This paper was written as part of the 2011 Alaska Oceans Sciences Bowl high school competition. The conclusions in this report are solely those of the student authors.

Effects of Harmful Algal Blooms in Southeast Alaska

Authors

Susie McKee
Caleb Hedin
Jessica Pringle
Kate Ross
Dylan Carlson

Team Phycodurus eques

Ketchikan High School
2610 Fourth Ave
Ketchikan, AK 99901

Abstract

The presence of paralytic shellfish poisoning (PSP) toxins in Southeast Alaska has the potential for a large impact on the growing regional shellfish industry, as well as personal use and subsistence harvest. The dangers of being affected by PSP are high, especially since there is currently no commercial fishery for them here and they do not routinely get monitored for PSP toxin. In conversation, Ray RaLonde, suggested that we gather some clams, and he would send them to the DEC to get them tested for PSP. They suggested we gather samples of Saxidomus giganteus for these tests. In addition to going to three beaches and digging the clams for testing, we created an impact survey in which we surveyed 170 students from Ketchikan High School. We chose the school because we figured it would be a better source of citizens, it was an easy access for us so we wouldn't need to go out and canvas the whole town, and we felt it was a good representative sample of our community.

Our objectives were twofold: first to determine how much toxicity is contained in butter clam samples from local beaches in November; and second to figure out actually how many people locally knew about PSP, and if they eat clams that they dug up on local beaches. We would then correlate this data to determine areas of future research and propose management policies that could be implemented.

With the results from the clams, we found that there was not an alarming amount of toxicity in the shellfish in November, but that there was enough to be detected in the shellfish. Taking these results and looking at the surveys, we noticed that the majority of the community is aware of paralytic shellfish poisoning but that more of the community believes that we need more awareness on PSP. Therefore, we suggest that testing become more readily available to local communities combined with increase efforts for public awareness.

Introduction

The growing industry of shellfish in Southeast Alaska has piqued our interest regarding paralytic shellfish poisoning (PSP) on the beaches of Ketchikan. In 2005, 97% of the proposed aquatic farm sites were for geoducks, a type of shellfish (Alaska Department of Fish and Game, 2005). PSP is a problem for commercial shellfish industries because outbreaks can lead to closures of fisheries, causing the fishery to lose money (Alaska Department of Fish and Game, 2008). Since there is not currently a commercial fishery for Saxidomus giganteus, or butter clams, there is no monitoring system for PSP. However, butter clams can potentially be highly toxic. The Saxidomus giganteus live in sandy/muddy areas, these shellfish are filter feeders, and while they filter feed they can potentially accumulate the saxitoxins. Since the Saxidomus giganteus live in a sandy/muddy ecosystem it is easy for anybody or anything to go down to the beach and dig up the clams to eat. Now if they eat a clam with a high presence of these saxitoxins, they can get a poisoning called PSP. Locals that dig for clams do not have access to an inexpensive, easy way of testing their clams for PSP toxin. They can be exposed to it in sometimes lethal amounts.

Paralytic shellfish poisoning was first recorded in Maine in 1958. In 1972 a substantially large bloom of Alexandrium fundyense stretched from southern Maine to Massachusetts. Ever since then, Maine has experienced PSP outbreaks in decreasing amounts (Anderson, 2010). In 1799, while the Russians inhabited Alaska, there was one of Alaska's worst PSP outbreaks. It killed over 100 Russians and Aleuts in Sitka (Ballentine, et al., 1982). In June 2010, there were five cases of PSP in Alaska. In Juneau, a woman ate a cockle and died from PSP. The following week, a man in Haines ate a Dungeness crab and also got paralytic shellfish poisoning and died. In addition, three cases were in Kodiak and were the result of eating butter clams. (http://sitkalocalfoodsnetwork.org/2010/06/24/•-paralytic-shellfish-poisoning-psp-warning-issued-for-southeast-alaska/).

Symptoms of PSP come in different stages. The early symptoms could be tingling of the lips and/or tongue; this could start within a few minutes of consuming toxic shellfish. The symptoms may get worse and progress to tingling of fingers and toes, and then complete paralysis of limbs. More life threatening symptoms include difficulty breathing, and chest and abdomen muscle paralysis. People could die from suffocation within 30 minutes (Washington State, Department of Health, 2010).

Clam Sampling Procedure

The first thing that we did to start our research was consult with local experts, Wayne Kinunen and Gary Freitag, about where butter clams are commonly found in our area. We chose to sample clams at Settler's Cove, Refuge Cove, and Pond Reef. After we decided on the areas, we looked at the tides and decided on three separate dates to collect our clams. We decided to go to Refuge Cove on Saturday, October 23, 2010 at 7:00 PM during the -1.2 foot tide. We went to Settler's Cove next, on Saturday, November 6, 2010 at 7:30 PM during the -3.4 foot tide. Our third location was at Pond Reef on Sunday, November 7, 2010 at 7:00 during the -3.1 foot tide.

Our purpose for sampling clams in our area was to see if clams in our area contained traces of paralytic shellfish poisoning toxin or saxitoxin and if so, in what amounts. We hypothesized that they would contain trace amounts of PSP, but not in fatal amounts.

Our next step was to obtain the clams. The materials we needed were: flashlights, buckets, shovels, and Ziploc bags. On October 23, we met each other at Refuge Cove. Once there, we went to the sandy parts of the beach and searched for evidence of clams by looking for siphon holes in the sand. We then dug about six or seven inches into the ground and pulled out the clams to identify them. We observed the clam shells to see whether they had horizontal or vertical lines on them. If they had just horizontal lines, this indicated that they were butter clams and we put them in the bucket. (Figure 1) If they had vertical lines or both vertical and horizontal lines, we put them back because that indicates that they are not butter clams. Once we obtained four clams from one part of Refuge Cove, we put them in a Ziploc bag with the shell still attached, and moved on to the second part of the beach. At the second part of the beach, we did the same thing, but instead of four clams, we collected five. We then moved on to another part of the beach and gathered three clams. On November 6, we went to Settler's Cove and used the same method for digging our clams. We collected three clams from Settler's Cove. On November 7, we went to Pond Reef and again used the same method to gather four clams. The clams from different sites were put into separate Ziploc bags and frozen until sent to Raymond RaLonde, Aquaculture Specialist at University of Alaska Fairbanks School of Fisheries and Ocean Sciences. RaLonde then brought the samples to Bruce Wright and Matthew Forester of DEC for PSP testing.

Impact Survey Procedure

The purpose of our impact survey was to see how much students at our school know about paralytic shellfish poisoning, whether they dig for their own clams and if they do, at which beaches, and if the risk of PSP affects their decisions about eating shellfish. To do this, we created a survey that included these questions. We passed out a copy of this survey (Figure 2) to all of the history teachers at our school to give to their students. Our hypothesis was that people in our school probably do not dig for their own clams and don't know much about PSP, or believe that it is a problem. We received 170 surveys back, two were not accounted for. This is roughly 18% of our school population.

Our results show that 157 students answered question one. Of those that answered 69% of the students surveyed know what PSP is and 31% do not. One hundred twenty four students answered question two. Of those, 70% think that there should be more information on PSP, whether it's in school or in the media and 30% think that there is enough information already. One hundred fifty seven students answered question three. Eighteen percent have heard of cases of PSP in our community or in their family and 82% have not heard of any cases of PSP. One hunderd thirty two students answered question four. Thirty percent of those surveyed eat clams or mussels and 70% do not. One hundred fifty six students answered question five. Nineteen percent have dug for their own clams or mussels and 81% have not. One hundred fifty six students answered question five. Sixty six percent have not heard of specific seasons during which it is unsafe to eat shellfish and 34% have not heard of specific seasons during which it is unsafe to eat shellfish. One hundred fifty six people answered question eight. Forty percent say that the risk of PSP does affect their decision of eating shellfish and 60% say that the risk does not affect their decision. Question number seven asked which beaches they dig at if they dig for their own clams. Of those that said they do dig for their own clams, the areas in around Ketchikan that they named were: Bugges Beach, Prince of Wales, Black Sands Beach, Vallenar, Bostwick, Settler's Cove, and Metlakatla. Some other places mentioned were the Phillipines and Washington. (Figure 3)

Impact Survey Results Analysis

In summary, our impact survey at Ketchikan High School came up with the following results:

Sampling Procedure

We followed the standard operating procedure for testing the clams, except we initially had all clams from each sampling site frozen in the Ziploc bags and that we had shucked them after we froze them. After we shucked them, we placed the clams in individual Ziploc bags then put them all in one large Ziploc bag. It was labeled with the locations that we collected them, who collected the clams, the date the clams were collected, and the species that the bags contained.

Meaning of the Name "Butter Clam"

Saxidomus giganteus: Saxi = rocks or petrifying; domus = house; giganteus = giant

Saxitoxin, an extremely toxic form of PSP. It got its name from the Saxidomus giganteus (butter clam) where it was originally found and identified. Saxitoxin develops at random, with some butter clams being affected and others not. Therefore there is no field-testing kit available to measure the amount of PSP in the shellfish that are being collected locally. The only FDA approved testing, currently is the mouse bioassay test. Where they inject ground up clam particles into a mouse and then time how long it takes for the mouse to die. Then they measure the amount of PSP that was present at the time of death. Though saxitoxin is usually very toxic, it can be found in less toxic forms. This is because some shellfish have a unique ability to use the saxitoxin as a defense mechanism (RaLonde, 1996).

PSP and the Marine Ecosystem

Saxitoxin can be passed up the food web when zooplankton eat the dinoflagellates that release the toxins. Zooplankton are more susceptible to saxitoxin than shellfish, making it lethal to most zooplankton. "Though some can limit the exosphere by decreasing their consumption. Large levels of saxitoxin can interfere with zooplankton's ability to avoid predators (RaLonde, 1996)." Zooplankton predators include herring, which are then eaten by salmon, bears, eagles, seals, seagulls, etc. Salmon are eaten by whales, wolves, etc., thus entering the Southeast Alaska food web and affecting almost the whole ecosystem both directly and indirectly.

PSP is responsible for the deaths of many species of marine wildlife. In birds the most often reported are the gulls, cormorants, terns, shorebirds, and sea ducks. Although these are the most reported birds, saxitoxin can affect any fish eating bird. There has also been one mortality report due to saxitoxin in penguins in South America. Saxitoxin has also been found in the stomach contends of humpback whales, that had eaten mackerel with saxitoxin in their livers. The whales had appeared to be behaving normally, and then they were found dead 90 minutes later, on the beaches of the coast of New England in 1997 and 2003 (Shearn-Bochsler, 2008).

Paralytic Shellfish Poisoning in Southeast Alaska

In our opinion, it appears that Southeast Alaska has a paralytic shellfish poisoning problem. PSP is a very serious illness caused by toxins or poisons concentrated in shellfish such as clams, mussels, geoducks, oysters, snails, and scallops. This is caused during the process in which the shellfish feed on the very small microorganisms called dinoflagellates which contain the toxin. The toxin is extremely poisonous and could be very deadly, ingesting amounts as small as one milligram is enough to kill an adult. (DEC, 2010).

Different types of marine bivalves keep the different parts of the toxins and have different rates of expulsion, for example butter clams can hold the toxins in their siphons for up to two years. There are numerous accounts of poisoning in Southeast Alaska.

There are no recreational beaches in Alaska where clamming is guaranteed to be safe because there aren't field tests available, and the laboratory analysis takes time and is costly. The Alaska Department of Environmental Conservation only tests personal use or recreational beaches on a random basis.

Facts and Fiction About PSP

Facts

Fiction

Is there a treatment?

Currently there is not an antidote for PSP. The only treatment for severe cases of PSP is a mechanical respirator and oxygen. It is recommended to induce vomiting, which may help get rid of some of the toxins that were eaten (RaLonde, 1996).

The different types of marine bivalves keep the different parts of the toxins and have different rates of expulsion. For example Saxidomus giganteus (butter clams) can hold the toxins in their siphons for up to two years. There are numerous accounts of poisoning in Southeast Alaska. There are no non-commercial or recreational beaches in Southeast Alaska where clamming is considered safe, because there aren't field tests available and the laboratory analysis takes time and is costly. Alaska Department of Environmental Conservation only tests personal use or recreational beaches on a random basis. (Scanlan, 2010)

Future Research

Due to the fact that there is little known about how the Alexandrium life cycle contributes to accumulation of saxitoxin in different shellfish, there are many research opportunities available. By researching this topic we could learn how to manage the effects of harmful algal blooms on the commercial shellfish industry, and lower the risk of PSP in Southeast Alaska. More people will then feel confident digging for clams on recreational beaches. There currently is a test strip available for testing the levels of toxicity in the water, but this test is difficult to obtain because it is too expensive for the general public. A future research topic we propose is to create an inexpensive, user-friendly test kit for testing PSP toxin levels in shellfish. Another future research project would be to test the clams for the toxins in different times of the year or in different regions to see which climate or time of year would be best suitable for avoiding the risk of obtaining PSP. Since Saxidomus giganteus are known to hold their toxins for up to two years, the clams would be a great indicator for presence of saxitoxin in that local area.

Proposed Management Plan

For our management plan, we suggest that the state incorporates more local testing labs that would do regular testing on recreational beaches in Southeast Alaska where clams are known to live. There should also be signs posted at the beaches to inform the public if it is safe to dig there or not. We do not suggest that the Alaska Department of Fish and Game change their regulations for shellfish harvest, but we do propose that they help warn people more about PSP on their web site and their regulation documents for shellfish.

Figures

butter clam

Figure 1. Saxidomus giganteus.
Source: Google Images


Paralytic Shellfish Poisoning!

  1. Do you know what Paralytic Shellfish Poisoning (PSP) is?
  2. If not, do you think that there should be more information about it?
  3. Have you ever heard of any cases of PSP in your family or in your community?
  4. Do you or your family eat clams or mussels? If so, which types of clams and mussels do you eat?
  5. Do you or your family dig for your own clams and mussels?
  6. Have you ever heard of specific seasons that it might be unsafe to eat clams and mussels from our area?
  7. Which beaches do you get your clams and mussels from?
  8. Does the risk of PSP affect your decisions on eating shellfish?

Figure 2. Paralytic Shellfish Poisoning Survey—KH


Survey Question

1

2

3

4

5

6

7

8

Students Surveyed

170

170

170

170

170

170

170

170

# that Answered

154

124

157

132

156

156

Fig 3.2

156

Yes

108

87

28

40

29

103

63

No

49

37

129

92

127

53

93

% Yes

69

70

18

30

19

66

40

% No

31

30

82

70

81

34

60

Figure 3.1 Data from Impact Survey


Local Collection Areas

Out of State Collection Areas

Figure 3.2 Collection Areas from Survey Question 7


69 percent of those surveyed know about PSP

Figure 4. Do you know what Paralytic Shellfish Poisoning is?


70 percent think there should be more information about it

Figure 5. If not, do you think there should be more information about it?


18 percent had heard of PSP cases in their family

Figure 6. Have you ever heard of any cases of PSP in your family or in your community?


30 percent eat clams or mussels

Figure 7. Do you or your family eat clams or mussels? If so, which types of clams and mussels do you eat?


19 percent dig for clams or mussels

Figure 8. Do you or your family dig for your own clams and mussels?


66 percent have heard of specific seasons that are unsafe to eat clams

Figure 9. Have you ever heard of specific seasons that it might be unsafe to eat clams and mussels from our area?


40 percent say PSP affects their decision to eat shellfish

Figure 10. Does the risk of PSP affect your decisions on eating shellfish?


Sampling Protocols: Standard Operational Practice (SOP) for Collection and Shipping of Shellfish for PSP Testing.

This SOP provides the procedure to be used when collecting shellfish for PSP testing. The collection practices apply to preparing shellfish for shipment. Shipping procedures apply only to samples that are freighted or mailed to another location (e.g. Anchorage or Dutch Harbor). The data sheet ("PSP Testing Data Entry Sheet") accompanying this SOP must be completed and placed in the plastic storage bag with the shellfish at the time the shellfish are collected.

Collection Procedure

  1. Fill out the collection portion of the data sheet.
  2. Harvest shellfish as follows
    • The general rule is that you will need at least 150 grams of drained tissue weight (about 2/3 cup) of meat to conduct the PSP test. Include a shell with each sample to confirm ID. These shell samples can be examined by the QC person regularly to confirm that ID is correct.
    • Blue mussels—30 shucked mussels per sample.
    • Butter clams—If they are greater than 3" in size 5 shucked clams per sample. If they are less than 2" in size at least 10.
  3. Be sure the data sheet is completed after sampling.
  4. Place sample into zip-lock bag along with the data sheet.

PSP Testing Data Entry Sheet

The data is entered on the following table and placed in the bag with the sample and frozen.

Location (Town, village etc) sample collected: _____________
Sampler's name: _______________
Date sample collected: ______________
Species: ______________

Instructions for Completing the Data Sheet

Appendix B. Standard Operational Practice (SOP) for Storage of Shellfish for PSP Testing.

This SOP provides the procedure to be used when storing shellfish for PSP testing.

Storage Procedure

Figure 11. SOP for clam sampling [PDF; 82 KB]
Source: Bruce Wright, Senior Scientist, Aleutian Pribilof Islands Association


Saxidomus giganteus

Distribution: Aleutian Islands to mid California

Habitat: Intertidal zone to 120 feet depth, on protected gravel, sandy beaches

Size: up to 5"

Identification: Dense shell, external surface with concentric rings, prominent growth rings

Toxicity: 7,750 μg

Figure 12. Details about butter clams
Source: Ray RaLonde, 1996


References