New Study Reveals Biodiversity’s Role in Fisheries Stability

A recent study published in the journal Ecological Applications highlights the critical role of biodiversity in enhancing the stability of commercial fisheries. This research, led by Sean Hardison, a former Ph.D. student at the University of Virginia and a Virginia Sea Grant Fellow, draws parallels between commercial fisheries and investment portfolios, emphasizing that diversity can bring stability to fishing operations.

The study examined data collected from the Chesapeake Bay between 2002 and 2018, utilizing resources from William & Mary’s Batten School of Coastal & Marine Sciences and the Virginia Institute of Marine Science (VIMS). The researchers discovered that harvesting various fish species at different times—a phenomenon referred to as “asynchrony”—results in less variability in overall fishing harvests and revenue. However, this dynamic is influenced by factors including seasonal availability, market demand, and fishery management practices.

Understanding the Impact of Asynchrony

Hardison, who is currently a postdoctoral researcher at the University of Alaska Fairbanks, noted the importance of natural ecosystem fluctuations in commercial fisheries. He explained, “The findings speak to how commercial fisheries benefit from natural fluctuations in the ecosystem, but also how these natural influences are mediated by factors like market prices and management practices.”

The Chesapeake Bay Multispecies Monitoring and Assessment Program (CHesMMAP) plays a pivotal role in this research by tracking fish populations throughout the Bay, from Poole’s Island in Maryland to the mouth of the Bay near the Chesapeake Bay Bridge Tunnel in Virginia. This unique monitoring approach provides vital data that informs sustainable fisheries management.

The study sought to analyze how seasonal asynchrony among commercially fished species affects both the quantity and economic value of fishers’ landings, while also evaluating the impact of varying management practices across state lines.

State-Specific Dynamics Affecting Fisheries

In Maryland, the commercial striped bass fishery experiences seasonal closures to protect spawning stocks. This management strategy disrupts the natural asynchrony between fish populations and harvests, as striped bass comprise a significant portion of the commercial portfolio. Although the closure encourages fishermen to target alternative species—temporarily increasing stability in landings—it does not stabilize overall revenue due to the higher economic value of striped bass compared to other species.

Conversely, Virginia’s lack of such seasonal closures allows for natural asynchrony to initially stabilize fisheries. However, as the populations of key species like Atlantic croaker and spot declined during the study period, harvests became less asynchronous and more unpredictable.

Max Castorani, an associate professor in the Department of Environmental Sciences at the University of Virginia and a co-author of the study, remarked, “Biodiversity doesn’t just make ecosystems healthier; it makes them steadier over time. It spreads risk and acts like insurance when certain fish are in short supply.”

Christopher Patrick, an associate professor and ecologist at the Batten School & VIMS, emphasized the importance of having a diverse range of species in fisheries. He stated, “The most stable system would be one where you’ve got a lot of different species and they’re all equally valuable. When you get an asymmetric value distribution, it kind of falls apart.”

A potential avenue for diversification highlighted in the research is the ongoing development of a commercial fishery for invasive blue catfish in the Chesapeake Bay. Although market prices for blue catfish have been modest historically, the study suggests that even slight increases in price could lead to significant gains in harvest and market participation.

The broader implications of this study underscore the necessity of examining fisheries from both ecological and economic perspectives. While biodiversity inherently contributes to stability, external factors like regulations, market trends, and fishing practices can either enhance or diminish these benefits.

Hardison concluded, “Fisheries portfolios benefit from natural fluctuations in the ecosystem, but those benefits are mediated by management and human behavior. Our research shows the ecological and economic benefits of biodiversity.”

For further details, the full manuscript of the study is available in Ecological Applications.