Rotenone: the fish killer

By Dana Sackett

Rotenone has been used for centuries by fishermen to harvest fish.  More recently, scientists and fishery managers have used rotenone to sample fishes and remove unwanted species from freshwater systems.   But how does this toxic chemical work so effectively to kill fish, is it toxic to other species including humans, and are the benefits of using this chemical worth the risks?  Find out below.

A 3-D image of the chemical structure of rotenone. http://en.wikipedia.org/wiki/Rotenone

Why are there fish in my peanut butter?

By Patrick Cooney

We have all heard of Jelly Fish, but what about Peanut Butter Fish?

If you found a fish in your peanut butter, would you take the jar back and demand a refund, or would you dive right in and smear the tainted spread across your sandwich?  What about finding a fish in your yogurt, eggs, milk, or pasta?  Whether you knew it or not, you and millions of others worldwide are consuming fish while eating other products, yet few seem to notice.

Bottom of the barrel - Expansion of fishing to the deep sea is not sustainable

Over the last 50-60 years many shallow water fish stocks have become depleted and others have outright collapsed. As a result fishers have targeted fish stocks in deeper and deeper waters. Studies on global catch have shown that the average depth of catch has increased in recent years and fishing now regularly occurs over 1000 meters and in some cases to 1800 meters. Fishers are literally reaching into the bottom of the barrel for fish. 

The average depth of the oceans is about 4000 meters. Waters greater than 200m cover half the planet making the deep-sea the single largest living space on earth. Despite all this space some of species that live in the deep-sea may not be there long if harvest continues at the current rate.                                                                                                  

                                                                                                 

Many deep water species seem foreign and rather ugly compared to the bright beauties on the coral reef or kelp bed. Have you eaten one? You may not even know it. As deep-sea fisheries developed, starting in the 1970’s, many deep-sea species were renamed and most are processed or sold as fillets. For instance fishes in the family Macrouridae were called rattails because of their long tapering tails but who wants to eat a rattail? They were renamed grenadiers by seafood savvy marketers. Chilean seabass, which are commonly on the menu, used to be called Patagonian toothfish and Orange roughy used to be called slimeheads. These fish all live at depths of 500 to as much as 2000 meters. 

Pictures of some deep-sea fish.  Some have been renamed to make them more marketable to fish consumers

Q-n-A: Catch Shares

Welcome to The Fisheries Blog's first Q-n-A!  We are introducing this segment to showcase the knowledge and specialty of someone in the fisheries world who flat out knows their stuff.  For this inaugural Q-n-A, we are featuring Kelly Denit, a Fisheries Management Specialist for NOAA.  I recently asked Kelly to clarify some of the information surrounding catch shares...


1. What are catch shares?

"Catch share" is a general term used in fisheries management strategies that dedicate a secure share of fish to individual fishermen, cooperatives, or fishing communities for their exclusive use.

Mercury in fish, what should I eat?

Mercury contamination in fish and aquatic systems has received a lot of attention because of the potential health concerns for people and wildlife. In fact, my own research has focused on mercury dynamics in aquatic systems and fishes over the last several years. Here I wanted to share some of my expertise and try to clarify the mixed messages often sent by popular news articles on eating fish in relation to mercury, but first let us begin with some background information.

Sign warning fish consumers about the risks of mercury from California.  Source:  http://www.electricbluefishing.com/eb_sub_menu/mercury_in_fish__shellfish.htm

Guatemala's Fish Face Threat From Aquatic Invader (Hydrilla)

By Patrick Cooney

Sitting just south of Mexico, Guatemala is a gorgeous country littered with ancient civilizations and beautiful landscapes.  Similar to how European invaders wiped out native people throughout Guatemala and the "New World", a recent plant invasion from Asia has people worried that native fishes that serve as a major food source may be the next to disappear.  I spent a summer with a Guatemalan researcher to help figure out if the native fish were doomed.

30 foot cast nets are used in shallow water
to catch fish for the dinner table (Photo: Patrick Cooney).

Guatemala’s lakes are diverse and host incredible fish communities.  Like other freshwater environments around the world, the fish populations of Guatemala’s lakes encounter significant pressure from fishermen and introduced species.

Not Too Big to Fail: Recovery of Collapsed Stocks

These days, we hear a lot about disasters and disaster recovery—hurricanes, earthquakes, tornadoes.  Turns out that fish stocks are not immune to disasters, either.  This week the Acting Secretary of the National Oceanic and Atmospheric Administration (NOAA) announced Fishery Disasters in three US fisheries.  Dating back to 1994, anywhere from 0 to 7 disasters have been announced per year, with a slight trend in more disasters per year in recent years.  A fishery disaster technically means that congress can begin to allocate funds to these fisheries, but of course, before, during, and even after the disaster designation, serious negative ecological, economic, and social impacts can be felt.

Cod have long been in the news regarding their fishery status, and are included in the Northeast US groundfishery that was this week declared a disaster. (Source)