Striped Bass
The state fish of Maryland, known colloquially as rockfish, stripers, linesiders, or their official name Striped Bass, are a major part of the Chesapeake Bay ecosystem and an important indicator of water quality. Striped bass can live up to 30 years and are found all along the Atlantic coast, often spawning in the Chesapeake Bay. Striped Bass are part of the few kinds of fish that migrate from saltwater into freshwater to spawn. With a streamlined silver body and long dark stripes running from their gills to their tail, they are powerful swimmers. Maryland has some landlocked populations in reservoirs like the Liberty, Piney Run, and Rocky Gorge reservoir.
They like to hide out in oyster reefs and rocks, where they earned their nickname ‘rockfish’, eating smaller fish like bay anchovies and menhaden, and crustaceans like young crabs and shrimp. Due to overfishing of the bass themselves and their prey, their population dropped to under 5 million in the 1980s. After putting in laws around commercial and recreational fishing, their population bounced back, but today their population is declining again, though not yet in an endangered or threatened category. At the top of the food pyramid for their area, striped bass have few predators except seals and sharks, and of course, their biggest predator, humans.
The Great Migrators
As days get brisker and autumn leaves fall, you’ll see flocks of birds migrating to warmer weathers. What you might not see, though, is the hundreds of millions of striped bass swimming south to the warmer water. Swimming up to 50 miles a day, Striped Bass have an impressive migration story. Every spring and fall, they swim thousands of miles along the coast of North America, ranging all the way from Canada to Florida. (Striped Bass are also found in the Gulf of Mexico but are recognized as a distinct population with a higher temperature tolerance.) They have been found to often spend summer in New England and winter near North Carolina. As ectotherms, striped bass make this journey because they rely on the temperature of the water around them to maintain their body heat. Warmer waters can be unsafe for fish because it holds less oxygen than cool water and their bodies will overheat. Stripers are anadromous fish, meaning they spend most their life in saltwater, but spawn in freshwater. Their journey back north in the spring is accompanied by spawning season, where they find a freshwater source like the Chesapeake Bay to lay their eggs. More than 70% of east coast stripers spawn in the Chesapeake Bay, and others find their homes in the Hudson and Potomac rivers.
Juvenile Stripers as Bay Indicators
With a majority of striped bass spawning in the Chesapeake Bay, they are heavily impacted by warming bay water and oxygen dead zones. A dead zone is an area where dissolved oxygen is too low to support life. Excess nitrogen and phosphorus from pollution cause algal blooms, especially in warmer waters, and as the algae die, bacteria take all of the oxygen out of the water. Dead zones ‘suffocate’ the life in them, causing mass death events. Striper populations and eggs cannot survive in these zones, and you might see many dead fish floating along the top of the water. Over the past few decades, Chesapeake Bay waters have increased on average almost 2°F, which is pushing over the life’s temperature tolerance, causing stress to many different species of marine life including striped bass. Sea level rise and intense storms change the habitat, and we can see changes in the populations affected by the poorer water quality.
The majority of striped bass in the bay are juvenile, as older fish migrate along the coast. Spawning is triggered by an increase in water temperature, often occurring in April, May and early June, but as water temperatures rise, their spawning season may be pushed earlier or disrupted. Females can lay up to 3 million eggs, but fish eggs are a favorite snack for many other bay animals like fish, jellyfish and shrimp, so only a small fraction of these eggs survive to adulthood. These eggs float downstream for a few days before hatching into larvae, which usually stay in the bay/river for two to five years before migrating into the Atlantic where they will spend their adult lives. Juvenile striped bass numbers have been “well below average” since 2018, and many places in the bay are dead zones, restricting their habitat and trapping them in harmfully warm water areas.
What can you do?
Reducing lawn pesticide and fertilizer, especially if you live near the water, can help protect the health of the Chesapeake Bay and all its life. When fishing, be sure to follow safe fishing practices and to check regulations to keep fish populations protected. Striped Bass are only allowed to be caught during certain months, and when they are allowed to be kept, they’re capped at one fish per person per day.
Written by Sam Banks
Sources:
https://dnr.maryland.gov/fisheries/Pages/Fish-Facts.aspx?fishname=Striped%20Bass
https://www.fws.gov/species/striped-bass-morone-saxatilis
https://www.fisheries.noaa.gov/species/atlantic-striped-bass