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Uncovering Patterns and Mechanisms of Paralytic Shellfish Toxicity in Alaska's Geoduck Clam Fishery.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Uncovering Patterns and Mechanisms of Paralytic Shellfish Toxicity in Alaska's Geoduck Clam Fishery./
Author:	Hart, Courtney E.
Description:	1 online resource (142 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-06, Section: B.
Contained By:	Dissertations Abstracts International85-06B.
Subject:	Ecology. -
Online resource:	click for full text (PQDT)
ISBN:	9798381173178

Uncovering Patterns and Mechanisms of Paralytic Shellfish Toxicity in Alaska's Geoduck Clam Fishery.
Hart, Courtney E.

Uncovering Patterns and Mechanisms of Paralytic Shellfish Toxicity in Alaska's Geoduck Clam Fishery. - 1 online resource (142 pages)

Source: Dissertations Abstracts International, Volume: 85-06, Section: B.

Thesis (Ph.D.)--University of Alaska Fairbanks, 2023.

Includes bibliographical references

This dissertation explores the patterns and mechanisms of paralytic shellfish toxicity in commercially harvested geoduck clams caused by the toxin-producing dinoflagellate Alexandrium catenella in Southeast Alaska. Alaska's commercial fishery for geoduck clams (Panopea generosa) is a small but lucrative fishery, with annual ex-vessel values averaging US $3.9 million (2010-2022). In recent years, the presence of paralytic shellfish toxins (PSTs) in clam tissue resulted in declines in fishery openings and harvest. PSTs can bioaccumulate in the tissues of filter feeders when A. catenella blooms in the spring and summer seasons. However, high levels of toxicity in geoduck clams occur sporadically during the fishery in the fall and winter months long after toxic blooms have subsided. Levels of PSTs in geoduck clams vary substantially from week-to-week, and elevated PSTs are increasingly causing economic loss to the fishery through sampling costs from repeated testing and by delaying or closing harvests. In the past decade (2011-2021), about 60% of geoduck clams tested for PST failed regulatory screenings, up from a 36% failure rate in the decade prior (2001-2010). Knowledge about patterns and distributions of this harmful algal species and its toxins will help improve management of geoduck dive fisheries and provide information to reduce impacts of PSTs on this fishery. In Chapter 1, Patterns in geoduck clam paralytic shellfish toxicity from two decades of shellfish testing in southeast Alaska, we show that geoduck clams are increasingly failing biotoxin screening tests in some areas and these patterns are most closely correlated with regional air temperatures. In Chapter 2, Alexandrium catenella benthic cyst distribution, sediment characteristics, and geoduck clam (Panopea generosa) toxicity in Southeast Alaska, we provide the first A. catenella cyst distribution map for this region and found that cyst counts declined over the three-year study, but patterns were not related to geoduck PST levels or sediment characteristics. Lastly in Chapter 3, Geoduck clam (Panopea generosa) toxicity dynamics across harvest areas, time, age, and cyst gut content in Alaska's commercial fishery, we confirmed the ability for geoduck clams to ingest dormant A. catenella cysts but revealed that neither this process, nor the age of a clam, is directly related to patterns of paralytic shellfish toxicity in this clam species. All together, these findings lead to a better understanding of the variability of PSTs in geoduck clams and are informative to future fishery management and the protection of human health.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798381173178Subjects--Topical Terms:

575279
Ecology.
Subjects--Index Terms:

Alexandrium catenellaIndex Terms--Genre/Form:

554714
Electronic books.

Uncovering Patterns and Mechanisms of Paralytic Shellfish Toxicity in Alaska's Geoduck Clam Fishery.
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500 $a Source: Dissertations Abstracts International, Volume: 85-06, Section: B.
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502 $a Thesis (Ph.D.)--University of Alaska Fairbanks, 2023.
504 $a Includes bibliographical references
520 $a This dissertation explores the patterns and mechanisms of paralytic shellfish toxicity in commercially harvested geoduck clams caused by the toxin-producing dinoflagellate Alexandrium catenella in Southeast Alaska. Alaska's commercial fishery for geoduck clams (Panopea generosa) is a small but lucrative fishery, with annual ex-vessel values averaging US $3.9 million (2010-2022). In recent years, the presence of paralytic shellfish toxins (PSTs) in clam tissue resulted in declines in fishery openings and harvest. PSTs can bioaccumulate in the tissues of filter feeders when A. catenella blooms in the spring and summer seasons. However, high levels of toxicity in geoduck clams occur sporadically during the fishery in the fall and winter months long after toxic blooms have subsided. Levels of PSTs in geoduck clams vary substantially from week-to-week, and elevated PSTs are increasingly causing economic loss to the fishery through sampling costs from repeated testing and by delaying or closing harvests. In the past decade (2011-2021), about 60% of geoduck clams tested for PST failed regulatory screenings, up from a 36% failure rate in the decade prior (2001-2010). Knowledge about patterns and distributions of this harmful algal species and its toxins will help improve management of geoduck dive fisheries and provide information to reduce impacts of PSTs on this fishery. In Chapter 1, Patterns in geoduck clam paralytic shellfish toxicity from two decades of shellfish testing in southeast Alaska, we show that geoduck clams are increasingly failing biotoxin screening tests in some areas and these patterns are most closely correlated with regional air temperatures. In Chapter 2, Alexandrium catenella benthic cyst distribution, sediment characteristics, and geoduck clam (Panopea generosa) toxicity in Southeast Alaska, we provide the first A. catenella cyst distribution map for this region and found that cyst counts declined over the three-year study, but patterns were not related to geoduck PST levels or sediment characteristics. Lastly in Chapter 3, Geoduck clam (Panopea generosa) toxicity dynamics across harvest areas, time, age, and cyst gut content in Alaska's commercial fishery, we confirmed the ability for geoduck clams to ingest dormant A. catenella cysts but revealed that neither this process, nor the age of a clam, is directly related to patterns of paralytic shellfish toxicity in this clam species. All together, these findings lead to a better understanding of the variability of PSTs in geoduck clams and are informative to future fishery management and the protection of human health.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2024
538 $a Mode of access: World Wide Web
650 4 $a Ecology. $3 575279
650 4 $a Aquatic sciences. $3 1178821
650 4 $a Toxicology. $3 580973
650 4 $a Environmental science. $3 1179128
653 $a Alexandrium catenella
653 $a Fisheries management
653 $a Geoduck clams
653 $a Harmful algal blooms
653 $a Shellfish poisoning
653 $a Shellfish
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710 2 $a University of Alaska Fairbanks. $b Fisheries. $3 1186029
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