What is a stock assessment? Part I

Introduction

Assessing in style

           Stock assessments are an important part of the way we manage fisheries in the U.S. A lot goes into a single stock assessment, and they can be quite daunting to navigate. However, when you break them down into their component parts they really aren’t so bad! In this post we will begin to explore stock assessments by introducing the concept and talking a bit about the process involved with stock assessments in Federal waters (*in Florida, marine waters past 3 miles offshore in the Atlantic and past 9 miles offshore in the Gulf of Mexico are governed by the Federal government through NOAA’s Fisheries branch, and waters inshore of that are governed by the State through the Florida Fish and Wildlife Conservation Commission; they also use stock assessments, and we will tackle their management process in a future post).

Ode to Batfish: Biology in Verse

Oh batfish, oh batfish of the briny deep

On modified pectoral fins you creep

“Walking” along the benthic sea floor

Of all the fishes, it’s you I adore

Seagrass Savanna

Check out this video detailing the work of graduate student Savanna Barry, who studies seagrass along Florida's Gulf coast:

What the heck is that? On sea robins and their awesomenitude

Florida is home to an incredible diversity of fish species, so it is unsurprising that every once in a while something weird comes up on an angler’s hook. Most of us can easily identify the common species, like snook, redfish and trout; but what would you say if you got this guy on the end of your line?

Climate Change and Florida's Fishes

We've all heard about many of the potential impacts of climate change, such as the polar bears losing their habitat or the melting of the polar ice. But what will climate change mean closer to home? How will it impact our marine habitats and the fish that live there? Check out this video for an overview:

Climate Change and Florida's Fishes on Vimeo.

Michael and the Peppermints II

Hey all! A while back I posted a teaser and promised a video on UF graduate student Michael Dickson's peppermint shrimp work; here it is! Woo! Presenting….. Michael and the Peppermints 

Michael and the Peppermints on Vimeo.

Do bananas mean bad luck fishing?

Ok team, today I am going to stray a bit from my video posts to talk about a very important topic: the bad luck bananas are thought to cause to fishing expeditions.

The question: Do bananas really bring bad luck to a boat?

Background: Where does the taboo come from?

        There are many theories as to where the "bad-luck-banana" superstition got started. Some people think it began back in the colonial shipping days, when trade vessels brought bananas from the New World across the Atlantic to Europe. Bananas spoiled quickly on board the boats, and so the ships had to travel fast; this pressure on speed may have led to riskier and more disastrous voyages. Alternately (and less sadly) the speed also meant that the boats had less time to stop and fish, which may have led to the association between bananas and low fishing success. 

image from: http://farm4.static.flickr.com

       Other theories focus more on the cargo than the voyage. Historically, creatures like spiders and snakes would stow away in banana cargo, and so it may have been that captains started the rumor to keep banana crates off their boats. Another theory is that because bananas give off ethylene gas as they ripen, they may have caused other food to spoil quickly in the cargo hold, resulting in their unpopularity on boats. One story from Hawaii says that bananas packed by fishing tribesman would spoil at the same time that the men paddled too far out for good fishing, hence their association with poor fishing.

Whatever its origins, the banana taboo is here to stay in angling culture; some fishers even extend the taboo to include anything associated with bananas, such as banana boat sunscreen or banana republic clothing. I for one have many friends who would be exceedingly angry were I to sneak a banana on board their boat, and anecdotes relating bananas to poor fishing days abound in Florida. So when as a student I was asked to design a study for a course I was taking, it seemed the time was ripe to set the records straight.

The Design: How do we test it?

How Old is That Fish?

Ever wondered how old a fish is? Check out this quick video to learn how scientists age fish and why it is important:

Michael and the Peppermints

We are working on a video series profiling fisheries scientists in action *to be posted soon*, so as a teaser we've put together some clips from a recent sampling trip with UF graduate student Michael Dickson. Mike is working on the population dynamics of peppermint shrimp (a species popular in the aquarium trade) and samples monthly aboard commercial shrimping vessels in the Gulf of Mexico. Enjoy, and more to come on Mike and others' work! <(Note: best watched with sound and in HD)>

Otolith Shape and Fish Movement

Hey there fishheads!

So as we learned in Joy’s post on the FACT array, tracking fish movements is an important part of fisheries science. In particular, it is important to know whether fish from different places are mixing or remaining geographically isolated (why? see below); however, this can often be a tricky thing to figure out. With this in mind, today I want to introduce a method I think is pretty darn cool…(cue drum roll)…otolith shape analysis! Now, for anyone who may be thinking oto-what now?, fear not! First, watch this handy 1:30 video, and then we can all share in the excitement-

Awesome, right? As a technique, otolith shape has been used to look at stock structure in a whole variety of different species, from goatfish to cod to king mackerel down here in Florida. I used otolith shape in my master's degree to look at stock structure of greater amberjack in the Gulf of Mexico (results coming soon). Now, otolith shape analysis doesn't always work or lend conclusive results (as can happen with any scientific method), but it is a nice technique that can be used to supplement tagging or genetic analysis methods, and as it is relatively simple and inexpensive (once the otoliths are collected, the analysis is essentially free), it can be a quick first step into examining stock structure.