brunswick ~

Figure 1. Estuary of the St. Lawrence River showing locations mentioned in this report.

'. Figure 2. Two whelk shells and t he op erculum from the smaller shell.

'.

Figure 3. Whelk trap used at Godb out, P.Q., in 1966. Diameters of 3/16 inch i ron hoop frames: upper 14 inches, lower 24 i nches. Stretched mesh of nylon netting 1/2 inch. Figure 4. Schematic drawing of string of traps rigged for deep-water fishing at Godbout, P.O., 1966.

" ..

1000 • 500

e Q) ~ o <..> en /,0, ., 0, / \ \.' -<..> / \ .,)? ? / . ~ 100 , ,. " "\ ~ o "a, I ,,' \ Whelks , " a.. I , "\ '/' I a'" . " I , 0' I \ e ,e o---r \ ' \ ~ ( , ,,' \ 50 \ . " I ,: / , \ ~a \ e ___e %I \ I : \ \ \ '.I I < 32 o'l ••• a" \

June Ju I Y . August Sept.

Figure 5. Seasonal variations in 1964 in toxicity scores of commercially processed meats of whelks from Godbout, of raw soft-shell clams from Franquelin and of raw blue mussels from Mistassini, P.Q. Scores are plotted against a l~ga~ithmic scale .

.. 30,000 .------, • 14 , 10,000 ,, " Water 12 o " Temperature 5,000 \ , \. " , 10 u \ . " o Q,) -' '- ,0 2,000 u \ \ \ en ""',. >. ". ~ Blue Mussel Score. -u 1,000 , ' \ , w 0 " \ ." ' 6 ~ o,.~.2..0.ft-~hell. Cla.~s.core.o-... " \ " . 500 ,\ 0 i' \ I 4 \ I \ I \ I \ I 200 \ / 2 \ / , // , ,------_..-. / . 100 ~s-ep-t~-----,--~-.-D-e-C~--J~a-n~~F~eb~~~~~A~p-r-l o ,LliQ '

Figure 6. Water temperature and toxicity scores of blue mussels at Les M~chins and of soft-shell clams at Baie des Capucins, P.O., after the causative organism (Gonyaul~ tamarensis) disappeared from the plankton, September 1969 to April 1970. The temperature curve is schematic and the scores are plotted against a logarithmic scale. • APPENDIX I ..

MONTREAL, THURSDAY, APRIL 2, 1970

Girl~ 12, dies · after eating poison snail . QUEBEC - (CP) - Joanne · Vallee, 12, died of poisoning after eating snails she gath- · ered at a beach near her .Cap Chat home Monday, an autop­ sy showed yesterday~ Her mother, . Mrs. Yvonic · · Vallee, and two otllel' children · also were poi son ed, but • survived. '· The provincial departments of health, industry . and com- · merce issued warnings yes­ terday against eating shellfish in the Gaspe and Quebec · north-shore are as. Several ' persons were poisoned by shcllfis(l in the area last summer . . Joanne gathered the snails early Monday and ate them at the evening meal. She com­ plained afterwards of violent stomach pains and died dur­ ing the night in hospital. Cap Chat is on the north shore of the Gaspe Peninsula, about 270 miles northeast of Quebec City.

Investirntor's Note 8 June, 1970.

It is now established that the snails were rough whelks (13ucci nurn undatum) and that they ,.;ere fi shed 30 ~'arch, l~)70 , with hoon traps set by rlr. Andre Roy at 10 fathoms directly off Can Chnt p;{)vernment wharL .1. C. ~L -.

Appendix II

Cas e his tor y rep 0 r t s com pile d by 0 r. A. Li tal i en 0 n his five Cap Chat patients who were admitted to Ste. Anne des Monts Hospital, 31 March 1970, after eating rough whelks.

0' From symptomatology, Or. Litalien diagnosed four of

these as t~ue cases of paralytic shellfish poisoning. He has indicated (personal communication, 1970) that the fifth may have been a true case but symptoms were too confused for certain diagnosis •

.. CAP CHAT 1970

ENDROIT OU lES MOLLUSQUE S ONT ETE Pi:CH':: :i (ANNE E )

1 FICHE m~ : CAS n 'F:.\l p ()J SO"J ~E:'Irf.NT PAH LES l\lOLLlJSQllES No

~lme' Cap Chat, P.Q.

(ADRESSE) 32 ans Poicl s Docteur A. Litalien r>at~ m::lladie rapportee 1e 31 mars 1970 A qui r(, pporl~! e Ste-A nne-des-t'lonts . . a r~pondu aux questions durant l'examen m~dical Comlllent rapporlee Ir,ntrevue etc.) .. 1e 31 mars 1970 n"te de 1<1 rna lar! ie . Dehllt ele 1a mabdie (heure)

Duree de la maladie (Hellres oilj()lIrs) 36 heures

E s p~ce de mollusqllf" milngl' Bucci num ",nda, tUI'rl Q,wtHl riidnge . (Heure, date) bouil1i Nombre mange . Pn:~p;}r:lti[jn (crti. l>olli!li)

Bouillon absorbe t\ 'ltres a1ilnt~ nt s Oll liquides absorbes

Toxicite ci€s mollusques (E l at cru) .11 .g.!]OO g. Dos£: estim r.e u.g.

S Y i'\1 P T 1) M E S (Demontrez par lin (X) a l'endroil approprie, les syrnptomes observes)

ENG Ol HDlSSEiVIEN'T DES : / SENSATION DE MALAISE D'ESTOMAC

LEVRES v ./ VOM1SSEMENT

FIGURE v MAL DE TETE

DO TGTS V MAL DE DOS

OHTEILS v DlFF'ICtlL'fE 1\ BI':SPlREH

BfU\ S DTFFICULTE .t\ Sf<: TENIR DEBOUT

JAMBES y DIFFICULTE 1\ S'ASSEOIR

Tnf'FIC"ULTE f\ PAHLEH

ETOURD1SSEMENT

AUTRES SYMPTOMES Somnolence

1970

ENDROli OU LE5 MOLLUSQUf':; ONT ErE ?<::CHE S (ANNEE)

3 FICHE DE CAS IYE!VIPmSONNE\tENT PAR LES MOLLUSQUES No

Cap Chat, P.Q. IADRESSE)

f\ gi' 1 2 an s Poids DocteurA. Litalien 1e 31 mars 1970 J)all' nl;ll;Hlie rappnrtcp ,\ filii r:1pportee Ste-Anne-des-r~onts

Comment rap]lorlt::c \Entrevlle ('Ic.) ar~ponduaux questions durant 11examen m~d;cal

J);:)tc de la rnaladic le 31 mars 19}0 Dehut de la malaclie (heure) 36 heures Duree de 1a malallie (Hellres Oll jOllrs )

Espece de mollusqlle mange BuC!C!inum undatum QlIilllrl mange ...... (Heure, dal.e)

Nomhre mange ' . . pf{~raration lenl , hOllilli)

Bouillon absorbe i\utres aliments Oil liqllides absorbes

Toxicite rles mollllsqlles (Etat. ('Ill) . n.g./IOO g. Dose estimpe u.g.

S Y l\'J r TO l\'1 E S (D~monlre7. pill' lin (X) J l'~nctroit approprit':, les symrt6rnes observes).

ENCOURDISSEME[\!T DES: SENSATION DE MALAISE D'ESTOMAC

LEVRES v VOMISSEMENT

FICURE IHA L Df. TETE

DOICTS v MAL DE DOS

ORTEILS V DWFTCULTF. A P.FSPJRE}{

RHAS DIFFJCULTF. 1\ SE TENIR DEROUT

JA\'lBES DIFFICULTEA S't\SSEOJR

DIPI

ETOURDISSEiVlENT

AUTflES SYlVllyrOMES

l\UTRES REl'aAfHWES OtT IN FOR~l.\TWNS : CAP CHAT 1970. ENCROIT au LES MOLLUSQUES ONT ETE PECHfS (ANNEEI

4 FICHE HE CAS rrEMPOlSON\,f. :\H:NT PA It LES MOLLVSQlJ £S No

Cap Chat, P.Q. (ADRESSE)

Sexe Age 13 an s Poicl s 9 S 1i 1/ res Docteur A. Litalien le 31 mars . 197.0 A qui 1';)ppllrt20 Ste .. Anne ... des-~lonts. Comment rapportee IEntrevue etC'.) a repondu aux questions durant . llexamen meciical

DJte de la mal,)(!i c le 31 mars 1970 Debut de 1a maiatlie (heure) 36 heures Duree de la mabdie (Heures Ol! jOIII'S) ? Espece de mollusqllc ITI':'lnge\ Buacin.um undatum Qlland rn:illg{~ 1 e 30 mars 1970 (Hetn'e, date)

Nombre mange 3 Pr6paration (cru , bOlliili) .. bout 11L ..

Bouillon absorbf~ non

,\utres aliments 011 liquides absoJ'he-; aucun

Tnxicile des mollllsques (EI

S Y M P T 0 I\l F S (])emoJ)trc7. p:ir 11rJ (X) ~ l'endroiL app J' npric, ics ~y mptiirlie s observes).

ENC OURDiSSEi\l ENT DES . V' SF~~S :\T ;m,y DF. l\ir'\LAISE D'ESTOMAC

LEVRES v .; VOMISSF:MENT

fIGURE v .; M:\L DE TETE

DOIGTS v M;\ L DF: DOS

OHTBILS v

.; DTF'FWULTE f\ Sf-; TI':~m DEBOUT

,JAMBES v ])fFFTCULTE !\ S'AS,'-:f,OIR

UIFFlC'tlLTE A fXRLER

ETOLlHmSSElltlENl' V

l\UTRES SY\Vll'TOMES

fHfTRK", RiEIYJ.'\R(~VF.S OU INFORMATIONS: CAP CHAT, P.O. 1970 ENDROIT ou LES MOLLUSCUC':i ONT ETE PECHES (ANNEE)

FICHE DE CAS D'FMPmSONNE!\tENT p :\n LES I\IOLU!SQUl~S No 5

Cap Chat. P.Q. (ADRESSE)

Scxe Age q ans P0ids D~c~eu~ A. Litalien Date m31ndie rap portee le 31 mars 19]0 A fJlli I'Zlpport{e Ste-A . nne':'"des~r~on . ts . par 1es parents de l'enfant durant l'examen medical Comment rapportcp IEntrevlle etc) ."

Dnte de la malndic le 31 mars 1970 D~hllt de la maladie (heure)

Duree de la mal:lctie (Hellres 011 .iours) , Bu~~i num unda tum E <; pcce de mollllsqlll' m4'lnge Qllane! mange. . .. . (Heure, date)

Nornbre mange ' 2 Prl'paralion (('fl!. bouilli) . bou; 11;

Bouillon ahsorbC non

Autres 4'lliments ou liquides ab::;orhps aU.cun .

Toxicite des 1YI0 llllsqucs rEt at ('I'll) . u.g./l00 g. Dose estim6e ug.

S Y 1\1 P TOM E S (Demontrez pJI' l!:1 (X) a l'endroit approprie, les symrtomes ohserves)

ENCOURDrSSEMENT DES: SENSATION DE MALAISE D'ESTOMAC

LEVRES .,I VOMISSEMENT

FIGURE lVIAL DE TETE nOIGTS MAL DE DOS

ORTEILS Dl FFWULTE 1\ RESPlTlEH

BR,\S .,I DIFFTClJLTE A SF. TENlR DEBOUT

JAMBES DlFF1ClJLTE A S'ASSEOIR

DfFFICULTE A PARLER

ETOURD1SSEl'vIENT

AUTRES SYMPTOMES

/\UTRES REJ\'1ARQUF:S Olf IN FOHI'rlATIONS : Patiente admise sous observation - Histoire de vomissements et de difficult~ ~ la marche - Aucune symptomatologie anormale observ~e apres 24 heures.