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Couple of interesting new shark items:
Anti-Shark Netting for Aquaculture
Sharks were recently in Las Vegas, and I don't mean the card shark kind. At a major aquaculture conference, a new proprietary shark-resistant netting was introduced which holds great promise in helping open-ocean aquaculture protect its harvest from curious sharks.
Open-ocean aquaculture primarily involves large pens that float at the surface and are big enough to allow species such as tuna reach a commercially-viable size. However, corralling fish together means that they will become a magnet for ocean predators like sharks, and previous netting material has not always done the job in resisting a hungry shark.
Working together, NET Systems and DSM Dyneema have developed PREDATOR-X, a netting that combines high-strength polyethylene fibers with stainless steel wire. It was field tested in the Bahamas by scientists from the Cape Eleuthera Institute, using the institute's aquaculture facility for full-grown cobia as the test guinea pig.
The results were positive. While the netting is able to withstand the abrasions and cutting of ocean predators, it is also lighter than other netting materials and allows for sufficient water flow which is important to aquaculture in maintaining a healthy level of oxygen for the fish.
Many times I have seen the tuna pens floating offshore off the Baja, Mexico coast and would wonder how many sharks died at the hands of armed aquaculture farmers protecting their stock. Now, perhaps both sharks and farmed fish will be able to coexist, saving a few sharks and some wild fish from commercial fishing in the process.
Neurotoxin Found in Shark Fins
A new study, released by Neil Hammerschlag of the University of Miami's R.J. Dunlap Marine Conservation Program and members of the Miller School of Medicine, has found potentially harmful levels of BMAA, a neurotoxin, in shark fins and related shark cartilage products from seven species of sharks in Florida. BMAA is associated with degenerative brain diseases such as Lou Gehrig's, Alzheimer's and Parkinson's.
Similar to other pollutants such as methylmercury that have been found in sharks and other large predators, the neurotoxin accumulation is a result of what is called biomagnification, a process whereby trace elements work their way up the predator-prey food chain. And as they do, their concentration levels increase. BMAA is found in cyanobacteria, an ocean bacteria, and from those humble beginnings it can move up through the various animals that feed on the bacteria and then preyed upon by others animals.
"The thing is very little has been done on BMAA because it is a new wave, a new understanding," says Hammerschlag. "We're only starting to understand the scope of the problem."
Given the documented evidence of biomagnification regarding other pollutants found in sharks and fish like tuna, the presence of BMAA does not come as a stretch of the imagination but you can expect pro-shark fishing industry forces to refute the findings as a scare tactic conjured up by anti-shark fishing advocates. One wonders who is the most scared by this development, those who consume shark products or those who are in the business of plundering one of the ocean's most vital inhabitants.
Source (Netting): Market Watch
Source (Neurotoxins): Miami New Times
I was reviewing the latest Marine Science Review from Seaweb on Contaminants and Pollution #318. It listed over 20 articles covering research studies on the impact of pollutants on marine ecosystems. From everything including pharmaceuticals to pesticides to manufacturing process ingredients, a chemical witches' brew is able to find its way into the seas through direct discharge into waterways, seepage through soil and groundwater, and from the sky.
The impact is felt worldwide, from deformed sturgeon in China due to triphenyltin, an agricultural fungicide; to contaminants found in seagull eggs as far north as Alaska; to the effect of pharmaceuticals and other pollutants on parasites and other single-celled organisms that form the foundation of a marine ecosystem.
Laying blame or divining efficient solutions is not so easy. Though banned for many years, there are still significant traces of the pesticide DDT being found in the egg shells of Arctic seabirds. There is plenty of research going on that is producing alarming, definitive data. The question is: What is being done to stop it?
In San Francisco, California, one positive move has occurred: under a settlement with the Center for Biological Diversity, last week the Environmental Protection Agency proposed to formally size up the harmful effects of 74 poisonous pesticides on nearly a dozen imperiled species in the San Francisco Bay Area. The settlement concludes a 2007 Center suit over the EPA's violation of the Endangered Species Act in registering the pesticides and allowing their use without considering the detrimental effects they may have on federally protected species -- decidedly not pests. The settlement could be a habitat-saving grace for 11 Bay Area animals, from the delta smelt to the San Joaquin kit fox. And until EPA's analysis of the pesticides' effects is completed, the agency promised, it will restrict the use of all 74 pesticides in and abutting endangered species habitat.
"The toxic stew of pesticides in the Bay-Delta has played a major role in the collapse of native fish populations, and pesticides are a leading cause of the loss of native amphibians," said Center Conservation Advocate Jeff Miller. "This agreement is a positive step for protection of some of the Bay Area's most endangered wildlife from pesticides."
Also, check out this very thorough report from the United Nations Environmental Programme, Marine Litter: A Global Challenge. Not only does it provide a detailed examination of marine litter in all of the major oceans, from plastic to, well, you name it, but it also provides strategies and solutions for each region. It's a great reference tool, not just a quick skim read. Check it out; it's a free PDF download.
The growth of Nanotechnology - the science of developing compounds at an extremely small, molecular level - has brought some interesting developments, from new pharmaceuticals to our odor-eating, anti-bacterial socks. But with the emergence of this new field there also has grown concerns that it might turn out to be a substantially sharp two-edge sword.
Many of these new nano-compounds can enter the environment and scientists are just beginning to see the implications. When these compounds enter aquatic ecosystems, the impacts may appear very subtle at first because the components of the ecosystem affected are they themselves quite small. Scientists are looking at the effects of nano-compounds like various metals or carbon-based particles on aquatic bacteria, algae, and small fish.
As an example, one recent study indicated that "carbon black nanoparticles" affect the fertilization of brown algae. And there is concern that the silver nanoparticles used as an odor-remover in socks can, when released through machine washing, impact the bacteria that is necessary in breaking down organic matter - a very important function in water treatment facilities, lakes, rivers, and oceans. When any aquatic system loses its ability to consume organic matter, you are looking at a major and probably fatal disruption of the entire balance of the ecosystem.
While we focus on aquatic pollutants that are more visible - like plastics, crude oil, and discharged chemicals, we must also hold commercial science responsible for the effects of even the smallest of compunds that are entering the water, land, and air. I have great faith in science, but whether for commercial or purely research purposes, it must be held to the highest standards in balancing the rewards versus the impact on the planet.
Open-ocean aquaculture primarily involves large pens that float at the surface and are big enough to allow species such as tuna reach a commercially-viable size. However, corralling fish together means that they will become a magnet for ocean predators like sharks, and previous netting material has not always done the job in resisting a hungry shark.
Similar to other pollutants such as methylmercury that have been found in sharks and other large predators, the neurotoxin accumulation is a result of what is called biomagnification, a process whereby trace elements work their way up the predator-prey food chain. And as they do, their concentration levels increase. BMAA is found in cyanobacteria, an ocean bacteria, and from those humble beginnings it can move up through the various animals that feed on the bacteria and then preyed upon by others animals.
