Displaying items by tag: stocks
The largest study to date of the cod stock in the eastern Baltic Sea shows that the fish has never had it worse. Behind the study are, among others, researchers from DTU Aqua, and according to senior researcher at the Department of Aquatic Resources, Stefan Neuenfeldt, the situation looks bleak. “I do not think we can save the stock as it looks now. But we can help the cod to survive, so that in 10-15 years it will have a second chance in a Baltic Sea, which hopefully is easier to live in by then.” Twice a year, researchers in Denmark and its neighbouring countries catch cod in the Baltic Sea to investigate how the stock is doing. Less than 20 years ago, the largest cod were up to 80 centimeters long, and healthy and strong fish were generally caught.
Of all the fish caught worldwide nearly half are from scientifically monitored stocks and, on average, these stocks are increasing. An international project led by the University of Washington has compiled and analysed data from fisheries around the world and effective management seems to be the main reason why these stocks are at sustainable levels or successfully rebuilding.
“There is a narrative that fish stocks are declining around the world, that fisheries management is failing and we need new solutions — and it’s totally wrong,” said Ray Hilborn, lead author and a professor in the University of Washington School of Aquatic and Fishery Sciences. “Fish stocks are not all declining around the world. They are increasing in many places, and we already know how to solve problems through effective fisheries management.”
ICCAT, the International Commission for the Conservation of Atlantic Tuna, the regional fisheries management body responsible for the conservation of tuna and tuna-like species in the Atlantic and adjacent seas, concluded negotiations at its 26th regular sesion by adopting a 15-year rebuilding plan for bigeye tuna. Although an imperfect plan in the eyes of many, it’s adoption was significant progress compared to the session last year, when the 52 contracting parties failed to agree on measures to protect the stock despite clear advice from the commission’s own scientists on the need to significantly reduce catches. The adopted plan reduces the total allowable catch forcing countries to make significant cuts to their current catches, a stricter limit on the number of fish aggregating devices (FAD) permitted per vessel, as well as an Atlantic-wide closure of FADs for two months in 2020 and three months in 2021. FAD closure was previously restricted to the Gulf of Guinea for two months. Other business conducted during the 8-day meeting included amending the 50-year-old ICCAT convention to provide the commission with a mandate to manage sharks and rays, which will help in the fight against IUU fishing, and the adoption of a measure to implement rebuilding efforts for Atlantic blue marlin and white marlin stocks.
Their fillets are used for fish burgers, fish fingers, as well as different surimi products. Alaska pollock can be utilized for different purposes and at relatively affordable cost. Their stocks constitute the largest and the most economically important ground fish resources in the North Pacific Ocean. They are both, well managed and fished on sustainable basis. Yet depletion of their stocks occurs primarily due to natural causes. On that score, a dramatic role is played by the climate change.
Although the walleye pollock (Theragra chalcogramma) known also as the Alaska pollock is a close relative of Atlantic cod, saithe and haddock, intensive fishing started only 50 years ago. Before that, interest in this species was surprisingly low which could possibly be explained by its relatively small body Despite a record length of 91 cm, the length of individuals caught in the net seldom exceeds 50 cm while the weight barely reaches 500 to 600 g. The brownish or greenish coloured, beautifully spotted fish live in large schools at a depth of between 30 and 500 m. In terms of biomass, the stocks of Alaska pollock belong to the largest and most important stocks of food fish due to three main reasons. First, they grow relatively quickly reaching 30 to 40 cm length already at the age of three or four years. From this point onwards, they can spawn virtually every year thus contributing to the survival of the species. It is universally assumed that Alaska pollock lives a maximum 14 to 15 years. Second, their fertility rate is really high. The exact number of eggs depends upon a number of factors including the age, the size and the nutritional status of females, however on average it ranges from 100,000 to 1.2 million. The third reason for the high importance of Alaska pollock is the wide spectrum of feed they use. Although carnivorous they can consume plankton-eating krill or young herrings available in copious amounts in the North Pacific. In the Bering Sea, Alaska pollock accounts for almost 60% of the total fish biomass, while in the Gulf of Alaska and Aleutian Islands they constitute about one fifth of the total fish biomass.
A number of institutions are involved in deciding how much fish can be harvested from the sea
Fishing quotas have an immediate impact on the players in the fisheries sector and the release of the numbers is closely watched by all concerned. The route by which raw data is converted into the precise figures that are published as fishing quotas is long, with inputs from several institutions, and gives an idea of the enormous significance attached to these numbers.
Fish, individually or in swarms, can usually be found in places offering them the best for their lives: where they find food, where it is safe to reproduce and survive as species. Such preferences, together with environmental conditions, may vary from year to year, and hence the number of fish coming together may vary as well. Fishermen know where to find the fish and are familiar with annual fluctuations. Fishing grounds, when seen as fish habitats, do not feature national borders, whereas fishing vessels carry the flags of their home ports. Fish stocks which are international by nature thus have national owners when turned into catches. The subsets of these fishable stocks allocated to and harvested by sovereign states are called fishing quotas.