Executive SummaryRockfish are vital for the environmental and economic health of the Chesapeake Bay. As rockfish face overfishing, limited prey availability, warmer water temperatures and increased hypoxic dead zones in the Bay, their populations are plummeting. If action is not taken by state governments, we may soon see a Chesapeake Bay without rockfish. It is necessary to protect Rockfish through: 1. Recreational catch limits 2. Commercial catch reductions, and 3. Coordination between Maryland and Virginia.

Background

Recovering after near extinction in the 1980s, the Chesapeake Bay rockfish (Morone saxatilis) are once again imperiled. Rockfish are both a prized catch of Bay fisherman and an indicator species for the Bay’s overall health. As such, a decline in their numbers is a worrying indicator of broader environmental decline (CBF Website, 2022).

    

Annually, the Maryland Department of Natural Resources quantifies juvenile rockfish to track the reproductive success of the fish. This index counts young rockfish at four important spawning sites throughout the Bay. Low abundance of juvenile fish correlates to poor reproductive success, indicating a population in severe decline (MD DNR, 2020). If index numbers continue to decline, rockfish in the Bay could disappear (Gallagher, 2018). Low reproductive success leaves fewer fish to grow into the spawning stock and regenerate populations. 

Consequences of Inaction

Dismal numbers of rockfish populations threaten the Bay’s economy and ecosystems. Economic reporting from NOAA indicates the seafood industry in Maryland and Virginia contributed $3.39 billion in sales, $890 million in income, and almost 34,000 jobs to the local economy. Rockfish remain the most popular commercial and recreational fish in the Bay, generating $500 million in economic activity annually. Further, rockfish occupy an important space in the food web of the Bay. As an apex predator, they play a vital role in controlling species they prey upon. As such, rockfish disappearance will cause cascading ecological changes with unclear consequences for multiple species in the fragile Bay ecosystem (Panayotova et. al., 2021). 

Root Causes

 There is no scientific consensus on what is currently causing rockfish populations to plummet (Wheeler, 2020). However, a myriad of factors contribute to rockfish decline and swift action is needed to keep rockfish swimming.

1. Overfishing. A federal stock assessment found that rockfish were severely overfished since 2013. As such, the Atlantic States Marine Fisheries Commission implored state governments to reduce catches of rockfish by 18% to give the populations a chance to replenish (ASMFC, 2021).
2. Limited Prey Availability. Menhaden, the main prey of the rockfish, exhibit plummeting reproduction levels as they are a popular commercial catch due to their desirability as feedstock, bait, and fish oils (Anstead et. al., 2021). 
3. Unhealthy Habitat. Nutrient pollution fuels large algal blooms which deplete dissolved oxygen. Dead zones result, where the water suffocates rockfish (Li et. al., 2020). Dead zones force rockfish to swim into shallow waters with higher-than-preferred temperatures, stressing them while exposing them to diseases such as mycobacteriosis (Ha, 2021).
4. Climate Stress. Climate change increases average water temperature and induces more stress for rockfish, reducing spawning success and growth in juvenile rockfish (Irby et. al., 2018). Warmer water further reduces a rockfish’s chance of recovery after injury; 9% of rockfish released alive die on average contributing to their decline (Secor et. al., 2020).

Policy Recommendations

With the causes of rockfish decline spanning the entire Chesapeake ecosystem, solutions must be wide-ranging with coordination between the Maryland and Virginia departments of Natural Resources. While the consequences of rockfish disappearance are worrying, there are steps the governments of Virginia and Maryland must take to support population regrowth. 

1. Recreational rockfish harvests must be reduced. In line with the Atlantic Marine Fisheries Commission target of an 18% catch reduction, Maryland and Virginia must shorten their rockfish season. Further, throughout July, when air and water temperatures are high and oxygen levels are low, each state should institute a moratorium window on fishing rockfish for at least 3 weeks. Fish caught and released in this time period often do not survive (ASMFC, 2021).
2. Commercial harvest must be reduced. While states have reduced recreational harvests, commercial harvests are unlimited. A 20% reduction would assure a better chance of recovery while reducing the likelihood of a complete moratorium which is imminent if populations continue to decline. While temporarily reducing revenues, this level reduction is preferred to a complete moratorium if population numbers continue to free-fall.
3. Coordination between Maryland and Virginia. Currently, Virginia and Maryland rockfish regulations do not line up. This incentivises fishermen to go into Maryland waters, where regulations are more lax. Further, the fishery departments should come together to advocate for solutions to issues of climate change, nutrient runoff, and urban runoff to improve habitat for the rockfish and Bay health. Addressing root causes for population decline beyond overfishing is vital to foster a healthier rockfish population.

Works Cited 

About the indicators. Chesapeake Bay Foundation. (2022). Retrieved February 25, 2022, from https://www.cbf.org/about-the-bay/state-of-the-bay-report/sotb-about-the-indicators.html 

Anstead, K. A., Drew, K., Chagaris, D., Schueller, A. M., McNamee, J. E., Buchheister, A., … & Townsend, H. (2021). The path to an ecosystem approach for forage fish management: A case study of Atlantic menhaden. Frontiers in Marine Science, 8, 491.

Atlantic States Marine Fisheries Commission. Striped Bass – Atlantic States Marine Fisheries Commission. (2021). Retrieved March 18, 2022, from http://www.asmfc.org/species/atlantic-striped-bass 

Chesapeake Bay Young-of-year survey results released. Natural Resources News. (2020, October 13). Retrieved February 25, 2022, from https://news.maryland.gov/dnr/2020/10/13/chesapeake-bay-young-of-year-survey-results-released/ 

Gallagher, B. K., Fabrizio, M. C., & Tuckey, T. D. (2018). Estimation of juvenile striped bass relative abundance in the Virginia portion of Chesapeake Bay. Annual Progress Report: 2017-2018.

Ha, A. (2021). Seasonal Pathological Differences of Mycobacteriosis in Striped Bass (Morone saxatilis).

Irby, I. D., Friedrichs, M. A., Da, F., & Hinson, K. E. (2018). The competing impacts of climate change and nutrient reductions on dissolved oxygen in Chesapeake Bay. Biogeosciences, 15(9), 2649-2668.

Li, M., Ni, W., Zhang, F., Glibert, P. M., & Lin, C. H. M. (2020). Climate-induced interannual variability and projected change of two harmful algal bloom taxa in Chesapeake Bay, USA. Science of The Total Environment, 744, 140947.

Panayotova, I. N., & Hallare, M. B. (2021). Modeling the Ecological Dynamics of a Three-Species Fish Population in the Chesapeake Bay. CODEE Journal, 14(1), 2.

Secor, D. H., O’Brien, M. H., Gahagan, B. I., Watterson, J. C., & Fox, D. A. (2020). Differential migration in Chesapeake Bay striped bass. Plos one, 15(5), e0233103.

Wheeler, T. (2020, May 16). Study: Bay rockfish die at twice the rate of those in Atlantic. Chesapeake Bay Magazine. Retrieved March 18, 2022, from https://chesapeakebaymagazine.com/bay-rockfish-die-at-twice-the-rate-of-those-in-atlantic/