Living in Suffolk and the rest of Hampton Roads can be a rollercoaster of monthly weather matters, especially for the wild diversity of life in Suffolk’s waterways that changes all year long.

More than 50 local residents, city officials and ecological volunteers filled the C.E.&H. Ruritan Hall on Tuesday evening to find out more about these changes of the seasons in the latest River Talk organized by the Nansemond River Preservation Alliance.

Chad Boyce, district fisheries biologist with the Virginia Department of Game and Inland Fisheries, brought his PowerPoint and expertise to wade into this deep topic with a beginner’s guide to fishes in the Nansemond River and Chuckatuck Creek. Some were recognizable, while others were formally introduced.

“I more or less hope to highlight some of the different fish assemblages that we find in these watersheds, mainly just in categorical fashion,” Boyce told his audience on Tuesday night.

These two major waterways fluctuate in water temperature throughout the year, Boyce said. Tidal extremes vary, as does salinity and even the amount of dissolved oxygen needed for fish to survive, the latter of which generally plunges after major tropical storms.

Another effective measure of water quality is turbidity, or the degree to which water loses its transparency because of solids suspended inside it.

“(Turbidity) generally increases with rainfall and the washing out of sediment from ditches and fields and things like that,” Boyce said.

The population of native, year-round fish includes some seldom-seen examples that are able to withstand these variables. Boyce included pictures in his PowerPoint to put the spotlight on some of these characters.

On the screen were bay anchovies, the most abundant fish in the Chesapeake Bay, yet hard to find unless one uses a small mesh net. There were mummichogs and silversides and the ugly, year-round resident of oyster reefs and shallow waters called the oyster toadfish.

“There’s a myth that they taste really good. I tried it, they don’t,” Boyce said.

While these natives are found in Suffolk year-round, others are diadromous fishes, meaning they spend some parts of their life cycles in fresh water and other times in salt water.

One half of this category are anadromous fishes like striped bass and sturgeon, who spend most of their adult lives at sea and return to fresh water to spawn. The other half consists of catadromous fishes, which spawn in the open ocean and then move into freshwater environments like the Nansemond River to spend several years maturing.

American eels are the only species of freshwater eel in North America and an example of facultative catadromy, meaning they may be found in freshwater or saltwater as they mature. According to the U.S. Fish and Wildlife Service, this smooth, snake-like fish hatches in the waters of the Sargasso Sea, an area of the Atlantic Ocean measuring two million square miles from its maturation habitats in the North Atlantic Ocean between the West Indies and the Azores.

This fish uses currents to move from its birth waters to destinations across the world like the Chesapeake Bay. It then makes the return trip later in life to spawn and keep the cycle alive. Boyce emphasized that this was a one-way trip for the eel.

“That’s a one-time deal. You swim out, you spawn and you’re done,” he said.

Croaker, spot, grouper and other summer migrant fishes go north to forage for bait fish, and juvenile fish migrate to marshes and estuaries to grow and escape predation, like spadefish and cobia.

“They’re simply coming for one reason: grow and don’t get eaten,” Boyce said.

There are also cases of freshwater fish swimming out into saltwater in freshets, in which a flood of freshwater empties into the ocean, which most often happens locally because of heavy rainfall and flooding.

They stay in that stratified portion of freshwater before the saltwater overtakes it and forces the fish to swim back.

“Big rainfall pushes freshwater out of the system, and the freshwater fish ride those freshets,” Boyce said. “It’s a pretty neat way of getting around.”

The audience on Tuesday was engaged with their own questions, like whether or not it’s possible to find dolphins, sharks and seahorses in the river and creek. Boyce hopes to be invited back for another River Talk and dive deeper into the residents’ questions, even if it’s something as simple as NRPA President Elizabeth Taraski taking a poll.

“Just to see if something that we spoke about tonight can be discussed in more detail,” Boyce said.