Climate change threatens one of the most important fish, the Alaska pollock

EM5 17 SP AlaskaPollackTheir 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.

Alaska pollock spawns on average 7 months a year. Reproductive activity begins with the onset of spring in the south, moving gradually farther to the north when the water temperature rises. Some weeks before the start of spawning, schools of fish leave their hibernation areas near the edges of the continental shelf to migrate to their spawning grounds either close to the coast or to shallow waters where they stay at a depth of 50 to 250 m. After spawning, the fish migrate to their feeding grounds, from which they will in the late autumn return back to their wintering areas. During the day, fish stay close to the ground, while at night, they spread themselves out over the whole water column to feed. The spawning periods in every region are fairly constant. Over a period of several weeks, the females release their eggs in batches to be immediately fertilized by males. Since the spawning process is synchronized and a great number of fish in a school release large amounts of eggs simultaneously, huge „clouds“ of eggs drift in the sea at spawning times gradually dispersing with the action of currents and waves. When the water temperature reaches 5°C, in 15 days’ time, the larvae hatch, barely 4 mm large. The mortality in this early phase of life before the juveniles have reached 10 cm length is huge as every day 9% die and sink to the ground. Despite that, many billions survive this critical phase so that the stocks are replenished each year. At the age of three, or sometimes, when feed is scarce, four years, the fish reach harvest size (recruitment).

Alaska pollock stocks are used on a sustainable basis

At the end of the 80s, the tonnage of Alaska pollock landed stayed at 7 million but since the turn of the millennium, the level of total landings has been reduced to 3 million tonnes a year.  This 50% reduction however is not a matter of concern but rather should be understood as an adjustment to the biological potential of the species indispensable for fisheries under the MSY principle. Since then, the stocks have been largely stable, the biomass and the numbers of fish harvested are sustainable from the ecosystem point of view. In terms of transparency and control, the management of the US Alaska pollock fishery sets international standards for the whole industry.  The conservative management approach takes account of the ecological importance of this species of fish in the marine food chains and is unequivocally oriented towards long-term use of the stocks.   The total allowable catch (TAC) quotas are based both on the status and development of the stocks. They are seldom set higher than 15% of the existing biomass which corresponds to about two thirds of what is actually biologically possible and acceptable. Although this precautionary principle has often been criticised for leaving part of the stocks unused, it has justified itself in practice. Since coming under the management of the state in 1976, the Alaska pollock fishery of Alaska has been developing very favourably.

In December 2016, the North Pacific Fishery Management Council (NPFMC) set the TAC for Alaska pollock for the year 2017 at 1.3 million tonnes in the East Bering Sea, an increase of 0.4% in comparison with 2016 and 2.3% more than in 2015. That is a straightforward signal that the stock is healthy. Also Russia had increased its quota for 2017 by 2.9 % or 1.9 million tonnes. This confirms the favourable trend of stocks in the Okhotsk Sea and the Western Bering Sea where catches since 2003 have almost doubled.  The MSC certification of the Alaska pollock Fishery in Okhotsk Sea, which brings in 840.000 t annually and is still valid for 2018, shows that the stocks of Alaska pollock are sustainably managed also in Russia.

Researchers in the field of fisheries distinguish four different stocks of Alaska pollock with distribution centres located accordingly in the Gulf of Alaska, the Okhotsk Sea, as well as in the Western and Eastern Bering Sea. NOAA, the US National Oceanic and Atmospheric Administration finds no major problems in respect of the world’s largest whitefish stocks. In the medium term, this could however change, as some trends which at this moment have just barely appeared, are already making scientists cautious. They suspect that climate change drives some of the stocks dwelling in American waters to Russia. In warmer summers, some schools would already move further to the north. The Russian Fishery administration estimates that one third of the Alaska pollock biomass could at least temporarily migrate from the US waters into the catchment area of the Russian fishing fleet. Furthermore, as the result of the rising water temperatures the survival rates of both, fish and larvae decrease and the mass development of krill, the main feed source of pollock, is weakened. A recent study by the University of Alaska („Climate Change and Alaska Fisheries“) suggests that there exists a link between the ice melting at the poles and the decline of biomass of the Alaska pollock stocks. In years with higher water temperatures both, the fish and their feed base is losing strength. Lacking feed alternatives, the young fish are much more often chased away from the feed by their natural enemies. Scientists fear that by the middle of century the recruitment of Alaska pollock could drop by 32 to 58%.

Pollock fishery in US EEZ entirely in American hands

Since entry into force of the American Fisheries Act (AFA), the American fishery has changed. The fishing capacity has been limited, a number of factory ships decommissioned and as from 1998, an individual catch quota for the Alaska pollock has been enacted. The allocation of individual catch quotas has eliminated the economically unreasonable hunting for fish and significantly improved the product quality. In times, when the fishing was freely open, it was carried out without due regard to either demand or quality.  Everyone wanted as large a piece as possible from the common pie. Nowadays, fishing activities are market-oriented, quality-conscious and altogether more reasonable from the raw material use and waste management point of view. As the revenue is quality-dependent, the fish are handled much more carefully.  While previously the bulk landings of fish could only be used for surimi production, today the processors can decide into which end products the particular batch will be processed into: fillets, blocks or surimi. 

In terms of landings, the fishing fleet off Alaskan coast is remarkably small. The fishing effort has been adjusted to the potential of the fish stocks.   At the beginning of the millennium, in the Bering Sea and round the Aleutian Islands, only 114 trawlers and 17 fishing and processing vessels, referred to as CPs (catcher/processor), were registered. The fishing season of Alaska pollock is divided in two parts. The A season lasts from January until mid-April while the B season starts in June and lasts till mid-November. Top catches are usually achieved in January/February, June/July and September/October. The by-catch rate of the Alaska pollock fishing is extremely low and seldom exceeds 3%. The American Fisheries Act foresees recording and reporting of all catch including by-catch and unrecognizable juveniles. Since everything is based on the ship’s quota, fishermen do their utmost to ensure clean batches consisting mostly of the target species.

Successful handling of catch at sea and on land

Alaska pollock is mostly fished with pelagic trawls which are either trawled by a single stern trawler or two trawlers in a team. In the Gulf of Alaska, there is also some bottom trawls operated for which a special permit is required. Approximately half of the US total catch is either processed on special factory ships constantly supplied with fish by smaller vessels, or on CP trawlers. The sea-frozen products enjoy a particularly high quality as the fish undergo processing immediately after catch.  The lack of space on board however, make fishermen look for trade-offs in the processing. A lot of C/P vessels can produce surimi and have the necessary equipment on board to fillet, IQF or freeze fish in blocks. In case of very large catches however, fish are often frozen only h&g (headed and gutted). For h&g freezing, fish are mostly sent to China where they are thawed for a short time at specialized plants, hand-filleted and frozen again (double-frozen). Less expensive than directly processed, single-frozen fillets, the double-frozen products temporarily dominated the markets. Moreover, the fillet yield from hand-filleting is significantly higher than that from machine processing which brings in barely 25 to 28%.  Meanwhile, the share of double-frozen product is falling as both, USA and Russia rely more and more on their own processing. This tendency is particularly pronounced in Russia, which in the past, used to deliver as much as 800.000 t to China. Since more and more trawlers are put into service with their own processing lines on board, deliveries to Chine dwindle. This tendency is also intensified by two additional factors. First, the raising salaries in China affect the price of double-frozen goods. Second, the single-frozen products currently enjoy better chances in Europe due to the EU labelling regulation setting down a mandatory requirement that information concerning both, the origin and the freezing date of products should be made available to consumers.

A considerable portion of the Alaska pollock catches are processed on land. A central role is played by Dutch Harbour, a small village in Unalaska, an Aleutian Island, which is the heart of the American Alaska pollock fishing.  Dutch Harbour is not only the largest fishing port in the US but also the most important site for fish processing in the country. What makes the place so important is its proximity to rich fish grounds allowing for short travel times to fishing spots. Furthermore, the island harbours the only deep, ice-free port in the region accessible without major problems also in winter.  

The land-based processing industry in Alaska is flexible and, depending on the demand and market situation, can switch between frozen fillets, frozen fish blocks or surimi. The profitability of the fishing companies is decided by the appropriate mix of products. From mid-2016 until the start of 2017, the industry stepped up surimi production and kept the production of frozen fish blocks as low as possible as the latter did not bring much profit at that time. The main reason for lack of demand for the fish blocks was insolvency of both, Pacific Andes-daughter company Pickenpack and TST (The Seafood Traders) in Germany which were wholesale buyers of fish blocks.  However, since Trident, the US Alaska pollock processor took over the state-of- the-art TST production plant in Riepe, and has been processing 30,000 t of frozen Alaska pollock blocks yearly, there is again some hope. It relates both to the employees of the ultra-modern plant and the company itself, which through this move towards vertical integration, has acquired even more efficient control over the value-added chain and got closer to the European market. 

Quick adjustments to mitigate unfavourable developments

The US Alaska pollock fishing is regulated and monitored in the framework of BSAI-Ground fish-FMP (Bering Sea-Aleutian Island–Ground fish-Fishery Management Plan). Among other items, the catalogue of controlling instruments contains:

  • Personal fishing licences
  • Limited entry to fishing; a new entry is possible only when some existing fisherman leaves or shares his quota
  • The allocation of individual quotas under TAC
  • Establishing of the timeframe for both fishing seasons of the year
  • Establishing TAC for quantities and species of fish
  • Establishment of restricted areas

Many fishing vessels have an observer on board, monitoring the catch and reporting all important data (catches and species, size of fish, their sex, age, fishing grounds and by-catches) to the fishing administration. On vessels longer than 38 m, there should be one observer on board, on processing vessels – two. On smaller fishing boats, controllers should be present for about one third of the season. Larger ships are also equipped with satellite monitoring systems which can be used to monitor the whereabouts of the vessel in real time. In addition, the landings in ports and processing plants are also controlled. Together, these data provide a fairly accurate picture of the situation on fishing grounds and of the fish stocks so that the fishing administration can immediately react to any unfavourable developments.