Fish

What happens to the critters in a hurricane?

Hurricane Irma – CNN image

Hurricanes are no fun! But, if there is a small silver lining to hurricanes, it’s that scientists are provided rare opportunities to gain new insights into some plant and animal species. It’s a field called disturbance ecology, and I suspect a lot of it will be taking place in the next few months to years.

Some insights from past disturbance are incredibly fascinating. For instance, in 2001, just prior to Tropical Storm Gabrielle’s landfall, 14 tagged blacktip sharks swam to deeper waters in Terra Ceia Bay. And, as Hurricane Charley approached Charlotte Harbor in 2004, six of eight tagged sharks moved to open water; the other two disappeared from the sampling array. In both cases, the timing of shark movement seemed to correspond to decreasing air and water pressure.

Another notable effect of Hurricane Charley, occurred in the Peace River and upper Charlotte Harbor, which went hypoxic (very low to no oxygen) following the storm’s passage. The hypoxia resulted in changes in fish assemblages, from our typical fish variety to only the hardiest, including the sailfin catfish and the invasive brown hoplo. The hypoxic event was short lasting, and the fish assemblages returned to normal within a month. Interestingly, the Myakka River, which did not see the eye of the storm was not affected by hypoxia or changes in fish assemblages.

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Hot fish seeking cool water!

The warmer our waters get, the more common tropical species like this African pompano will become here. Florida Sea Grant Photo

All fish, minus opah and some tunas, are cold blooded. Thus, their body temperatures are regulated by the environment around them. Every fish species has an optimal temperature range — not only for survival, but also for growth and reproduction. Fish exhibit control over their thermal environment by seeking waters that are closer to their temperature optimum when waters become too warm or too cool.

High and low temperatures that are lethal for a particular species determines the distribution and abundance of its population. With water temperatures trending upward — the result of climate change — many fish are responding by shifting their latitudinal range, expanding their range, and/or moving to
deeper depths.

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Salty Topics: Exploring Oil Spill Impacts in the Gulf of Mexico

oil

In April of 2010, a gas release on the Deepwater Horizon oil rig caused an explosion that caused devastation in the Gulf of Mexico. Approximately 210 million gallons of oil spilled into the Gulf of Mexico over the course of 87 days to make this oil spill the worst one in recent history. Because of this oil spill, the coastlines of states like Texas, Louisiana, and Florida have portions that were polluted by the oil spill in 2010, and there are still sightings of oil washing up on these state’s shores today. Nearly 8,000 marine animals, such as turtles and birds, were reportedly dead within six-months of the oil spill.

Even though the Deepwater Horizon oil spill occurred over six years ago, scientists and researchers are still discovering the oil spill’s effects on the Gulf of Mexico. Come join us and Dr. Monica Wilson as she discusses recent research findings and explores the Deepwater Horizon oil spill’s impacts on habitats, aquatic wildlife, and human health.

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Interested in Charlotte Harbor Fisheries? Your input is needed!

photo 4Are you interested in the fisheries of Charlotte Harbor? Are you a recreational angler? A commercial fishermen? A clam farmer? Do you work at a bait and tackle shop? A marina? A fish house? Or maybe you work for some other business that relies on Charlotte Harbor fisheries?  If you answered yes to any of these questions then the Charlotte Harbor Fisheries Forum wants to hear from you!

How? – The Fisheries Forum through the University of Florida has developed an online survey which may be accessed here: Charlotte Harbor Survey .

What is the Charlotte Harbor Fisheries Forum? – The fisheries forum is comprised of a group of recreational anglers, commercial fishermen, researchers, resource managers, law enforcement officers, tourism officials, and business owners who have been meeting monthly for the past year to discuss issues related to Charlotte Harbor fisheries. The forum aims to: provide a venue for long-term engagement; provide for in-depth consideration of local fisheries issues; improve links between local knowledge and science; and represent local-based perspectives to management agencies. Anyone who is interested in Charlotte Harbor fisheries can participate in the forum.

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Deciphering Scientific Names

Tarpon, Megalops atlanticus - Photo: Capt. Billy Barton

Tarpon (Megalops atlanticus) – Photo: Capt. Billy Barton

So when was the last time you bragged to your friends about catching a big Megalops atlanticus or a nice Centropomus undecimalis?

Umm, yeah … probably never! Most of us don’t speak scientific geek and aren’t impressed when others do. But for geeky scientists there’s good reason to use those scientific or Latin names.

Worldwide, there are around 28,000 named fish species. Some species have multiple common names, often differing by geographic region. For example, the black crappie. No, wait, it’s a speckled perch — unless, of course, it’s a sac au lait. These are all the same fish — Pomoxis nigromaculatus.

Even more complicating, some common names are used to describe more than one fish species; think kingfish. Depending where you are, this name might be applied to the fish we usually call king mackerel, whiting, cobia, wahoo, giant trevally, jack crevalle, opah and Pacific yellowtail. Scientific names might be tongue twisters, but they do eliminate confusion, which is exactly why scientists rely them. No matter where they are in the world, when they say Mycteroperca microlepis, it means the same thing (most of us would call it a gag grouper).

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Big Old Female Fish – the future of our fishery!

Big, female snook make huge contributions to future fish stocks—Ralph Allen, King Fisher Fleet Image

Big, female snook make huge contributions to future fish stocks—Ralph Allen, King Fisher Fleet Image

Most anglers understand we have two snook closures annually; each for very different reasons. The December through February closure protects snook during the cold weather and the May to September closure protects spawning snook. The size limits for snook are designed to protect juveniles and older spawning female snook. Many people understand the reason to protect juveniles; after all they are the future generation. But why protect the old girls?

Well it turns out size matters when it comes to fish spawning. That’s right Big, Old, Fat, Fecund, Female Fish or BOFFFFs contribute far more to future fish stocks than their smaller, younger same species representatives, and the old girls contribute in many ways.

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Reproductive Strategies in the Marine World

With the exception of humans, and our spayed and neutered pet friends, survival and passing on genes through reproduction are all encompassing for the remainder of the animal kingdom, the marine environment included. Marine organisms have a fascinating array of reproductive behavior patterns. They can be pelagic spawners, benthic spawners, nest spawners, or bearers of live young. They may be guarders, non-guarders, or brood hiders. Further they may have elaborate courtship or no courtship.

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So there you have it, a sneak peek into some interesting reproduction strategies employed by a few of our more remarkable marine species.

 

Estuary Nurseries: Early life histories of popular sportfish

Perhaps the most well-known function of estuaries, such as Charlotte Harbor, is their role as nursery grounds for growing fish, shrimp and shellfish.  Very few marine species spawn in estuaries, but estuaries are used extensively as nursery grounds.  Most fish and crustaceans (crabs, shrimp, etc.) spawn offshore.  The eggs are typically planktonic (free floating).  Eggs develop into larvae that depend upon tides and currents to transport them to suitable habitats to settle out and grow within.  Settling young fish and crustaceans utilize a number of different survival strategies, but common to all is a quest to not be eaten.

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Summertime Fish Kills

Each summer, fish kills occur in freshwater and saltwater environments. They occur in natural systems, retention ponds and aquaculture production facilities. Such kills often occur seemingly unexpectedly, and many times result in emotional and/or economic loss.

There are a number of reasons for fish kills, but during the summer months, the most common cause is low dissolved oxygen.

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