Shellfish aquaculture production combines occupational hazards of fisheries and agriculture, and gaps exist regarding hazard characterization and mitigation strategies.^3,4 A growing literature base examines risks facing shellfish aquaculture workers in various contexts. Recognized bivalve aquaculture hazards include electric shock, solar radiation, drownings, noise, biological and ergonomic hazards, and slip/trip/falls, which can result in traumatic and soft tissue injuries, work-related musculoskeletal injuries (WMSDs), and others.^5,6 Further, bivalve aquaculture workers’ risk perceptions may underestimate dangers associated with tasks, minimization of work-related pain, and attribution of “accidents” to human error rather than unsafe conditions.⁷ Previous research highlights the need for organizational-level safety supports, including formal and context-specific occupational safety and health (OSH) training.⁷

A few studies have explored OSH in U.S. shellfish production. In Washington State, a secondary analysis of coastal shellfish workers’ compensation claims (2006–2012) found high injury and illness rates. Reported injuries and illnesses included Vibrio vulnificus infections, non-viral conjunctivitis, eye injuries, work-related musculoskeletal disorders (WMSDs), and hand tool injuries.⁸ A recent study by Dunleavy and colleagues⁹ found Florida-based clam aquaculturists experience ergonomic hazards, chronic pain, and WMSDs, yet lack injury prevention resources.

Little primary research or surveillance exists to characterize conditions and hazards faced by U.S. shellfish aquaculture workers.⁴ This is especially true for small-scale operations (defined as lacking on-site temporary worker housing and employing fewer than 10 non-family workers, annually), which are considered agricultural, and therefore exempted from national OSH reporting requirements and not represented in national OSH datasets.¹⁰

National data suggest injury and illness rates for U.S. aquaculture workers (5.6 per 100 full-time equivalents [FTE] in 2021) exceed Agriculture/Forestry/Fisheries (AgFF) sector rates (4.6 per 100 FTE) and average U.S. worker rates (2.9 per 100 FTE).¹¹ However, these rates are considered unreliable due to small U.S. aquaculture worker populations, suspected underreporting,⁴ and aforementioned agricultural surveillance exemptions.¹⁰ Considering these gaps, a 2016 policy analysis identified OSH as a major concern, given federal plans to expand the U.S. maritime aquaculture industry.¹²

Though the global literature base around shellfish aquaculture production is growing, the diversity of production methods and volumes, gear types, worker populations, and environmental settings contributes to gaps in context-specific OSH research, highlighting the need for primary investigations of hazards and safety methods. ^4,13 Through this qualitative study, we aimed to engage directly with industry members and capture their perspectives in their own words. These insights not only highlight the current gaps in worker safety but also lay the groundwork for identifying opportunities to adopt strategies to meaningfully improve conditions and safeguard the well-being of those integral to this vital industry. This study gathered insights from Chesapeake Bay shellfish producers regarding: (1) operation characteristics; (2) injury/illness experiences; (3) risk perceptions; (4) safety interventions; and (5) needed interventions in shellfish aquaculture, to identify avenues for future research and intervention.

The Chesapeake Bay is the U.S.’s largest estuary, bordered by the states Maryland and Virginia. It has brackish water of varying salinity levels, and averages 21 feet (~6 meters) deep, with a maximum depth of 174 feet (~53 meters).¹⁴ Although operation numbers and volumes may reflect temporary COVID-19 pandemic-related impacts,¹⁵ the Maryland and Virginia-based aquaculture industries are growing. Virginia produces the most oysters on the East Coast and the most hard clams in the United States.¹⁶ Virginia’s bivalve aquaculture operations decreased slightly from 194 to 178 operations between 2017 and 2022, but production values increased from $70.5 million to $93.5 million.¹⁷ Maryland’s small bivalve aquaculture industry almost doubled, increasing from 35 to 70 operations, between 2017 and 2022, with $11,463 million and $9 million in sales, respectively.¹⁸ Although this growth has slowed in recent years, it aligns with global trends demonstrating increases in aquaculture-produced seafood for human consumption.¹⁹

Eastern oyster aquaculture growth methods include “off-bottom,” “suspended” and “on-bottom,” aquaculture.²⁰ In off-bottom culture, juvenile oysters grow in cages or bags on the intertidal zone sea floor. Buoys, racks, or frames attached to anchored lines hold these containers in place. Suspended production involves floating bags or cages off the bottom.²⁰ Production requires removing cages/bags, cleaning them, counting, separating, sizing, and “tumbling” the oysters, then returning them to grow-out sites.²¹ This process increases growth and survival rates and repeats every few weeks until harvest or until growth slows.²¹

“On-bottom” culture resembles wild-caught methods after the seed production phase.²² Growers “plant” seed directly on the sea bottom,²³ where the oysters grow undisturbed for years before harvesting using a dredge.²²

Oyster production sites in the Chesapeake Bay are susceptible to biological contamination from pollution and runoff.²⁴ The Bay also contains naturally occurring pathogens, like, Vibrio spp., which proliferate in warmer waters²⁵ and can cause infections, septicemia, and gastroenteritis in humans.²⁶ While Vibrio spp. infections can be foodborne, aquaculturists can also develop skin, eye, or soft tissue infections from occupational Vibrio spp. exposures.⁴ Climate change-driven increases in oceanic temperatures have seemingly driven increased Vibrio spp. infections from consuming seafood.²⁷ Shellfish producers in Maryland and Virginia abide by Food and Drug Administration (FDA) Hazard Analysis and Critical Control Point (HACCP) regulations to mitigate potential foodborne pathogen spread. HACCP curfews require that harvesting cease by 10 or 11 AM, when ambient temperatures rise during summer months.^28,29

Recruitment occurred at a Maryland aquaculture industry meeting in November 2019 (n=5) and through referrals from industry contacts (n=4). The lead author recruited interested participants by phone or email and 100% agreed to participate. Interviewees were offered a $20 gift card incentive, but all declined. Interviews occurred in person or via telephone based on participants’ preferences. Participants had to be over 18 years old, work in Virginia or Maryland-based shellfish aquaculture, and work 20 hours/week on aquaculture tasks. Recruitment and interviews ended in April 2020 due to the COVID-19 pandemic’s impacts on the industry.

The semi-structured interview guide (Appendix 1) was developed with input from industry members, aquaculture experts, and occupational health experts, and pilot-tested³⁰ with a shellfish aquaculturist in October 2019. The interview guide focused on: (1) operation and work descriptions, (2) injury and illness prevention and contributors, and (3) safety knowledge and interventions. Interviewees provided oral consent prior to interviews, which were audio-recorded. The Johns Hopkins University Bloomberg School of Public Health Review Board classified this study as category two, exempt.

Nine interviews were performed, averaging 75 minutes long (range: 52–110 minutes). Two occurred by phone, six at worksites, and one at a public library. Worksite interviews facilitated observation of work areas and equipment, but work tasks had always ended for the day.

We used ATLAS.ti 24 – a qualitative coding software³¹ – for data management and code application. We used a qualitative coding approach to categorize results and search for patterns and contrasts within and between interviews.³² This approach facilitates interpretation by first assigning similar text passages to summative categories and sub-categories, which are then systematically re-examined and explicated as detailed narrative results.³² First, two researchers conducted close-reads of interviews and developed a codebook that contained deductive codes based on the study’s aims and interview questions and inductive codes capturing novel concepts identified by the researchers.²² The final codebook contained 11 code groups (e.g., “injury”) and 174 codes (e.g., severity, frequency, mechanism).³² At the outset of analysis, both team members coded the same two interviews, followed by discussions to align their interpretations. To ensure rigorous and consistent coding, coders met frequently to discuss coding strategies, ensure code agreement, and maintained analytic memos³².

Following coding, code group results were exported to Microsoft Excel (Microsoft 365, version 2408) by code and synthesized into narratives answering the research questions.³² Throughout analysis, constant comparisons identified within- and between-participant similarities and differences.³² Current interventions were extracted and organized by the NIOSH Hierarchy of Controls model (Figure 1), which ranks safety and health interventions by effectiveness, with hazard elimination considered the most effective, followed by substitution, engineering, and administrative controls (e.g., policies, staffing), and using personal protective equipment (PPE).³³

All respondents owned or operated farms in the Chesapeake Bay. Almost all (n=8) grew only oysters, and one grew oysters and clams. Table 1 contains demographics. Production methods included surface floats (n=1), bags/cages (n=6), bottom culture (n=1), and a combination (n=1). Five growers produced oyster seed. Respondents described seasonally variable daily work activities, with “grow-out” typically occurring between May and December. During grow-out, work could occur 12 hours per day, 6–7 days per week. While some growers harvest year-round, others mostly harvest from Thanksgiving to April.

All operations were small, with one to seven full-time employees and seasonal fluctuations in part-time, informal workers. Hiring informal workers (referred to as “day laborers” and local “blue collar” workers) during busy periods to meet production demands was described as relatively common. Operations averaged 8.5 years in business, ranging from less than one year to 20 years. Before starting their operations, five producers worked in related industries, including finfish or shellfish aquaculture or wild capture fisheries. Four producers transitioned from careers in unrelated sectors to aquaculture and initially lacked industry familiarity. These respondents took shellfish husbandry classes from agricultural extension offices, did their own research, and/or sought financial or technical assistance from state programs. These growers described a long trial and error period, with minimal outside guidance, to identify successful practices. One respondent explained: “I worked with [agriculture-extension] a bit... I ended up getting a loan from the state ... but I never took any formal training... learned as I went, killed a lot of oysters.”

All interviewees described creating their own production practices based on production goals, lease characteristics, and other needs. One participant explained, “Everybody makes up their own system based on the environment and what they’re doing and their type of growing.” In addition to planning tasks, most growers reported fabricating their own equipment to save money or because needed equipment was unavailable.

Work task mechanization varied. Some operators considered mechanizing systems ideal - for example, using winches and davits for lifting, or automating tumblers and sizing activities. Mechanization was considered important to maintain consistent production volumes in what one operator referred to as “an outdoor factory.” Other respondents likened themselves to “vintners” producing artisanal, hand-made products, uncompromised by mechanization.

Table 2 summarizes results for hazards, injuries, illnesses, and hazard mitigation techniques observed or reported during interviews. Respondents reported exposures to ergonomic, biological, physical, and chemical hazards. Generally, conditions were described as “rough,” challenging, and austere. One producer stated, “if you can’t be hot, wet and dirty, [and] cold, wet and dirty, then you can’t work for me.”

Respondents reported various hazard mitigation techniques. Table 3 details reported safety practices, categorized by levels of the NIOSH Hierarchy of Controls model.³³ Operators who discussed motivations for OSH interventions described wanting to decrease liability, maximize efficiency, and maintain high production volumes. One operator described: “if my people are hurt, and can’t function, then they can’t work and that tears up my [oyster production] mechanism.” Several producers stated they desired more time, funding, or bandwidth to enact safety interventions on their operations; one explained, “I don’t think, the motive or initiative is lacking. I think we just need to find the time.”

No interviewee had encountered formal OSH training or resources. Though many operators knew about or used state or federal industry programs supporting aquaculture businesses, they noted that no program provided resources about OSH. Most growers desired information about common hazards and effective mitigation strategies. Several producers stated that ideal supports would be easily accessible, include industry input, and either not incur extra work or help reduce their workloads. Importantly, some respondents emphasized that they oppose any new aquaculture worker safety regulations.

To our knowledge, no other study examines OSH challenges in Chesapeake Bay shellfish aquaculture. The interviews generated highly detailed information across multiple production methods and characterized various hazards. The small sample size represents a key limitation. This research occurred in late 2019 and early 2020. We attempted to continue recruitment during the COVID-19 pandemic, but major industry impacts like closures, furloughs, and stress made it unfeasible. Our sample size falls within a range where saturation is possible,⁴³ and we believe we achieved it for the hazards and challenges facing small-scale shellfish aquaculture producers. Our rigorous analysis, including double coding, enhances our findings’ credibility. As in all qualitative studies, generalizability beyond the study context is limited. We cannot comment on prevalence of the hazards, injuries, illnesses, and interventions reported here, though our results provide important information for quantitative studies to establish such estimates.