“Cod population changed in response to intensified fishing”

“New research by scientists at the University of Iceland’s Research Centre of the Westfjords and their colleagues has revealed that the trophic niche of the Atlantic cod in Icelandic coastal regions remained stable for centuries, but changed in the 19th century alongside intensified fishing. It is likely that this reflects changes to both the age and size of the cod stocks, but also changes to marine food webs as populations fall due to extensive fishing and food chains shorten. The research was reported in Scientific Reports, a respected journal from the publishers of Nature. According to the authors of the study, the results underline the importance of conserving different migratory cod in Icelandic coastal regions, for example to boost the population’s resilience to environmental changes.

The research team included Guðbjörg Ásta Ólafsdóttir, biologist and director of the UI Research Centre of the Westfjords, and Ragnar Edvardsson, archaeologist at the Research Centre, along with their colleagues in Canada and Norway. 

Guðbjörg Ásta and Ragnar have worked together for many years on interdisciplinary research into fish bones, particularly cod, that they have excavated from ancient fishing stations in the Westfjords. The oldest bones are 1000 years old.  “The main aim of the research is to understand how changes in fishing and the marine environment have affected fish populations over the centuries. Using a data series spanning several centuries, we can establish a kind of baseline and try to estimate how extensive human exploitation could have affected marine ecosystems,” explains Guðbjörg Ásta. “

Read the full article here and the scientific article here.

Scientists Use Underwater Sounds to Rejuvenate Coral Reef Populations

Writing by Michelle Estevez

” The same way we might hear a specific song and experience a range of emotions, underwater speakers surprise researchers as unhealthy corals positively respond to their study. They placed underwater speakers to emit sound frequencies resembling what a healthy coral reef would sound like. Not only did this influence the unhealthy coral reefs to regenerate, but it also attracted a variety of fish to help reestablish degradation.

“We use loudspeakers to broadcast healthy soundscapes on experimental coral-rubble patch reefs for 40 days during a natural recruitment season (November–December 2017) on Australia’s northern Great Barrier Reef. We compare the developing fish communities on these acoustically enriched reefs with those on two categories of acoustically unmanipulated control reefs (with and without dummy loudspeaker rigs). We find that acoustic enrichment enhances fish community development within an important reef fish family, across a range of specific trophic guilds and at the level of the whole community,“ researcher Timothy A. C. Gordon mentions. ”

Article by Michelle Estevez for Educate Inspire Change, Read the full article here. 

Fly Fishing in the Anthropocene | Documentary 2017

This was so incredibly beautiful, and it definitely brought tears to my eyes.

“The Ozernaya River winds serpentine-like through a remote corner of Kamchatka in Far East Russia. In one of the most intact eco-systems left in the Northern Pacific, rainbow trout eat mice for breakfast, and the salmon run in the hundred of thousands. This bounty attracts two kinds of people; those who want to protect, and those who want to exploit. Rampant salmon poaching is big business on Kamchatka, and once the salmon are gone, entire eco-systems collapse. “Fly Fishing in the Anthropocene” explores how fly fishing can help protect the wilderness, and celebrates the beauty and wonder of one of the most vibrant places on earth.”

A film by Peter Christensen and Rolf Nylinder http://RolfNylinder.com

Iceland Review: Tonnes of Salmon Die in Arnarlax Fish Farms

“Around 500 tonnes of salmon have died recently in Arnarlax’s open-net fish farms in the Westfjords. The company’s board chairman told RÚV that number is within the limits projected by the company. The chairman of the Federation of Icelandic River Owners expressed concern about the deaths and the impact Arnarlax’s operations could have on wild salmon.

Though salmon regularly die in open-net fish farms, 500 tonnes is more than is usual for this time of year. Kjartan Ólafsson, the chairman of Arnarlax’s board says recent extreme weather has led to casualties. According to Kjartan, cool sea temperatures cause salmon to move further down in the nets and rub up against them. The rubbing can cause wounds that eventually lead to the fish’s death.

It is currently slaughter season for Arnarlax’s fish farms, and several ships are docked in the Westfjords to assist with the process. One of them is the Norwegian Gannet: equipped with 14 gutting machines, it is the world’s largest floating salmon processor. Arnarlax expects to harvest 10,000 tonnes of salmon this year, and Kjartan says the 500 tonnes of casualties were within the company’s projections.

Jón Helgi Björnsson, chairman of the Federation of Icelandic River Owners (Landssamband veiðifélaga), said the farmed salmon deaths were concerning. “Basically, it just can’t be normal for 500 tonnes of fish to die in a short period of time. If that’s natural, then of course people have to start wondering if this is an industry people can justify being engaged in. That’s a huge amount of fish that’s dying there.”

Jón Helgi also expressed worry that foreign ships like the Norwegian Gannet could transmit infections to Icelandic fish farms which could then affect wild stocks. “How are these ships disinfected? How does one disinfect an entire ship that is working at salmon farms abroad? We are very concerned that infections from abroad can be transmitted via these ships because of course they are used when similar situations occur elsewhere.””

Article by Jelena Ćirić, February 17, for Iceland Review

Planet Alaska: Woven with herring

“Down on the dock I say, “Gunalchéesh,” as my friend hands me a five-gallon bucket filled with herring eggs on hemlock branches. I take the bucket home and start a small pot of water boiling. I blanch a small batch of eggs and then eat them with soy sauce. It tastes like home. I am home when I eat herring eggs. Later, I take the herring eggs around to friends and elders. Sharing is an important Tlingit value and sharing herring eggs is a ritual connecting me to my people and place. This ritual is in danger of being lost.

Sadly, we are running out of time to save the herring. The herring fishery in Southeast Alaska is one of our “canaries in the cave,” meaning the herring decline is an early indicator of problems throughout our food web. One after another, 11 herring management areas in Southeast Alaska have been over-fished to near extinction. Extinction is a serious word. Historical herring fisheries once thrived at Kah Shakes/Cat Island, West Behm Canal, Ernest Sound, Hobart Bay, Seymour Canal, Chatham Strait, Hoonah Sound, Tenakee Inlet, Auke Bay, Lynn Canal, Icy Strait and Yakutat Bay. The Sitka Sac Roe Fishery is the last population of herring in Alaska to provide a significant commercial harvest and subsistence herring egg harvest. Despite these losses, Alaska Department of Fish and Game has ignored the traditional ecological science and testimonials of the Tlingit who’ve harvested in a sustainable way here for more than 10,000 years. Mismanagement has resulted in the decline of our herring population. This frightens me. Our elders tell us that life in Southeast is not possible without the herring. Why is this so hard for the state of Alaska to understand?”

Read the full Juneau Empire article here

Top: Herring eggs hang from a hemlock branch in Sitka. (Courtesy Photo | Vivian Prescott), Bottom: In this photo from the William L. Paul Sr. Archives, herring eggs dry on the beach in Sitka circa 1900 (Courtesy Photo | Sealaska Heritage Institute).

Anthropology Research Proposal: On Chinook Salmon

Replenishing Major Food Sources of Native Alaskan Tribes: Managing Yukon River Chinook Salmon Populations

Megan Lorino, UAF Wildlife Biology and Conservation Studies

 

Abstract

Populations of Chinook Salmon have been dwindling in the Yukon River for many years and have been monitored closely by scientists with the goal of bringing healthy populations back. Native Alaskan tribes have always relied heavily on these salmon populations as a major food source. The United States and Canada came to an agreement in 2016 known as the Yukon River Salmon Agreement; the goal of this agreement was to begin working on restoring healthy salmon populations which end up being harvested in both Canada and the United States. Climate Central reported that in 2014 Chinook Salmon populations in the Yukon River dropped so low that there was a hold put on subsistence fishing. Native Alaskans rely heavily on these salmon populations for subsistence in their tribes. “Subsistence salmon fishing is at the core of many residents’ livelihood; integrating fish wheels, dip netting and fish smoking into many Alaskans’ everyday life. Salmon are more than food or just fish – they are a way of life to many Alaskans (Beutler, 2016).” I examine possible solutions for preserving and rebuilding salmon populations in the Yukon River with the goal of replenishing this important food source for Native Alaskan tribes which still rely on harvesting wild resources in order to survive. Environmental factors such as sea ice temperature and salt concentrations will need to continue being monitored to determine where fisheries management can assist in spawning and abundance of this critical food source. 

 

References Cited

Alaska Department of Fish and Game, 2019. 2019 Yukon River Salmon Fisheries Outlook. http://www.adfg.alaska.gov/static/applications/dcfnewsrelease/1029815354.pdf

 

Alaska Department of Fish and Game, n.d. Subsistence in Alaska. Overview: Definition, Responsibilities and Management. https://www.adfg.alaska.gov/index.cfm?adfg=subsistence.definition

 

Beutler, H. 2016. Threat to Salmon Imperils Alaska’s Culture. Climate Central. https://www.climatecentral.org/news/when-salmon-disappear-alaskan-culture-may-follow-20522

 

Burke, J. 2012. Alaska Natives rally for restored aboriginal hunting, fishing rights. Anchorage Daily News. https://www.adn.com/alaska-news/article/alaska-natives-rally-restored-aboriginal-hunting-fishing-rights/2012/10/18/

 

Gautier, A. 2019. Running against time: Forecasting Chinook salmon runs on the Yukon River. NSIDC Highlights. National Snow & Ice Data Center. https://nsidc.org/nsidc-highlights/2019/08/running-against-time-forecasting-chinook-salmon-runs-yukon-river

 

U.S. Fish & Wildlife Service. 2002. U.S. and Canada Sign Historic Yukon River Salmon Agreement. News Releases. https://www.fws.gov/news/ShowNews.cfm?ref=us-and-canada-sign-historic-yukon-river-salmon-agreement&_ID=2592

 

Our fish are disappearing

Overfishing, CPUE, and Commercially Extinct Species.

Overfishing, CPUE, and Commercially Extinct Species. 
February, 17, 2019. By Megan Lorino

University of Port Elizabeth published an article in 1981 on the topic of catch per unit effort using gill-nets in the Sundays River estuary of South Africa. Their data was obtained from 55 catches using gill-nets. Nets were positioned in lower, middle, and upper reaches of the estuary. Each site was selected with avoidance of boat traffic in mind. Measurements were taken of salinity as well as (surface) water temperature of each site. CPUE was recorder for each caught species on a monthly basis and always included number per species as well as weight of each given species.

The most abundantly caught species was the sea catfish Tachysurus feliceps which totaled 226 individual fish, followed by the flathead mullet Mugil cephalus with a total of 191 individual fish, the souther mullet Liza richardsoni with a total of 185 individual fish, and the kob Argyrosomus hololepidotus with a total of 175 individual fish. The Argyrosomus hololepidotus (kob) was the  dominant catch in terms of weight, weighing 315kg, followed by the spotted grunter Pomadasys commersonni weighing 165kg. This particular study was to evaluate the abundance of varying species within the communities of the Eastern Cape estuaries. Gill-nets were set up between 1976 and 1979. 1,258 total fish were caught during this study. The CPUE (catch per unit effort) was 21kg/standard net.

 

References
Marais, J. (1981) African Journals Online. African Zoology. Seasonal abundance, distribution, and catch per unit effort using gill-nets, of fishes in the Sundays estuary. Retrieved from https://www.ajol.info/index.php/az/article/view/152270/141866

 

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Commercial extinction (of fish) is determined when a particular species of fish has become too rare to be caught for profit any longer. This occurs after a process of depletion – the reduction of that particular species due to overfishing. Recovery from overfishing causing an oceanic fishery to collapse can be combatted in several ways. One way is to create stronger regulations and plans of action toward illegal fishing in order to give stocks a chance to recover. More aggressive fisheries management, the increased use of aquaculture, and better law enforcement of catch-governing laws could all help to reduce overfishing and restore populations. Illegal fishing and unsustainable harvesting of fish is still one of the biggest issues causing overfishing that needs to be managed more diligently in order to really save our fish populations and truly reduce overfishing.

 

References
Doyle, A. (2015) Reuters. Ocean fish numbers on ‘brink of collapse’: WWF. Retrieved from https://www.reuters.com/article/us-environment-oceans/ocean-fish-numbers-on-brink-of-collapse-wwf-idUSKCN0RG1JW20150916

National Geographic (2010) Overfishing. Retrieved from https://www.nationalgeographic.com/environment/oceans/critical-issues-overfishing/

Dredge Fisheries Analysis

Dredge Fisheries Analysis by Megan Lorino.
February, 7, 2019.

Dredge fishing involves dragging a dredge across the sea floor in order to collect targeted fish species. There are many targeted species for dredge fishing practices including clams, oysters, mussels, scallops, sea urchins, sea cucumbers, conch, and crabs. There is a known risk of significant amounts of bycatch – the undesired catch of species other than those being targeted. There is also a great risk of harming other marine life with dredge fishing, one of the most harmed marine species being sea turtles. While the dredges are being pulled along the sea floor turtles are often crushed or captured in collection bags. Many other marine animals endure this risk including whales and dolphins, which may become entangled by the tow lines.

There are two types of dredges, scraping dredges and penetrating dredges. The scraping dredges have teeth or sharp bars that dig into the bottom of the sediment in order to pick up and collect marine animals which live on the sea floor. Penetrating dredges, which are also called hydraulic dredges, shoot jets of water into the sea floor in order to chase out the animals which live deeper in the sea floor out into collection bags. Dredges can weigh 2,600 pounds or more. Dredges have actively been called the most damaging gear to bottom ocean habitats. When dredges are dragged along the sea floor they also kill many smaller species including snails and worms. Areas abundant in seagrass can be damaged by destruction of the grass roots. This negatively impacts species of fish and other marine animals that rely on seagrass for food supply, habitat and protection from predators.

Proper management of dredge fisheries can help reduce the habitat destruction, bycatch, and harm to marine species during dredge fishing. Using lighter weight dredges where possible can lower the risk of crushing marine animals. Protecting certain habitats to allow some areas to remain untouched from dredges can also help protect many species. Regulating the allowance or minimum size requirements between teeth or bars on dredges can allow smaller species to pass through and avoid becoming injured while the dredges pass through their habitats. Remaining areas that have not been disturbed by dredging should be protected.

Policy decisions should be based on science where it is often proved how damaging certain fishing methods are. It is the responsibility of fisheries managers to maintain ethical policies to protect our natural ecosystems and maintain appropriate regulations to help lessen the risks of harming marine species while capturing those for commercial use. Scientific method now addresses what types of impacts from fishery practices are considered most harmful. There is enough scientific evidence present day to consciously make an effort to manage fisheries while reducing the number of marine species being harmed or resulting in population declines. “The time has come for fishery managers and conservation organizations to add fishing selectively, avoiding habitat damage, and protecting marine biodiversity as important components in maintaining ocean ecosystems and healthy fisheries.” (MCBI, vi)

Resources
NOAA Fisheries. Fishing Gear: Dredges. Retrieved from https://www.fisheries.noaa.gov/national/bycatch/fishing-gear-dredges

Safina Center. Fishing Gear 101: Dredges. Retrieved from http://safinacenter.org/2015/05/fishing-gear-101-dredges-the-bottom-scrapers/

MCBI Marine Conservation. Shifting Gears. Retrieved from https://mcbi.marine-conservation.org/publications/pub_pdfs/ShiftingGears.pdf

 

Ghost Catfish

Kryptopterus vitreolus, also known as the phantom catfish, or traditionally known as the glass catfish.  Photo from AquaticMag.